Reproduction in Organisms

Topic: Apomixis and Hybrid Crops; Subtopic: Genetic Engineering in Crop Improvement

Keyword Definitions:

• Apomixis: Asexual reproduction through seeds without fertilization, producing offspring genetically identical to the parent.

• Hybrid Varieties: Plants produced by crossing genetically distinct parents, showing heterosis or hybrid vigor.

• Polyembryony: Formation of multiple embryos from a single fertilized egg or ovule, can be natural or induced.

• Dormancy: Period in which seeds do not germinate despite favorable conditions.

• Segregation: Separation of alleles during gamete formation, leading to variation in progeny.

• Genetic Engineering: Manipulation of DNA to introduce desired traits into organisms.

• Crop Improvement: Enhancing yield, quality, or stress tolerance in cultivated plants.

• Clonal Propagation: Asexual reproduction producing genetically identical plants.

• Seed Saving: Farmers reusing seeds from previous harvests to grow new crops.

• Heterosis: Hybrid vigor showing superior traits compared to parents.

• Progeny: Offspring resulting from reproduction, sexually or asexually.

Lead Question - 2022 (Ganganagar)

Which of the following can be expected if scientists succeed in introducing apomictic gene into hybrid varieties of crops?

1. Polyembryony will be seen and each seed will produce many plantlets

2. Seeds of hybrid plants will show longer dormancy

3. Farmers can keep on using the seeds produced by the hybrids to raise new crop year after year

4. There will be segregation of the desired characters only in the progeny

Explanation: Introducing the apomictic gene in hybrid crops allows asexual reproduction through seeds, producing offspring genetically identical to the parent. This ensures that hybrid vigor is maintained and farmers can reuse seeds to grow successive crops without losing traits. Polyembryony is not necessarily induced in all cases, dormancy is not significantly affected, and no segregation occurs because meiosis is bypassed. Therefore, the expected outcome is that farmers can continually use hybrid seeds with stable traits. Correct answer is 3. This approach is significant for crop improvement and sustainable agriculture.

1. Single Correct Answer MCQ:

Apomixis in plants primarily results in:

a) Increased segregation of traits

b) Offspring genetically identical to parent

c) Formation of hybrids

d) Longer seed dormancy

Explanation: Apomixis bypasses fertilization, producing clonal seeds genetically identical to the parent plant. No segregation occurs, and hybrid traits are maintained. Correct answer is b) Offspring genetically identical to parent.

2. Single Correct Answer MCQ:

The main benefit of apomixis in hybrid crops is:

a) Greater genetic variability

b) Maintaining hybrid vigor in progeny

c) Increased seed dormancy

d) Inducing polyembryony in all seeds

Explanation: Apomixis preserves the superior traits of hybrids across generations by producing genetically identical seeds. Variability and polyembryony are not primary outcomes. Correct answer is b) Maintaining hybrid vigor in progeny.

3. Single Correct Answer MCQ:

Which process is bypassed in apomictic reproduction?

a) Pollination

b) Fertilization

c) Seed germination

d) Photosynthesis

Explanation: Fertilization is bypassed in apomixis, allowing seed formation without gamete fusion. Pollination is irrelevant, germination and photosynthesis continue normally. Correct answer is b) Fertilization.

4. Single Correct Answer MCQ:

Seeds produced by apomictic hybrid crops can be:

a) Used only once

b) Reused for multiple generations

c) Segregating for traits

d) Less viable than sexual seeds

Explanation: Apomictic seeds maintain hybrid traits, allowing farmers to reuse seeds over multiple seasons without loss of desired characteristics. Correct answer is b) Reused for multiple generations.

5. Single Correct Answer MCQ:

Polyembryony in apomixis leads to:

a) Increased genetic variability

b) Multiple plantlets from a single seed

c) Seed dormancy

d) Segregation of traits

Explanation: Polyembryony can result in multiple embryos developing in a seed, potentially forming several genetically identical plantlets. Correct answer is b) Multiple plantlets from a single seed.

6. Single Correct Answer MCQ:

Which statement is false regarding apomictic hybrid crops?

a) Offspring are clones of the parent

b) Desired traits are preserved

c) Segregation occurs normally

d) Farmers can reuse seeds

Explanation: Segregation does not occur in apomictic reproduction as meiosis is bypassed; offspring are genetically identical to parent, preserving hybrid traits. Correct answer is c) Segregation occurs normally.

7. Assertion-Reason MCQ:

Assertion (A): Apomixis allows farmers to reuse hybrid seeds.

Reason (R): Apomixis produces offspring genetically identical to parent, maintaining hybrid vigor.

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: Apomixis produces clonal seeds preserving hybrid traits, enabling repeated seed usage. Both the assertion and reason are true, and the reason correctly explains the assertion. Correct answer is a) Both A and R are true, R explains A.

8. Matching Type MCQ:

Match the term with its definition:

Column I | Column II

A) Apomixis | 1) Bypasses fertilization to form seeds

B) Polyembryony | 2) Multiple embryos in a single seed

C) Hybrid vigor | 3) Superior traits in hybrid offspring

D) Segregation | 4) Separation of alleles during gamete formation

Choices: A-__ B-__ C-__ D-__

Explanation: A-1 (Apomixis bypasses fertilization), B-2 (Polyembryony forms multiple embryos), C-3 (Hybrid vigor expresses superior traits), D-4 (Segregation is separation of alleles). Correct matching demonstrates key concepts in plant breeding and apomixis.

9. Fill in the Blanks / Completion MCQ:

Apomictic reproduction in hybrid crops results in ______ of hybrid traits.

a) Segregation

b) Preservation

c) Loss

d) Mutation

Explanation: Apomixis maintains genetic identity, preserving hybrid traits in successive generations. Correct answer is b) Preservation.

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

Statement I: Apomictic hybrid seeds allow continuous cultivation without loss of hybrid vigor.

Statement II: Apomixis increases segregation of desired traits.

a) Both I and II are correct

b) Only I is correct

c) Only II is correct

d) Both are incorrect

Explanation: Apomixis preserves hybrid traits allowing repeated use of seeds (Statement I correct). It bypasses meiosis, so no segregation occurs (Statement II incorrect). Correct answer is b) Only I is correct. 

Chapter: Reproduction in Flowering Plants; Topic: Seed Structure and Development; Subtopic: Perisperm and Nutritive Tissue in Seeds

Keyword Definitions:

• Perisperm: Nutritive tissue derived from the nucellus that persists in some seeds, supporting embryo development.

• Nucellus: Central part of the ovule surrounding the embryo sac, providing nutrition.

• Endosperm: Triploid tissue formed after double fertilization, serving as nutrient source in seeds.

• Calyx: Outer whorl of sepals protecting the flower bud.

• Integument: Protective layer enclosing the nucellus in an ovule, forming seed coat after fertilization.

• Embryo: Young sporophyte in seed formed after fertilization.

• Seed coat: Protective covering of a seed derived from integuments.

• Fertilization: Fusion of male and female gametes in ovule.

• Residual tissue: Tissue remaining after development of seed structures.

• Beet seed: Example of perispermous seed where nucellus persists.

• Nutritive tissue: Tissue supplying nutrients to developing embryo and endosperm.

Lead Question - 2022 (Ganganagar)

The residual persistent part which forms the perisperm in the seeds of beet is:

1. Calyx

2. Endosperm

3. Nucellus

4. Integument

Explanation: In beet seeds, the nucellus does not completely degenerate during seed development. Instead, the residual nucellus persists as a nutritive tissue called perisperm, providing nourishment to the developing embryo. Endosperm may also be present in some species, but the perisperm is specifically derived from nucellus, not from integuments or calyx. This structural adaptation ensures sufficient nutrient supply for embryo growth, particularly in seeds where endosperm is reduced or absent. Therefore, the correct answer is 3. Nucellus. Understanding perisperm formation is crucial in seed anatomy and development studies, highlighting the diverse sources of nutritive tissue in angiosperms.

1. Single Correct Answer MCQ:

Which tissue forms the perisperm in seeds?

a) Integument

b) Nucellus

c) Endosperm

d) Seed coat

Explanation: The perisperm originates from the nucellus, the central part of ovule, and remains persistent in certain seeds to nourish the embryo. Integuments form seed coat, endosperm is separate triploid tissue, and seed coat protects the seed. Correct answer is b) Nucellus.

2. Single Correct Answer MCQ:

Endosperm in angiosperm seeds is formed by:

a) Fusion of two polar nuclei with one male gamete

b) Fusion of male and female gametes

c) Nucellus persistence

d) Seed coat development

Explanation: Endosperm arises after double fertilization: one male gamete fuses with two polar nuclei in the embryo sac, forming triploid endosperm. Nucellus persistence forms perisperm, not endosperm. Correct answer is a) Fusion of two polar nuclei with one male gamete.

3. Single Correct Answer MCQ:

The perisperm is absent in seeds of:

a) Beet

b) Coconut

c) Groundnut

d) Maize

Explanation: Coconut has perisperm, beet has perisperm, groundnut and maize do not; they rely mainly on endosperm for embryo nourishment. Perisperm is characteristic of certain seeds where nucellus persists. Correct answer is d) Maize.

4. Single Correct Answer MCQ:

Residual nucellus in seed acts as:

a) Protective layer

b) Nutritive tissue

c) Fertilizing agent

d) Water storage tissue

Explanation: The persistent nucellus provides nutrients to the developing embryo, functioning as perisperm. It does not protect, fertilize, or primarily store water. Correct answer is b) Nutritive tissue.

5. Single Correct Answer MCQ:

Which of the following is a perispermous seed?

a) Wheat

b) Beet

c) Maize

d) Mustard

Explanation: Beet seeds retain residual nucellus as perisperm. Wheat, maize, and mustard have endospermic seeds with little or no perisperm. Correct answer is b) Beet.

6. Single Correct Answer MCQ:

Calyx contributes to:

a) Perisperm

b) Seed coat

c) Flower protection

d) Embryo nutrition

Explanation: Calyx comprises sepals that protect flower buds. It does not form perisperm, seed coat, or nourish embryo. Correct answer is c) Flower protection.

7. Assertion-Reason MCQ:

Assertion (A): Perisperm in beet is derived from nucellus.

Reason (R): Nucellus persists after fertilization to provide nourishment.

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 residual nucellus remains after fertilization and forms perisperm to nourish the embryo. Both assertion and reason are correct, with reason explaining the assertion. Correct answer is a) Both A and R are true, R explains A.

8. Matching Type MCQ:

Match seed type with tissue providing nutrition:

Column I

A) Perispermous

B) Endospermic

C) Non-endospermic

D) Coconut

Column II

1) Nucellus

2) Endosperm

3) Cotyledons

4) Both perisperm and endosperm

Choices:

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

Explanation: Perispermous: nucellus (A-1), Endospermic: endosperm (B-2), Non-endospermic: cotyledons (C-3), Coconut: perisperm and endosperm (D-4). Correct matches: A-1, B-2, C-3, D-4.

9. Fill in the Blanks / Completion MCQ:

The tissue forming perisperm in seeds is __________.

a) Endosperm

b) Nucellus

c) Integument

d) Cotyledon

Explanation: Perisperm is derived from nucellus, which persists as a nutritive tissue for embryo. Endosperm is separate, integument forms seed coat, cotyledons store food. Correct answer is b) Nucellus.

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

Statement I: Nucellus may persist as perisperm in certain seeds.

Statement II: Endosperm is always derived from nucellus.

a) Both I and II are correct

b) Only I is correct

c) Only II is correct

d) Both are incorrect

Explanation: Nucellus can persist as perisperm, supplying nutrients. Endosperm forms via double fertilization, not from nucellus. Statement I is correct, Statement II is false. Correct answer is b) Only I is correct. 

Topic: Floral Parts and Aestivation; Subtopic: Types of Aestivation and Examples

Keyword Definitions:
• Aestivation: Arrangement of sepals or petals in a floral bud before it opens.
• Imbricate: Overlapping petals, where some overlap and some are overlapped (e.g., Cassia).
• Valvate: Petals just touch each other without overlapping (e.g., Calotropis).
• Vexillary: Standard petal covers wings and keel (e.g., Bean).
• Twisted: Each petal overlaps the next one in regular order (e.g., Cotton).

Lead Question – 2022 (Ganganagar)
Match List-I with List-II
List-I        List-II
(a) Imbricate     (i) Calotropis
(b) Valvate       (ii) Cassia
(c) Vexillary      (iii) Cotton
(d) Twisted        (iv) Bean
Choose the correct answer from the options given below:
(a)   (b)   (c)   (d)
1. (ii)  (i)  (iii)  (iv)
2. (ii)  (i)  (iv)  (iii)
3. (ii)  (iv)  (iii)  (i)
4. (i)  (iii)  (iv)  (ii)

Explanation: The correct answer is option 2. Imbricate aestivation occurs in Cassia, valvate in Calotropis, vexillary in Bean, and twisted in Cotton. These patterns describe how petals or sepals are arranged before blooming. Such arrangements help in identification of plant families and are taxonomically important.

Guessed Questions:

1. (Single Correct Answer)
Which type of aestivation is found in China rose?
1. Imbricate
2. Valvate
3. Twisted
4. Vexillary
Explanation: The correct answer is option 3. In China rose (Hibiscus), petals are arranged so that each overlaps the next, forming a regular twisted pattern. This twisted aestivation aids in identifying members of the Malvaceae family and is a key floral characteristic in their classification.

2. (Single Correct Answer)
In which of the following plants valvate aestivation is found?
1. Calotropis
2. Cassia
3. Pea
4. Cotton
Explanation: The correct answer is option 1. Calotropis shows valvate aestivation where petals or sepals just touch each other at the margins without overlapping. This arrangement provides a symmetrical flower appearance, often associated with members of the Asclepiadaceae family.

3. (Single Correct Answer)
Vexillary aestivation is a characteristic feature of which family?
1. Malvaceae
2. Fabaceae
3. Solanaceae
4. Brassicaceae
Explanation: The correct answer is option 2. Vexillary aestivation is typical of the Fabaceae family, where the largest petal (standard) covers the lateral wings and keel. This specialized arrangement helps in pollination and provides protection to reproductive organs inside the corolla.

4. (Single Correct Answer)
Which of the following correctly matches flower and aestivation?
1. Cotton – Imbricate
2. Bean – Valvate
3. Cassia – Imbricate
4. Calotropis – Twisted
Explanation: The correct answer is option 3. Cassia exhibits imbricate aestivation where petals overlap irregularly. This feature helps identify members of the Caesalpinioideae subfamily and aids in differentiating them from others showing valvate or twisted arrangements.

5. (Single Correct Answer)
Which type of aestivation shows all petals touching but not overlapping?
1. Twisted
2. Valvate
3. Imbricate
4. Vexillary
Explanation: The correct answer is option 2. Valvate aestivation is where sepals or petals are arranged edge to edge without overlapping. It is commonly seen in Calotropis. This simple floral arrangement contributes to easy floral dissection and family identification.

6. (Single Correct Answer)
Twisted aestivation occurs in which of the following plants?
1. China rose
2. Mustard
3. Pea
4. Cassia
Explanation: The correct answer is option 1. China rose, a member of Malvaceae, shows twisted aestivation where each petal overlaps the next one in a fixed direction. This regular overlapping is characteristic of hibiscus flowers and aids in identifying this family morphologically.

7. (Assertion–Reason)
Assertion (A): Vexillary aestivation is characteristic of Papilionaceous flowers.
Reason (R): In such flowers, standard petal overlaps wings, and wings overlap keel.
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 1. Both A and R are true, and R correctly explains A. Vexillary aestivation is seen in Papilionaceous flowers like peas and beans where the large standard petal overlaps wings and keel in a specific arrangement aiding in pollination.

8. (Matching Type)
Match the following:
A. Valvate — 1. Hibiscus
B. Twisted — 2. Calotropis
C. Imbricate — 3. Cassia
D. Vexillary — 4. Pea
1. A–2, B–1, C–3, D–4
2. A–3, B–2, C–4, D–1
3. A–1, B–3, C–4, D–2
4. A–4, B–2, C–1, D–3
Explanation: The correct answer is option 1. Valvate – Calotropis, Twisted – Hibiscus, Imbricate – Cassia, and Vexillary – Pea. This matching illustrates how floral aestivation varies among families and assists in their identification during plant taxonomy classification.

9. (Fill in the Blanks)
In _______ aestivation, the margins of petals overlap one another in a definite direction, as in China rose.
Options:
1. Valvate
2. Twisted
3. Imbricate
4. Vexillary
Explanation: The correct answer is option 2. Twisted aestivation involves each petal overlapping the next one consistently. This is common in Malvaceae (e.g., Hibiscus) and provides a spiral floral pattern that helps botanists identify related species through morphological study.

10. (Choose the Correct Statements)
Statement I: Imbricate aestivation is seen in Calotropis.
Statement II: Vexillary aestivation is found in Pea.
1. Both statements are correct.
2. Both statements are incorrect.
3. Only Statement I is correct.
4. Only Statement II is correct.
Explanation: The correct answer is option 4. Only Statement II is correct. Pea exhibits vexillary aestivation characteristic of Papilionaceae, whereas Calotropis shows valvate aestivation. Correct identification of aestivation helps in understanding floral morphology and taxonomic classification.

incorrect because antipodal cells are located at the chalazal end. (Answer: Statement I is correct, Statement II is incorrect)

Topic: Vegetative Propagation; Subtopic: Asexual Reproduction

Keyword Definitions:

• Vegetative Propagule: A plant part capable of giving rise to a new individual, used in asexual reproduction.

• Eyes of Potato: Buds on the tuber capable of sprouting new plants.

• Rhizome of Ginger: Underground horizontal stem that can develop into a new plant.

• Bulbil of Agave: Small bulb-like structures on the plant that can grow into a new plant.

• Zoospore: Motile spore produced by some algae for asexual reproduction but not a vegetative propagule.

• Buds in Hydra: Formed by asexual reproduction in animals and not a plant vegetative propagule.

Lead Question - 2022 (Abroad)
Which of the following is/are vegetative propagule(s)?
(a) Eyes of Potato
(b) Zoospore of Chlamydomonas
(c) Rhizome of Ginger
(d) Buds in Hydra
(e) Bulbil of Agave
Choose the most appropriate answer from the options given below:
1. (e) only
2. (a), (c), (e) only
3. (a), (b), (c), (d) only
4. (b), (d) only
Explanation: The correct answer is (a), (c), (e) only. Vegetative propagules are plant parts that develop into a new individual asexually. Eyes of potato, rhizome of ginger, and bulbil of agave are classic vegetative propagules. Zoospores of Chlamydomonas are asexual reproductive spores, not vegetative propagules, and buds in Hydra are animal-based asexual reproduction. These vegetative structures allow rapid multiplication and preservation of plant traits without sexual reproduction, which is especially useful in agriculture and horticulture for uniform crop production and propagation of desirable varieties.

1. Single Correct Answer Type:
Which of the following is an underground vegetative propagule?
1. Bulbil of Agave
2. Rhizome of Ginger
3. Eyes of Potato
4. Zoospore of Chlamydomonas
Explanation: The correct answer is Rhizome of Ginger. Rhizomes are underground horizontal stems that can produce new shoots and roots, forming new plants. They are vegetative propagules used in asexual reproduction. Unlike bulbs or eyes of potato which are modified stems or buds, rhizomes spread underground and store nutrients, facilitating propagation and survival during unfavorable conditions, making them highly efficient for vegetative multiplication.

2. Single Correct Answer Type:
Which propagule is used for asexual propagation in potato?
1. Bulbil
2. Rhizome
3. Eyes of Potato
4. Zoospore
Explanation: The correct answer is Eyes of Potato. Eyes are dormant buds present on potato tubers capable of sprouting into new plants. They serve as vegetative propagules for asexual reproduction. Planting tubers with healthy eyes ensures rapid multiplication and uniform growth of crops, preserving parental traits. Unlike zoospores or rhizomes, these structures are modified stems specifically adapted for agricultural propagation of potatoes.

3. Single Correct Answer Type:
Bulbils are commonly found in which plant?
1. Potato
2. Ginger
3. Agave
4. Chlamydomonas
Explanation: The correct answer is Agave. Bulbils are small bulb-like structures produced on aerial parts of Agave. They detach and grow into new plants asexually. Bulbils act as vegetative propagules, ensuring rapid multiplication. Unlike eyes of potato or rhizomes of ginger, they form above ground, providing an effective natural method of propagation and maintaining genetic uniformity without sexual reproduction.

4. Single Correct Answer Type:
Which of the following is NOT a vegetative propagule?
1. Rhizome of Ginger
2. Eyes of Potato
3. Zoospore of Chlamydomonas
4. Bulbil of Agave
Explanation: The correct answer is Zoospore of Chlamydomonas. Zoospores are motile asexual spores produced by algae for reproduction, not vegetative propagation. Vegetative propagules are plant parts like rhizomes, eyes, or bulbils that give rise to a new individual. Zoospores differ because they are reproductive cells capable of dispersal and germination, rather than existing plant structures used for cloning.

5. Single Correct Answer Type:
Rhizome as a vegetative propagule is advantageous because:
1. It produces genetically variable offspring
2. It stores nutrients for sprouting
3. It requires pollination
4. It grows only above ground
Explanation: The correct answer is It stores nutrients for sprouting. Rhizomes store food materials, enabling new shoots and roots to emerge, ensuring survival and propagation. This vegetative propagule allows rapid, uniform multiplication without pollination, unlike sexual reproduction. Nutrient storage also helps plants withstand adverse conditions and ensures energy supply for growth of new plants from the rhizome.

6. Single Correct Answer Type:
Which propagule grows on the body of the parent plant?
1. Rhizome
2. Bulbil
3. Eyes of Potato
4. Zoospore
Explanation: The correct answer is Bulbil. Bulbils are formed on aerial parts of the parent plant and can detach to grow into new plants. Unlike underground rhizomes or eyes of potato, bulbils develop externally. They are vegetative propagules providing asexual reproduction, preserving genetic traits, and facilitating rapid plant multiplication without the need for seeds.

7. Assertion-Reason Type:
Assertion (A): Eyes of potato, rhizome of ginger, and bulbil of Agave are vegetative propagules.
Reason (R): They develop into new individuals without fertilization.
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: Both Assertion and Reason are correct. Eyes of potato, rhizomes of ginger, and bulbil of Agave are vegetative propagules because they give rise to new plants asexually. The reason explains the assertion accurately, as these structures bypass sexual reproduction and fertilization, allowing rapid multiplication and preservation of parental genetic traits, which is especially useful in agriculture and horticulture.

8. Matching Type:
Match the propagule with its type:
A. Eyes of Potato → (i) Aerial bud
B. Rhizome of Ginger → (ii) Underground stem
C. Bulbil of Agave → (iii) Aerial bulb-like structure
D. Zoospore → (iv) Motile spore
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: Correct matching is A-(i), B-(ii), C-(iii), D-(iv). Eyes of potato are buds on tubers, rhizomes are underground stems, bulbils are aerial bulb-like propagules, and zoospores are motile spores in algae. Vegetative propagules like eyes, rhizomes, and bulbils enable asexual reproduction, whereas zoospores are reproductive but not vegetative, highlighting structural and functional differences.

9. Fill in the Blanks Type:
______ and ______ are examples of vegetative propagules used in agriculture.
1. Zoospore, Buds in Hydra
2. Eyes of Potato, Rhizome of Ginger
3. Zoospore, Bulbil of Agave
4. Buds in Hydra, Rhizome of Ginger
Explanation: The correct answer is Eyes of Potato, Rhizome of Ginger. Both are vegetative propagules, allowing asexual reproduction in plants. They produce new individuals identical to the parent and are widely used in agriculture for rapid, uniform crop propagation. Unlike zoospores or animal buds, these plant structures ensure trait preservation, nutrient storage, and consistent crop yield without sexual reproduction or fertilization.

10. Choose the Correct Statements Type:
Which of the following statements are correct regarding vegetative propagules?
1. Eyes of potato, rhizome, and bulbil are vegetative propagules
2. Zoospore and Hydra buds are vegetative propagules
3. Vegetative propagules reproduce sexually
4. Bulbils develop into new individuals asexually
Explanation: Correct statements are 1 and 4. Eyes of potato, rhizomes, and bulbils are vegetative propagules, reproducing asexually without fertilization. They enable rapid propagation and trait preservation. Zoospores and Hydra buds are asexual reproductive structures but not vegetative propagules. Vegetative propagation is essential in agriculture and horticulture for uniformity, high yield, and fast multiplication of desirable plant varieties.

Topic: Sexual Reproduction
Subtopic: Gametic Fusion Processes

Keyword Definitions:

• Plasmogamy: Fusion of the cytoplasm of two gametes.

• Karyogamy: Fusion of nuclei of gametes after plasmogamy.

• Saprophytes: Organisms obtaining nutrition from dead and decaying matter.

• Heterocyst: Specialized cell in cyanobacteria for nitrogen fixation.

Lead Question - 2021

Which of the following statements is correct?

(1) Fusion of protoplasms between two motile or non-motile gametes is called plasmogamy.
(2) Organisms that depend on living plants are called saprophytes.
(3) Some of the organisms can fix atmospheric nitrogen in specialized cells called sheath cells.
(4) Fusion of two cells is called Karyogamy.

Explanation: The correct answer is option (1) because plasmogamy refers to cytoplasmic fusion of two gametes. Karyogamy specifically denotes nuclear fusion. Saprophytes live on dead matter, not living plants. Nitrogen fixation occurs in heterocysts, not sheath cells. Thus, plasmogamy is the accurate definition here, highlighting the initial stage in sexual reproduction.

Guessed Questions

1) In fungi, after plasmogamy but before karyogamy, the stage is:
(1) Diploid
(2) Dikaryotic
(3) Haploid
(4) Polyploid

Explanation: The correct answer is (2). After plasmogamy, nuclei from different gametes remain unfused, resulting in a dikaryotic stage. This is unique to fungi and persists until karyogamy occurs. It allows genetic variation and adaptation. This prolonged dikaryotic phase helps fungi survive under diverse environmental conditions before nuclear fusion.

2) Karyogamy results in:
(1) Diploid zygote
(2) Haploid gamete
(3) Dikaryon
(4) Spore mother cell

Explanation: The correct answer is (1). Karyogamy refers to the fusion of nuclei from two haploid gametes, forming a diploid zygote. This process is essential for sexual reproduction, leading to recombination and variation. The diploid stage formed undergoes meiosis later to restore haploid conditions in offspring.

3) Which organisms typically possess heterocysts?
(1) Blue-green algae
(2) Green algae
(3) Fungi
(4) Protozoa

Explanation: The correct answer is (1). Heterocysts are thick-walled cells present in cyanobacteria (blue-green algae) like Anabaena and Nostoc. They are specialized for nitrogen fixation, providing anaerobic conditions necessary for nitrogenase activity. These cells ensure survival and growth of cyanobacteria in nitrogen-deficient environments, playing a critical role in the nitrogen cycle.

4) In plants, saprophytes derive nutrition from:
(1) Living hosts
(2) Soil minerals only
(3) Dead and decaying matter
(4) Symbiotic association

Explanation: The correct answer is (3). Saprophytes feed on dead and decaying organic matter by secreting enzymes to decompose it. Examples include fungi like mushrooms. They recycle nutrients back to the ecosystem, making them vital decomposers. Unlike parasites, they do not harm living hosts while obtaining nutrition.

5) The dikaryotic phase is absent in:
(1) Basidiomycetes
(2) Ascomycetes
(3) Algae
(4) Higher fungi

Explanation: The correct answer is (3). Algae typically lack a prolonged dikaryotic phase. In fungi such as basidiomycetes and ascomycetes, the dikaryotic condition is common after plasmogamy, before karyogamy. This stage is absent in algae, which usually follow a simpler life cycle involving gamete fusion directly leading to zygote formation.

6) In sexual reproduction, plasmogamy is followed by:
(1) Syngamy
(2) Karyogamy
(3) Sporulation
(4) Fertilization

Explanation: The correct answer is (2). Plasmogamy is the fusion of gamete cytoplasm, while karyogamy is nuclear fusion. These sequential events complete syngamy or fertilization. Sporulation occurs later in some organisms. Thus, karyogamy follows plasmogamy to produce diploid nuclei that later undergo meiosis for gamete formation.

7) Assertion (A): Plasmogamy occurs before karyogamy in fungi.
Reason (R): Cytoplasmic fusion precedes nuclear fusion.
(1) A and R are true, R explains A
(2) A true, R false
(3) A false, R true
(4) A and R false

Explanation: The correct answer is (1). In fungi, plasmogamy (cytoplasmic fusion) occurs first, followed by karyogamy (nuclear fusion). This sequential process allows a dikaryotic stage in many fungi. The reason correctly explains the assertion. It ensures genetic recombination while maintaining adaptability before nuclear fusion finally occurs.

8) Match the following:

(a) Plasmogamy → (i) Fusion of cytoplasm
(b) Karyogamy → (ii) Fusion of nuclei
(c) Saprophyte → (iii) Nutrition from dead matter
(d) Heterocyst → (iv) Nitrogen fixation

(1) a-i, b-ii, c-iii, d-iv
(2) a-ii, b-i, c-iii, d-iv
(3) a-i, b-iii, c-iv, d-ii
(4) a-iv, b-i, c-ii, d-iii

Explanation: The correct answer is (1). Plasmogamy is cytoplasmic fusion, karyogamy is nuclear fusion, saprophytes feed on dead matter, and heterocysts specialize in nitrogen fixation. Each process or structure plays a vital role in biological cycles, reproduction, or ecosystem balance, reflecting the diversity of adaptations in living organisms.

9) Fill in the blanks: In fungi, __________ occurs first, followed by __________ during sexual reproduction.
(1) Karyogamy, plasmogamy
(2) Plasmogamy, karyogamy
(3) Syngamy, sporulation
(4) Sporulation, syngamy

Explanation: The correct answer is (2). In fungi, plasmogamy (cytoplasmic fusion) occurs first, creating a dikaryotic condition. Later, karyogamy (nuclear fusion) follows to complete fertilization. This unique sequence differentiates fungi from many organisms and allows them to maintain diversity and adaptability across varied ecological niches.

10) Choose the correct statements:
(1) Plasmogamy refers to cytoplasmic fusion.
(2) Karyogamy refers to nuclear fusion.
(3) Saprophytes depend on living hosts.
(4) Heterocysts are meant for nitrogen fixation.

(1) 1, 2, and 4
(2) 1 and 3 only
(3) 2 and 4 only
(4) 1, 2, 3, and 4

Explanation: The correct answer is (1). Plasmogamy involves cytoplasmic fusion, karyogamy involves nuclear fusion, and heterocysts are specialized for nitrogen fixation. Saprophytes feed on dead matter, not living hosts. Thus, statements 1, 2, and 4 are correct, while 3 is incorrect, highlighting differences among reproductive and nutritional strategies.

ii, iii, i, iv
(4) iv, i, ii, iii

Explanation

Topic: Asexual Reproduction
Subtopic: Vegetative Propagation

Keyword Definitions:

• Vegetative Propagation: Type of asexual reproduction using vegetative parts like stem, root, or leaf to form new plants.

• Agave: Xerophytic plant that reproduces vegetatively through bulbils.

• Bulbil: Small, bulb-like structure that develops on the parent plant and gives rise to new plants.

• Rhizome: Underground stem that propagates plants like ginger and turmeric.

• Offset: Short lateral shoot that helps water hyacinth multiply rapidly.

• Eye: Vegetative bud found on potato tubers for propagation.

Lead Question - 2020 (COVID Reexam)

Vegetative propagule in Agave is as:

1. Rhizome
2. Bulbil
3. Offset
4. Eye

Explanation: In Agave, vegetative propagation occurs through bulbils. These are small bulb-like structures that detach and grow into new plants. Rhizome is used by ginger, offset by water hyacinth, and eye in potato. Thus, the propagule in Agave is bulbil. Answer: Option 2.

1. Which plant propagates through rhizome?

1. Potato
2. Ginger
3. Agave
4. Bryophyllum

Explanation: Ginger propagates vegetatively through rhizomes. Rhizomes are underground stems with nodes and buds that grow into new plants. Potato uses eyes, Agave uses bulbils, and Bryophyllum uses leaf buds. Answer: Option 2.

2. In water hyacinth, the mode of vegetative propagation is:

1. Runner
2. Offset
3. Sucker
4. Tuber

Explanation: Water hyacinth propagates through offsets, which are short lateral branches with nodes that develop roots and new plants. This makes it invasive and called the “terror of Bengal.” Answer: Option 2.

3. Vegetative reproduction in potato occurs through:

1. Rhizome
2. Bulbil
3. Eye
4. Offset

Explanation: Potato tubers propagate vegetatively through eyes, which are axillary buds present on tuber surface. These buds sprout to form new plants. Rhizomes and bulbils belong to other plants. Answer: Option 3.

4. Assertion (A): Bryophyllum reproduces vegetatively through leaf buds.
Reason (R): Adventitious buds on leaf margins of Bryophyllum develop into new plants.

1. Both A and R are true, R is correct explanation
2. Both A and R are true, R not correct explanation
3. A true, R false
4. A false, R true

Explanation: Bryophyllum reproduces by leaf buds formed along leaf margins. These buds detach, fall on soil, and develop into new plants. Thus both assertion and reason are true, with reason explaining assertion correctly. Answer: Option 1.

5. Match the following:
Column I    Column II
(a) Agave    (i) Eye
(b) Potato    (ii) Offset
(c) Ginger    (iii) Bulbil
(d) Water hyacinth    (iv) Rhizome

1. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
2. (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
3. (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
4. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

Explanation: Agave uses bulbil, potato uses eye, ginger uses rhizome, and water hyacinth uses offset for vegetative propagation. Correct matching is option 1.

6. Fill in the blank:
________ is known as the “Terror of Bengal” because of rapid propagation.

1. Agave
2. Water hyacinth
3. Bryophyllum
4. Potato

Explanation: Water hyacinth multiplies rapidly by offsets and chokes water bodies, causing oxygen depletion and harming aquatic life. Therefore, it is called the “Terror of Bengal.” Answer: Option 2.

7. Choose the correct statements:
(a) Ginger propagates through rhizomes.
(b) Potato propagates through bulbils.
(c) Agave propagates through bulbils.
(d) Bryophyllum propagates through leaf buds.

1. a, c, d only
2. b and c only
3. a and b only
4. a, b, c and d

Explanation: Ginger propagates through rhizome, Agave through bulbils, and Bryophyllum through leaf buds. Potato does not use bulbils but eyes. Therefore, correct statements are a, c, d. Answer: Option 1.

8. Vegetative reproduction in onion is carried out by:

1. Corm
2. Bulb
3. Rhizome
4. Runner

Explanation: Onion reproduces vegetatively through bulbs, which are underground modified stems surrounded by fleshy scales. They sprout into new plants when favorable. Corm belongs to gladiolus, rhizome to ginger, runner to grass. Answer: Option 2.

9. Which vegetative propagule is used by Eichhornia?

1. Offset
2. Runner
3. Corm
4. Bulbil

Explanation: Eichhornia, also called water hyacinth, propagates vegetatively by offsets. This helps rapid spread in aquatic ecosystems, making it invasive. Answer: Option 1.

10. In which plant are adventitious buds present on leaf margins?

1. Bryophyllum
2. Onion
3. Ginger
4. Agave

Explanation: Bryophyllum leaves have adventitious buds along leaf margins that develop into new plants when detached. This is a unique vegetative propagation method in Bryophyllum. Answer: Option 1.

Topic: Asexual and Sexual Reproduction

Subtopic: Vegetative Propagation

Keyword Definitions:

• Offsets: Small daughter plants produced from the base of parent plants, a form of vegetative propagation.

• Parthenogenesis: Development of an organism from an unfertilized egg.

• Mitotic divisions: Cell divisions that result in two genetically identical daughter cells, important in vegetative growth.

• Parthenocarpy: Development of fruit without fertilization.

• Meiotic divisions: Cell divisions producing gametes with half the chromosome number.

• Vegetative propagation: Asexual reproduction where new plants grow from vegetative parts like stem, root, or leaf.

Lead Question (2018):

Offsets are produced by:

(A) Parthenogenesis

(B) Meiotic divisions

(C) Parthenocarpy

(D) Mitotic divisions

Explanation:

The correct answer is (D) Mitotic divisions. Offsets are produced through mitotic divisions in vegetative parts of plants, creating genetically identical daughter plants. Parthenogenesis and parthenocarpy involve reproduction or fruit formation without fertilization, while meiotic divisions produce gametes, not offsets.

1. Which plant propagates naturally via offsets?

(A) Bryophyllum

(B) Banana

(C) Pistia

(D) Sugarcane

Explanation:

Correct answer is (B) Banana. Banana produces offsets (suckers) from its rhizome through mitotic divisions. These vegetative propagules grow into independent plants identical to the parent.

2. Parthenogenesis leads to:

(A) Fruit formation

(B) Seed formation without fertilization

(C) Vegetative growth

(D) Photosynthesis

Explanation:

Correct answer is (B) Seed formation without fertilization. Parthenogenesis is asexual reproduction where an embryo develops from an unfertilized egg. It does not produce offsets or vegetative propagules.

3. Parthenocarpy is characterized by:

(A) Seedless fruit

(B) Vegetative growth

(C) Formation of offsets

(D) Gamete formation

Explanation:

Correct answer is (A) Seedless fruit. Parthenocarpy is the development of fruits without fertilization, resulting in seedless fruits. It is unrelated to mitotic production of offsets.

4. Mitotic divisions result in:

(A) Genetically identical cells

(B) Halved chromosome number

(C) Fertilization

(D) Seedless fruit

Explanation:

Correct answer is (A) Genetically identical cells. Mitotic divisions produce identical cells, allowing vegetative propagation and formation of offsets in plants.

5. Which method of reproduction produces genetically identical offspring?

(A) Sexual reproduction

(B) Vegetative propagation

(C) Meiosis

(D) Pollination

Explanation:

Correct answer is (B) Vegetative propagation. Offsets are part of vegetative propagation, which relies on mitotic divisions to produce offspring identical to the parent plant.

6. Sugarcane propagates mainly through:

(A) Seeds

(B) Offsets

(C) Buds on stem cuttings

(D) Parthenocarpy

Explanation:

Correct answer is (C) Buds on stem cuttings. Sugarcane propagates via vegetative stem cuttings (suckers or offsets), where mitotic divisions produce new shoots identical to the parent.

7. Assertion-Reason Question:

Assertion (A): Offsets are produced by mitotic divisions.

Reason (R): Mitotic divisions create genetically identical cells for vegetative propagation.

(A) Both A and R true, R explains A

(B) Both A and R true, R does not explain A

(C) A true, R false

(D) A false, R true

Explanation:

Correct answer is (A). Offsets are formed via mitotic divisions. These divisions produce genetically identical cells, enabling vegetative propagation. Both assertion and reason are true, and the reason correctly explains the assertion.

8. Matching Type Question:

Match the plant with its vegetative propagation method:

(i) Bryophyllum – (a) Leaf buds

(ii) Sugarcane – (b) Stem cutting

(iii) Banana – (c) Suckers/Offsets

(iv) Potato – (d) Tubers

(A) i-a, ii-b, iii-c, iv-d

(B) i-b, ii-c, iii-d, iv-a

(C) i-c, ii-a, iii-b, iv-d

(D) i-d, ii-c, iii-a, iv-b

Explanation:

Correct answer is (A). Bryophyllum produces offsets from leaf buds, sugarcane propagates via stem cuttings, banana through suckers/offsets, and potato forms tubers. All involve mitotic divisions producing genetically identical new plants.

9. Fill in the Blanks:

Offsets are produced by ______ divisions, whereas gametes are produced by ______ divisions.

(A) Mitotic, Mitotic

(B) Mitotic, Meiotic

(C) Meiotic, Mitotic

(D) Meiotic, Meiotic

Explanation:

Correct answer is (B) Mitotic, Meiotic. Offsets arise from mitotic divisions in vegetative parts, producing identical cells. Gametes form via meiotic divisions, reducing the chromosome number for sexual reproduction.

10. Choose the correct statements:

(A) Offsets are asexual propagules

(B) Mitotic divisions produce offsets

(C) Parthenogenesis produces offsets

(D) Parthenocarpy produces seedless fruit

Options:

(1) A, B, D

(2) A, C, D

(3) B, C

(4) C, D

Explanation:

Correct answer is (1) A, B, D. Offsets are produced asexually by mitotic divisions. Parthenocarpy results in seedless fruit, while parthenogenesis produces embryos without fertilization but not offsets.

Topic: Asexual Reproduction and Aquatic Plants

Subtopic: Vegetative Propagation and Environmental Effects

Keyword Definitions:

• Clone: Group of genetically identical individuals produced by asexual reproduction.

• Zoospore: Motile, asexual spore with flagella found in algae and fungi.

• Internode: Stem region between two nodes where leaves and buds arise.

• Asexual Reproduction: Reproduction without gamete fusion, producing genetically identical offspring.

• Vegetative Propagation: Formation of new plants from vegetative parts like stems, leaves, or roots.

Lead Question - 2016 (Phase 2):

Which one of the following statements is not correct?

(1) Water hyacinth, growing in the standing water, drains oxygen from water that leads to the death of fishes

(2) Offspring produced by the asexual reproduction are called clone

(3) Microscopic, motile asexual reproductive structures are called zoospores

(4) In potato, banana and ginger, the plantlets arise from the internodes present in the modified stem

Explanation: Statement 4 is incorrect. In potato, banana, and ginger, the plantlets arise from nodes, not internodes, of modified stems. Water hyacinth reduces oxygen causing fish death, asexual reproduction produces clones, and zoospores are motile asexual structures. Correct answer: (4) In potato, banana and ginger, the plantlets arise from the internodes.

1. Single Correct Answer MCQ:

Which part of potato tuber gives rise to new plants?

(1) Node

(2) Internode

(3) Root tip

(4) Leaf base

Explanation: New potato plants arise from buds located at nodes of the tuber called eyes. Internodes do not directly give rise to new plants. Correct answer: (1) Node, crucial for NEET UG asexual reproduction concepts.

2. Single Correct Answer MCQ:

Zoospores are produced by

(1) Sexual reproduction

(2) Asexual reproduction

(3) Vegetative propagation

(4) Grafting

Explanation: Zoospores are motile, flagellated spores formed asexually in algae and fungi. They do not involve sexual fusion. Correct answer: (2) Asexual reproduction, important for NEET UG plant reproduction questions.

3. Single Correct Answer MCQ:

Clones are produced by

(1) Sexual reproduction

(2) Asexual reproduction

(3) Cross-pollination

(4) Fertilization

Explanation: Asexual reproduction produces genetically identical offspring called clones. Sexual reproduction generates genetic variability. Correct answer: (2) Asexual reproduction, essential NEET UG concept for reproduction.

4. Single Correct Answer MCQ:

Water hyacinth negatively affects aquatic life by

(1) Releasing toxins

(2) Draining oxygen from water

(3) Blocking sunlight only

(4) Consuming fish food

Explanation: Dense growth of water hyacinth reduces dissolved oxygen in water, causing hypoxia and fish death. Other effects are secondary. Correct answer: (2) Draining oxygen from water, relevant for NEET UG environmental plant biology.

5. Single Correct Answer MCQ (Clinical-type):

Which vegetative propagation method is used in ginger?

(1) Rhizome

(2) Bulb

(3) Tuber

(4) Runner

Explanation: Ginger propagates vegetatively via rhizomes, which are horizontal underground stems producing new shoots and roots. Correct answer: (1) Rhizome, essential for NEET UG asexual reproduction studies.

6. Single Correct Answer MCQ:

Banana plantlets develop from

(1) Nodes of rhizome

(2) Nodes of corm

(3) Nodes of stem

(4) Leaf lamina

Explanation: Banana plantlets arise from nodes of underground stem (corm). Growth is vegetative and clonal. Correct answer: (3) Nodes of stem, fundamental for NEET UG vegetative propagation.

7. Assertion-Reason MCQ:

Assertion (A): Asexual reproduction produces genetically identical plants.

Reason (R): No fusion of gametes occurs in asexual reproduction.

(1) Both A and R are true and R is correct explanation of A

(2) Both A and R are true but R is not correct explanation of A

(3) A is true but R is false

(4) A is false but R is true

Explanation: Both assertion and reason are correct. Asexual reproduction produces clones because gametes do not fuse, resulting in identical genetic makeup. Correct answer: (1) Both A and R are true and R is correct explanation of A.

8. Matching Type MCQ:

Match plant with its vegetative propagation method:

A. Potato

B. Ginger

C. Banana

D. Onion

1. Bulb

2. Rhizome

3. Node of stem

4. Tuber

Options:

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

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

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

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

Explanation: Potato propagates via tuber, ginger via rhizome, banana via stem nodes, and onion via bulb. Correct answer: (1) A-4, B-2, C-3, D-1, essential for NEET UG vegetative propagation.

9. Fill in the Blanks MCQ:

Offspring produced by asexual reproduction are called ______.

(1) Gametes

(2) Clone

(3) Zygote

(4) Seed

Explanation: Asexual reproduction generates genetically identical offspring called clones, without gamete fusion. Correct answer: (2) Clone, fundamental NEET UG reproduction topic.

10. Choose the Correct Statements MCQ:

Select correct statements:

(1) Zoospores are motile asexual spores

(2) Clones arise from sexual reproduction

(3) Vegetative propagation occurs via modified stems

(4) Water hyacinth reduces oxygen in water

Options:

(1) 1, 3, 4 only

(2) 1 and 2 only

(3) 2, 3, 4 only

(4) All statements are correct

Explanation: Statements 1, 3, and 4 are correct. Zoospores are motile asexual spores; vegetative propagation occurs via modified stems; water hyacinth reduces oxygen. Clones are produced asexually, not sexually. Correct answer: (1) 1, 3, 4 only.

stamen bundles. Gynoecium is female part producing ovules, and calyx consists of sepals, not petals.