- Which of the following plants shows a short-day photoperiodic response for flowering?
a) Wheat
b) Rice
c) Lettuce
d) Barley
Answer: b) Rice
Explanation:
Rice is a short-day plant, meaning it flowers when the length of the day is shorter than a critical duration. Short-day plants typically bloom in the late summer or fall when the days are shorter.
- Which plant hormone is used to promote rooting in plant cuttings?
a) Cytokinin
b) Auxin
c) Ethylene
d) Gibberellin
Answer: b) Auxin
Explanation:
Auxins, particularly synthetic forms like IBA (Indole-3-butyric acid), are commonly used in horticulture to promote root formation in plant cuttings.
- Which of the following hormones inhibits seed germination and growth during unfavorable conditions?
a) Auxin
b) Abscisic acid
c) Ethylene
d) Cytokinin
Answer: b) Abscisic acid
Explanation:
Abscisic acid (ABA) inhibits seed germination and growth under unfavorable conditions, such as drought, by inducing dormancy and closing stomata to conserve water.
- Which hormone plays a significant role in controlling stomatal closure during drought?
a) Auxin
b) Gibberellin
c) Ethylene
d) Abscisic acid
Answer: d) Abscisic acid
Explanation:
Abscisic acid (ABA) triggers the closing of stomata during drought or water stress, reducing water loss through transpiration and helping the plant conserve water.
- Vernalization is essential for which type of plants?
a) Biennial plants
b) Short-day plants
c) Perennial plants
d) Day-neutral plants
Answer: a) Biennial plants
Explanation:
Vernalization is the exposure of biennial plants (such as winter wheat and cabbage) to cold temperatures to induce flowering in their second year of growth.
- Which hormone is responsible for the initiation of flowering in long-day plants?
a) Ethylene
b) Cytokinin
c) Auxin
d) Gibberellin
Answer: d) Gibberellin
Explanation:
Gibberellins promote flowering in long-day plants by stimulating the growth and elongation of floral stalks, allowing the plants to flower in response to longer daylight hours.
- Which of the following promotes seed germination by stimulating the production of hydrolytic enzymes?
a) Ethylene
b) Gibberellins
c) Cytokinins
d) Auxins
Answer: b) Gibberellins
Explanation:
Gibberellins stimulate the production of hydrolytic enzymes, such as amylase, which break down stored starch into sugars, providing energy for seed germination.
- Which plant hormone is responsible for fruit ripening and also promotes abscission of leaves?
a) Gibberellin
b) Cytokinin
c) Auxin
d) Ethylene
Answer: d) Ethylene
Explanation:
Ethylene is responsible for accelerating fruit ripening and also promotes the abscission of leaves, flowers, and fruits by weakening the cell walls in the abscission zone.
- What is the effect of auxins on apical dominance?
a) Inhibit apical dominance
b) Promote lateral bud growth
c) Promote apical dominance
d) Induce senescence
Answer: c) Promote apical dominance
Explanation:
Auxins promote apical dominance by inhibiting the growth of lateral buds, allowing the apical bud to grow more vigorously and maintain the plant’s vertical growth.
- Which hormone promotes the formation of adventitious roots on cuttings?
a) Cytokinins
b) Ethylene
c) Auxins
d) Gibberellins
Answer: c) Auxins
Explanation:
Auxins are widely used to promote the formation of adventitious roots on plant cuttings, aiding in plant propagation.
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