Anatomy of Flowring Plants

Topic: Internal Structure of Monocot Stem; Subtopic: Vascular Bundle Arrangement and Tissues

Keyword Definitions:
• Monocot stem: The stem of monocotyledonous plants, showing scattered vascular bundles without secondary growth.
• Vascular bundle: A strand of xylem and phloem tissues involved in conduction of water and nutrients.
• Conjoint and closed: Vascular bundle with xylem and phloem together and lacking cambium.
• Phloem parenchyma: Living cells in phloem responsible for storage and transport of food.

Lead Question - 2025
Find the statement that is NOT correct with regard to the structure of monocot stem.
(1) Hypodermis is parenchymatous.
(2) Vascular bundles are scattered.
(3) Vascular bundles are conjoint and closed.
(4) Phloem parenchyma is absent.

Explanation:
In monocot stems such as maize, the hypodermis is made of sclerenchyma, not parenchyma, which provides mechanical strength. Therefore, option (1) is incorrect. Vascular bundles are scattered, conjoint, and closed with no cambium. Phloem parenchyma is also absent. The ground tissue is undifferentiated and stores food. Hence, the correct answer is (1) Hypodermis is parenchymatous. This arrangement prevents secondary growth in monocots.

1. Which of the following features is typical of a monocot stem?
(1) Presence of cambium
(2) Scattered vascular bundles
(3) Secondary growth
(4) Phloem with fibers

Explanation:
A monocot stem shows scattered vascular bundles throughout the ground tissue, with no distinct cortex or pith. Cambium is absent, so secondary growth does not occur. Phloem fibers are rare. Hence, the correct answer is (2) Scattered vascular bundles. This arrangement provides mechanical stability and flexibility, allowing efficient conduction and support in plants like maize and bamboo.

2. In a monocot stem, vascular bundles are described as “closed” because:
(1) Cambium is absent
(2) Secondary xylem is formed
(3) Phloem is absent
(4) Xylem vessels are not developed

Explanation:
In monocot stems, vascular bundles are termed “closed” because they lack cambium, meaning secondary growth cannot occur. The xylem and phloem remain fixed in number. Therefore, the correct answer is (1) Cambium is absent. Closed vascular bundles are typical of monocots such as grasses and sugarcane, ensuring flexibility and water transport efficiency.

3. Which plant part shows scattered vascular bundles and sclerenchymatous hypodermis?
(1) Dicot root
(2) Dicot stem
(3) Monocot stem
(4) Monocot root

Explanation:
The monocot stem exhibits scattered vascular bundles embedded in the ground tissue and has a sclerenchymatous hypodermis providing strength. Dicot stems have vascular bundles arranged in a ring. Hence, the correct answer is (3) Monocot stem. This anatomical design supports upright posture and efficient transport in herbaceous monocots like maize and wheat.

4. Which of the following is absent in the vascular bundles of monocot stem?
(1) Xylem
(2) Phloem
(3) Phloem parenchyma
(4) Xylem vessels

Explanation:
Phloem parenchyma, responsible for storage and lateral transport of food, is absent in monocot stems. The phloem comprises sieve tubes and companion cells only. Hence, the correct answer is (3) Phloem parenchyma. This simplification makes conduction efficient but restricts lateral movement, aligning with the absence of secondary growth in monocots.

5. The ground tissue of monocot stem is:
(1) Differentiated into cortex and pith
(2) Uniform, without differentiation
(3) Made entirely of collenchyma
(4) Absent between vascular bundles

Explanation:
In monocot stems, the ground tissue is uniform and undifferentiated, filling the space between vascular bundles and epidermis. It consists mainly of parenchyma that stores food. Hence, the correct answer is (2) Uniform, without differentiation. This feature distinguishes monocot stems from dicot stems, where ground tissue is divided into cortex, endodermis, pericycle, and pith.

6. Which type of vascular bundle is present in monocot stem?
(1) Radial and open
(2) Conjoint and open
(3) Conjoint and closed
(4) Radial and closed

Explanation:
Vascular bundles in monocot stems are conjoint (xylem and phloem together) and closed (without cambium). This absence of cambium prevents secondary growth. Hence, the correct answer is (3) Conjoint and closed. It ensures stable conduction and mechanical support for the plant structure, commonly seen in maize, bamboo, and sugarcane stems.

7. Assertion–Reason Type Question
Assertion (A): Monocot stems do not show secondary growth.
Reason (R): Vascular bundles in monocot stems lack cambium.
(1) Both A and R are true and R explains A
(2) Both A and R are true but R does not explain A
(3) A is true but R is false
(4) A is false but R is true

Explanation:
The absence of cambium in monocot vascular bundles prevents secondary growth. Hence, both Assertion and Reason are true, and R correctly explains A. Therefore, the correct answer is (1). This characteristic results in a uniform stem diameter throughout the plant’s life, as seen in grasses and palms, unlike dicots that undergo secondary thickening.

8. Matching Type Question
Match the following structures with their characteristics:

A. Hypodermis — (i) Sclerenchymatous
B. Vascular bundle — (ii) Conjoint and closed
C. Phloem parenchyma — (iii) Absent
D. Ground tissue — (iv) Undifferentiated

(1) A–i, B–ii, C–iii, D–iv
(2) A–ii, B–i, C–iv, D–iii
(3) A–iii, B–iv, C–i, D–ii
(4) A–iv, B–iii, C–ii, D–i

Explanation:
In monocot stems, the hypodermis is sclerenchymatous (A–i), vascular bundles are conjoint and closed (B–ii), phloem parenchyma is absent (C–iii), and ground tissue is undifferentiated (D–iv). Hence, the correct match is (1). These features together distinguish monocot stems anatomically from dicot stems, supporting their mechanical strength and efficient transport.

9. Fill in the Blanks Question
The hypodermis of a monocot stem is __________ in nature.
(1) Collenchymatous
(2) Parenchymatous
(3) Sclerenchymatous
(4) Chlorenchymatous

Explanation:
The hypodermis of a monocot stem is sclerenchymatous, providing mechanical strength. It lies below the epidermis and protects inner tissues. Therefore, the correct answer is (3) Sclerenchymatous. This layer supports the plant against bending or pressure and distinguishes monocot stems from dicots, where the hypodermis is typically collenchymatous or parenchymatous.

10. Choose the Correct Statements Question
Statement I: Monocot stems show secondary thickening due to cambium.
Statement II: Monocot stems have scattered vascular bundles without cambium.
(1) Both statements are correct
(2) Both statements are incorrect
(3) Only Statement I is correct
(4) Only Statement II is correct

Explanation:
Monocot stems lack cambium and secondary thickening; instead, vascular bundles are scattered and closed. Therefore, only Statement II is correct. Hence, the correct answer is (4). This structural feature provides mechanical support and flexibility in monocots, ensuring efficient transport while maintaining uniform stem thickness throughout the plant’s life.

Topic: Transport Tissues; Subtopic: Xylem and Phloem Structure and Function

Keyword Definitions:

• Xylem: Complex tissue responsible for conduction of water and minerals from roots to other plant parts.

• Phloem: Tissue that transports organic nutrients, mainly sucrose, from leaves to other parts of the plant.

• Companion Cells: Specialized parenchyma cells associated with sieve tube elements that help in maintaining pressure gradient for translocation.

• Sieve Tube Elements: Living tubular cells in phloem that conduct food materials; they lack a nucleus at maturity but retain cytoplasm.

• Gymnosperms: Non-flowering plants that produce naked seeds and typically lack vessels in their xylem.

Lead Question - 2024 (Jhajjar)
Read the following statements and find out the correct set of statements:
A. Companion cells help in maintaining the pressure gradient in the sieve tubes.
B. Gymnosperms lack vessels in their xylem.
C. The xylem vessels are devoid of cytoplasm.
D. Xylem fibres may be septate or aseptate.
E. A mature sieve element in phloem possesses cytoplasm, vacuole and nucleus.
Choose the correct answer from the options given below:
1. B, C, D, E only
2. A, B, D, E only
3. A, B, C, D only
4. C, D, E only

Explanation: The correct answer is 3. A, B, C, D only. Companion cells assist in translocation by maintaining osmotic pressure. Gymnosperms lack vessels; their xylem contains tracheids. Xylem vessels lack cytoplasm and form dead conduits. Xylem fibres may be septate or aseptate. Sieve tube elements lack nucleus and vacuole at maturity but retain cytoplasm, hence statement E is incorrect.

1. Which one of the following statements about phloem is correct?
1. Sieve tube elements are dead at maturity.
2. Phloem fibres are living cells.
3. Companion cells are absent in gymnosperms.
4. Phloem transports only water.

Explanation: The correct answer is 3. Companion cells are absent in gymnosperms. Gymnosperms possess albuminous cells instead of companion cells. These cells perform similar functions by maintaining pressure gradient for translocation. Phloem transports organic solutes, primarily sucrose, and most phloem elements are living except for phloem fibres which are dead.

2. The main function of xylem parenchyma is:
1. Transport of organic nutrients
2. Storage and lateral transport of water
3. Mechanical support only
4. Secretion of enzymes

Explanation: The correct answer is 2. Storage and lateral transport of water. Xylem parenchyma is the only living component of xylem. It stores starch, fats, and other materials and helps in lateral conduction of water and minerals across tissues. It plays a vital role in maintaining water movement continuity inside plants.

3. Which of the following xylem elements is living?
1. Vessels
2. Tracheids
3. Xylem fibres
4. Xylem parenchyma

Explanation: The correct answer is 4. Xylem parenchyma. Unlike other xylem elements that are dead at maturity, xylem parenchyma remains living and stores nutrients. It plays a crucial role in radial transport and serves as a pathway for water and solute exchange between xylem and surrounding tissues.

4. The conducting elements in phloem are:
1. Tracheids and vessels
2. Sieve tubes and companion cells
3. Parenchyma and fibres
4. Xylem fibres and vessels

Explanation: The correct answer is 2. Sieve tubes and companion cells. Sieve tubes form long continuous channels for food transport, while companion cells regulate their metabolic activities. Together, they enable pressure flow or mass flow movement of nutrients from source to sink regions of the plant efficiently.

5. In which plant group are vessels absent?
1. Angiosperms
2. Gymnosperms
3. Monocots
4. Dicots

Explanation: The correct answer is 2. Gymnosperms. Gymnosperms do not have true vessels in their xylem. Instead, water conduction occurs through tracheids. The absence of vessels makes gymnosperm wood less efficient in conduction but provides more mechanical strength and resistance to cavitation.

6. The dead elements of xylem include:
1. Vessels, tracheids, xylem fibres
2. Xylem parenchyma
3. Phloem fibres
4. Companion cells

Explanation: The correct answer is 1. Vessels, tracheids, xylem fibres. These components form the dead, lignified framework of xylem responsible for conduction and support. The thickened secondary walls allow efficient water transport under tension while providing mechanical strength to the vascular tissue and plant body.

7. Assertion-Reason Type:
Assertion (A): Xylem vessels form a continuous tube for water transport.
Reason (R): The end walls of xylem vessels are completely dissolved to form open channels.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. Both A and R are false.

Explanation: The correct answer is 1. Both A and R are true and R is the correct explanation of A. Xylem vessels are dead tube-like structures whose end walls dissolve completely, forming continuous channels that allow unimpeded movement of water and minerals under transpiration pull through the plant.

8. Matching Type Question:
Match the following plant tissues with their functions:
A. Xylem vessels – (i) Storage of food
B. Phloem fibres – (ii) Transport of organic solutes
C. Xylem parenchyma – (iii) Transport of water
D. Sieve tube elements – (iv) Mechanical support
1. A-(iii), B-(iv), C-(i), D-(ii)
2. A-(ii), B-(i), C-(iii), D-(iv)
3. A-(iv), B-(iii), C-(ii), D-(i)
4. A-(i), B-(ii), C-(iv), D-(iii)

Explanation: The correct answer is 1. A-(iii), B-(iv), C-(i), D-(ii). Xylem vessels transport water, phloem fibres provide mechanical support, xylem parenchyma stores food, and sieve tube elements conduct organic solutes. These coordinated functions ensure efficient transport and support in vascular plants.

9. Fill in the Blanks:
In phloem, the conducting elements are ________ and ________.
1. Vessels and tracheids
2. Sieve tubes and companion cells
3. Fibres and parenchyma
4. Tracheids and parenchyma

Explanation: The correct answer is Sieve tubes and companion cells. These form a functional unit for translocation of food through pressure flow. The sieve tubes conduct the solutes, while companion cells regulate their activity and maintain the required energy supply for transport between source and sink regions.

10. Choose the Correct Statements:
Statement I: Xylem conducts both water and minerals.
Statement II: Phloem conducts only water.
1. Only Statement I is correct.
2. Only Statement II is correct.
3. Both statements are correct.
4. Both statements are incorrect.

Explanation: The correct answer is 1. Only Statement I is correct. Xylem conducts water and minerals from roots to aerial parts. Phloem, however, conducts organic food materials like sugars, not water. This division of functions maintains nutrient and water balance essential for plant growth and metabolism.

Topic: Permanent Tissues; Subtopic: Collenchyma and Sclerenchyma

Keyword Definitions:

• Collenchyma: A simple permanent tissue that provides mechanical support and elasticity to young plant organs.

• Sclerenchyma: A permanent tissue with thick, lignified walls that provides rigidity to mature plant parts.

• Cellulose: A polysaccharide forming the primary structural component of plant cell walls.

• Lignin: A complex polymer providing hardness and impermeability to plant cell walls.

Lead Question - 2024 (Jhajjhar)

Given below are two statements:

Statement I: In collenchyma, cell walls are thickened at corners due to deposition of cellulose, hemicellulose, and pectin.

Statement II: Sclerenchyma consists of lignified cell walls and possesses pits.

In the light of the above statements, choose the correct answer from the options given below:

1. Both Statement I and Statement II are True

2. Both Statement I and Statement II are False

3. Statement I is True but Statement II is False

4. Statement I is False but Statement II is True

Explanation: The correct answer is option 1. Both statements are true. Collenchyma provides flexible support and has unevenly thickened corners due to deposition of cellulose, hemicellulose, and pectin. Sclerenchyma cells are dead at maturity with lignified secondary walls and possess simple or bordered pits, giving rigidity and strength to stems, veins, and seeds.

1. Collenchyma differs from parenchyma by:

1. Living protoplasm

2. Presence of thickened corners

3. Lignified walls

4. Absence of intercellular spaces

Explanation: The correct answer is Presence of thickened corners. Collenchyma has unevenly thickened cell walls at the corners, while parenchyma walls are thin. Both are living cells, but collenchyma provides mechanical strength in young stems and leaves. This structural adaptation helps plants resist bending and mechanical stress during growth.

2. The function of sclerenchyma is to:

1. Transport water

2. Store food

3. Provide rigidity and mechanical strength

4. Perform photosynthesis

Explanation: The correct answer is Provide rigidity and mechanical strength. Sclerenchyma is composed of thick-walled, lignified cells, such as fibers and sclereids, which provide structural support to plant parts like stems, seeds, and nuts. These cells are dead at maturity and prevent collapse under mechanical stress or pressure changes.

3. The thickening material in collenchyma is composed of:

1. Lignin and cutin

2. Cellulose, hemicellulose, and pectin

3. Suberin and lignin

4. Chitin and pectin

Explanation: The correct answer is Cellulose, hemicellulose, and pectin. These substances are deposited in the primary cell wall, particularly at cell corners, providing elasticity and flexibility to the tissue. This composition helps collenchyma support growing organs without restricting elongation, essential for leaves and young stems.

4. Assertion-Reason Type:

Assertion (A): Collenchyma provides tensile strength to young plant parts.

Reason (R): Collenchyma has thick, lignified cell walls.

1. Both A and R are true and R is the correct explanation of A

2. Both A and R are true but R is not the correct explanation of A

3. A is true but R is false

4. A is false but R is true

Explanation: The correct answer is option 3. Collenchyma provides mechanical support, but its walls are not lignified—they are thickened with cellulose and pectin. Hence, while the assertion is true, the reason is false. Lignification occurs in sclerenchyma, not in collenchyma.

5. Match the following:

A. Collenchyma — I. Dead at maturity

B. Sclerenchyma — II. Living and flexible

C. Xylem — III. Conducts water

D. Phloem — IV. Transports food

1. A-II, B-I, C-III, D-IV

2. A-I, B-II, C-IV, D-III

3. A-IV, B-II, C-I, D-III

4. A-II, B-IV, C-III, D-I

Explanation: The correct answer is A-II, B-I, C-III, D-IV. Collenchyma is living and flexible, Sclerenchyma consists of dead cells that provide rigidity, Xylem conducts water and minerals, while Phloem transports food produced during photosynthesis. These tissues collectively ensure plant strength, transport, and physiological balance.

6. Fill in the Blanks:

In sclerenchyma, cell walls are thickened due to deposition of _______.

1. Cellulose

2. Lignin

3. Pectin

4. Cutin

Explanation: The correct answer is Lignin. Sclerenchyma cells have secondary walls impregnated with lignin, making them hard and impermeable to water. Lignification provides rigidity, prevents collapse of tissues, and forms structural elements in xylem fibers, sclereids, and seed coats in plants.

7. Choose the Correct Statements (Statement I & II):

Statement I: Collenchyma cells are dead at maturity.

Statement II: Collenchyma provides mechanical support to young organs.

1. Statement I is true and Statement II is false

2. Statement I is false and Statement II is true

3. Both statements are true

4. Both statements are false

Explanation: The correct answer is option 2. Collenchyma cells remain living at maturity and possess the ability to stretch and elongate. Their thickened corners provide mechanical support without restricting growth, making them ideal for young stems and leaves during developmental stages.

8. Which type of sclerenchyma cell forms the husk of coconut?

1. Sclereid

2. Fiber

3. Collenchyma

4. Parenchyma

Explanation: The correct answer is Fiber. Coconut husk consists of sclerenchymatous fibers that are long, thick-walled, and lignified. These fibers provide mechanical strength and durability, serving as a protective layer. Sclereids, in contrast, are shorter and are found in nutshells and seed coats.

9. In which plant part is collenchyma absent?

1. Monocot stem

2. Dicot stem

3. Petiole

4. Leaf midrib

Explanation: The correct answer is Monocot stem. Collenchyma is absent in monocots due to the lack of secondary growth and the presence of scattered vascular bundles. In dicots, collenchyma is found below the epidermis and provides flexibility to young stems, leaves, and petioles.

10. Which of the following correctly describes collenchyma and sclerenchyma?

1. Both are living

2. Both have lignified walls

3. One is living, the other dead

4. Both conduct food

Explanation: The correct answer is One is living, the other dead. Collenchyma is a living mechanical tissue that provides elasticity, whereas sclerenchyma consists of dead, lignified cells offering rigidity. Together, they ensure both flexibility and strength in the plant body for survival under environmental stress.

Topic: Plant Tissues; Subtopic: Xylem Elements and Their Structure

Keyword Definitions:

• Xylem: A complex permanent tissue responsible for the conduction of water and minerals from roots to aerial parts.

• Tracheid: Elongated, dead, lignified cells with tapering ends and pits on their walls that conduct water and provide mechanical support.

• Vessel: Cylindrical xylem element formed by a series of vessel members with perforations for efficient water transport.

• Xylem fibre: Narrow, thick-walled lignified cells that provide mechanical strength to the xylem tissue.

• Xylem parenchyma: Living cells of xylem that store starch, tannins, and aid in lateral transport of water.

• Lignin: A complex organic polymer that strengthens and waterproofs cell walls of xylem elements.

• Pits: Thin, un-lignified areas in the secondary wall allowing water movement between adjacent cells.

• Conduction: Process of movement of water and minerals through xylem from roots to shoots.

• Mechanical support: Function of lignified tissues that maintain rigidity and strength in plants.

• Secondary wall: A thick, lignified wall layer deposited inside the primary wall in mature plant cells.

Lead Question – 2024 (Jhajjhar)

The given figure with reference to the anatomy of plants represents (Elongated and lignified cell with pits on cell walls):
1. Tracheid
2. Xylem fibre
3. Xylem parenchyma
4. Vessel

Explanation: The figure shows elongated, lignified cells with tapering ends and bordered pits on their walls. Such structures are characteristic of tracheids, which are the chief water-conducting and supportive elements of xylem, particularly in gymnosperms. They lack perforations, unlike vessels, and conduct water less efficiently. Therefore, the correct answer is Tracheid (Option 1).

Guessed Questions:

1. Which among the following xylem elements is a living cell?
1. Tracheid
2. Vessel
3. Xylem parenchyma
4. Xylem fibre
Explanation: Xylem parenchyma is the only living element in xylem tissue. It stores food materials like starch, resins, and tannins and also helps in lateral conduction of water. The other xylem elements—tracheids, vessels, and fibres—are dead at maturity. Hence, the correct answer is Xylem parenchyma.

2. Which xylem element is most efficient in water transport?
1. Vessel
2. Tracheid
3. Xylem fibre
4. Xylem parenchyma
Explanation: Vessels are highly efficient water-conducting elements found in angiosperms. Their wide lumen and perforated ends allow rapid flow of water compared to tracheids. Hence, the correct answer is Vessel.

3. In which group of plants are tracheids the only water-conducting cells?
1. Pteridophytes
2. Gymnosperms
3. Angiosperms
4. Bryophytes
Explanation: Gymnosperms have xylem composed mainly of tracheids without true vessels. These elongated cells provide both conduction and support. Therefore, the correct answer is Gymnosperms.

4. What is the function of xylem fibres?
1. Conduction of water
2. Transport of food
3. Mechanical support
4. Storage of starch
Explanation: Xylem fibres are thick-walled, lignified, dead cells that primarily provide mechanical strength to the plant. They do not participate in conduction but offer rigidity to vascular tissues. Hence, the correct answer is Mechanical support.

5. Assertion-Reason:
Assertion (A): Vessels are more efficient than tracheids in water transport.
Reason (R): Vessels have perforated end walls that facilitate continuous water flow.
1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.
Explanation: Both the assertion and reason are true, and R correctly explains A. Perforated vessel elements form long continuous tubes allowing faster water flow. Correct answer: Option 1.

6. Match List-I with List-II:
List-I         List-II
A. Tracheid           1. Water conduction and support
B. Xylem parenchyma   2. Storage
C. Vessel            3. Efficient water transport
D. Xylem fibre         4. Mechanical strength
1. A-1, B-2, C-3, D-4
2. A-2, B-3, C-1, D-4
3. A-3, B-1, C-4, D-2
4. A-4, B-2, C-3, D-1
Explanation: Tracheids conduct water and give support, vessels transport water efficiently, xylem parenchyma stores food, and xylem fibres provide mechanical strength. Hence, the correct answer is Option 1.

7. Fill in the blank:
The water-conducting tissue in gymnosperms is mainly composed of __________.
1. Vessels
2. Tracheids
3. Sieve tubes
4. Xylem parenchyma
Explanation: Gymnosperms lack true vessels; their xylem is mainly composed of tracheids that conduct water and provide support. Hence, the correct answer is Tracheids.

8. Choose the correct statements:
Statement I: Xylem fibres are living cells.
Statement II: Xylem parenchyma is responsible for food storage.
1. Both statements are true.
2. Statement I true, Statement II false.
3. Statement I false, Statement II true.
4. Both statements false.
Explanation: Xylem fibres are dead cells that provide support, while xylem parenchyma is living and stores food. Hence, Statement I is false, and Statement II is true. Correct answer: Option 3.

9. Which component of xylem helps in lateral conduction of water?
1. Tracheids
2. Vessels
3. Xylem parenchyma
4. Xylem fibre
Explanation: Xylem parenchyma cells are living and assist in lateral movement of water and minerals between xylem vessels and other tissues. Therefore, the correct answer is Xylem parenchyma.

10. Which among the following features is common to tracheids and vessels?
1. Living protoplasm
2. Thick lignified walls
3. Presence of sieve plates
4. Storage function
Explanation: Both tracheids and vessels are dead at maturity and have thick, lignified walls with pits that facilitate water conduction. Hence, the correct answer is Thick lignified walls.

Topic: Anatomy of Root; Subtopic: Internal Structure of Monocot Root

Keyword Definitions:

• Monocot Root: The root of a monocot plant characterized by a large pith and many xylem and phloem bundles.

• Epidermis: The outermost protective layer of the root.

• Cortex: The region between the epidermis and endodermis composed mainly of parenchyma cells.

• Endodermis: The innermost layer of the cortex, regulating water movement.

• Pericycle: A layer inside the endodermis that gives rise to lateral roots.

• Pith: The central region composed of parenchyma cells storing food.

Lead Question – 2024 (Jhajjar)

The transverse section of monocot root shows the following internal tissue organization. Arrange them in correct sequence starting from periphery to centre:

A. Endodermis

B. Pith

C. Epidermis

D. Pericycle

E. Cortex

1. D, C, E, A, B

2. A, C, E, B, D

3. C, E, A, D, B

4. C, E, D, B, A

Explanation: The correct order of tissues from periphery to centre in a monocot root is C, E, A, D, B. The epidermis forms the outer layer, followed by the cortex and the innermost endodermis. Beneath the endodermis lies the pericycle, and the central region is occupied by the pith. This arrangement aids absorption and conduction.

1. The endodermis of a monocot root is characterized by:

1. Casparian strips

2. Sclerenchyma cells

3. Xylem tracheids

4. Collenchyma cells

Explanation: The endodermis of a monocot root possesses Casparian strips made of suberin and lignin, forming a waterproof barrier. These strips regulate the movement of water and solutes into the vascular tissues. They prevent backflow of materials, maintaining unidirectional flow of water and minerals toward the xylem in roots.

2. The pericycle in roots is responsible for the formation of:

1. Root hairs

2. Lateral roots

3. Endodermis

4. Cortex

Explanation: The pericycle is a layer of thin-walled parenchyma cells located inside the endodermis. It plays a vital role in the formation of lateral roots through cell division. In dicots, it also contributes to secondary growth, but in monocots, it primarily helps in the initiation of lateral roots.

3. Which of the following statements is true for monocot roots?

1. They have a well-developed pith.

2. Secondary growth is common.

3. They lack pericycle.

4. They have few vascular bundles.

Explanation: Monocot roots have a large central pith made of parenchyma cells. Unlike dicot roots, they do not show secondary growth. Numerous vascular bundles are present in a ring. The large pith provides storage and structural support, making this feature a key identifier of monocot root anatomy.

4. The vascular bundles in monocot roots are:

1. Radial and polyarch

2. Conjoint and collateral

3. Bicollateral

4. Amphicribral

Explanation: In monocot roots, vascular bundles are radial and polyarch. “Radial” means xylem and phloem are arranged in separate radii, while “polyarch” indicates many xylem arms. This arrangement ensures efficient transport of water and nutrients from root to shoot, characteristic of monocot root structure.

5. What type of cells are present in the cortex of monocot roots?

1. Parenchyma

2. Collenchyma

3. Sclerenchyma

4. Meristematic cells

Explanation: The cortex of monocot roots is mainly composed of parenchyma cells with intercellular spaces. These cells store food and allow free movement of water and solutes. The cortical region provides support and helps in maintaining osmotic balance during water absorption from the soil.

6. The function of pith in monocot roots is:

1. Mechanical support

2. Food storage

3. Water conduction

4. Gas exchange

Explanation: The pith of monocot roots is composed of living parenchyma cells that store starch and other nutrients. It occupies a large central region and helps in maintaining the structural stability of the root. Unlike dicots, monocots retain a prominent pith throughout their life cycle.

7. Assertion-Reason Type:

Assertion (A): Monocot roots do not undergo secondary growth.

Reason (R): Cambium is absent between xylem and phloem in monocot roots.

1. Both A and R are true, and R is the correct explanation of A.

2. Both A and R are true, but R is not the correct explanation of A.

3. A is true, but R is false.

4. A is false, but R is true.

Explanation: The correct answer is 1. Both A and R are true, and R is the correct explanation of A. In monocot roots, there is no vascular cambium between xylem and phloem, preventing secondary thickening. Thus, the absence of cambium explains the lack of secondary growth in monocot roots.

8. Matching Type:

Match List I with List II

List I – Structure | List II – Function

A. Pericycle | I. Initiates lateral roots

B. Endodermis | II. Regulates water flow

C. Cortex | III. Stores food

D. Pith | IV. Central parenchyma region

1. A-I, B-II, C-III, D-IV

2. A-II, B-I, C-IV, D-III

3. A-III, B-IV, C-I, D-II

4. A-IV, B-III, C-II, D-I

Explanation: The correct answer is 1. A-I, B-II, C-III, D-IV. The pericycle initiates lateral roots, endodermis controls water transport, cortex stores nutrients, and pith forms the central tissue. Each structure plays a vital role in maintaining the functionality and structural integrity of monocot roots.

9. Fill in the Blanks:

The innermost layer of cortex in monocot root is called ________.

1. Endodermis

2. Pericycle

3. Phloem

4. Epidermis

Explanation: The innermost layer of the cortex is the endodermis. It contains Casparian strips that control water and ion entry into the stele. This selective barrier ensures water flows through the symplast rather than the apoplast, maintaining controlled absorption and transport within the root system.

10. Choose the Correct Statements:

Statement I: In monocot root, pith is large and well developed.

Statement II: Vascular bundles are conjoint and collateral.

1. Both statements are correct.

2. Only Statement I is correct.

3. Only Statement II is correct.

4. Both statements are incorrect.

Explanation: The correct answer is 2. Only Statement I is correct. Monocot roots have a large central pith, but their vascular bundles are radial, not conjoint and collateral. This radial arrangement allows efficient conduction of water and nutrients, while the pith supports the root’s structure and stores food reserves. 

Topic: Plant Tissues; Subtopic: Bulliform Cells and Their Function

Keyword Definitions:

• Bulliform cells: Large, thin-walled cells found on the upper epidermis of monocot leaves that help in leaf rolling during water stress.

• Monocots: Flowering plants having one cotyledon, parallel venation, and fibrous roots.

• Leaf rolling: The inward folding of leaves to reduce surface area and minimize water loss.

• Epidermis: The outermost protective layer of plant organs.

Lead Question (2024):
Bulliform cells are responsible for:
(1) Protecting the plant from salt stress.
(2) Increased photosynthesis in monocots.
(3) Providing large spaces for storage of sugars.
(4) Inward curling of leaves in monocots.

Explanation:
Bulliform cells are large epidermal cells found on the upper surface of monocot leaves like grasses. During water stress, these cells lose turgor, causing the leaf to roll inward, reducing the exposed surface area and thus minimizing water loss. Hence, they are responsible for inward curling of leaves. The correct answer is option (4).

1. Which plant group commonly possesses bulliform cells?
(1) Dicots
(2) Monocots
(3) Bryophytes
(4) Gymnosperms
Explanation: Bulliform cells occur in monocot leaves, especially grasses. They help reduce water loss by rolling the leaf inward under stress. Dicots lack these specialized cells, relying more on cuticle thickness and stomatal regulation for water conservation. Therefore, monocots are the plant group commonly possessing bulliform cells. The correct answer is (2).

2. The bulliform cells are found in which part of the leaf?
(1) Lower epidermis
(2) Upper epidermis
(3) Mesophyll
(4) Phloem
Explanation: Bulliform cells are large, bubble-like cells found on the upper epidermis of monocot leaves. They occur in groups and aid in leaf folding during dehydration. Their position on the upper surface allows efficient curling to prevent water loss. Thus, the correct answer is (2).

3. The bulliform cells help the plant mainly during
(1) Excess rainfall
(2) Strong sunlight and water scarcity
(3) Nutrient deficiency
(4) Seed germination
Explanation: Bulliform cells help plants cope with water scarcity and strong sunlight. When water is lost, these cells lose turgor, causing leaves to roll inward, reducing transpiration and protecting mesophyll from drying. This adaptive feature ensures water conservation. Therefore, the correct answer is (2).

4. Assertion (A): Bulliform cells cause leaf rolling under water stress.
Reason (R): They absorb water and expand, straightening the leaf.
(1) Both A and R are true, and R is the correct explanation of A.
(2) Both A and R are true, but R is not the correct explanation of A.
(3) A is true, but R is false.
(4) A is false, but R is true.
Explanation: Bulliform cells lose turgidity during water stress, leading to inward leaf rolling. When they regain turgidity, the leaf flattens again. Thus, they do not expand during stress; they shrink. Therefore, Assertion is true but Reason is false. The correct answer is (3).

5. Match the following structures with their functions:
A. Bulliform cells – I. Leaf rolling
B. Guard cells – II. Gas exchange
C. Phloem – III. Food transport
D. Xylem – IV. Water conduction
(1) A–I, B–II, C–III, D–IV
(2) A–II, B–I, C–IV, D–III
(3) A–III, B–IV, C–II, D–I
(4) A–IV, B–III, C–I, D–II
Explanation: Bulliform cells (A) regulate leaf rolling (I), guard cells (B) control gas exchange (II), phloem (C) transports food (III), and xylem (D) conducts water (IV). All are specialized plant structures performing specific physiological roles essential for plant survival. Hence, the correct matching is option (1).

6. The leaf of a grass plant rolls inward during drought because
(1) Bulliform cells gain turgidity.
(2) Bulliform cells lose turgidity.
(3) Guard cells shrink.
(4) Mesophyll cells collapse.
Explanation: During drought, bulliform cells lose turgor pressure due to water deficiency. This loss of turgidity causes the upper epidermis to contract, resulting in inward leaf rolling to minimize water loss. Thus, leaf rolling is due to loss of turgidity in bulliform cells. The correct answer is (2).

7. Fill in the blank: Bulliform cells are specialized epidermal cells found in ______ leaves.
(1) Dicot
(2) Monocot
(3) Gymnosperm
(4) Bryophyte
Explanation: Bulliform cells are characteristic of monocot leaves, especially grasses like maize and sugarcane. These cells help conserve water by inducing leaf folding under water stress. Their absence in dicots highlights anatomical differences between the two groups. Hence, the correct answer is (2).

8. Choose the correct statements:
Statement I: Bulliform cells are part of mesophyll tissue.
Statement II: They help in leaf folding during water scarcity.
(1) Both I and II are true.
(2) Both I and II are false.
(3) I is true, II is false.
(4) I is false, II is true.
Explanation: Bulliform cells are not part of mesophyll; they are epidermal in nature and located on the upper surface of monocot leaves. Their main role is leaf folding during water stress. Therefore, only Statement II is true. The correct answer is (4).

9. Which among the following best describes the role of bulliform cells in grasses?
(1) Regulation of CO₂ absorption
(2) Leaf folding and unfolding
(3) Nutrient storage
(4) Photosynthesis
Explanation: Bulliform cells function in leaf folding and unfolding. They help conserve water by rolling the leaf inward during stress and unrolling when hydrated. Their role is structural and physiological, not directly related to photosynthesis or gas exchange. Hence, the correct answer is (2).

10. In bulliform cells, loss of water leads to
(1) Leaf flattening
(2) Leaf rolling
(3) Leaf chlorosis
(4) Leaf abscission
Explanation: Bulliform cells lose water and turgor during dehydration, which causes the upper epidermis to contract, resulting in leaf rolling. This prevents excess water loss and protects inner tissues. When rehydrated, leaves flatten again. Therefore, loss of water leads to leaf rolling. The correct answer is (2).

Topic: Tissue System; Subtopic: Simple and Complex Tissues

Keyword Definitions:

• Parenchyma: A living plant tissue with thin walls, capable of cell division and storage, photosynthesis, and secretion.

• Collenchyma: A living tissue in young plants providing flexible support; has unevenly thickened cell walls.

• Xylem: A complex tissue conducting water and minerals from roots to aerial parts, composed of vessels, tracheids, fibers, and parenchyma.

• Vessels: Tube-like structures in xylem of angiosperms that facilitate efficient water conduction.

• Tracheids: Elongated xylem cells that conduct water and provide structural support; present in gymnosperms and angiosperms.

• Angiosperms: Flowering plants with seeds enclosed in fruits; usually possess xylem vessels.

• Gymnosperms: Non-flowering plants with naked seeds, generally lacking xylem vessels.

Lead Question – 2024

Given below are two statements:
Statement I: Parenchyma is living but collenchyma is dead tissue.
Statement II: Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of angiosperms.
In the light of the above statements, choose the correct answer from the options given below:

(1) Both Statement I and Statement II are false
(2) Statement I is true but Statement II is false
(3) Statement I is false but Statement II is true
(4) Both Statement I and Statement II are true

Explanation: Statement I is incorrect because collenchyma is a living supportive tissue in plants with thickened walls, not dead tissue; sclerenchyma is dead. Statement II is correct: gymnosperms generally lack xylem vessels and rely on tracheids, while xylem vessels are characteristic of angiosperms for efficient water transport. This distinction is fundamental in understanding plant tissue evolution and physiology. Knowledge of living versus dead tissues and presence of vessels helps differentiate plant groups accurately. Hence, Statement I is false and Statement II is true. (Answer: 3)

1. Single Correct Answer:
Which of the following tissues provides flexible support to young stems and leaves?
(1) Parenchyma
(2) Collenchyma
(3) Sclerenchyma
(4) Xylem

Explanation: Collenchyma is a living tissue with unevenly thickened walls that provides mechanical support to growing organs. Parenchyma is mainly for storage and photosynthesis. Sclerenchyma is dead at maturity and provides rigid support. Understanding this helps in identifying tissue function in different plant parts. (Answer: 2)

2. Single Correct Answer:
Which tissue in angiosperms is primarily dead at maturity and provides mechanical strength?
(1) Collenchyma
(2) Parenchyma
(3) Sclerenchyma
(4) Phloem

Explanation: Sclerenchyma cells are dead at maturity with thick lignified walls, providing mechanical strength. Collenchyma is living and flexible. Parenchyma is living for storage and photosynthesis. Phloem is living and transports food. Recognizing dead versus living tissues is key in anatomy studies. (Answer: 3)

3. Single Correct Answer:
Xylem vessels are absent in which group of plants?
(1) Angiosperms
(2) Gymnosperms
(3) Monocots
(4) Dicots

Explanation: Gymnosperms generally lack xylem vessels and rely on tracheids for water conduction. Angiosperms possess vessels for efficient water transport. Recognizing this difference is critical in identifying plant groups. Monocots and dicots are angiosperms and contain vessels. (Answer: 2)

4. Single Correct Answer:
Which tissue is primarily responsible for photosynthesis and storage in plants?
(1) Collenchyma
(2) Parenchyma
(3) Sclerenchyma
(4) Phloem

Explanation: Parenchyma is living tissue with thin walls that carries out photosynthesis, storage, and secretion. Collenchyma provides support. Sclerenchyma is dead and rigid. Phloem conducts food. Identifying parenchyma is fundamental in understanding basic plant tissue functions. (Answer: 2)

5. Single Correct Answer:
Which of the following cells in xylem is dead at maturity?
(1) Vessel elements
(2) Tracheids
(3) Xylem fibers
(4) All of the above

Explanation: Vessel elements, tracheids, and xylem fibers are dead at maturity and function in water conduction and support. This contrasts with living parenchyma in xylem. Recognizing dead versus living xylem components helps in anatomical identification. (Answer: 4)

6. Single Correct Answer:
Which of the following tissues has unevenly thickened primary walls?
(1) Parenchyma
(2) Collenchyma
(3) Sclerenchyma
(4) Phloem

Explanation: Collenchyma has unevenly thickened primary cell walls, providing flexible support. Parenchyma has thin walls, sclerenchyma has thick lignified secondary walls. Understanding cell wall characteristics helps identify tissue types in plants. (Answer: 2)

7. Assertion-Reason:
Assertion (A): Sclerenchyma provides mechanical support.
Reason (R): Sclerenchyma cells are dead at maturity with thick lignified walls.
(1) Both A and R are true, R explains A
(2) Both A and R are true, R does not explain A
(3) A true, R false
(4) A false, R true

Explanation: Sclerenchyma cells are dead with thick lignified walls, which provide mechanical support to plant organs. Both assertion and reason are true, and the reason explains why sclerenchyma serves as supportive tissue. (Answer: 1)

8. Matching Type:
Match List I (Tissue) with List II (Characteristic):
A. Parenchyma – (i) Dead, lignified walls
B. Collenchyma – (ii) Living, thin or unevenly thickened walls
C. Sclerenchyma – (iii) Living, flexible support
Options:
(1) A-ii, B-iii, C-i
(2) A-iii, B-ii, C-i
(3) A-ii, B-i, C-iii
(4) A-i, B-ii, C-iii

Explanation: Parenchyma is living with thin walls (ii), collenchyma is living with unevenly thickened walls providing flexible support (iii), and sclerenchyma is dead with lignified walls (i). Correct matching helps in understanding tissue function and anatomy. (Answer: 1)

9. Fill in the Blanks:
_________ cells are living supportive tissue, whereas _________ cells are dead at maturity and provide mechanical strength.
(1) Parenchyma, Collenchyma
(2) Collenchyma, Sclerenchyma
(3) Sclerenchyma, Collenchyma
(4) Collenchyma, Parenchyma

Explanation: Collenchyma cells are living and provide flexible support. Sclerenchyma cells are dead at maturity and provide mechanical strength. Recognizing living versus dead tissue types is essential in plant anatomy and function analysis. (Answer: 2)

10. Choose Correct Statements:
Statement I: Gymnosperms lack xylem vessels.
Statement II: Angiosperms have xylem vessels for efficient water transport.
Options:
(1) Both statements are true
(2) Statement I true, Statement II false
(3) Statement I false, Statement II true
(4) Both statements are false

Explanation: Gymnosperms primarily have tracheids and lack vessels. Angiosperms possess xylem vessels, allowing more efficient water conduction. Both statements are correct and highlight key anatomical differences between plant groups. (Answer: 1)

Topic: Stomatal Structure; Subtopic: Guard Cells and Stomata Components

Keyword Definitions:

• Stoma: Pore present on the leaf surface that allows gas exchange and transpiration.

• Guard Cells: Specialized cells surrounding the stoma; regulate opening and closing of the stomatal pore.

• Epidermal Cells: Outermost layer of cells in leaves, stems, and roots providing protection.

• Subsidiary Cells: Cells adjacent to guard cells that provide structural support and assist in stomatal movement.

• Thickened Inner Walls: Inner walls of guard cells which are rigid and help in stomatal opening.

• Thin Outer Walls: Flexible outer walls of guard cells that allow expansion when turgid.

• Transpiration: Loss of water vapor from plant surfaces, mainly through stomata.

• Gas Exchange: Movement of O₂ and CO₂ through stomata for photosynthesis and respiration.

• Turgor Pressure: Pressure of water inside cells that maintains cell shape and drives stomatal movement.

• Plant Anatomy: Study of internal structure and organization of plant tissues and organs.

• Stomatal Pore: Opening formed between guard cells facilitating gas exchange.

Lead Question - 2024:

In the given figure, which component of stomata has thin outer walls and highly thickened inner walls?
(1) Stoma
(2) Epidermal Cells
(3) Guard Cells
(4) Subsidiary Cells

Explanation: Correct answer is (3) Guard Cells. Guard cells are specialized epidermal cells that flank the stomatal pore. They have thin outer walls and thickened inner walls facing the stoma, which enables them to bend and open the stomatal pore when turgid. This structural arrangement facilitates controlled gas exchange and transpiration in plants. Subsidiary cells support guard cells, while epidermal cells form the general leaf surface, and stoma is the pore itself, not a cell. The unique wall thickness and turgor-driven movement of guard cells are essential for stomatal function, photosynthesis, and water regulation in plants.

Guessed MCQs:

1. Single Correct Answer MCQ: Which cells regulate stomatal opening?
(A) Epidermal cells
(B) Guard cells
(C) Subsidiary cells
(D) Parenchyma cells
Explanation: Correct answer is (B). Guard cells control stomatal aperture by changing turgor pressure, facilitating gas exchange and transpiration. Epidermal cells form leaf surface, subsidiary cells support, and parenchyma cells perform photosynthesis.

2. Single Correct Answer MCQ: Thickened inner walls of guard cells help in:
(A) Strengthening epidermis
(B) Opening of stomatal pore
(C) Water absorption
(D) Photosynthesis
Explanation: Correct answer is (B). Thickened inner walls create a hinge effect, allowing guard cells to bow outward under turgor pressure, thus opening the stomatal pore for gas exchange and transpiration.

3. Single Correct Answer MCQ: Subsidiary cells in stomata primarily:
(A) Form stomatal pore
(B) Assist guard cells in movement
(C) Perform photosynthesis
(D) Store water
Explanation: Correct answer is (B). Subsidiary cells flank guard cells and provide mechanical support during opening and closing of stomata, helping maintain turgor-driven stomatal function.

4. Single Correct Answer MCQ: Stoma refers to:
(A) Epidermal cell
(B) Pore between guard cells
(C) Subsidiary cell
(D) Chloroplast
Explanation: Correct answer is (B). Stoma is the opening between guard cells that facilitates gas exchange and transpiration. It is not a cell but the aperture regulated by guard cells.

5. Single Correct Answer MCQ: Which property enables guard cells to bend and open stomata?
(A) Thin outer walls and thick inner walls
(B) Photosynthetic pigments
(C) Epidermal support
(D) Random growth
Explanation: Correct answer is (A). The differential wall thickness of guard cells allows bending under turgor pressure, creating stomatal opening essential for gas exchange and transpiration regulation.

6. Single Correct Answer MCQ: Turgor pressure in guard cells is influenced by:
(A) Water absorption
(B) Sunlight
(C) Temperature
(D) All of the above
Explanation: Correct answer is (D). Guard cell turgor depends on water uptake, which is influenced by environmental factors like sunlight (photosynthesis), temperature, and humidity, regulating stomatal opening and closing.

7. Assertion-Reason MCQ:
Assertion (A): Guard cells have thickened inner walls.
Reason (R): Thickened inner walls allow guard cells to bend and open the stomatal pore.
(A) Both A and R are true and R explains A
(B) Both A and R are true but R does not explain A
(C) A is true, R is false
(D) A is false, R is true
Explanation: Correct answer is (A). The thickened inner walls create rigidity on the inner side of guard cells. When turgid, the cells bend outward, opening the stomatal pore for gas exchange and transpiration, making R the correct explanation for A.

8. Matching Type MCQ: Match List-I with List-II:
List-I: (A) Guard Cells (B) Subsidiary Cells (C) Stoma (D) Epidermal Cells
List-II: (I) Pore for gas exchange (II) Provide support to guard cells (III) Thin outer, thick inner walls (IV) General leaf covering
Options: (A) (B) (C) (D)
1. III II I IV
2. II III IV I
3. I II III IV
4. IV III II I
Explanation: Correct answer is 1. Guard cells have thin outer and thick inner walls (III), subsidiary cells provide mechanical support (II), stoma is the pore (I), and epidermal cells form the leaf surface (IV).

9. Fill in the Blanks / Completion MCQ: The stomatal pore is flanked by _______ which control its opening and closing.
(A) Epidermal cells
(B) Guard cells
(C) Subsidiary cells
(D) Mesophyll cells
Explanation: Correct answer is (B). Guard cells regulate the stomatal aperture through turgor changes, facilitating gas exchange and transpiration, while other cells play supportive or protective roles.

10. Choose the correct statements MCQ:
Statement I: Guard cells control gas exchange by opening and closing stomata.
Statement II: Epidermal cells have thickened inner walls for stomatal movement.
Options:
(A) Both I and II are correct
(B) Only I is correct
(C) Only II is correct
(D) Both are incorrect
Explanation: Correct answer is (B). Statement I is true as guard cells regulate stomatal opening for gas exchange. Statement II is false; epidermal cells provide surface protection but do not control stomatal movement or have thickened inner walls.

Topic: Meristematic Tissues; Subtopic: Lateral Meristems

Keyword Definitions:

• Meristematic tissue: Cells capable of division and growth in plants.

• Lateral meristem: Tissue responsible for increase in girth or secondary growth.

• Vascular cambium: Produces secondary xylem and phloem.

• Cork cambium: Produces periderm for protective outer covering.

• Interfascicular cambium: Cambium between vascular bundles that joins with fascicular cambium.

Lead Question – 2023 (Manipur)

Consider the following plant tissues:
(A) Axillary buds
(B) Fascicular vascular cambium
(C) Interfascicular cambium
(D) Cork cambium
(E) Intercalary meristem
Identify the lateral meristems among the above:
1. (A), (C) and (D) only
2. (B), (C) and (D) only
3. (A), (B), (C) and (E) only
4. (A), (B), (D) and (E) only

Explanation: Lateral meristems are those responsible for secondary growth, increasing girth of stems and roots. Fascicular vascular cambium, interfascicular cambium, and cork cambium are all lateral meristems. Axillary buds and intercalary meristems are not lateral meristems. Therefore, the correct answer is option 2: (B), (C) and (D) only.

1. Single Correct Answer Type:
Which of the following is not a lateral meristem?
1. Cork cambium
2. Interfascicular cambium
3. Apical meristem
4. Vascular cambium
Explanation: Apical meristem causes primary growth at root and shoot tips, not secondary growth. Lateral meristems, like vascular and cork cambium, increase girth. Hence, apical meristem is not a lateral meristem. Correct answer: 3. Apical meristem.

2. Single Correct Answer Type:
The activity of vascular cambium results in formation of:
1. Secondary xylem and secondary phloem
2. Primary xylem and phloem
3. Cork and cortex
4. Pith and epidermis
Explanation: The vascular cambium divides periclinally to form secondary xylem towards the inside and secondary phloem towards the outside. This contributes to increase in stem girth. Hence, the correct answer is 1. Secondary xylem and secondary phloem.

3. Single Correct Answer Type:
Cork cambium originates from which layer?
1. Pericycle
2. Phelloderm
3. Secondary xylem
4. Secondary phloem
Explanation: Cork cambium (phellogen) usually originates in the outer cortex or sometimes from the pericycle. It produces phellem (cork) towards the outside and phelloderm towards the inside. Thus, the correct answer is 1. Pericycle.

4. Single Correct Answer Type:
Which of the following plant parts exhibit secondary growth?
1. Monocot stem
2. Dicot stem
3. Leaf
4. Petal
Explanation: Secondary growth mainly occurs in dicot stems and roots, due to the activity of lateral meristems like vascular and cork cambium. Monocots generally lack secondary growth. Therefore, the correct answer is 2. Dicot stem.

5. Single Correct Answer Type:
In secondary growth of stem, new cambium originates from:
1. Xylem parenchyma
2. Phloem parenchyma
3. Medullary rays and pericycle
4. Endodermis
Explanation: The new cambium, interfascicular cambium, arises from parenchyma cells of medullary rays between vascular bundles. It joins the fascicular cambium to form a continuous ring. Hence, the correct answer is 3. Medullary rays and pericycle.

6. Single Correct Answer Type:
Cork cells are impermeable to water due to deposition of:
1. Cutin
2. Suberin
3. Lignin
4. Pectin
Explanation: Cork cells are dead at maturity and have their walls impregnated with suberin, a waxy substance making them impermeable to water and gases. This helps in protection. Thus, the correct answer is 2. Suberin.

7. Assertion-Reason Type:
Assertion (A): Cork cambium produces cork towards the outside.
Reason (R): Cork cells are dead and suberized, preventing water loss.
1. Both A and R are true, and R is the correct explanation.
2. Both A and R are true, but R is not correct explanation.
3. A true, R false.
4. A false, R true.
Explanation: Cork cambium forms cork cells towards the outside. These cork cells are dead and suberized, providing a waterproof protective layer. Hence, both statements are true, and R explains A correctly. Correct answer: 1.

8. Matching Type:
Match the following:
A. Vascular cambium – (i) Secondary xylem
B. Cork cambium – (ii) Periderm
C. Apical meristem – (iii) Primary growth
D. Intercalary meristem – (iv) Regeneration
1. A–i, B–ii, C–iii, D–iv
2. A–ii, B–i, C–iii, D–iv
3. A–i, B–iv, C–ii, D–iii
4. A–iv, B–i, C–ii, D–iii
Explanation: Vascular cambium forms secondary xylem; cork cambium produces periderm; apical meristem causes primary growth; intercalary meristem aids in regeneration in grasses. Therefore, the correct matching is A–i, B–ii, C–iii, D–iv (option 1).

9. Fill in the Blanks:
The periderm consists of ______, ______ and ______.
1. Phellogen, phellem and phelloderm
2. Cork, cortex and epidermis
3. Xylem, phloem and cambium
4. Pith, pericycle and cortex
Explanation: The periderm replaces the epidermis during secondary growth and consists of phellogen (cork cambium), phellem (cork), and phelloderm (secondary cortex). Hence, the correct answer is 1. Phellogen, phellem and phelloderm.

10. Choose the Correct Statements Type:
Statement I: Lateral meristems contribute to secondary growth.
Statement II: Apical meristems contribute to secondary growth.
1. Both statements are true.
2. Both statements are false.
3. Statement I true, Statement II false.
4. Statement I false, Statement II true.
Explanation: Lateral meristems like vascular and cork cambium are responsible for secondary growth, while apical meristems cause primary growth. Hence, Statement I is true and Statement II is false. Correct answer: 3.

Topic: Secondary Growth; Subtopic: Arrangement of Vascular Tissues

Keyword Definitions:

• Secondary Growth: It refers to the increase in thickness or girth of the plant body due to the activity of lateral meristems like vascular cambium and cork cambium.

• Xylem: Conducts water and minerals from roots to other parts of the plant.

• Phloem: Transports food materials from leaves to other plant parts.

• Pith: The central part of a stem composed of parenchyma cells for storage and support.

• Cortex: Outer region between epidermis and vascular tissues, mainly for support and storage.

Lead Question - 2023 (Manipur)

Consider the following tissues in the stellar region of a stem showing secondary growth.
(A) Primary xylem
(B) Secondary xylem
(C) Primary phloem
(D) Secondary phloem
Arrange these in the correct sequence of their position from pith towards cortex.

1. (A), (B), (D), (C)
2. (B), (A), (C), (D)
3. (A), (B), (C), (D)
4. (B), (A), (D), (C)

Explanation: From pith outward, the order is primary xylem → secondary xylem → secondary phloem → primary phloem. Secondary xylem develops inwards from the cambium, and secondary phloem forms outwards. Thus, the correct sequence from pith to cortex is (A), (B), (D), (C). The correct answer is Option 1. This arrangement helps in conduction and mechanical strength during secondary thickening of stems.

Guessed Questions:

1. In which tissue does secondary growth start first in dicot stems?
1. Cork cambium
2. Vascular cambium
3. Interfascicular cambium
4. Phloem parenchyma
Explanation: Secondary growth begins with the activity of the vascular cambium in dicot stems. It forms secondary xylem and phloem, increasing stem thickness and mechanical support. Therefore, the correct answer is vascular cambium, which initiates the process by dividing both inward and outward.

2. The cork cambium produces:
1. Secondary phloem and secondary xylem
2. Cork and secondary cortex
3. Cork and phelloderm
4. Phelloderm and pericycle
Explanation: Cork cambium or phellogen produces cork (phellem) on the outer side and secondary cortex (phelloderm) on the inner side. These layers protect internal tissues from water loss and infection. Hence, the correct answer is cork and phelloderm, which constitute part of the periderm.

3. Which of the following is formed towards the pith during secondary growth?
1. Secondary xylem
2. Secondary phloem
3. Primary phloem
4. Cork
Explanation: During secondary growth, vascular cambium cuts off secondary xylem cells towards the pith and secondary phloem towards the cortex. Thus, secondary xylem is formed on the inner side, contributing to the wood mass. Hence, the correct answer is secondary xylem.

4. Secondary xylem and phloem are produced by:
1. Interfascicular cambium only
2. Fascicular cambium only
3. Both fascicular and interfascicular cambium
4. Cork cambium
Explanation: Secondary xylem and phloem originate from the continuous vascular cambium ring formed by the joining of fascicular and interfascicular cambium. This ring produces secondary xylem inward and secondary phloem outward. Therefore, the correct answer is both fascicular and interfascicular cambium.

5. In dicot stem, during secondary growth, new cambium originates from:
1. Phloem parenchyma
2. Endodermis
3. Pericycle
4. Medullary rays
Explanation: In dicot stems, secondary growth begins when cambium cells from medullary rays (interfascicular region) join with fascicular cambium to form a continuous ring. This ring leads to the formation of secondary xylem and phloem. Hence, the correct answer is medullary rays.

6. Which of the following forms annual rings in trees?
1. Xylem parenchyma
2. Secondary xylem
3. Secondary phloem
4. Cork cambium
Explanation: Annual rings are formed due to variations in the activity of vascular cambium during different seasons. It produces earlywood (spring wood) and latewood (autumn wood), both parts of secondary xylem. Thus, the correct answer is secondary xylem, indicating the age of the tree.

7. Assertion-Reason:
Assertion (A): Annual rings are distinct in temperate regions.
Reason (R): Cambium shows differential activity in different seasons.
Options:
1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, R is false.
4. A is false, R is true.
Explanation: In temperate climates, cambium is active in spring and inactive in winter, forming early and latewood distinctly, creating visible annual rings. Hence, both A and R are true, and R correctly explains A. The correct answer is option 1.

8. Matching Type:
Match the following pairs:
(A) Phellogen → (i) Secondary xylem
(B) Vascular cambium → (ii) Cork
(C) Phelloderm → (iii) Secondary cortex
Options:
1. A-(ii), B-(i), C-(iii)
2. A-(iii), B-(ii), C-(i)
3. A-(i), B-(ii), C-(iii)
4. A-(ii), B-(iii), C-(i)
Explanation: Phellogen (cork cambium) produces cork (phellem) and secondary cortex (phelloderm), while vascular cambium forms secondary xylem and phloem. Hence, the correct match is A-(ii), B-(i), C-(iii). These tissues together contribute to secondary thickening and protection.

9. Fill in the Blanks:
During secondary growth, cork cambium is also known as ______.
1. Phellogen
2. Phellem
3. Phelloderm
4. Periderm
Explanation: Cork cambium is called phellogen, a lateral meristem forming cork (phellem) and phelloderm. It provides a protective outer layer known as the periderm. Therefore, the correct answer is phellogen, which arises from the outer cortical cells during secondary growth.

10. Choose the Correct Statements:
Statement I: Secondary xylem is formed outside the vascular cambium.
Statement II: Secondary phloem is formed outside the vascular cambium.
1. Both statements are true.
2. Both statements are false.
3. Statement I is false, Statement II is true.
4. Statement I is true, Statement II is false.
Explanation: Vascular cambium produces secondary xylem on the inner side and secondary phloem on the outer side. Thus, Statement I is false, and Statement II is true. The correct answer is option 3. This pattern maintains efficient transport and structural strength in growing stems.

Topic: Plant Tissue Systems; Subtopic: Root and Stem Structure

• Xylem: Vascular tissue that conducts water and minerals from roots to shoots.

• Phloem: Vascular tissue that transports organic nutrients, mainly sugars, throughout the plant.

• Polyarch: Xylem with many protoxylem poles, characteristic of monocot roots.

• Radial vascular arrangement: Xylem and phloem arranged in separate radii, typical of roots.

• Exarch: Protoxylem located towards the periphery, seen in roots.

• Endodermis: Inner layer of cortex regulating water and mineral uptake.

• Pericycle: Layer inside endodermis, gives rise to lateral roots.

• Monocot Root: Root with polyarch xylem, exarch protoxylem, and scattered vascular bundles.

• Dicot Root: Root with tetrarch/pentarch xylem, typically with xylem in central star shape.

• Monocot Stem: Stem with scattered vascular bundles and no secondary growth.

• Dicot Stem: Stem with vascular bundles arranged in a ring, allowing secondary growth.

Lead Question - 2023 (Manipur)

The transverse section of plant part showed polyarch, radial and exarch xylem, with endodermis and pericycle. The plant part is identified as:

• 1. Monocot root

• 2. Dicot root

• 3. Dicot stem

• 4. Monocot stem

Explanation: The transverse section described shows polyarch xylem with radial and exarch arrangement, along with endodermis and pericycle, all characteristic features of a monocot root. Dicot roots typically show tetrarch or pentarch xylem with endarch protoxylem. Monocot and dicot stems have different vascular arrangements, with stems lacking exarch xylem and pericycle as in roots. These anatomical traits help in identifying plant organs and understanding their water-conduction patterns. Correct answer: 1. Monocot root.

1. The pericycle in roots gives rise to:

• a) Lateral roots

• b) Leaf primordia

• c) Flowers

• d) Xylem vessels

Explanation: The pericycle is a layer of cells just inside the endodermis. It retains the ability to divide and gives rise to lateral roots, contributing to the branching system of roots. Leaf primordia arise from shoot apical meristem, flowers from floral meristems, and xylem vessels from procambium. Correct answer: a.

2. Exarch xylem is typically found in:

• a) Stems of dicots

• b) Roots of monocots

• c) Dicot roots

• d) Monocot stems

Explanation: Exarch xylem has protoxylem towards the periphery and metaxylem towards the center, characteristic of roots. It is typical of monocot roots, whereas dicot roots show endarch xylem. Stems do not show exarch arrangement. Correct answer: b.

3. Radial vascular arrangement is seen in:

• a) Root

• b) Stem

• c) Leaf

• d) Flower

Explanation: In roots, xylem and phloem are arranged in separate radii around the central axis, forming a radial vascular pattern. Stems have conjoint, collateral, or bicollateral arrangement. Leaves have reticulate or parallel venation, while flowers do not have vascular arrangement visible in transverse sections. Correct answer: a.

4. Polyarch condition is characteristic of:

• a) Monocot roots

• b) Dicot roots

• c) Monocot stems

• d) Dicot stems

Explanation: Polyarch xylem has multiple protoxylem poles and is typically found in monocot roots, allowing efficient water conduction. Dicot roots are tetrarch or pentarch. Stems, whether monocot or dicot, do not exhibit polyarch xylem. Correct answer: a.

5. Endodermis in roots contains:

• a) Suberin in radial walls

• b) Lignin in all walls

• c) Chloroplasts

• d) Pollen grains

Explanation: Endodermis cells have Casparian strips containing suberin in radial and transverse walls, which regulates water and mineral uptake. Lignin is mainly in xylem, chloroplasts in mesophyll, and pollen grains in flowers. Correct answer: a.

6. Primary xylem in monocot root is:

• a) Exarch

• b) Endarch

• c) Mesarch

• d) Amphicribral

Explanation: In monocot roots, primary xylem is exarch, with protoxylem at the periphery and metaxylem in the center, facilitating root elongation. Endarch xylem is seen in dicot roots. Mesarch occurs in pteridophytes. Amphicribral arrangement is in some stems. Correct answer: a.

7. Assertion (A): Pericycle initiates lateral roots.
Reason (R): Pericycle cells retain meristematic activity even after differentiation.

• a) Both A and R are true, and R is the correct explanation of A

• b) Both A and R are true, but R is not the correct explanation of A

• c) A is true, R is false

• d) A is false, R is true

Explanation: The pericycle remains meristematic after differentiation, allowing initiation of lateral roots. This activity ensures root branching and nutrient absorption. Both assertion and reason are correct, with the reason correctly explaining the assertion. Correct answer: a.

8. Match the following:

• Column I: 1. Monocot root 2. Dicot root 3. Monocot stem 4. Dicot stem

• Column II: a. Polyarch, exarch xylem b. Tetrarch/pentarch, endarch xylem c. Scattered vascular bundles d. Vascular bundles in ring

Choices:
a) 1-a, 2-b, 3-c, 4-d
b) 1-b, 2-a, 3-d, 4-c
c) 1-c, 2-d, 3-a, 4-b
d) 1-d, 2-c, 3-b, 4-a

Explanation: Monocot root: polyarch, exarch xylem (1-a), dicot root: tetrarch/pentarch, endarch xylem (2-b), monocot stem: scattered vascular bundles (3-c), dicot stem: vascular bundles arranged in a ring (4-d). Correct answer: a.

9. Fill in the blank: The ____________ regulates water and mineral uptake in roots.

• a) Endodermis

• b) Pericycle

• c) Xylem

• d) Phloem

Explanation: The endodermis is the inner cortical layer with Casparian strips, controlling movement of water and dissolved minerals into the vascular system. Pericycle initiates lateral roots, xylem conducts water, and phloem transports nutrients. Correct answer: a.

10. Choose the correct statements:

Statement I: Monocot roots have polyarch, exarch xylem.
Statement II: Dicot roots have polyarch, exarch xylem.

• a) Both Statement I and Statement II are correct

• b) Statement I is correct, Statement II is incorrect

• c) Statement I is incorrect, Statement II is correct

• d) Both Statement I and Statement II are incorrect

Explanation: Monocot roots show polyarch

Chapter: Plant Anatomy; Topic: Secondary Growth; Subtopic: Bark Structure

Keyword Definitions:

• Lenticels: Small, lens-shaped openings in the bark that allow gas exchange between internal tissues and the atmosphere.

• Bark: All tissues exterior to the vascular cambium, including secondary phloem and periderm.

• Hard bark: Bark formed early in the growing season, usually more lignified and rigid.

• Periderm: Protective tissue in secondary growth comprising phellem, phellogen, and phelloderm.

• Secondary phloem: Tissue responsible for transport of food from leaves to other parts of the plant during secondary growth.

• Phellogen: Cork cambium, a lateral meristem that produces phellem (cork) outward and phelloderm inward.

• Gas exchange: Movement of oxygen, carbon dioxide, and other gases between plant tissues and the environment.

• Vascular cambium: Lateral meristem that produces secondary xylem inward and secondary phloem outward.

• Periderm layers: Include phellem (cork), phellogen (cork cambium), and phelloderm (parenchyma layer).

• Secondary growth: Increase in girth of stems and roots due to lateral meristems like vascular cambium and cork cambium.

• Plant tissue: Group of cells with similar structure and function, forming organs like stem, root, and bark.

Lead Question - 2023:

Identify the correct statements:
A. Lenticels are the lens-shaped openings permitting the exchange of gases
B. Bark formed early in the season is called hard bark
C. Bark is a technical term that refers to all tissues exterior to vascular cambium
D. Bark refers to periderm and secondary phloem
E. Phellogen is single-layered in thickness
Choose the correct answer from the options given below:
(1) A, B and D only
(2) B and C only
(3) B, C and E only
(4) A and D only

Answer & Explanation: (1) A, B and D only. Lenticels are indeed lens-shaped openings that allow gas exchange. Bark formed early in the growing season is called hard bark due to its rigidity and lignification. Bark encompasses both periderm and secondary phloem; thus, statements A, B, and D are correct. Statement C is partially correct but less precise than D, and E is incorrect because phellogen is typically multi-layered rather than single-layered in thickness. Bark formation during secondary growth protects internal tissues, facilitates transport, and contributes to gas exchange, with lenticels playing a critical role in maintaining aeration within woody stems.

1. Lenticels are responsible for:
(1) Transport of water
(2) Transport of food
(3) Gas exchange
(4) Root anchorage
Explanation: Lenticels are specialized openings in bark that facilitate the exchange of gases such as oxygen and carbon dioxide between internal tissues and the environment. Correct answer is (3).

2. Hard bark is formed:
(1) Late in the season
(2) Early in the season
(3) During dormancy
(4) Only in roots
Explanation: Hard bark forms early in the growing season, is more lignified and rigid, and provides structural support. Correct answer is (2).

3. Bark includes:
(1) Only periderm
(2) Only secondary phloem
(3) Periderm and secondary phloem
(4) Primary xylem
Explanation: Bark consists of all tissues exterior to the vascular cambium, mainly periderm and secondary phloem. Correct answer is (3).

4. Phellogen produces:
(1) Only phellem
(2) Phellem outward, phelloderm inward
(3) Only phelloderm
(4) Secondary xylem
Explanation: Phellogen, or cork cambium, produces phellem outward and phelloderm inward, contributing to periderm formation. Correct answer is (2).

5. Secondary phloem is involved in:
(1) Transport of water
(2) Transport of food
(3) Gas exchange
(4) Mechanical support
Explanation: Secondary phloem conducts organic food (mainly sugars) from leaves to other plant parts during secondary growth. Correct answer is (2).

6. Vascular cambium produces:
(1) Secondary xylem and secondary phloem
(2) Phellem and phelloderm
(3) Primary xylem only
(4) Primary phloem only
Explanation: Vascular cambium is a lateral meristem producing secondary xylem inward and secondary phloem outward. Correct answer is (1).

Assertion-Reason Question
7. Assertion (A): Lenticels facilitate respiration in woody stems.
Reason (R): Gas exchange occurs through stomata in all parts of the plant.
(1) Both A and R true, R explains A
(2) Both A and R true, R does not explain A
(3) A true, R false
(4) A false, R true
Explanation: Lenticels enable gas exchange specifically in woody stems where stomata are absent. Statement A is true; R is false. Correct answer is (3).

Matching Type Question
8. Match List I with List II:
A. Phellem – i. Cork
B. Phelloderm – ii. Parenchyma
C. Phellogen – iii. Cork cambium
D. Secondary phloem – iv. Food conduction
(1) A-i, B-ii, C-iii, D-iv
(2) A-ii, B-i, C-iv, D-iii
(3) A-iii, B-iv, C-i, D-ii
(4) A-iv, B-iii, C-ii, D-i
Explanation: Phellem is cork, phelloderm is parenchyma, phellogen is cork cambium, and secondary phloem conducts food. Correct answer is (1).

Fill in the Blanks Question
9. The lateral meristem responsible for producing periderm is called ________.
(1) Vascular cambium
(2) Phellogen
(3) Apical meristem
(4) Intercalary meristem
Explanation: Phellogen (cork cambium) is the lateral meristem producing periderm, replacing epidermis in secondary growth. Correct answer is (2).

Choose the Correct Statements Question
10. Statement I: Bark includes periderm and secondary phloem.
Statement II: Phellogen is always single-layered.
(1) Only Statement I is correct
(2) Only Statement II is correct
(3) Both I and II are correct
(4) Both I and II are incorrect
Explanation: Bark includes periderm and secondary phloem (I correct). Phellogen is usually multi-layered, so II is incorrect. Correct answer is (1).

Chapter: Anatomy of Angiosperms; Topic: Secondary Xylem and Vascular Tissue; Subtopic: Endarch and Exarch Conditions

Keyword Definitions:

• Endarch: Condition in which protoxylem is towards the center and metaxylem towards the periphery of stem or vascular bundle.

• Exarch: Condition in which protoxylem is towards the periphery and metaxylem towards the center, usually in roots.

• Secondary Xylem: The xylem formed from the vascular cambium during secondary growth, contributing to wood formation.

• Vascular Cambium: A lateral meristem producing secondary xylem inward and secondary phloem outward.

• Root System: The underground part of a plant responsible for anchorage and absorption.

• Stem: The aerial part of a plant providing support and conduction of nutrients and water.

Lead Question - 2023:

Given below are two statements:
Statement I: Endarch and exarch are the terms often used describing the position of secondary xylem in the plant body.
Statement II: Exarch condition is the most common feature of the root system.
In the light of the above statement, choose the correct answer from the options given below:
(1) Statement I is correct but Statement II is false
(2) Statement I is incorrect but Statement II is true
(3) Both Statement I and Statement II are true
(4) Both Statement I and Statement II are false

Answer & Explanation: (3) Both Statement I and Statement II are true. The terms endarch and exarch describe the relative positions of protoxylem and metaxylem. In stems, endarch condition predominates, while in roots, exarch condition is common with protoxylem towards the periphery. Secondary xylem formed by vascular cambium contributes to wood and conduction of water. These anatomical features are essential for understanding plant vascular organization and the adaptation of roots and stems to conduction and support functions.

1. In which plant part is endarch condition most common?
(1) Root
(2) Stem
(3) Leaf
(4) Flower
Explanation: Endarch condition is commonly observed in the stem where protoxylem is towards the center and metaxylem towards the periphery. This arrangement supports the stem’s function of conduction and mechanical strength. Hence, the correct answer is (2) Stem.

2. Exarch xylem is characterized by:
(1) Protoxylem towards the center
(2) Protoxylem towards the periphery
(3) Metaxylem absent
(4) Random arrangement of xylem
Explanation: Exarch condition shows protoxylem towards the periphery and metaxylem towards the center. This is typical of roots, allowing early maturation of protoxylem for water conduction and structural adaptation. Hence, the correct answer is (2) Protoxylem towards the periphery.

3. Which lateral meristem produces secondary xylem?
(1) Cork cambium
(2) Vascular cambium
(3) Apical meristem
(4) Intercalary meristem
Explanation: Vascular cambium is the lateral meristem producing secondary xylem inward and secondary phloem outward, contributing to secondary growth and wood formation. Cork cambium produces protective tissue, and apical meristem is responsible for primary growth. Hence, the correct answer is (2) Vascular cambium.

4. The first-formed xylem in roots is called:
(1) Metaxylem
(2) Protoxylem
(3) Secondary xylem
(4) Cambium
Explanation: Protoxylem is the first-formed xylem in roots, usually positioned towards the periphery in exarch condition. It has narrow vessels to withstand stretching during elongation. Metaxylem develops later with wider vessels. Hence, the correct answer is (2) Protoxylem.

5. Which plant part generally shows exarch condition?
(1) Stem
(2) Root
(3) Leaf
(4) Flower stalk
Explanation: Roots predominantly exhibit exarch condition, where protoxylem is peripheral and metaxylem central. This arrangement supports early water conduction during root elongation and ensures proper development of secondary xylem. Hence, the correct answer is (2) Root.

6. Secondary xylem contributes mainly to:
(1) Photosynthesis
(2) Wood formation and water conduction
(3) Seed formation
(4) Leaf expansion
Explanation: Secondary xylem, formed by vascular cambium, provides mechanical support and conducts water and minerals from roots to leaves. It constitutes the wood in stems and roots, essential for plant structural integrity and efficient transport. Hence, the correct answer is (2) Wood formation and water conduction.

Assertion-Reason Type Question
7. Assertion (A): Endarch condition is typical of stems.
Reason (R): In stems, protoxylem is towards the center and metaxylem towards the periphery.
(1) Both A and R are true, and R is the correct explanation of A.
(2) Both A and R are true, but R is not the correct explanation of A.
(3) A is true but R is false.
(4) A is false but R is true.
Explanation: Endarch condition with protoxylem centrally and metaxylem peripherally is characteristic of stems. This arrangement ensures adequate conduction and mechanical support. Hence, both statements are true and R explains A correctly. Correct answer is (1).

Matching Type Question
8. Match the following:
A. Root xylem – (i) Endarch
B. Stem xylem – (ii) Exarch
(1) A-(ii), B-(i)
(2) A-(i), B-(ii)
(3) A-(i), B-(i)
(4) A-(ii), B-(ii)
Explanation: Root xylem is exarch (protoxylem peripheral) and stem xylem is endarch (protoxylem central). This arrangement supports organ-specific conduction and growth. Hence, the correct answer is (1) A-(ii), B-(i).

Fill in the Blanks Question
9. The xylem which forms later in the vascular bundle is called ________.
(1) Protoxylem
(2) Metaxylem
(3) Secondary phloem
(4) Cambium
Explanation: Metaxylem is the later-formed xylem with wider vessels, providing efficient conduction of water and minerals. It follows protoxylem in development. Hence, the correct answer is (2) Metaxylem.

Choose the Correct Statements Question
10. Statement I: Exarch xylem is typical of roots.
Statement II: Endarch xylem is found in stems.
(1) Both statements are true.
(2) Statement I is true, Statement II is false.
(3) Statement I is false, Statement II is true.
(4) Both statements are false.
Explanation: Roots exhibit exarch condition and stems show endarch arrangement. Both statements correctly describe anatomical xylem positions for respective organs, aiding in conduction and mechanical support. Hence, the correct answer is (1) Both statements are true.

Chapter: Plant Anatomy; Topic: Secondary Growth; Subtopic: Activity of Cambium and Formation of Wood

Keyword Definitions:

• Late wood: The dense, dark, and hard part of annual rings formed during the later part of the growing season.

• Xylary elements: The components of xylem tissue that conduct water and minerals.

• Cambium: A meristematic layer responsible for secondary growth in plants, producing secondary xylem and phloem.

• Vessels: Tube-like structures in xylem that transport water from roots to leaves.

• Secondary growth: Growth in thickness due to activity of vascular cambium and cork cambium.

Lead Question (2023):
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion (A): Late wood has fewer xylary elements with narrow vessels.
Reason (R): Cambium is less active in winters.
In the light of the above statements, choose the correct answer from the options given below:
(1) A is true but R is false
(2) A is false but R is true
(3) Both A and R are true and R is the correct explanation of A
(4) Both A and R are true but R is not the correct explanation of A

Answer & Explanation:
(3) Both A and R are true and R is the correct explanation of A. During winter, the cambium becomes less active due to lower temperature, forming fewer xylary elements with narrow vessels. This results in denser, darker late wood, contributing to the annual ring pattern used to estimate the plant’s age and growth conditions.

1. Which layer of the vascular cambium is responsible for the formation of secondary xylem?
(1) Outer layer
(2) Inner layer
(3) Both layers equally
(4) Ray initials

Answer & Explanation:
(2) Inner layer. The inner surface of vascular cambium actively divides to produce secondary xylem (wood), while the outer surface forms secondary phloem. Continuous activity of the cambium ring causes thickening of the stem and root, forming annual rings indicating the age and growth conditions of the plant.

2. The annual rings in a tree trunk represent:
(1) Secondary xylem and phloem
(2) Secondary phloem only
(3) Secondary xylem formed in one season
(4) Cork cambium activity

Answer & Explanation:
(3) Secondary xylem formed in one season. Each ring includes both spring wood and late wood, formed by periodic activity of the cambium. The difference in vessel diameter between early and late wood creates visible rings that help in dendrochronology and indicate climatic variations experienced by the tree.

3. The spring wood is characterized by:
(1) Narrow vessels and dark color
(2) Large vessels and light color
(3) High lignin content
(4) Absence of vessels

Answer & Explanation:
(2) Large vessels and light color. During spring, cambium is highly active and forms xylem with wide vessels for rapid water conduction. This wood appears lighter and less dense compared to late wood, forming the softer portion of the annual growth ring in temperate trees.

4. In which season does cambial activity stop completely in most deciduous trees?
(1) Spring
(2) Summer
(3) Autumn
(4) Winter

Answer & Explanation:
(4) Winter. Cambial activity halts in winter due to cold temperatures, low photoperiod, and dormancy. This inactivity separates the late wood of one growing season from the early wood of the next, forming clear annual rings in deciduous trees.

5. Identify the incorrect statement about secondary growth.
(1) It increases girth of stem
(2) It occurs due to cork cambium and vascular cambium
(3) It takes place in all herbaceous plants
(4) It results in formation of wood and bark

Answer & Explanation:
(3) It takes place in all herbaceous plants. Secondary growth mainly occurs in dicot stems and gymnosperms. Most herbaceous plants remain primary in structure because their cambium is either absent or short-lived, preventing significant increase in girth.

6. Heartwood differs from sapwood in that it:
(1) Conducts water efficiently
(2) Contains living cells
(3) Is dark and non-functional
(4) Lies in the outer region of the stem

Answer & Explanation:
(3) Is dark and non-functional. Heartwood forms due to deposition of tannins, resins, and oils, rendering it inert. It provides mechanical strength but does not conduct water. Sapwood, in contrast, contains active xylem elements for water and mineral transport.

7. Fill in the Blanks:
The part of secondary xylem that actively conducts water is called ________.

(1) Heartwood
(2) Sapwood
(3) Late wood
(4) Cork

Answer & Explanation:
(2) Sapwood. Sapwood consists of the newer, outer layers of secondary xylem that remain functional in water conduction. As cells age, they lose conductivity and transform into heartwood, which supports mechanical strength and prevents decay.

8. Matching Type Question:
Match the following and choose the correct option:
A. Spring wood — (i) Formed in winter
B. Late wood — (ii) Formed in spring
C. Annual ring — (iii) Combination of early and late wood
(1) A–ii, B–i, C–iii
(2) A–i, B–ii, C–iii
(3) A–ii, B–iii, C–i
(4) A–iii, B–ii, C–i

Answer & Explanation:
(1) A–ii, B–i, C–iii. Spring wood forms during the growing season with wide vessels, late wood forms during dormant periods with narrow vessels, and the combination of both makes up one annual ring representing one year’s secondary growth cycle in trees.

9. Assertion-Reason Question:
Assertion (A): Heartwood is non-functional in water conduction.
Reason (R): Heartwood lacks living parenchyma and vessels are blocked by tyloses.
(1) A true, R false
(2) A false, R true
(3) Both A and R true, R correct explanation of A
(4) Both A and R true, R not correct explanation of A

Answer & Explanation:
(3) Both A and R true, R correct explanation of A. Heartwood vessels get blocked by tyloses and deposits like gums and resins, stopping conduction. The absence of living cells further supports its role as a mechanical tissue rather than a conductive one.

10. Choose the Correct Statements (Statement I & II):
Statement I: Secondary xylem is produced by the inner side of vascular cambium.
Statement II: Secondary phloem is produced towards the outer side.
(1) Only I correct
(2) Only II correct
(3) Both I and II correct
(4) Both I and II incorrect

Answer & Explanation:
(3) Both I and II correct. The vascular cambium divides periclinally, forming secondary xylem on the inner side and secondary phloem outwardly. This bidirectional activity thickens the stem and enables continuous secondary growth, forming wood and bark.

Chapter: Anatomy of Flowering Plants; Topic: Secondary Growth; Subtopic: Cambium and Vascular Tissue

Keyword Definitions:

• Interfascicular cambium: Meristematic tissue formed between vascular bundles during secondary growth.

• Primary xylem: Xylem formed during primary growth from procambium.

• Primary phloem: Phloem formed during primary growth from procambium.

• Secondary xylem: Xylem produced by vascular cambium during secondary growth.

• Secondary phloem: Phloem produced by vascular cambium during secondary growth.

• Pericycle: Layer of cells just inside the endodermis in roots, involved in lateral root formation.

• Endodermis: Innermost layer of cortex regulating water and solute movement.

• Vascular bundle: Combination of xylem and phloem in a plant stem or root.

• Cambium: Lateral meristem responsible for secondary growth.

• Secondary growth: Increase in girth of stems and roots due to activity of cambium.

• Fascicular cambium: Cambium located within vascular bundles.

Lead Question - 2022 (Ganganagar)

Interfascicular cambium is present between:

1. Primary xylem and primary phloem

2. Pericycle and endodermis

3. Two vascular bundles

4. Secondary xylem and secondary phloem

Explanation: Interfascicular cambium develops between the vascular bundles (interfascicular regions) during secondary growth and connects with fascicular cambium within vascular bundles to form a continuous ring. It contributes to the formation of secondary xylem and phloem. Primary xylem and phloem are associated with fascicular cambium, not interfascicular. Pericycle and endodermis are unrelated to vascular cambium. Hence, the correct answer is 3. Two vascular bundles. Interfascicular cambium plays a crucial role in increasing stem girth by producing secondary vascular tissues.

1. Single Correct Answer MCQ:

Fascicular cambium is located within:

a) Xylem parenchyma

b) Phloem parenchyma

c) Vascular bundles

d) Cortex

Explanation: Fascicular cambium is the meristem within vascular bundles, lying between primary xylem and primary phloem. It produces secondary xylem inward and secondary phloem outward. Cortex and parenchyma are unrelated. Correct answer is c) Vascular bundles.

2. Single Correct Answer MCQ:

The main function of interfascicular cambium is:

a) Lateral root formation

b) Forming a continuous cambial ring

c) Water conduction

d) Photosynthesis

Explanation: Interfascicular cambium connects fascicular cambium segments to form a continuous ring in stems, enabling uniform secondary growth. Lateral roots and photosynthesis are unrelated, and water conduction is performed by xylem. Correct answer is b) Forming a continuous cambial ring.

3. Single Correct Answer MCQ:

Secondary growth results in the formation of:

a) Primary xylem only

b) Primary phloem only

c) Secondary xylem and phloem

d) Cortex and epidermis

Explanation: Secondary growth increases stem/root girth through vascular cambium activity, producing secondary xylem inward and secondary phloem outward. Primary tissues are formed during primary growth, and cortex/epidermis remain unchanged in thickness. Correct answer is c) Secondary xylem and phloem.

4. Single Correct Answer MCQ:

Which meristem contributes to secondary growth?

a) Apical meristem

b) Lateral meristem

c) Intercalary meristem

d) Root cap meristem

Explanation: Lateral meristems, including vascular cambium and cork cambium, are responsible for secondary growth, increasing stem and root diameter. Apical meristem contributes to length, intercalary meristem occurs in grasses, and root cap protects root tip. Correct answer is b) Lateral meristem.

5. Single Correct Answer MCQ:

Secondary xylem is produced by:

a) Apical meristem

b) Fascicular and interfascicular cambium

c) Cortex cells

d) Endodermis

Explanation: Secondary xylem is produced inward by both fascicular and interfascicular cambium during secondary growth, forming wood. Apical meristem extends length, cortex and endodermis are not involved. Correct answer is b) Fascicular and interfascicular cambium.

6. Single Correct Answer MCQ:

Interfascicular cambium is derived from:

a) Parenchyma cells

b) Collenchyma cells

c) Sclerenchyma cells

d) Epidermal cells

Explanation: Parenchyma cells located between vascular bundles become meristematic and form interfascicular cambium. Collenchyma, sclerenchyma, and epidermal cells do not contribute. Correct answer is a) Parenchyma cells.

7. Assertion-Reason MCQ:

Assertion (A): Interfascicular cambium helps in stem thickening.

Reason (R): It forms a continuous ring with fascicular cambium producing secondary xylem and phloem.

a) Both A and R are true, R explains A

b) Both A and R are true, R does not explain A

c) A is true, R is false

d) A is false, R is true

Explanation: Interfascicular cambium joins fascicular cambium to form a ring, producing secondary vascular tissues, which increases stem diameter. Both statements are true and the reason explains the assertion. Correct answer is a) Both A and R are true, R explains A.

8. Matching Type MCQ:

Match the cambium type with its location:

Column I

A) Fascicular cambium

B) Interfascicular cambium

C) Cork cambium

D) Apical meristem

Column II

1) Between vascular bundles

2) Within vascular bundles

3) Stem periphery forming cork

4) Tip of root and shoot

Choices:

A-__ B-__ C-__ D-__

Explanation: Fascicular cambium is inside vascular bundles (A-2), interfascicular cambium lies between bundles (B-1), cork cambium arises at stem periphery (C-3), and apical meristem is at shoot/root tips (D-4). Correct matches: A-2, B-1, C-3, D-4.

9. Fill in the Blanks / Completion MCQ:

The vascular cambium formed by fascicular and interfascicular cambium produces __________.

a) Epidermis

b) Secondary xylem and phloem

c) Cortex

d) Root hairs

Explanation: Vascular cambium, combining fascicular and interfascicular regions, produces secondary xylem inward and secondary phloem outward, increasing stem girth. Epidermis, cortex, and root hairs are not produced by cambium. Correct answer is b) Secondary xylem and phloem.

10. Choose the correct statements MCQ (Statement I & II):

Statement I: Interfascicular cambium is present between vascular bundles.

Statement II: It helps in producing secondary vascular tissues.

a) Both I and II are correct

b) Only I is correct

c) Only II is correct

d) Both are incorrect

Explanation: Interfascicular cambium lies between vascular bundles and joins fascicular cambium to form a ring, producing secondary xylem and phloem. Both statements are accurate and illustrate its role in secondary growth. Correct answer is a) Both I and II are correct. 

Chapter: Anatomy of Flowering Plants; Topic: Plant Tissues; Subtopic: Permanent Tissues and their Types

Keyword Definitions:

• Parenchyma: Living plant tissue with thin cell walls, involved in photosynthesis and storage.

• Collenchyma: Living supporting tissue with unevenly thickened cell walls, providing flexibility.

• Sclerenchyma: Dead supportive tissue with lignified walls, providing rigidity and strength.

• Sclereids: Specialized sclerenchyma cells with irregular shapes, found in nutshells and seed coats.

• Lignin: A complex organic polymer that strengthens cell walls in supporting tissues.

Lead Question - 2022 (Ganganagar)
The type of tissue commonly found in the fruit wall of nuts is:
1. Parenchyma
2. Collenchyma
3. Sclerenchyma
4. Sclereid

Explanation:
Sclereids are specialized, irregularly shaped sclerenchyma cells found in hard structures such as nutshells and seed coats. They provide mechanical strength and protection due to their thick, lignified cell walls. These cells are non-living at maturity and make fruit walls of nuts hard and tough. Hence, the correct answer is sclereid.

1. Which of the following tissues provides mechanical support but allows flexibility in young stems?
1. Collenchyma
2. Sclerenchyma
3. Parenchyma
4. Xylem
Explanation:
Collenchyma is a living mechanical tissue found below the epidermis in stems and petioles. Its unevenly thickened cellulose and pectin walls provide tensile strength while allowing flexibility. It supports growth regions without restricting elongation. Hence, the correct answer is collenchyma, which maintains flexibility and support in young plant parts.

2. Which type of plant tissue is dead at maturity and provides strength?
1. Collenchyma
2. Parenchyma
3. Sclerenchyma
4. Xylem parenchyma
Explanation:
Sclerenchyma consists of dead cells with heavily lignified secondary walls. It provides mechanical support and strength to plant organs. The two types, fibres and sclereids, help resist bending and compression. Fibres are elongated, while sclereids are irregular and short. Hence, the answer is sclerenchyma, which ensures rigidity and protection.

3. In which of the following plant parts is parenchyma tissue commonly found?
1. Xylem
2. Fruit pulp
3. Nut shell
4. Leaf veins
Explanation:
Parenchyma forms the bulk of soft tissues in plants, such as fruit pulp, cortex, and pith. These living cells have thin walls, large vacuoles, and intercellular spaces. They perform storage, photosynthesis, and secretion. In fruits, parenchyma stores nutrients and provides juiciness. Hence, the correct answer is fruit pulp.

4. Which of the following tissues makes the husk of coconut hard?
1. Collenchyma
2. Parenchyma
3. Sclerenchyma fibres
4. Sclereids
Explanation:
The husk of a coconut contains sclerenchyma fibres, which are elongated, lignified, and dead at maturity. These fibres provide tensile strength and durability, protecting the fruit. Sclereids, by contrast, make the shell hard, not the husk. Thus, the husk’s strength is due to sclerenchyma fibres, the correct answer.

5. Which tissue helps in gaseous exchange and buoyancy in aquatic plants?
1. Parenchyma
2. Collenchyma
3. Aerenchyma
4. Sclerenchyma
Explanation:
Aerenchyma is a type of parenchyma with large air spaces between cells, allowing buoyancy and gaseous exchange in aquatic plants. It helps in oxygen diffusion to submerged parts. It occurs commonly in hydrophytes like Hydrilla and Nymphaea. Hence, the correct answer is aerenchyma, a modification of parenchyma tissue.

6. Which of the following statements about collenchyma is true?
1. It is dead at maturity.
2. It has lignified cell walls.
3. It provides mechanical support and flexibility.
4. It lacks cytoplasm.
Explanation:
Collenchyma is a living supportive tissue found in young stems and petioles. It has unevenly thickened primary walls rich in cellulose and pectin. It provides both support and flexibility, allowing growth without damage. The cells have cytoplasm and a prominent nucleus. Hence, the correct answer is statement 3.

7. Assertion-Reason Type:
Assertion (A): Sclerenchyma cells are living and flexible.
Reason (R): Their cell walls are made of lignin and cellulose.
1. Both (A) and (R) are correct and (R) explains (A)
2. Both (A) and (R) are correct but (R) does not explain (A)
3. (A) is correct but (R) is incorrect
4. (A) is incorrect but (R) is correct
Explanation:
Sclerenchyma cells are non-living at maturity with lignified thick walls, providing rigidity and strength. Hence, the assertion is incorrect, but the reason is correct since lignin strengthens cell walls. Therefore, the correct answer is option 4: (A) is incorrect but (R) is correct.

8. Matching Type:
Match the following:
(a) Parenchyma – (i) Storage tissue
(b) Collenchyma – (ii) Mechanical support in young stems
(c) Sclerenchyma – (iii) Mechanical strength
(d) Sclereids – (iv) Hard shell of nuts
1. (a-i), (b-ii), (c-iii), (d-iv)
2. (a-ii), (b-i), (c-iv), (d-iii)
3. (a-iv), (b-iii), (c-ii), (d-i)
4. (a-iii), (b-ii), (c-i), (d-iv)
Explanation:
Parenchyma is a storage tissue, Collenchyma provides support in young stems, Sclerenchyma offers mechanical strength, and Sclereids make nutshells hard. These tissues together form the structural framework of plants. Hence, the correct answer is option 1: (a-i), (b-ii), (c-iii), (d-iv).

9. Fill in the Blanks Type:
The cell wall of sclereids is thick due to the deposition of __________.
1. Cellulose
2. Cutin
3. Lignin
4. Pectin
Explanation:
Sclereids are thick-walled due to lignin deposition, which makes them hard and impermeable. Lignin is a complex organic polymer providing compressive strength and durability. It is found in wood, nutshells, and xylem elements. Therefore, the correct answer is lignin, responsible for the hardness of sclereids.

10. Choose the Correct Statements:
Statement I: Sclerenchyma is a dead mechanical tissue.
Statement II: Collenchyma provides flexibility to growing parts.
1. Both statements are correct
2. Both statements are incorrect
3. Only Statement I is correct
4. Only Statement II is correct
Explanation:
Both statements are correct. Sclerenchyma consists of dead cells with thick lignified walls giving rigidity, while Collenchyma is a living tissue that offers flexibility and mechanical support to young organs. These tissues together maintain plant structure and adaptability. Hence, the correct answer is option 1.

Chapter: Plant Anatomy and Growth; Topic: Secondary Growth in Plants; Subtopic: Lateral Roots and Vascular Cambium

Keyword Definitions:

• Lateral roots: Roots that arise from the primary root to increase surface area for absorption.

• Vascular cambium: A cylindrical layer of meristematic cells that contributes to secondary growth in plants, forming xylem and phloem.

• Secondary growth: Increase in thickness or girth of stems and roots due to activity of lateral meristems.

• Pericycle: A layer of cells just inside the endodermis of roots, involved in the formation of lateral roots and vascular cambium.

• Endodermis: Innermost layer of cortex in roots, regulates water and mineral uptake.

• Epiblema: Outermost layer of root, also called root epidermis, mainly for absorption.

• Cortex: Ground tissue between epidermis and vascular tissue in roots, storing food and water.

Lead Question – 2022 (Ganganagar)
Initiation of lateral roots and vascular cambium during secondary growth takes place in cells of:
1. Epiblema
2. Cortex
3. Endodermis
4. Pericycle

Explanation:
Correct answer is option 4. The pericycle is a thin layer of cells located just inside the endodermis of roots and is crucial for initiating lateral roots. During secondary growth, certain pericycle cells become meristematic and contribute to the formation of vascular cambium, which produces secondary xylem and phloem. Epiblema and cortex primarily function in absorption and storage, while endodermis acts as a selective barrier. The pericycle's ability to divide and differentiate ensures the formation of new roots and the thickening of stems and roots, which are essential for the plant's growth and nutrient transport.

1. Single Correct Answer MCQ:
Which tissue is responsible for producing lateral roots in dicot roots?
1. Epiblema
2. Pericycle
3. Cortex
4. Endodermis
Explanation: Correct answer is Pericycle. The pericycle cells adjacent to xylem poles in roots become meristematic to initiate lateral root formation. This allows the root system to expand and enhance water and nutrient absorption. Other tissues like epiblema, cortex, and endodermis do not directly give rise to lateral roots.

2. Single Correct Answer MCQ:
Which cells form the vascular cambium during secondary growth?
1. Cortex cells
2. Epiblema cells
3. Pericycle cells
4. Collenchyma cells
Explanation: Correct answer is Pericycle cells. Certain pericycle cells undergo dedifferentiation to become meristematic and contribute to the formation of interfascicular cambium, which joins fascicular cambium to form the complete vascular cambium. This cambium produces secondary xylem and phloem, resulting in thickening of roots and stems during secondary growth.

3. Single Correct Answer MCQ:
Which of the following tissues forms the outer protective layer of roots?
1. Cortex
2. Epiblema
3. Pericycle
4. Vascular cambium
Explanation: Correct answer is Epiblema. The epiblema, also called root epidermis, covers the root surface and is responsible for absorption of water and minerals. It is not involved in the formation of lateral roots or vascular cambium, which are initiated in pericycle cells.

4. Single Correct Answer MCQ:
The innermost layer of cortex in roots that regulates water movement is:
1. Epiblema
2. Pericycle
3. Endodermis
4. Collenchyma
Explanation: Correct answer is Endodermis. Endodermis acts as a selective barrier controlling water and mineral uptake into the vascular cylinder. It surrounds the pericycle, which forms lateral roots and vascular cambium. Epiblema functions in absorption, while cortex stores nutrients and water.

5. Single Correct Answer MCQ:
Secondary xylem and phloem are produced by:
1. Epiblema
2. Cortex
3. Pericycle-derived cambium
4. Endodermis
Explanation: Correct answer is Pericycle-derived cambium. During secondary growth, some pericycle cells become meristematic and contribute to interfascicular cambium, which joins fascicular cambium to form vascular cambium. This cambium produces secondary xylem (wood) and phloem, increasing root and stem girth.

6. Single Correct Answer MCQ:
Which layer gives rise to both lateral roots and vascular cambium in roots?
1. Epiblema
2. Pericycle
3. Endodermis
4. Cortex
Explanation: Correct answer is Pericycle. Pericycle cells located just inside the endodermis initiate lateral roots at xylem poles and participate in vascular cambium formation. This dual role is critical for root branching and secondary thickening, ensuring structural support and enhanced nutrient uptake.

7. Assertion-Reason MCQ:
Assertion (A): Pericycle cells initiate lateral roots in dicot roots.
Reason (R): Pericycle is located just inside endodermis and retains meristematic potential.
1. Both A and R are correct and R is the correct explanation of A
2. Both A and R are correct but R is not the correct explanation of A
3. A is correct, R is false
4. A is false, R is correct
Explanation: Correct answer is option 1. Lateral root initiation occurs in pericycle cells due to their meristematic potential. Being just inside the endodermis, pericycle cells can divide and differentiate to form new roots. This location allows coordination with vascular tissues for proper root development.

8. Matching Type MCQ:
Match root layers with functions:
A. Epiblema – 1. Absorption
B. Pericycle – 2. Lateral root initiation and vascular cambium formation
C. Endodermis – 3. Selective barrier for water
D. Cortex – 4. Storage
1. A-1, B-2, C-3, D-4
2. A-2, B-1, C-4, D-3
3. A-3, B-4, C-2, D-1
4. A-4, B-3, C-1, D-2
Explanation: Correct answer is option 1. Epiblema absorbs water, pericycle initiates lateral roots and forms cambium, endodermis regulates water entry, and cortex stores nutrients. This functional specialization supports root growth, branching, and secondary thickening.

9. Fill in the Blanks MCQ:
The ______ layer of root gives rise to vascular cambium and lateral roots.
1. Epiblema
2. Pericycle
3. Endodermis
4. Cortex
Explanation: Correct answer is Pericycle. Pericycle cells retain meristematic ability and initiate lateral roots at xylem poles. They also contribute to formation of vascular cambium during secondary growth, increasing root thickness and providing structural support for the plant.

10. Choose the Correct Statements MCQ:
Statement I: Lateral roots originate from pericycle cells.
Statement II: Epiblema participates in vascular cambium formation.
1. Both Statement I and II are correct
2. Statement I is correct, II is incorrect
3. Statement I is incorrect, II is correct

Topic: Permanent Tissues; Subtopic: Collenchyma

Keyword Definitions:

• Collenchyma: A living mechanical tissue that provides flexibility and support to growing plant parts.

• Parenchyma: A simple permanent tissue responsible for storage and photosynthesis.

• Sclerenchyma: Dead supportive tissue with lignified thick walls providing strength to mature parts.

• Epidermis: The outermost protective layer of cells in plants.

• Cellulose: A carbohydrate forming the main component of plant cell walls.

Lead Question - 2022 (Abroad)
Which of the following is not a character of collenchyma tissue?
1. They provide mechanical support to the growing part of the plant
2. They occur in layers below epidermis in dicotyledonous plants
3. They consist of cells with thick corners due to cellulose deposition
4. They are usually dead and without protoplasts
Explanation: Collenchyma cells are living and have a protoplast, unlike sclerenchyma which are dead. They possess unevenly thickened cellulose walls and occur beneath the epidermis in dicot stems to provide mechanical support. Hence, the statement “They are usually dead and without protoplasts” is incorrect. Therefore, the correct answer is option 4.

1. Collenchyma differs from sclerenchyma in being:
1. Living and flexible
2. Dead and rigid
3. Dead but elastic
4. Living and lignified
Explanation: Collenchyma is a living tissue with cellulose-thickened corners that provides flexibility and mechanical strength to young plant parts. Sclerenchyma is dead and lignified. Hence, collenchyma is living and flexible. Therefore, the correct answer is option 1.

2. Which of the following plant organs commonly contains collenchyma?
1. Mature roots
2. Petioles and leaf midribs
3. Secondary xylem
4. Pith of stem
Explanation: Collenchyma occurs in the petioles and leaf midribs of dicots where flexibility and strength are required. It is rarely found in roots or secondary xylem. The pith mainly consists of parenchyma. Hence, the correct answer is option 2.

3. Collenchyma thickening is mainly due to deposition of:
1. Lignin
2. Cutin
3. Cellulose and pectin
4. Suberin
Explanation: The thickening of collenchyma cell walls occurs due to deposition of cellulose, hemicellulose, and pectin in the corners, making them flexible yet strong. Lignin deposition is characteristic of sclerenchyma. Hence, the correct answer is option 3.

4. In dicot stems, collenchyma is located:
1. Just below the epidermis
2. In the central pith region
3. Around vascular bundles
4. Within xylem elements
Explanation: In dicot stems, collenchyma forms a continuous or discontinuous layer just below the epidermis (hypodermis). It provides mechanical support and flexibility to growing parts. Therefore, the correct answer is option 1.

5. The mechanical tissue that remains alive at maturity is:
1. Sclerenchyma
2. Collenchyma
3. Xylem fibers
4. Tracheids
Explanation: Among the mechanical tissues, only collenchyma remains alive at maturity and provides flexibility to young stems and leaves. Sclerenchyma, xylem fibers, and tracheids are dead at maturity. Hence, the correct answer is option 2.

6. Collenchyma is absent in:
1. Dicot stem
2. Monocot stem
3. Dicot petiole
4. Leaf midrib
Explanation: Collenchyma is typically absent in monocot stems, where mechanical support is provided by sclerenchyma fibers and vascular bundles. Dicot stems and petioles commonly possess collenchyma beneath the epidermis. Hence, the correct answer is option 2.

7. Assertion (A): Collenchyma provides flexibility to plants.
Reason (R): Collenchyma cells have lignified secondary walls.
1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Explanation: Collenchyma provides flexibility because its cell walls are thickened by cellulose and pectin, not lignin. Lignin causes rigidity and is found in sclerenchyma. Hence, A is true but R is false. The correct answer is option 3.

8. Match the following:
A. Collenchyma — (i) Lignified thick walls
B. Parenchyma — (ii) Storage tissue
C. Sclerenchyma — (iii) Flexible support
1. A-(iii), B-(ii), C-(i)
2. A-(ii), B-(i), C-(iii)
3. A-(i), B-(iii), C-(ii)
4. A-(ii), B-(iii), C-(i)
Explanation: Collenchyma provides flexible support, parenchyma serves as storage tissue, and sclerenchyma has lignified walls giving rigidity. Hence, the correct matching is A-(iii), B-(ii), C-(i). The correct answer is option 1.

9. Fill in the blank:
_________ is a living mechanical tissue found beneath the epidermis of dicot stems.
1. Sclerenchyma
2. Collenchyma
3. Parenchyma
4. Chlorenchyma
Explanation: Collenchyma is a living mechanical tissue present beneath the epidermis in dicot stems. It supports growing parts and allows bending without breaking. Sclerenchyma is dead, while parenchyma and chlorenchyma are mainly storage and photosynthetic tissues. Hence, the correct answer is option 2.

10. Choose the correct statements:
1. Collenchyma is dead at maturity.
2. Collenchyma provides flexibility to plant organs.
3. Collenchyma cells have uniformly thickened walls.
4. Collenchyma is present in monocot roots.
Explanation: Collenchyma is a living, flexible mechanical tissue with unevenly thickened walls providing support to young plant organs. It is found mainly in dicot stems and petioles. Hence, only statement 2 is correct. Therefore, the correct answer is option 2.

Topic: Secondary Growth; Subtopic: Cork Cambium (Phellogen) Activity

• Cork Cambium: A lateral meristem in plants producing cork (phellem) externally and sometimes phelloderm internally.

• Phelloderm: Living parenchymatous tissue produced internally by cork cambium.

• Phellem (Cork): Dead protective tissue produced externally by cork cambium, often impregnated with suberin.

• Suberin: Waxy substance making cell walls impermeable to water and gases.

• Lateral Meristem: Meristematic tissue that increases girth of stem and root.

• Periderm: Protective tissue replacing epidermis in secondary growth, composed of cork, cork cambium, and phelloderm.

• Secondary Growth: Increase in thickness of plant organs by activity of lateral meristems.

• Tannins: Phenolic compounds deposited in cork cells making them resistant to decay.

• Resins: Viscous substances in plants aiding in protection of tissues.

• Protective Tissue: Tissue preventing water loss, mechanical injury, and pathogen attack.

• Meristematic Activity: Active cell division in meristem producing new cells for growth.

Lead Question - 2022 (Abroad)

Select the correct statements related to the activity of cork cambium

1. The outer cells differentiate into phelloderm

2. The cork differentiated from cork cambium, is impervious to water due to deposition of tannins and resins

3. Cuts the cells only on the outer side

4. Cuts the cells on inner as well as outer side

Explanation: Cork cambium (phellogen) is a lateral meristem producing cork (phellem) externally and sometimes phelloderm internally. Cork cells are dead and impregnated with suberin, tannins, and resins making them impermeable. The cambium cuts cells both inward and outward to form protective periderm. Correct statements: 1, 2, 4. Answer: 1, 2, 4

Q1: Cork cambium is classified as:

1. Apical meristem

2. Lateral meristem

3. Intercalary meristem

4. Primary meristem

Explanation: Cork cambium is a lateral meristem involved in secondary growth, increasing the girth of stem and root. Apical meristems are for length, intercalary meristems are at nodes, and primary meristems give rise to primary tissues. Answer: Lateral meristem. Answer: 2

Q2: Phelloderm is formed by:

1. External cells of cork cambium

2. Internal cells of cork cambium

3. Cork cells

4. Parenchyma of cortex

Explanation: Cork cambium produces phelloderm internally (towards cortex) and cork externally (towards outside). Phelloderm is living parenchymatous tissue. External cells differentiate into cork, not phelloderm. Answer: Internal cells of cork cambium. Answer: 2

Q3: Cork cells become impervious to water due to:

1. Suberin deposition

2. Lignin deposition

3. Cellulose thickening

4. Cutin deposition

Explanation: Cork cells produced by phellogen die and develop walls impregnated with suberin, tannins, and resins, making them impermeable to water and gases. Lignin or cellulose alone do not provide complete impermeability. Answer: Suberin deposition. Answer: 1

Q4: Periderm is composed of:

1. Cork only

2. Cork and cork cambium only

3. Cork, cork cambium, and phelloderm

4. Phelloderm only

Explanation: Periderm is a protective tissue formed during secondary growth. It consists of three layers: cork (phellem) externally, cork cambium (phellogen), and phelloderm internally. This replaces the epidermis and protects the stem and root. Answer: Cork, cork cambium, and phelloderm. Answer: 3

Q5: Tannins in cork cells serve to:

1. Provide color

2. Prevent microbial attack

3. Increase cell division

4. Stimulate photosynthesis

Explanation: Tannins are phenolic compounds deposited in cork cells, making them resistant to decay and microbial attack. They are not involved in cell division, photosynthesis, or merely providing color. Answer: Prevent microbial attack. Answer: 2

Q6: Cork cambium cuts cells in which directions?

1. Outward only

2. Inward only

3. Both inward and outward

4. None of the above

Explanation: Cork cambium (phellogen) produces cork externally and phelloderm internally, thus cutting cells in both directions to form protective periderm. Cutting in only one direction is incorrect. Answer: Both inward and outward. Answer: 3

Q7: Assertion (A): Cork cells are dead and impermeable.
Reason (R): Cork cambium produces suberized cells externally.

1. A is correct but R is not correct

2. A is not correct but R is correct

3. Both A and R are correct and R explains A

4. Both A and R are correct but R does not explain A

Explanation: Cork cambium produces cork cells externally, which become dead and impregnated with suberin, tannins, and resins, making them impermeable. Both assertion and reason are correct, and reason explains why cork cells are dead and water-proof. Answer: Both A and R are correct and R explains A. Answer: 3

Q8: Match cork cambium products with their direction:

1. Cork    A. Outward
2. Phelloderm    B. Inward

1. 1-A, 2-B

2. 1-B, 2-A

3. 1-A, 2-A

4. 1-B, 2-B

Explanation: Cork (phellem) is produced externally by cork cambium (outward), while phelloderm is produced internally (inward). This directional growth forms protective periderm. Answer: 1-A, 2-B. Answer: 1

Q9: Protective tissue formed during secondary growth replacing epidermis is called ______.

1. Cork

2. Phelloderm

3. Periderm

4. Cortex

Explanation: Periderm replaces epidermis during secondary growth and consists of cork externally, cork cambium, and phelloderm internally. Cork alone is part of periderm; phelloderm is internal, cortex is primary tissue. Answer: Periderm. Answer: 3

Q10: Choose correct statements about cork cambium:

1. It is a lateral meristem

2. It produces cork externally

3. It produces phelloderm internally

4. Cork cells are living and permeable

Explanation: Cork cambium is a lateral meristem producing cork externally and phelloderm internally. Cork cells are dead and impermeable. Therefore, statements 1, 2, and 3 are correct. Statement 4 is incorrect. Answer: 1, 2, 3

Topic: Secondary Growth
Subtopic: Xylem and Annual Rings

Keyword Definitions:
• Springwood/Earlywood: Part of annual ring formed in early growing season, light-colored and less dense.
• Autumnwood/Latewood: Part of annual ring formed later in the season, darker and denser.
• Cambium: Lateral meristem responsible for secondary growth producing xylem and phloem.
• Xylem: Vascular tissue conducting water and minerals from roots to aerial parts.
• Annual Rings: Concentric rings in wood representing one year’s growth.
• Density: Mass per unit volume of wood.
• Vessel Elements: Long tubular cells in xylem for water conduction.
• Secondary Growth: Increase in girth due to cambium activity.
• Concentric Rings: Rings of alternating springwood and autumnwood.
• Light Colour: Characteristic of earlywood due to thin-walled xylem elements.

Lead Question (2022):
The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood.
(a) It is also called as the earlywood
(b) In spring season cambium produces xylem elements with narrow vessels
(c) It is lighter in colour
(d) The springwood along with autumnwood shows alternate concentric rings forming annual rings
(e) It has lower density
Choose the correct answer from the options given below:
1. (a), (c), (d) and (e) Only
2. (a), (b) and (d) Only
3. (c), (d) and (e) Only
4. (a), (b), (d) and (e) Only

Explanation: The correct answer is 1. Springwood or earlywood has light-colored, thin-walled xylem elements with lower density. Cambium produces wider vessels, not narrow ones. Along with autumnwood, it forms annual rings, marking seasonal growth. These characteristics allow efficient water conduction during early growth in spring, distinguishing it from latewood.

Guessed MCQs:

1. Which wood is formed early in the growing season?
Options:
(a) Springwood
(b) Autumnwood
(c) Heartwood
(d) Sapwood
Explanation: The correct answer is (a) Springwood. Springwood, also called earlywood, forms during early growth in spring. It has thin-walled, light-colored xylem elements with lower density, enabling efficient water transport. Autumnwood forms later with thick-walled, dense xylem, contributing to annual ring formation.

2. Autumnwood is characterized by:
Options:
(a) Light-colored, thin-walled cells
(b) Darker, thick-walled cells
(c) Lower density
(d) Absence of annual rings
Explanation: The correct answer is (b) Darker, thick-walled cells. Autumnwood develops later in the growing season and is denser than springwood. It, along with springwood, forms annual rings. Its thick-walled structure helps mechanical support and water conduction regulation during dry seasons.

3. Assertion-Reason MCQ:
Assertion (A): Springwood has wider vessels for water conduction.
Reason (R): Early season growth requires efficient water transport.
Options:
(a) Both A and R are true, R explains A
(b) Both A and R are true, R does not explain A
(c) A is true, R is false
(d) A is false, R is true
Explanation: The correct answer is (a). Springwood vessels are wider and thin-walled, allowing maximum water conduction during early growth when demand is high. This structural adaptation supports rapid growth in spring, explaining the relationship between vessel width and functional requirement.

4. Matching Type MCQ:
Match the type of wood with its features:
List - I List - II
(a) Springwood (i) Dense, thick-walled cells
(b) Autumnwood (ii) Light-colored, thin-walled cells
Options:
1. a-i, b-ii
2. a-ii, b-i
3. a-i, b-i
4. a-ii, b-ii
Explanation: The correct answer is 2. Springwood is light-colored, thin-walled, and less dense. Autumnwood is darker, thick-walled, and denser. Together, they form annual rings. This differentiation is key in dendrochronology for studying plant growth patterns and environmental conditions.

5. What is the main function of springwood?
Options:
(a) Mechanical support
(b) Water conduction
(c) Photosynthesis
(d) Storage
Explanation: The correct answer is (b) Water conduction. Springwood’s thin-walled xylem cells and wide vessels allow efficient water transport during early growth in spring. Mechanical support is primarily contributed by denser autumnwood, while photosynthesis and storage are performed by leaves and parenchyma, respectively.

6. Which statement about annual rings is correct?
Options:
(a) Formed only by autumnwood
(b) Formed by alternating springwood and autumnwood
(c) Formed only by springwood
(d) Not visible in woody plants
Explanation: The correct answer is (b). Annual rings are concentric rings in wood formed by alternation of light-colored springwood and dense autumnwood. They indicate seasonal growth, help in age estimation of trees, and reflect environmental conditions during the year.

7. Fill in the Blanks:
The __________ formed in spring is light-colored and less dense.
Options:
(a) Autumnwood
(b) Heartwood
(c) Springwood
(d) Sapwood
Explanation: The correct answer is (c) Springwood. Formed during early growth in spring, it has thin-walled xylem elements and lower density, facilitating water transport. Its light color distinguishes it from autumnwood, which develops later with thick-walled, dense cells, contributing to structural support.

8. Single Correct Answer:
Which feature is NOT characteristic of springwood?
Options:
(a) Light color
(b) Thin-walled vessels
(c) High density
(d) Forms part of annual ring
Explanation: The correct answer is (c) High density. Springwood has low density due to thin-walled xylem cells. It is light-colored, forms part of annual rings along with autumnwood, and facilitates water conduction during early growth, contrasting with dense autumnwood formed later.

9. Which statement correctly describes earlywood and latewood?
Options:
(a) Earlywood dense, latewood light
(b) Both have same density
(c) Earlywood light, latewood dense
(d) Neither forms annual rings
Explanation: The correct answer is (c) Earlywood light, latewood dense. Earlywood forms in spring, with thin-walled, light-colored cells for water transport. Latewood forms later with thick-walled, dense cells providing mechanical support. Together, they create visible annual rings in woody plants.

10. Choose the correct statements:
(i) Springwood is less dense
(ii) Autumnwood is darker
(iii) Springwood forms part of annual rings
(iv) Autumnwood has thin-walled cells
Options:
(a) i, ii, iii
(b) i, iii, iv
(c) ii, iv
(d) i, ii, iv
Explanation: The correct answer is (a) i, ii, iii. Springwood is lighter and less dense, autumnwood is darker and dense. Together they form annual rings. Autumnwood has thick-walled, dense cells, not thin-walled. These features help in water conduction and mechanical support throughout the growing season.

Topic: Vascular Tissue System
Subtopic: Vascular Bundles

Keyword Definitions:

• Xylem: Vascular tissue that conducts water and minerals from roots to shoots and leaves.

• Phloem: Vascular tissue that transports organic nutrients, mainly sucrose, from leaves to other parts of the plant.

• Vascular Bundle: A strand of xylem and phloem tissue in stems, roots, or leaves.

• Cambium: A lateral meristem responsible for secondary growth in plants.

• Endarch: Protoxylem located towards the center of the stem.

• Conjoint Bundle: Xylem and phloem present together in a single bundle.

• Open Bundle: Vascular bundle with cambium present, allowing secondary growth.

• Closed Bundle: Vascular bundle without cambium, no secondary growth possible.

• Alternate Arrangement: Xylem and phloem arranged alternately along radii in root.

Lead Question (2022)
Read the following statements about the vascular bundles:
(a) In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii
(b) Conjoint closed vascular bundles do not possess cambium
(c) In open vascular bundles, cambium is present in between xylem and phloem
(d) The vascular bundles of dicotyledonous stem possess endarch protoxylem
(e) In monocotyledonous root, usually there are more than six xylem bundles present
Options:
(1) (b), (c), (d) and (e) only
(2) (a), (b), (c) and (d) only
(3) (a), (c), (d) and (e) only
(4) (a), (b) and (d) only

Explanation:
In vascular bundles, roots show alternate arrangement of xylem and phloem. Open bundles have cambium, closed bundles lack cambium. Dicot stems show endarch protoxylem, while monocot roots usually have fewer than six xylem bundles. Hence, statements (b), (c), (d), and (e) correctly describe vascular bundle characteristics. Correct answer is (1).

1. Which type of vascular bundle is present in monocot stem?
(1) Conjoint open
(2) Conjoint closed
(3) Radial
(4) Bicollateral

Explanation:
Monocot stems possess conjoint closed vascular bundles, meaning xylem and phloem are together without cambium, so secondary growth does not occur. Hence, the correct answer is (2).

2. In dicot root, the arrangement of vascular bundle is:
(1) Radial
(2) Conjoint open
(3) Conjoint closed
(4) Collateral closed

Explanation:
Dicot roots have radial vascular bundles, where xylem and phloem alternate along different radii. Cambium is absent in primary root bundles. Hence, the correct answer is (1).

3. The cambium is present in:
(1) Open vascular bundles
(2) Closed vascular bundles
(3) Monocot stem bundles
(4) All of the above

Explanation:
Cambium is a lateral meristem present in open vascular bundles, located between xylem and phloem, allowing secondary growth. Closed bundles lack cambium. Hence, the correct answer is (1).

4. In dicot stem, protoxylem is:
(1) Exarch
(2) Endarch
(3) Mesarch
(4) None of these

Explanation:
Dicot stem vascular bundles are endarch, meaning protoxylem is located towards the center while metaxylem is towards periphery. This is typical of dicot stems. Hence, the correct answer is (2).

5. In monocot root, the number of xylem bundles is usually:
(1) More than six
(2) Exactly four
(3) Less than six
(4) Variable but always even

Explanation:
Monocot roots generally contain fewer than six xylem bundles arranged radially. This contrasts with dicot roots, which usually have more. Hence, the correct answer is (3).

6. The vascular bundles of dicot stem are:
(1) Conjoint open
(2) Conjoint closed
(3) Radial
(4) Collateral closed

Explanation:
Dicot stems have conjoint open vascular bundles with cambium present, allowing secondary growth. Xylem is inner, phloem is outer. Hence, the correct answer is (1).

7. Assertion-Reason MCQ:
Assertion (A): Closed vascular bundles do not allow secondary growth.
Reason (R): They lack cambium between xylem and phloem.
(1) Both A and R are correct and R explains A
(2) Both A and R are correct but R does not explain A
(3) A is correct but R is false
(4) Both A and R are false

Explanation:
Closed vascular bundles lack cambium, so secondary growth is not possible. This directly explains why secondary growth does not occur. Hence, both A and R are correct, and R explains A. Correct answer is (1).

8. Matching Type:
Match the plant part with vascular bundle type:
A. Dicot stem — 1. Conjoint open
B. Monocot stem — 2. Conjoint closed
C. Dicot root — 3. Radial
D. Monocot root — 4. Radial
Options:
(1) A–1, B–2, C–3, D–4
(2) A–2, B–1, C–3, D–4
(3) A–1, B–2, C–4, D–3
(4) A–2, B–1, C–4, D–3

Explanation:
Dicot stems have conjoint open bundles, monocot stems have conjoint closed bundles. Dicot roots show radial arrangement, monocot roots also radial but usually simpler. Hence, the correct match is (1).

9. Fill in the Blanks:
The cambium is present in ______ vascular bundles, enabling secondary growth.
(1) Closed
(2) Open
(3) Radial
(4) Monocot stem bundles

Explanation:
Open vascular bundles possess cambium between xylem and phloem, allowing secondary growth. Closed bundles and monocot stems lack cambium. Hence, the correct answer is (2).

10. Choose the Correct Statements:
(a) Radial vascular bundles are present in roots.
(b) Endarch protoxylem is found in dicot stems.
(c) Closed bundles contain cambium.
(d) Open bundles allow secondary growth.
Options:
(1) (a), (b), (d) only
(2) (a), (c), (d) only
(3) All statements
(4) (b) and (c) only

Explanation:
Radial bundles are seen in roots, dicot stems have endarch protoxylem, and open bundles allow secondary growth. Closed bundles do not contain cambium. Hence, statements (a), (b), and (d) are correct. Correct answer is (1).

Topic: Secondary Growth

Subtopic: Heartwood and Sapwood Formation

Keyword Definitions:

• Secondary Xylem: The wood formed during secondary growth by the vascular cambium, consisting of tracheids, vessels, and fibers.

• Heartwood: The darker, non-functional inner wood formed by deposition of tannins, gums, and resins, providing strength and resistance to decay.

• Sapwood: The lighter, outer functional xylem that conducts water and minerals.

• Tannins and Resins: Secondary metabolites that make wood resistant to microbial and insect attack.

Lead Question (2022):

In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to:

(a) Secretion of secondary metabolites and their deposition in the lumen of vessels.
(b) Deposition of organic compounds like tannins and resins in the central layers of stem.
(c) Deposition of suberin and aromatic substances in the outer layer of stem.
(d) Deposition of tannins, gum, resin and aromatic substances in the peripheral layers of stem.
(e) Presence of parenchyma cells, functionally active xylem elements and essential oils.
(1) (c) and (d) Only
(2) (d) and (e) Only
(3) (b) and (d) Only
(4) (a) and (b) Only

Explanation (Answer: 4)
Old trees develop dark-colored heartwood due to the deposition of secondary metabolites like tannins, gums, and resins within xylem vessels. This process makes the wood hard, durable, and resistant to insect and fungal attacks, marking it distinct from sapwood, which remains physiologically active.

1. Heartwood differs from sapwood in being:

(1) Dark and non-functional
(2) Light and functional
(3) Living and soft
(4) Containing active vessels

Explanation (Answer: 1)
Heartwood is dark, non-functional, and contains deposits like gums, tannins, and resins. These make it resistant to microbial and insect damage, unlike sapwood, which is lighter and conducts water and minerals.

2. The lighter outer region of secondary xylem is called:

(1) Heartwood
(2) Sapwood
(3) Periderm
(4) Secondary phloem

Explanation (Answer: 2)
Sapwood is the lighter-colored outer xylem that remains functional in water and mineral transport. It eventually becomes heartwood as secondary growth continues and deposition of substances occurs.

3. Which of the following substances are commonly deposited in heartwood?

(1) Tannins, gums, and resins
(2) Starch and proteins
(3) Lipids and chlorophyll
(4) Pectins and cellulose

Explanation (Answer: 1)
Heartwood develops its characteristic color and durability from tannins, gums, and resins deposited in the xylem lumen, reducing permeability and preventing decay or insect infestation.

4. In secondary growth, vascular cambium produces:

(1) Secondary xylem and phloem
(2) Primary xylem and phloem
(3) Cork and cortex
(4) Pericycle and endodermis

Explanation (Answer: 1)
The vascular cambium forms secondary xylem (wood) toward the inside and secondary phloem toward the outside, leading to an increase in the girth of the stem during secondary growth.

5. The main function of heartwood is to:

(1) Conduct water
(2) Provide mechanical strength
(3) Transport minerals
(4) Store food

Explanation (Answer: 2)
Heartwood is non-conducting but provides strength and rigidity to the plant. Its cells are dead and filled with deposits that make the wood resistant to decay and pressure.

6. Which of the following correctly differentiates sapwood and heartwood?

(1) Sapwood - lighter, Heartwood - darker
(2) Sapwood - darker, Heartwood - lighter
(3) Both are dark
(4) Both are light

Explanation (Answer: 1)
Sapwood appears lighter as it contains living tissues and conducts water. Heartwood is darker due to the accumulation of secondary metabolites and loss of function.

7. Assertion-Reason Type:

Assertion (A): Heartwood provides mechanical strength to the stem.
Reason (R): It conducts water and minerals efficiently.
(1) Both A and R are true, and R is the correct explanation of A.
(2) Both A and R are true, but R is not the correct explanation of A.
(3) A is true, R is false.
(4) A is false, R is true.

Explanation (Answer: 3)
Heartwood provides mechanical strength but does not conduct water or minerals, as it consists of dead, lignified cells filled with deposits. Thus, the reason is false.

8. Matching Type:

Match the following:
A. Heartwood — (i) Conducts water
B. Sapwood — (ii) Functional xylem
C. Cambium — (iii) Produces secondary xylem
(1) A–i, B–ii, C–iii
(2) A–ii, B–i, C–iii
(3) A–iii, B–i, C–ii
(4) A–ii, B–iii, C–i

Explanation (Answer: 1)
Heartwood provides strength but does not conduct water, sapwood is functional xylem conducting water, and cambium produces secondary xylem during growth.

9. Fill in the Blanks:

Heartwood is formed due to the deposition of ________ like tannins, resins, and gums in the xylem vessels.

(1) Secondary metabolites
(2) Primary metabolites
(3) Minerals
(4) Pigments

Explanation (Answer: 1)
Heartwood forms as secondary metabolites such as tannins, resins, and gums accumulate within xylem vessels, making it darker, durable, and resistant to decay.

10. Choose the Correct Statements:

(1) Heartwood is non-functional but strong.
(2) Sapwood conducts water and minerals.
(3) Heartwood is dark due to secondary metabolites.
(4) All of the above.

Explanation (Answer: 4)
All statements are correct. Heartwood is dark, strong, and non-conducting, whereas sapwood remains functional in water transport. The deposition of secondary metabolites adds color and durability to the heartwood.

Subtopic: Vascular and Epidermal Cells

• Dicot Leaves: Leaves with two cotyledons in seed, usually reticulate venation and distinct mesophyll layers.

• Vascular Bundles: Arrangements of xylem and phloem in leaf or stem, may have conjunctive tissue.

• Medullary Rays: Parenchymatous cells between vascular bundles aiding in radial transport.

• Spongy Parenchyma: Loosely arranged cells in leaf mesophyll for gaseous exchange.

• Subsidiary Cells: Specialized cells surrounding guard cells in stomata.

• Epidermis: Outer protective layer of cells in leaves and stems.

• Conjunctive Tissue: Tissue connecting xylem and phloem within a bundle.

• Interfascicular Cambium: Cambium located between vascular bundles in stems.

• Lens-shaped Opening: Small ruptures in bark or epidermis for gas exchange.

• Colorless Epidermal Cells: Cells in grass leaves lacking chloroplasts, often forming subsidiary cells.

• Leaf Anatomy: Structural arrangement of tissues within a leaf including epidermis, mesophyll, and vascular tissues.

Lead Question - 2021

Select the correct pair.

1. In dicot leaves, vascular bundles are surrounded by large thick-walled cells.
Options:
A. Collenchyma
B. Conjunctive tissue
C. Spongy parenchyma
D. Epidermis

Explanation: The large thick-walled cells surrounding vascular bundles in dicot leaves provide mechanical support and are called conjunctive tissue. These cells lie between xylem and phloem within the bundle, ensuring proper connection and stability, maintaining leaf structural integrity. Answer: Conjunctive tissue.

2. Cells of medullary rays form part of cambial ring.
Options:
A. Vascular cambium
B. Interfascicular cambium
C. Conjunctive tissue
D. Spongy parenchyma

Explanation: Medullary ray cells lying between vascular bundles contribute to the interfascicular cambium, which forms part of the continuous cambial ring in dicot stems. This facilitates radial transport and secondary growth. Answer: Interfascicular cambium.

3. Loose parenchyma cells rupturing the epidermis and forming a lens-shaped opening in bark.
Options:
A. Spongy parenchyma
B. Collenchyma
C. Cork cells
D. Subsidiary cells

Explanation: Certain spongy parenchyma cells become loose, rupture the epidermis, and form lens-shaped openings called lenticels, aiding in gaseous exchange through bark. Answer: Spongy parenchyma.

4. Large colorless empty cells in the epidermis of grass leaves.
Options:
A. Subsidiary cells
B. Guard cells
C. Mesophyll cells
D. Collenchyma

Explanation: Grass leaves have subsidiary cells surrounding guard cells, which are large, colorless, and empty. They provide structural support to stomata and assist in opening and closing. Answer: Subsidiary cells.

5. Which tissue connects xylem and phloem in a vascular bundle?
Options:
A. Collenchyma
B. Conjunctive tissue
C. Sclerenchyma
D. Epidermis

Explanation: The tissue that connects xylem and phloem within a vascular bundle is called conjunctive tissue. It provides mechanical support and ensures proper functioning of the vascular system. Answer: Conjunctive tissue.

6. Medullary rays primarily aid in:
Options:
A. Radial transport
B. Photosynthesis
C. Mechanical support
D. Transpiration

Explanation: Medullary rays consist of parenchyma cells that facilitate radial transport of water, nutrients, and metabolites across vascular bundles in stems. They are crucial for secondary growth and maintaining stem function. Answer: Radial transport.

7. Assertion-Reason:
Assertion (A): Subsidiary cells in grasses are large and colorless.
Reason (R): They surround guard cells and assist in stomatal opening.
Options:
A. Both A and R are true, R is correct explanation of A
B. Both A and R are true, R is not correct explanation
C. A is true, R is false
D. A is false, R is true

Explanation: Grass leaves have subsidiary cells that are large, colorless, and surround guard cells. They help in opening and closing stomata efficiently, supporting the assertion. Answer: Both A and R are true, R is correct explanation of A.

8. Match the following:
Column I: 1. Conjunctive tissue 2. Interfascicular cambium 3. Spongy parenchyma 4. Subsidiary cells
Column II: A. Radial transport B. Surrounding xylem-phloem C. Lens-shaped openings D. Guard cell support
Options:
A. 1-B, 2-A, 3-C, 4-D
B. 1-B, 2-A, 3-D, 4-C
C. 1-A, 2-B, 3-C, 4-D
D. 1-D, 2-B, 3-A, 4-C

Explanation: Correct matching: Conjunctive tissue surrounds xylem-phloem (B), Interfascicular cambium aids radial transport (A), Spongy parenchyma forms lens-shaped openings (C), and Subsidiary cells support guard cells (D). Answer: 1-B, 2-A, 3-C, 4-D.

9. Fill in the blank: Large thick-walled cells between xylem and phloem in dicot leaves are called __________.
Options:
A. Collenchyma
B. Conjunctive tissue
C. Sclerenchyma
D. Parenchyma

Explanation: The large thick-walled cells between xylem and phloem in dicot leaves are conjunctive tissue, providing mechanical support and linking xylem and phloem within vascular bundles. They are crucial for maintaining structural integrity of leaves. Answer: Conjunctive tissue.

10. Choose the correct statements:
1. Medullary rays form part of cambial ring.
2. Subsidiary cells support stomatal function.
3. Spongy parenchyma ruptures epidermis forming lenticels.
Options:
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3

Explanation: All statements are correct. Medullary rays contribute to cambial ring, subsidiary cells support stomata, and spongy parenchyma forms lens-shaped openings in bark. These are key features of leaf and stem anatomy. Answer: 1, 2 and 3.

Topic: Tissues
Subtopic: Types of Plant Tissues

Keyword Definitions:

• Meristematic cells: Cells with active division capacity responsible for plant growth.

• Simple tissue: Tissue composed of similar cells performing the same function.

• Sclereids: Dead cells with highly thickened walls providing mechanical support.

• Vascular tissue: Tissue responsible for conduction of water, minerals, and nutrients.

• Parenchyma: A simple tissue with thin-walled living cells, often involved in storage and photosynthesis.

• Collenchyma: Simple living tissue providing flexible support to plant organs.

• Xylem: Complex vascular tissue conducting water and minerals from roots to shoots.

• Phloem: Complex vascular tissue conducting food from leaves to other plant parts.

Lead Question - 2021

Match List - I with List - II.
List - I List - II
(a) Cells with active cell division capacity    (i) Vascular tissue
(b) Tissue having all cells similar in tissue structure and function    (ii) Meristematic
(c) Tissue having different types of cells    (iii) Sclereids
(d) Dead cells with highly thickened walls and narrow lumen    (iv) Simple tissue
Select the correct answer from the options given below:
(a) (b) (c) (d)
(1) (iv) (iii) (ii) (i)
(2) (i) (ii) (iii) (iv)
(3) (iii) (ii) (iv) (i)
(4) (ii) (iv) (i) (iii)

Explanation: Correct answer is (4) (ii) (iv) (i) (iii). Meristematic cells (a) have active division capacity. Simple tissue (b) has similar cells. Vascular tissue (c) contains different cell types for transport. Sclereids (d) are dead cells with thickened walls providing mechanical support, demonstrating plant tissue diversity.

Guessed Questions:

1) Single Correct Answer: Which tissue is responsible for water conduction?
(1) Parenchyma
(2) Xylem
(3) Collenchyma
(4) Sclerenchyma

Explanation: Correct answer is (2) Xylem. Xylem is a vascular tissue composed of tracheids and vessels, responsible for conducting water and minerals from roots to aerial parts of the plant.

2) Single Correct Answer: Which tissue consists of living thin-walled cells for storage?
(1) Parenchyma
(2) Collenchyma
(3) Xylem
(4) Sclerenchyma

Explanation: Correct answer is (1) Parenchyma. Parenchyma cells are living, thin-walled, and function mainly in storage, photosynthesis, and tissue repair.

3) Single Correct Answer: Tissue providing flexible support in stems and petioles is:
(1) Collenchyma
(2) Sclerenchyma
(3) Parenchyma
(4) Xylem

Explanation: Correct answer is (1) Collenchyma. Collenchyma cells are living with unevenly thickened walls, providing flexible support to growing organs without restricting elongation.

4) Single Correct Answer: Meristematic tissue is primarily:
(1) Permanent
(2) Dead
(3) Actively dividing
(4) Conductive

Explanation: Correct answer is (3) Actively dividing. Meristematic tissues contain undifferentiated cells capable of continuous division, responsible for growth in length and girth of plants.

5) Single Correct Answer: Sclerenchyma cells are:
(1) Alive and thin-walled
(2) Dead with thickened walls
(3) Conductive
(4) Photosynthetic

Explanation: Correct answer is (2) Dead with thickened walls. Sclerenchyma cells like sclereids provide mechanical strength and are typically dead at maturity with lignified walls.

6) Assertion-Reason:
A: Collenchyma provides flexible support.
R: Collenchyma cells have unevenly thickened walls.
Options:
(1) Both A and R true, R explains A
(2) Both A and R true, R does not explain A
(3) A true, R false
(4) A false, R true

Explanation: Correct answer is (1). Collenchyma's unevenly thickened walls provide structural flexibility, allowing stems and leaves to resist bending without breaking.

7) Matching Type: Match tissue type with characteristic:
List–I List–II
(a) Parenchyma    (i) Dead and thick-walled
(b) Collenchyma    (ii) Storage and photosynthesis
(c) Sclerenchyma    (iii) Flexible support
(d) Xylem    (iv) Water conduction

Explanation: Correct answer: (a) ii, (b) iii, (c) i, (d) iv. Parenchyma stores food, Collenchyma provides flexible support, Sclerenchyma is dead and strengthens, Xylem conducts water.

8) Single Correct Answer: Simple tissue includes:
(1) Xylem
(2) Phloem
(3) Collenchyma
(4) Sclerenchyma

Explanation: Correct answer is (3) Collenchyma. Simple tissues are composed of similar cells, including parenchyma, collenchyma, and some sclerenchyma types, performing uniform functions.

9) Fill in the blank: Vascular tissues consist of ______ types of cells.
(1) Similar
(2) Different
(3) Dead only
(4) Living only

Explanation: Correct answer is (2) Different. Vascular tissues (xylem and phloem) contain various cell types performing conduction, support, and storage functions.

10) Choose the correct statements:
(a) Parenchyma cells are living
(b) Sclerenchyma provides mechanical support
(c) Collenchyma cells are dead
(d) Meristematic cells divide actively
Options:
(1) a, b, d
(2) a, c, d
(3) b, c
(4) All of the above

Explanation: Correct answer is (1). Parenchyma cells are living, Sclerenchyma provides mechanical support, and meristematic cells actively divide. Collenchyma cells are alive; therefore, statement c is incorrect.

Topic: Secondary Growth in Plants
Subtopic: Structure and Function of Periderm

Keyword Definitions:

• Lenticels: Small openings in bark that allow exchange of gases between internal tissues and the atmosphere.

• Cork Cambium (Phellogen): Lateral meristem that produces cork cells outward and phelloderm inward during secondary growth.

• Secondary Cortex: Tissue formed between cork cambium and phloem, often called phelloderm.

• Cork (Phellem): Protective tissue formed outward from cork cambium, often with suberin for waterproofing.

• Suberin: Waxy substance deposited in cork cell walls, making them impermeable to water and gases.

• Phelloderm: Inner layer of cork cambium producing parenchymatous cells forming part of secondary cortex.

• Secondary Growth: Increase in girth of plant stems and roots due to activity of lateral meristems.

• Periderm: Protective outer tissue replacing epidermis in older stems and roots, composed of cork, cork cambium, and phelloderm.

Lead Question - 2021

Match List - I with List - II.
List–I    List–II
(a) Lenticels (i) Phellogen
(b) Cork cambium    (ii) Suberin deposition
(c) Secondary cortex    (iii) Exchange of gases
(d) Cork    (iv) Phelloderm
Choose the correct answer from the options given below:
(a) (b) (c) (d)
(1) (iii) (i) (iv) (ii)
(2) (ii) (iii) (iv) (i)
(3) (iv) (ii) (i) (iii)
(4) (iv) (i) (iii) (ii)

Explanation: The correct answer is (1) (iii) (i) (iv) (ii). Lenticels facilitate exchange of gases (iii). Cork cambium or phellogen produces cork and phelloderm (i). Secondary cortex refers to phelloderm (iv). Cork cells are deposited with suberin to provide protection and waterproofing (ii). This sequence illustrates periderm organization in secondary growth.

Guessed Questions:

1) Single Correct Answer: Which tissue forms the outer protective layer in secondary growth?
(1) Secondary cortex
(2) Cork
(3) Xylem
(4) Phloem

Explanation: The correct answer is (2) Cork. Cork forms the outer protective layer in stems and roots during secondary growth. Its suberized cells prevent water loss, mechanical injury, and pathogen entry, replacing the epidermis in mature stems.

2) Single Correct Answer: Cork cambium is also known as:
(1) Phelloderm
(2) Phellem
(3) Phellogen
(4) Lenticels

Explanation: The correct answer is (3) Phellogen. Cork cambium, a lateral meristem, produces cork cells outward and phelloderm inward, forming the periderm. It plays a key role in secondary growth by replacing the epidermis and providing protective tissue.

3) Single Correct Answer: Lenticels primarily help in:
(1) Water transport
(2) Food storage
(3) Gas exchange
(4) Mechanical support

Explanation: The correct answer is (3) Gas exchange. Lenticels are spongy openings in the periderm that allow oxygen to enter and carbon dioxide to leave the inner tissues, ensuring respiration in stems and roots covered by cork.

4) Single Correct Answer: Suberin is deposited in:
(1) Xylem vessels
(2) Cork cell walls
(3) Phloem fibers
(4) Secondary cortex parenchyma

Explanation: The correct answer is (2) Cork cell walls. Suberin is a waxy substance deposited in cork to make the cells impermeable to water and gases, providing protection and minimizing water loss in stems and roots during secondary growth.

5) Single Correct Answer: Secondary cortex in plants refers to:
(1) Phelloderm
(2) Collenchyma
(3) Sclerenchyma
(4) Phloem fibers

Explanation: The correct answer is (1) Phelloderm. Secondary cortex consists of parenchymatous cells formed inwardly by cork cambium (phellogen). It lies between cork and phloem and forms part of the protective periderm system in secondary growth.

6) Single Correct Answer: Cork cambium produces phelloderm in which direction?
(1) Outward
(2) Inward
(3) Both directions
(4) Laterally

Explanation: The correct answer is (2) Inward. Cork cambium produces cork (phellem) outward and phelloderm inward. Phelloderm forms part of the secondary cortex, while cork provides external protection.

7) Matching Type: Match the tissue with its function.
List-I    List-II
(a) Cork    (i) Gas exchange
(b) Lenticels    (ii) Protection and waterproofing
(c) Phelloderm    (iii) Storage and support
(d) Cork cambium    (iv) Cell production

Explanation: Correct answer: (a) ii, (b) i, (c) iii, (d) iv. Cork provides protection (ii), lenticels enable gas exchange (i), phelloderm forms part of secondary cortex (iii), and cork cambium produces cells inward and outward (iv), illustrating periderm function.

8) Single Correct Answer: Which layer forms the periderm in older stems?
(1) Epidermis
(2) Cork, cork cambium, and phelloderm
(3) Secondary phloem
(4) Collenchyma

Explanation: The correct answer is (2) Cork, cork cambium, and phelloderm. These layers collectively replace epidermis in mature stems, forming the periderm, a protective tissue system essential for secondary growth.

9) Single Correct Answer: The term “phellem” refers to:
(1) Cork cambium
(2) Cork
(3) Secondary cortex
(4) Lenticels

Explanation: The correct answer is (2) Cork. Phellem or cork cells are produced outwardly by cork cambium, impregnated with suberin, and serve as a protective barrier against mechanical injury, pathogens, and water loss.

10) Choose the correct statements:
(a) Lenticels allow gas exchange.
(b) Cork is suberized and impermeable.
(c) Phelloderm is produced outward by cork cambium.
(d) Cork cambium is also called phellogen.
Options:
(1) a, b, d
(2) a, c, d
(3) b, c, d
(4) All are correct

Topic: Secondary Growth
Subtopic: Cork Cambium

Keyword Definitions:
• Cork Cambium: A lateral meristem that produces periderm tissues during secondary growth.
• Periderm: Protective tissue replacing epidermis in secondary growth, including phellogen, phellem, and phelloderm.
• Phellogen: Another name for cork cambium.
• Phellem: Cork cells produced outwardly by cork cambium.
• Phelloderm: Secondary cortex formed inwardly by cork cambium.
• Lenticels: Aerating pores formed in periderm for gas exchange.

Lead Question - 2020 (COVID Reexam)
Which of the following statements about cork cambium is incorrect?
1. It forms a secondary cortex on its outside
2. It forms a part of periderm
3. It is responsible for the formation of lenticels
4. It is a couple of layers thick
Explanation: The correct answer is (1). Cork cambium produces secondary cortex (phelloderm) towards the inside, not outside. It forms periderm and gives rise to lenticels. It is only a few layers thick. Hence, the incorrect statement is that it forms secondary cortex outside, making option (1) correct.

Question 1: Cork cambium is also called:
(1) Phellem
(2) Phellogen
(3) Phelloderm
(4) Lenticel
Explanation: The correct answer is (2). Cork cambium is scientifically termed phellogen. It is a secondary meristem forming periderm during secondary growth. Phellem refers to cork, phelloderm to secondary cortex, and lenticels are aerating structures. Thus, option (2) is the correct synonym for cork cambium in plants.

Question 2: Outward products of cork cambium are:
(1) Phelloderm
(2) Cork (Phellem)
(3) Xylem
(4) Phloem
Explanation: The correct answer is (2). Cork cambium produces phellem or cork cells towards the outside, which are dead, suberized, and protective. Inwardly, it produces phelloderm, a living tissue. Xylem and phloem arise from vascular cambium, not cork cambium. Hence, outward product is cork, confirming option (2).

Question 3: Inward product of cork cambium is:
(1) Phellem
(2) Phelloderm
(3) Secondary phloem
(4) Epidermis
Explanation: The correct answer is (2). Phelloderm or secondary cortex is produced inwardly by cork cambium. Phellem is produced outwardly. Secondary phloem is produced by vascular cambium, not cork cambium. Epidermis is the original outer protective tissue. Thus, inward product is phelloderm, validating option (2).

Question 4: Which of the following is not part of periderm?
(1) Phellogen
(2) Phellem
(3) Phelloderm
(4) Vascular cambium
Explanation: The correct answer is (4). Periderm consists of phellogen (cork cambium), phellem (cork), and phelloderm (secondary cortex). Vascular cambium is a separate lateral meristem involved in secondary xylem and phloem production. Therefore, vascular cambium is not a periderm component, making option (4) correct.

Question 5: Lenticels arise due to activity of:
(1) Vascular cambium
(2) Phellogen
(3) Apical meristem
(4) Intercalary meristem
Explanation: The correct answer is (2). Lenticels are spongy openings formed in periderm for gaseous exchange. They arise from phellogen or cork cambium. Vascular cambium produces vascular tissues, apical meristem produces primary tissues, and intercalary meristem elongates internodes. Thus, lenticels originate from phellogen activity, confirming option (2).

Question 6: Cork cells are impregnated with:
(1) Cutin
(2) Suberin
(3) Lignin
(4) Cellulose
Explanation: The correct answer is (2). Cork or phellem cells are dead and have walls impregnated with suberin, a hydrophobic material that prevents water loss and pathogen entry. Cutin is present in cuticle, lignin strengthens xylem, and cellulose forms primary wall. Therefore, option (2) is the accurate answer.

Question 7 (Assertion-Reason):
Assertion (A): Cork cambium contributes to secondary growth protection.
Reason (R): It forms vascular bundles.
(1) Both A and R true, R explains A
(2) Both A and R true, R does not explain A
(3) A true, R false
(4) A false, R true
Explanation: The correct answer is (3). Cork cambium protects plants during secondary growth by forming periderm. It does not form vascular bundles, which arise from vascular cambium. Hence, assertion is true but reason is false. This makes option (3) the correct choice for assertion-reason relationship here.

Question 8 (Matching Type):
Match the tissue with origin:
A. Cork – 1. Vascular cambium
B. Secondary cortex – 2. Phellogen
C. Secondary xylem – 3. Phellogen
D. Secondary phloem – 4. Vascular cambium
Options:
(1) A-2, B-3, C-1, D-4
(2) A-3, B-2, C-4, D-1
(3) A-2, B-2, C-1, D-4
(4) A-2, B-2, C-4, D-4
Explanation: The correct answer is (3). Cork (phellem) and secondary cortex (phelloderm) originate from phellogen. Secondary xylem and phloem arise from vascular cambium. This accurate mapping explains roles of different meristems, making option (3) correct in matching origin of these tissues in plant secondary growth.