Plant growth and development - plant hormones auxin gibberellin cytokinin ethylene abscisic acid photoperiodism vernalization - Question Bank

1. The inhibition of lateral bud growth by the terminal bud is known as apical dominance and is primarily mediated by:
A) High levels of Cytokinin and low levels of Auxin
B) Low levels of Cytokinin and high levels of Auxin
C) High levels of Gibberellin
D) High levels of Ethylene
2. Which hormone is synthesized in the developing seeds and plays a role in embryo development and seed dormancy?
A) Gibberellin
B) Auxin
C) Abscisic Acid
D) Cytokinin
3. The term 'phytochrome' is most closely associated with the plant's ability to perceive:
A) Gravity
B) Touch
C) Light quality and quantity
D) Temperature
4. Which plant hormone promotes the formation of female flowers in certain species like cucumber?
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
5. The hormone that counteracts the effect of ABA in breaking seed dormancy is:
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
6. Which of the following is NOT a characteristic of etiolated plants?
A) Elongated internodes
B) Reduced leaf expansion
C) Presence of chlorophyll
D) Pale yellow or white color
7. The phenomenon of flowering in plants like soybeans, which flower irrespective of the day length, indicates they are:
A) Short-day plants
B) Long-day plants
C) Day-neutral plants
D) Obligate short-day plants
8. Which hormone plays a role in the formation of adventitious roots on stem cuttings?
A) Gibberellin
B) Abscisic Acid
C) Ethylene
D) Auxin
9. Which hormone is essential for the formation of vascular tissues (xylem and phloem)?
A) Gibberellin
B) Ethylene
C) Auxin and Cytokinin
D) Abscisic Acid
10. The process of breaking seed dormancy by exposing seeds to cold temperatures is known as:
A) Stratification
B) Vernalization
C) Scarification
D) Gibberellin treatment
11. A plant that flowers in response to a continuous night of 8 hours and a day of 16 hours would be classified as a:
A) Short-day plant
B) Long-day plant
C) Day-neutral plant
D) Intermediate-day plant
12. Ethylene promotes abscission (shedding) of:
A) Roots
B) Mature leaves and flowers
C) Xylem
D) Phloem
13. Which hormone is synthesized primarily in the developing leaves and seeds?
A) Gibberellin
B) Auxin
C) Cytokinin
D) Ethylene
14. The phenomenon where roots grow away from light and shoots grow towards light is called:
A) Geotropism
B) Phototropism
C) Thigmotropism
D) Hydrotropism
15. Which hormone is involved in delaying senescence and maintaining the 'greenness' of leaves?
A) Abscisic Acid
B) Ethylene
C) Cytokinin
D) Gibberellin
16. The process of moving a plant from a cold environment to a warm environment to induce flowering is an example of:
A) Photoperiodism
B) Vernalization
C) Stratification
D) Scarification
17. Which of the following is a critical factor in determining whether a plant is a short-day, long-day, or day-neutral plant?
A) Soil pH
B) Humidity
C) Critical duration of light or darkness
D) Wind speed
18. Ethylene is produced in:
A) Meristematic tissues
B) Developing fruits and senescing leaves
C) Root tips
D) Xylem
19. The concentration of which hormone is high in dormant seeds and buds?
A) Gibberellin
B) Ethylene
C) Cytokinin
D) Abscisic Acid
20. Which hormone promotes bolting (elongation of the internodes) in plants like cabbage?
A) Auxin
B) Cytokinin
C) Gibberellin
D) Ethylene
21. Auxin is synthesized in:
A) Root tips and developing seeds
B) Mature leaves
C) Xylem vessels
D) Phloem sieve tubes
22. What is the primary role of phytochrome in photoperiodism?
A) To absorb light energy for photosynthesis
B) To detect the duration of light and darkness
C) To regulate water potential in cells
D) To synthesize plant hormones
23. Vernalization is a process that ensures flowering occurs:
A) Only after a period of drought
B) Only after experiencing winter conditions
C) Immediately after germination
D) During the summer solstice
24. Photoperiodism plays a crucial role in regulating:
A) Nutrient uptake
B) Flowering time
C) Water absorption
D) Photosynthetic rate
25. Which hormone is often referred to as the 'stress hormone'?
A) Ethylene
B) Auxin
C) Gibberellin
D) Abscisic Acid
26. Cytokinins primarily affect cell division and differentiation in:
A) Roots
B) Stems
C) Meristematic tissues and differentiating tissues
D) Mature leaves
27. The 'triple response' in seedlings, characterized by inhibition of stem elongation, thickening of stem, and horizontal growth, is induced by:
A) Auxin
B) Gibberellin
C) Ethylene
D) Abscisic Acid
28. Which plant hormone can break seed dormancy and promote germination?
A) Abscisic Acid
B) Ethylene
C) Gibberellin
D) Cytokinin
29. The synthesis of Gibberellins occurs mainly in:
A) Root tips and young leaves
B) Mature leaves
C) Flowers
D) Fruits
30. Which hormone is involved in stomatal closure during water stress?
A) Gibberellin
B) Ethylene
C) Abscisic Acid
D) Cytokinin
31. The phenomenon of etiolation in plants grown in darkness is characterized by:
A) Short, sturdy stems and green leaves
B) Long, weak stems, pale color, and unexpanded leaves
C) Rapid flowering
D) Thickened roots
32. Which hormone is synthesized in the root tips and transported upwards?
A) Cytokinin
B) Gibberellin
C) Abscisic Acid
D) Ethylene
33. Which of the following is NOT a function of Auxin?
A) Promotes cell elongation
B) Induces root formation at low concentrations
C) Inhibits lateral bud growth
D) Promotes fruit development
34. The pigment involved in detecting photoperiod is:
A) Carotene
B) Xanthophyll
C) Phytochrome
D) Chlorophyll
35. Day-neutral plants are plants that:
A) Flower only under long-day conditions
B) Flower only under short-day conditions
C) Flower irrespective of the day length
D) Require vernalization to flower
36. Long-day plants are those that flower when:
A) Day length is shorter than a critical period
B) Day length is longer than a critical period
C) Continuous darkness is provided
D) Only artificial light is used
37. Short-day plants are those that flower when:
A) Day length is longer than a critical period
B) Day length is shorter than a critical period
C) Day and night lengths are equal
D) There is no light
38. The process of leaf senescence (aging) is generally promoted by:
A) Auxin
B) Gibberellin
C) Cytokinin
D) Abscisic Acid and Ethylene
39. Which hormone promotes the formation of callus and adventitious roots in tissue culture?
A) Gibberellin
B) Abscisic Acid
C) Cytokinin
D) Auxin
40. The 'foolish seedling' or 'bakanae' disease of rice seedlings is caused by excessive production of which hormone?
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
41. Seed dormancy is often maintained by which plant hormone?
A) Cytokinin
B) Auxin
C) Gibberellin
D) Abscisic Acid
42. Which hormone can be used commercially to promote flowering in pineapple plants?
A) Abscisic Acid
B) Ethylene
C) Auxin
D) Gibberellin
43. The phenomenon of apical dominance, where the terminal bud grows preferentially, is primarily regulated by:
A) Gibberellins
B) Cytokinins
C) Auxins
D) Ethylene
44. Vernalization is a process by which a plant's flowering is promoted by:
A) Exposure to high temperatures
B) Exposure to low temperatures
C) Prolonged darkness
D) Short day length
45. Photoperiodism is the plant's response to:
A) Temperature changes
B) Light duration
C) Water availability
D) Soil nutrient levels
46. Abscisic Acid (ABA) is generally considered a:
A) Growth promoter
B) Stress hormone and inhibitor of growth
C) Hormone involved in flowering
D) Hormone regulating photosynthesis
47. Which gaseous plant hormone is most famous for accelerating fruit ripening?
A) Auxin
B) Gibberellin
C) Ethylene
D) Abscisic Acid
48. Cytokinins are plant hormones that primarily promote:
A) Apical dominance
B) Lateral bud growth and cell division
C) Root initiation
D) Stress response
49. Gibberellins are known for their role in promoting which of the following processes?
A) Fruit ripening
B) Seed dormancy
C) Stem elongation and breaking dormancy
D) Senescence of leaves
50. Which plant hormone is primarily responsible for cell elongation and root formation?
A) Gibberellin
B) Cytokinin
C) Auxin
D) Abscisic Acid