ICSE Class 9: Pollination and Fertilization – Comprehensive Answer Set

Pollination and Fertilization

Section 1: Association Task

Section 2: Fill in the Blanks

• The process involving the transfer of pollen grains is termed pollination.
• are self-pollination and cross-pollination.
• Self-pollinated flowers do not require being fragrant or visually attractive.
• For effective self-pollination, anthers and stigmas should mature simultaneously.
• Self-pollination does not lead to genetic variations.
• Wind pollination often results in a considerable amount of pollen wastage.

Check 2: True or False

• The intine forms the outer layer of the pollen grain. False
• The zygote develops into an embryo. True
• The ovule eventually forms the fruit. False (It forms the seed)
• Some fruits retain dry sepals after maturation. True

Multiple Choice Questions

1. B) Pollen grain
2. C) Synchronization of stigma and anther maturation
3. B) Autogamy
4. A) Homogamy
5. C) Ornithophily
6. C) Bignonia
7. C) Insect-pollinated
8. C) Tassel
9. A) Pea plants
10. A) Generative nucleus

Very Short Answer Questions

1. Primary Pollinators:
   • Dahlia: Butterflies
   • Maize: Wind
   • Vallisneria: Water
2. Fill in the Blanks:
   • The transfer of pollen grains to the stigma of the same flower is termed autogamy.
   • The difference in maturation times of gynoecium and androecium is known as dichogamy.
   • Vallisneria is a classic example of water-pollinated flowers.
3. Matching:

4. Parts of the Ovary:
   • Seed: Ovule
   • Fruit: Ovary
   • Fruit wall: Ovary wall
5. Single Terms:
   • A flower with both reproductive organs: Bisexual flower
   • The arrangement of flowers on a stem: Inflorescence
   • Pollination where pollen reaches its own stigma: Autogamy
   • Differing maturation times in reproductive parts: Dichogamy
   • Unequal growth of stigma and anthers promoting cross-pollination: Herkogamy
   • Pollination facilitated by insects: Entomophily
   • Pollination facilitated by birds: Ornithophily

Short Answer Questions

1. Definitions:
   • Ornithophily: Pollination facilitated by birds.
   • Elephophily: Pollination facilitated by elephants.
   • Artificial pollination: Manually transferring pollen grains to facilitate fertilization.
2. Explanation of Terms:
   • Pollination is the process of transferring pollen from the anther to the stigma.
   • Herkogamy: Physical barrier preventing self-pollination.
   • Cleistogamy: Pollination that occurs in closed flowers.
   • Emasculation: Removal of stamens to prevent self-pollination.
   • Fertilization: Fusion of male and female gametes.
3. Transformations after Fertilization:
   • Ovules: Develop into seeds.
   • Calyx: May fall off or remain as protective covering.
   • Petals: Usually fall off post-pollination.
   • Stamens: Wither and fall off.
4. Floral Adaptations for Cross-Pollination:
   • Brightly colored petals to attract pollinators.
   • Nectar to lure insects.

Long Answer Questions

1. Differences:
   • Autogamy vs Geitonogamy: Autogamy occurs within the same flower; Geitonogamy occurs between different flowers on the same plant.
   • Homogamy vs Dichogamy: Homogamy is simultaneous maturity of anther and stigma; Dichogamy is asynchronous maturation.
   • Protandry vs Protogyny: Protandry is when the anther matures first; Protogyny is when the stigma matures first.
   • Entomophilous vs Anemophilous flowers: Entomophilous attract insects; Anemophilous rely on wind.
   • Advantages of Self vs Cross-Pollination:
     • Self-pollination ensures seed formation and is energy efficient.
     • Cross-pollination introduces genetic diversity.
2. Benefits of Plant Features:
   • Long, feathery stigma: Captures wind-borne pollen.
   • Brightly colored petals: Attract pollinators.
   • Lightweight, smooth pollen: Easier wind dispersal.
   • Exposed, movable anthers: Facilitates pollen release.
   • Fragrant nectar: Lures insects.
3. Pros and Cons of Cross-Pollination:
   • Pros: Genetic diversity, better adaptability.
   • Cons: Dependence on external agents, more energy required.
4. Role of Pollen Tube:
   • The pollen tube carries the male gamete to the ovule for fertilization.
   • (Illustrative diagram should be provided)

Structured/Application Questions

1. Diagram Analysis:
   • (a) Process: Pollination
   • (b) Term: Cross-pollination
   • (c) Examples: Mango, Hibiscus
   • (d) Advantage: Genetic diversity; Disadvantage: Dependency on external factors.
   • (e) Agents: Wind, insects
2. Pollen Grain Diagram:
   • (a) Labels: Exine, Intine, Germ pore, Generative nucleus, Tube nucleus.
   • (b) Occurs on the stigma; pollen absorbs moisture and germinates.
   • (c) Role of ‘4’ (Generative nucleus): Produces sperm cells.
   • (d) ‘5’ (Tube nucleus) guides the growth of the pollen tube.
3. Fertilization Diagram:
   • (a) Labels: Stigma, Style, Ovary, Ovule, Embryo sac, Egg cell.
   • (b) Ovary develops into fruit; Ovule develops into seed.
   • (c) Synergids help guide the pollen tube to the egg cell.
   • (d) Stigma receives and supports pollen germination.

This comprehensive answer set covers every section of the provided ICSE Class 9 Pollination and Fertilization worksheet.