Question

Which among the following hormones is associated with wilting of leaves?
A. Auxin
B. Cytokinin
C. ABA
D. Ethylene

Answer 1

Hint: Phytohormones or plant hormones are the hormones produced by the plants under stressed environmental conditions thus helping the plant to overcome these stressed conditions and continue to function properly. The term wilting stands for the loss of rigidity of the parts of the non-woody plant.

Complete step by step answer:
-Option (A) is incorrect. Auxin is a plant growth-promoting hormone that is known for stem elongation, inhibition of the growth of lateral buds (i.e., promoting apical dominance). It allows cell differentiation and also helps in mediating the tropic movement in plants.
-Option (B) is incorrect. Cytokinin is also a plant growth-promoting hormone that promotes cell division in the roots and shoots of the plants. It also plays a role in the growth of axillary bud, delay of leaf senescence, breaking of seed dormancy, and also promotes the opening of stomata.
-Option (C) is correct. Abscisic acid or ABA is a stress hormone in plants as it is produced by plants under stressed environmental conditions such as drought, salinity, cold tolerance, heat stress, and heavy metal ion stress. This hormone is known for promoting the dormancy of seed and bud, closing of stomata which prevent the wilting of leaves. Thus, ABA is associated with wilting of leaves as it prevents the wilting phenomenon in leaves.
-Option (D) is incorrect. Ethylene is regarded as the multifunctional gaseous phytohormone as it performs the function of regulating the growth and senescence in plants. It promotes the abscission of leaves and flowers and also promotes the ripening of fruits.
Hence, the correct option is (C).

Note: Phytohormones serve the function of promoting plant growth and development. The wilting of leaves is prevented by abscisic acid because these hormones promote the closing of stomata thereby, inhibiting the process of transpiration, and hence water loss is minimum. Thus, leaves do not wilt.