1. What is the primary function of auxins in plants?
A) Growth promotion
B) Flowering initiation
C) Fruit ripening
D) Leaf senescence
Answer: A) Growth promotion
2. Which of the following is a natural auxin?
A) Gibberellin
B) Cytokinin
C) Indole-3-acetic acid (IAA)
D) Abscisic acid
Answer: C) Indole-3-acetic acid (IAA)
3. Which plant hormone is responsible for the elongation of stems and inhibition of lateral buds?
A) Cytokinins
B) Gibberellins
C) Auxins
D) Abscisic acid
Answer: C) Auxins
4. Which of the following is a characteristic effect of gibberellins on plants?
A) Inhibition of seed germination
B) Promotion of flowering in certain plants
C) Inhibition of stem elongation
D) Induction of dormancy
Answer: B) Promotion of flowering in certain plants
5. Cytokinins are primarily involved in which of the following processes in plants?
A) Promoting root growth
B) Stimulating cell division
C) Inducing fruit ripening
D) Preventing wilting
Answer: B) Stimulating cell division
6. Which of the following hormones is most effective in promoting seed germination?
A) Auxins
B) Gibberellins
C) Cytokinins
D) Abscisic acid
Answer: B) Gibberellins
7. Auxins are produced primarily in which part of the plant?
A) Roots
B) Leaves
C) Shoot tips
D) Flowers
Answer: C) Shoot tips
8. Which hormone regulates the apical dominance in plants?
A) Cytokinins
B) Gibberellins
C) Auxins
D) Ethylene
Answer: C) Auxins
9. Which of the following hormones helps in the prevention of premature leaf abscission?
A) Cytokinins
B) Auxins
C) Abscisic acid
D) Ethylene
Answer: A) Cytokinins
10. What effect do cytokinins have on plant roots?
A) Inhibit root growth
B) Promote lateral root formation
C) Enhance root hair development
D) Induce root dormancy
Answer: B) Promote lateral root formation
11. Gibberellins are known to cause which of the following in plants?
A) Dwarfism
B) Stem elongation
C) Leaf abscission
D) Stomatal closure
Answer: B) Stem elongation
12. Which of the following processes is inhibited by auxins?
A) Germination
B) Lateral bud growth
C) Cell elongation
D) Root formation
Answer: B) Lateral bud growth
13. The production of gibberellins in plants is most commonly associated with which stage of growth?
A) Seed germination
B) Leaf senescence
C) Fruit ripening
D) Flowering
Answer: A) Seed germination
14. Which of the following is true regarding the interaction between cytokinins and auxins?
A) Cytokinins promote root growth, while auxins inhibit it.
B) Cytokinins promote cell division, while auxins promote cell elongation.
C) Cytokinins and auxins work independently.
D) Cytokinins promote leaf abscission, while auxins prevent it.
Answer: B) Cytokinins promote cell division, while auxins promote cell elongation.
15. Which hormone is primarily involved in regulating the response of plants to environmental stress, such as drought?
A) Gibberellins
B) Auxins
C) Cytokinins
D) Abscisic acid
Answer: D) Abscisic acid
16. What is the effect of gibberellins on fruit development?
A) They promote fruit ripening.
B) They inhibit fruit ripening.
C) They promote fruit development and size.
D) They cause fruit abortion.
Answer: C) They promote fruit development and size.
17. Which of the following hormones causes leaf senescence?
A) Gibberellins
B) Cytokinins
C) Auxins
D) Ethylene
Answer: D) Ethylene
18. Which of the following is the primary site of production of gibberellins in plants?
A) Roots
B) Leaves
C) Stem tips
D) Fruits
Answer: C) Stem tips
19. Which of the following hormones is involved in the process of phototropism in plants?
A) Gibberellins
B) Cytokinins
C) Auxins
D) Abscisic acid
Answer: C) Auxins
20. Which of the following hormones is involved in the regulation of stomatal opening and closing?
A) Cytokinins
B) Gibberellins
C) Auxins
D) Abscisic acid
Answer: D) Abscisic acid
21. Which of the following hormones is responsible for the promotion of lateral bud growth?
A) Cytokinins
B) Gibberellins
C) Auxins
D) Abscisic acid
Answer: A) Cytokinins
22. The movement of auxins in plants is typically:
A) Unidirectional
B) Bidirectional
C) Radial
D) Random
Answer: A) Unidirectional
23. Which of the following hormones helps to break seed dormancy?
A) Cytokinins
B) Gibberellins
C) Ethylene
D) Abscisic acid
Answer: B) Gibberellins
24. Which plant hormone plays a key role in controlling the timing of flowering?
A) Cytokinins
B) Auxins
C) Gibberellins
D) Abscisic acid
Answer: C) Gibberellins
25. Which hormone is known to promote the growth of the stem and roots and is primarily active in young tissues?
A) Gibberellins
B) Cytokinins
C) Auxins
D) Abscisic acid
Answer: C) Auxins
26. The primary function of cytokinins in plant growth is to:
A) Inhibit cell division
B) Promote flowering
C) Promote cell division
D) Inhibit seed germination
Answer: C) Promote cell division
27. Which of the following hormones is involved in regulating the plant’s response to water stress?
A) Gibberellins
B) Auxins
C) Cytokinins
D) Abscisic acid
Answer: D) Abscisic acid
28. Which hormone is known for its role in inducing the ripening of fruits?
A) Cytokinins
B) Gibberellins
C) Ethylene
D) Auxins
Answer: C) Ethylene
29. The production of auxins in plants is primarily concentrated in which region?
A) Root tips
B) Leaf tips
C) Shoot tips
D) Flower buds
Answer: C) Shoot tips
30. Which of the following is the primary function of gibberellins in seedless fruit production?
A) Stimulate the formation of seeds
B) Induce fruit ripening
C) Promote fruit size increase
D) Inhibit seed germination
Answer: C) Promote fruit size increase
These MCQs cover the core concepts related to the plant hormones auxins, gibberellins, and cytokinins and their roles in various physiological processes in plants.
