Plant Growth Regulators and Development - One Line Questions

1. Which plant hormone is most effective in delaying leaf senescence? — Cytokinin
2. The phenomenon of delayed senescence and enhanced nutrient mobilization in aging leaves is attributed to: — Cytokinin
3. Vernalization is a process that requires a period of cold treatment to induce flowering. Which plant hormone is thought to be involved in mediating this response? — Gibberellin
4. The process of flowering in many plants is regulated by photoreceptors like phytochrome and the hormone: — Florigen (hypothetical hormone)
5. Which plant hormone is involved in the abscission (shedding) of leaves, fruits, and flowers? — Ethylene and Abscisic Acid
6. Which plant hormone is critical for maintaining the totipotency of plant cells and is used in tissue culture to induce cell division and shoot formation? — Cytokinin
7. Which plant hormone is a key regulator of seed dormancy? — Abscisic Acid
8. The opening and closing of stomata are influenced by which plant hormone? — Abscisic Acid
9. Which plant hormone is involved in the ripening of climacteric fruits like bananas and tomatoes? — Ethylene
10. Plant growth regulators are often classified into two main groups: growth promoters and growth inhibitors. Which of the following is primarily a growth inhibitor? — Abscisic Acid
11. The ability of plant cells to divide and differentiate is significantly influenced by the ratio of: — Cytokinin to Auxin
12. Which class of plant hormones is primarily responsible for promoting cell division and expansion? — Cytokinins
13. The process of seed germination is often promoted by which class of plant hormones? — Gibberellins
14. The elongation of internodes in grasses is a well-known effect of: — Gibberellins
15. The phenomenon of delayed flowering in response to photoperiod is regulated by the pigment: — Phytochrome
16. Ethylene is a gaseous plant hormone primarily associated with: — Fruit ripening and senescence
17. The phenomenon of apical dominance, where the terminal bud inhibits the growth of lateral buds, is mainly controlled by which plant hormone? — Auxin
18. Which hormone is synthesized in the root tips and transported upwards to influence shoot growth? — Cytokinin
19. The process by which plants respond to gravity is called gravitropism. The hormone primarily responsible for sensing gravity and mediating the response in shoots and roots is: — Auxin
20. Which plant hormone is essential for the development of fruit set and preventing premature fruit drop? — Gibberellin
21. Which plant hormone promotes the formation of adventitious roots and is used in rooting powders? — Indole-3-butyric acid (IBA)
22. Which plant hormone is synthesized in the shoot apical meristem and transported basipetally to control apical dominance? — Auxin
23. Plant tropisms, such as phototropism and gravitropism, are primarily mediated by: — Auxins
24. The formation of secondary growth (e.g., increase in stem diameter) in woody plants is influenced by: — Cytokinins and auxins
25. Which plant hormone acts as an antagonist to auxins and gibberellins, often inhibiting growth? — Abscisic Acid (ABA)
26. Which hormone is involved in the formation of vascular tissues (xylem and phloem)? — Auxin and Cytokinin
27. Which plant hormone is synthesized in the leaves and transported to other parts of the plant, often promoting dormancy? — Abscisic Acid
28. Gibberellins are known for their role in: — Stem elongation and breaking seed dormancy
29. Which plant growth regulator is widely used commercially to promote flowering in pineapple? — Ethephon
30. Which plant hormone is synthesized in response to environmental stresses like water deficit, salinity, and cold? — Abscisic Acid
31. Which plant growth regulator is used to promote fruit thinning in apples and pears? — Auxin (e.g., NAA)
32. Which hormone is often referred to as the 'stress hormone' of plants due to its role in mediating responses to adverse conditions? — Abscisic Acid
33. Which plant hormone is synthesized in the developing seeds and is involved in maintaining seed dormancy and preventing vivipary? — Abscisic Acid
34. Which hormone promotes lateral bud growth and is often applied along with auxin to induce callus formation in tissue culture? — Cytokinin
35. The phenomenon of short-day plants flowering only when the nights are longer than a critical period is related to the perception of: — Phytochrome and light duration
36. The development of female flowers in cucurbits can be induced by applying: — Ethylene
37. The phenomenon where a plant bends towards a light source is known as: — Phototropism
38. The 'triple response' in etiolated seedlings, characterized by inhibition of stem elongation, swelling of the hypocotyl, and horizontal root growth, is induced by: — High levels of ethylene
39. The development of adventitious roots from stem cuttings is often enhanced by the application of synthetic auxins like: — Indole-3-butyric acid (IBA)
40. Which of the following is a naturally occurring auxin in plants? — Indole-3-butyric acid (IBA)
41. Which of the following is a brassinosteroid, a class of plant hormones known to promote growth and development? — Brassinolic acid
42. The production of ethylene is often increased in response to: — Mechanical stress and wounding
43. The plant hormone indole-3-acetic acid (IAA) is synthesized primarily in: — Root tips and young leaves
44. The growth of plant organs in response to touch or mechanical stimulation is called: — Thigmotropism
45. The process by which plants respond to touch, leading to twining or coiling, is called: — Thigmotropism
46. The growth of roots in response to gravity is known as: — Positive gravitropism
47. The process of photomorphogenesis, the light-mediated development of plants, involves photoreceptors like phytochromes and cryptochromes, and is influenced by: — A balance of auxins and cytokinins
48. What is the role of jasmonates in plant development? — Mediating defense responses against herbivores and pathogens
49. What is the main function of auxins in plant growth? — Promoting root formation and apical dominance
50. What is the primary role of abscisic acid (ABA) during drought stress? — Inducing stomatal closure to conserve water
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