Question

Match List I with List II :

List I (Growth Regulator)
A. 2,4-D
B. $GA_3$
C. Kinetin
D. ABA

List II (Function/Effect)
I. Brewing industry
II. Stimulation of stomatal closure
III. Herbicide
IV. Nutrient mobilisation

Choose the correct answer from the options given below :

• A. A-IV, B-III, C-II, D-I
• B. A-I, B-II, C-IV, D-III
• C. A-I, B-IV, C-III, D-II
• D. A-III, B-I, C-IV, D-II

Hint:

Remember the "Stress" link: ABA helps plants "close up" during stress. For $GA_3$, think "G" for "Germination" and "Grain" (malting in brewing).

Answer 1

The Correct Option is D

Plant Growth Regulators (PGRs) are small, simple molecules that exert profound effects on plant physiological processes. Each class of hormone has specific industrial and biological applications:
• 2,4-D (A): 2,4-Dichlorophenoxyacetic acid is a synthetic auxin widely used as a Herbicide (III). It is highly effective in killing broad-leaved (dicotyledonous) weeds while leaving mature monocotyledonous plants unaffected.
• $GA_3$ (B): Gibberellic acid is used in the Brewing industry (I) to speed up the malting process. It stimulates the production of hydrolytic enzymes like $\alpha$-amylase in the aleurone layer of germinating seeds.
• Kinetin (C): This is a type of cytokinin that promotes Nutrient mobilisation (IV). By enhancing the movement of nutrients to different parts of the plant, cytokinins help in delaying leaf senescence (the Richmond-Lang effect).
• ABA (D): Abscisic acid is often called the "stress hormone." It plays a critical role in the Stimulation of stomatal closure (II) during water stress to prevent excessive transpiration.