Part 1 — Seed Germination & Basic Concepts

Part 1 — Seed Germination & Basic Concepts

1. Seed germination begins with:
   A. Photosynthesis
   B. Imbibition
   C. Pollination
   D. Fertilization
   Answer: B
   Explanations:

• A: Incorrect. Photosynthesis occurs after germination when leaves develop.

• B: Correct. Imbibition (water uptake) is the first physical step swelling seed tissues.

• C: Incorrect. Pollination is transfer of pollen; precedes seed formation, not germination.

• D: Incorrect. Fertilization happens to form seed; germination is subsequent.

2. The process by which a seedling pushes the seed coat above ground (cotyledons above soil) is called:
   A. Hypogeal germination
   B. Vivipary
   C. Epigeal germination
   D. Scarification
   Answer: C
   Explanations:

• A: Incorrect. Hypogeal: cotyledons remain below ground.

• B: Incorrect. Vivipary: seeds germinate while still on parent plant.

• C: Correct. Epigeal: hypocotyl elongates, lifting cotyledons above soil.

• D: Incorrect. Scarification is breaking seed coat to aid germination, not type.

3. In hypogeal germination:
   A. Cotyledons are pushed above ground
   B. Cotyledons remain below ground
   C. Seedling lacks radicle
   D. Embryo fails to develop
   Answer: B
   Explanations:

• A: Incorrect. That’s epigeal.

• B: Correct. Cotyledons stay underground; epicotyl grows above.

• C: Incorrect. Radicle develops in hypogeal germination.

• D: Incorrect. Embryo develops normally in hypogeal germination.

4. Which enzyme is secreted by aleurone layer under gibberellin influence to mobilize seed reserves?
   A. Nitrate reductase
   B. α-amylase
   C. Rubisco
   D. Lipase
   Answer: B
   Explanations:

• A: Incorrect. Nitrate reductase reduces nitrate; not for starch mobilization.

• B: Correct. α-amylase breaks down starch into sugars during germination.

• C: Incorrect. Rubisco is for photosynthesis, not reserve mobilization.

• D: Incorrect. Lipase acts on fats but aleurone primarily induces α-amylase for starch.

5. Which factor is NOT essential for seed germination?
   A. Oxygen
   B. Water
   C. Light (in all seeds)
   D. Suitable temperature
   Answer: C
   Explanations:

• A: Incorrect. Oxygen required for respiration during germination.

• B: Incorrect. Water is essential for imbibition and metabolic activation.

• C: Correct. Some seeds require light, many do not; light is not universally essential.

• D: Incorrect. Suitable temperature is essential for enzyme activity and germination.

6. Vivipary refers to:
   A. Seed dormancy
   B. Germination on mother plant
   C. Artificial stratification
   D. Formation of seedless fruits
   Answer: B
   Explanations:

• A: Incorrect. Dormancy is opposite of vivipary.

• B: Correct. Vivipary = precocious germination while seed remains attached to parent.

• C: Incorrect. Stratification is cold treatment to break dormancy.

• D: Incorrect. Seedless fruit formation is parthenocarpy.

7. Scarification helps germination by:
   A. Increasing O₂ concentration
   B. Breaking seed dormancy by physical damage to seed coat
   C. Providing nutrients to embryo
   D. Killing pathogens
   Answer: B
   Explanations:

• A: Incorrect. It doesn’t directly raise oxygen concentration.

• B: Correct. Scarification weakens or removes hard seed coats to permit water uptake.

• C: Incorrect. Scarification doesn’t supply nutrients; it facilitates water/oxygen entry.

• D: Incorrect. While reducing pathogens might be incidental, primary role is coat weakening.

8. Which hormone promotes seed dormancy and inhibits germination?
   A. Auxin
   B. Gibberellin
   C. Abscisic acid (ABA)
   D. Ethylene
   Answer: C
   Explanations:

• A: Incorrect. Auxin mainly promotes cell elongation and apical dominance.

• B: Incorrect. Gibberellins promote germination.

• C: Correct. ABA enforces seed dormancy and inhibits premature germination.

• D: Incorrect. Ethylene generally promotes some germination processes; not major dormancy inducer.

9. A seed that germinates immediately after maturity without dormancy is called:
   A. Orthodox seed
   B. Recalcitrant seed
   C. Viviparous seed
   D. Quiescent seed
   Answer: B
   Explanations:

• A: Incorrect. Orthodox seeds tolerate drying and can be stored; often have dormancy.

• B: Correct. Recalcitrant seeds cannot tolerate desiccation and often germinate quickly.

• C: Incorrect. Vivipary = germination on parent; not necessarily immediate after maturity.

• D: Incorrect. Quiescent seed is dormant but viable; not necessarily immediate germination.

10. Imbibition is primarily:
    A. Chemical synthesis of proteins
    B. Absorption of water by dry seed tissues
    C. Mitosis in meristem
    D. Photosynthesis in cotyledons
    Answer: B
    Explanations:

• A: Incorrect. Imbibition is physical water uptake, not synthesis.

• B: Correct. It’s the rapid uptake of water by dry tissues causing swelling.

• C: Incorrect. Mitosis occurs later as growth resumes.

• D: Incorrect. Photosynthesis occurs later, after leaves form.

11. Which of the following facts supports that gibberellin is involved in seed germination?
    A. GA causes fruit ripening.
    B. GA application to dormant cereal seeds stimulates α-amylase in aleurone.
    C. GA inhibits cell elongation.
    D. GA induces stomatal closure.
    Answer: B
    Explanations:

• A: Incorrect. GA is not primarily responsible for fruit ripening.

• B: Correct. GA triggers aleurone cells to synthesize α-amylase, mobilizing starch.

• C: Incorrect. GA promotes cell elongation/expansion.

• D: Incorrect. ABA, not GA, is associated with stomatal closure.

12. Which seed tissue provides nutrients to the embryo in monocots (like wheat)?
    A. Testa
    B. Endosperm
    C. Cotyledon alone
    D. Pericarp
    Answer: B
    Explanations:

• A: Incorrect. Testa is seed coat; protects embryo but doesn’t store major nutrients.

• B: Correct. Endosperm stores starch and is main nutrient source in monocots.

• C: Incorrect. Monocots often have a single cotyledon (scutellum) that transfers reserves from endosperm.

• D: Incorrect. Pericarp is part of fruit, not primary nutrient tissue in seed.

13. Which of the following is a sign of germination completion?
    A. Emergence of plumule and radicle
    B. Production of pollen
    C. Formation of flowers
    D. Leaf senescence
    Answer: A
    Explanations:

• A: Correct. Visible protrusion of radicle/plumule indicates germination has occurred.

• B: Incorrect. Pollen refers to reproduction later in plant life.

• C: Incorrect. Flowering comes much later.

• D: Incorrect. Senescence is aging, not germination marker.

14. Which seed requires light to germinate (photoblastic)?
    A. Rumex (light-requiring)
    B. Bean (generally light-independent)
    C. Orchid (many are tiny and light/germination dependent on fungi)
    D. All seeds equally require light
    Answer: A
    Explanations:

• A: Correct. Many small-seeded species like Rumex are positively photoblastic and need light.

• B: Incorrect. Beans are often indifferent to light for germination.

• C: Incorrect. Orchids require symbiotic fungi; light alone isn’t the main factor.

• D: Incorrect. Light requirement varies by species.

15. Which process is critical for awakening the embryo from dormancy?
    A. Increase in ABA levels
    B. Decrease in GA levels
    C. Decrease in ABA or increase in GA/other favorable signals
    D. Complete drying of the seed
    Answer: C
    Explanations:

• A: Incorrect. ABA maintains dormancy; increase keeps seed dormant.

• B: Incorrect. Decrease in GA would maintain dormancy; GA promotes germination.

• C: Correct. Breaking dormancy usually requires reduced ABA influence and/or increased GA or environmental signals.

• D: Incorrect. Drying generally enforces dormancy, not break it.

16. Which is TRUE about orthodox seeds?
    A. They cannot survive drying
    B. They can be stored at low moisture and temperature
    C. They generally show vivipary
    D. They are always recalcitrant
    Answer: B
    Explanations:

• A: Incorrect. That describes recalcitrant seeds.

• B: Correct. Orthodox seeds tolerate desiccation and storage.

• C: Incorrect. Vivipary is unrelated to orthodox definition.

• D: Incorrect. Recalcitrant is opposite of orthodox.

17. During germination, which respiration type predominates initially?
    A. Photophosphorylation
    B. Anaerobic respiration only
    C. Aerobic respiration (once oxygen available)
    D. No respiration
    Answer: C
    Explanations:

• A: Incorrect. Photophosphorylation is light-dependent ATP synthesis in chloroplasts.

• B: Incorrect. Some anaerobic respiration may transiently occur, but aerobic predominates when oxygen is present.

• C: Correct. Seeds respire aerobically to generate ATP if oxygen is available; anaerobic occurs under low O₂.

• D: Incorrect. Respiration resumes immediately upon imbibition.

18. Which of these treatments can break seed dormancy in many temperate seeds?
    A. Heat shock only
    B. Stratification (cold treatment)
    C. Continuous darkness
    D. High ABA application
    Answer: B
    Explanations:

• A: Incorrect. Heat shock works for some species but not generally for temperate seeds.

• B: Correct. Stratification mimics winter and breaks physiological dormancy in many seeds.

• C: Incorrect. Darkness usually doesn’t break dormancy; some seeds need light.

• D: Incorrect. ABA maintains dormancy, so application enforces dormancy, not break it.

19. The event “radicle emergence through seed coat” is controlled by:
    A. Turgor and enzymatic weakening of tissues
    B. Flower opening
    C. Fruit ripening hormones only
    D. Pollen germination
    Answer: A
    Explanations:

• A: Correct. Cell expansion (turgor) and enzymes that soften tissues enable radicle protrusion.

• B: Incorrect. Flower opening is reproductive, not germination-related.

• C: Incorrect. Fruit ripening hormones don’t directly cause radicle emergence.

• D: Incorrect. Pollen germination is unrelated to seed radicle emergence.

20. Which statement about seed dormancy is correct?
    A. Dormancy and quiescence are synonymous.
    B. Dormancy is active inhibition of germination despite favorable conditions.
    C. Quiescent seeds won’t germinate even in favorable conditions.
    D. Dormancy depends only on seed coat and nothing else.
    Answer: B
    Explanations:

• A: Incorrect. Quiescence is lack of germination due to unfavorable conditions; dormancy is active inhibition.

• B: Correct. Dormant seeds do not germinate even when conditions are favorable until dormancy is broken.

• C: Incorrect. That’s dormancy; quiescence is opposite.

• D: Incorrect. Dormancy can be physiological (hormonal), morphological, or physical; coat is only one factor.

21. Which gas exchange requirement is most critical for seeds during germination?
    A. High CO₂ only
    B. No gas exchange required
    C. O₂ for aerobic respiration
    D. N₂ to synthesize proteins
    Answer: C
    Explanations:

• A: Incorrect. Elevated CO₂ inhibits some processes; not required in excess.

• B: Incorrect. Seeds need oxygen for respiration.

• C: Correct. Oxygen is required for efficient ATP production through aerobic respiration.

• D: Incorrect. Nitrogen is needed for building proteins, but atmospheric N₂ is not directly assimilated by seeds.

22. Which of the following statements is TRUE for seeds showing photo-dormancy?
    A. They require cold to germinate.
    B. They require light for germination.
    C. They germinate only under water.
    D. They require mechanical scarification.
    Answer: B
    Explanations:

• A: Incorrect. Cold requirement is stratification, not photodormancy.

• B: Correct. Photo-dormant seeds are positively photoblastic — need light to germinate.

• C: Incorrect. Water requirement is general; not specific to photo-dormancy.

• D: Incorrect. Scarification is physical; unrelated to photo-dormancy.

23. In cereal grains like barley, which structure releases α-amylase under GA stimulus?
    A. Aleurone layer
    B. Pericarp
    C. Endosperm only produces α-amylase
    D. Seed coat
    Answer: A
    Explanations:

• A: Correct. Aleurone cells respond to GA from embryo and secrete α-amylase into endosperm.

• B: Incorrect. Pericarp is maternal tissue; aleurone is correct.

• C: Incorrect. Endosperm is the site of starch; aleurone is the secretory tissue.

• D: Incorrect. Seed coat doesn’t produce α-amylase.

24. Which one of these is a symptom of vivipary in mangroves?
    A. Seed remains dormant for years
    B. Seed germinates on parent and produces propagule
    C. Seed dries and becomes orthodox
    D. Seed forms an endosperm only
    Answer: B
    Explanations:

• A: Incorrect. Vivipary is opposite (no dormancy).

• B: Correct. Many mangroves exhibit vivipary producing elongated propagules while attached.

• C: Incorrect. Recalcitrant or viviparous seeds don’t dry as orthodox seeds do.

• D: Incorrect. Vivipary is about early germination, not just endosperm formation.

25. Which is the primary energy source during the earliest hours after imbibition?
    A. Photosynthesis in cotyledons
    B. Stored reserves (starch, lipids, proteins)
    C. Atmospheric CO₂ fixation
    D. External organic nutrients only
    Answer: B
    Explanations:

• A: Incorrect. Photosynthesis begins after green tissues form.

• B: Correct. Stored reserves are mobilized to provide ATP and building blocks.

• C: Incorrect. CO₂ fixation (photosynthesis) is not yet functional early on.

• D: Incorrect. External nutrients can help but seeds primarily rely on internal reserves initially.

  ---

  Plant Growth Class 11, Biology Growth Regulators, CBSE Biology Notes, Class 11 NEET MCQs, NCERT Plant Growth, Seed Germination Biology, Differentiation Redifferentiation, Plant Growth NEET Preparation, plant growth and development mcqs for neet, cbse class 11 biology plant growth notes, auxin gibberellin cytokinin neet questions, seed germination class 11 biology mcqs, differentiation and dedifferentiation examples biology, plant growth regulators mcqs for neet ug, conditions of plant growth ncert biology, phases of growth class 11 ncert questions