Question

Which of the following commercial applications of phytohormones are correct?

• a) Auxins are extensively used in agriculture to promote flowering in pineapples.

• b) Ethephon is used for promoting female flowers in cucumber, thereby increasing the yield.

• c) Abscisic acid is of great use in the ripening the fruits like mango, orange pineapple etc

• d) Cytokinins are used for keeping freshness in leafy and green vegetables.

A. a, b and c
B. b, c and d
C. a, c and d
D. a, b and d

Answer 1

Phytohormones are small molecules circulated within cells which influence the plant physiological responses. Phytohormones can affect the main aspects of flowers like flowering, fruit maturation, and senescence. It can regulate cellular activities such as cell division, cell elongation and differentiation, reproduction, and responses to abiotic and biotic stress.

Complete step by step answer:
-Auxin or IAA (indole-3-acetic acid) is a multi-functional phytohormones and is vital not only for plant growth and development of plant parts but also for coordinating plant growth under stress conditions.
-It plays a main part in plant adaptation to salinity stress.
-Ethephon (2-chloroethylphosphonic acid) is one of the commonly used plant growth regulators.
-It is being used on fruits, vegetables, and cereals for promoting pre- and post-harvest ripening.
-Abscisic acid is a stress hormone which is released when the plant is in stress condition but not used for ripening the fruits like mango, orange, pineapple etc.
-It is the most studied phytohormone for its response and distinct role in plant adaptation to abiotic stresses, and is accordingly termed a “stress hormone.”
-Cytokinins are synthesized and are transported to the green parts of the plant via xylem.
-Cytokinins promote shoot formation and prevent protein degradation by inhibiting nuclease and protease formation in foliage and thus delay aging makes the leaves and other parts fleshy.
So, the correct statements are a, b and d, i.e option (D).

Note:
-Plant hormones affect all aspects in the life of a plant, from flowering to fruit setting and maturation, from phototropism to leaf fall. The hormones can either act in their cell of origin or be transported to other portions of the plant body.
-The five major plant hormones are auxins, cytokinins, gibberellins, ethylene, and abscisic acid.