Question

Match List I with List II:

Choose the correct answer from the options given below:

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

Hint:

Triple response is the classic "signature" of ethylene in lab exams.
$\alpha$-amylase induction is the most common GA bioassay.
Pairing these two usually solves the whole matching grid.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question requires matching major plant hormones (List I) with their most characteristic physiological effects or bioassays (List II).
Detailed Explanation:

• Gibberellins (A - IV):
Gibberellins (GA) are famous for inducing the synthesis of hydrolytic enzymes like $\alpha$-amylase in the aleurone layer of germinating cereal seeds (like barley). This enzyme breaks down starch into sugar for the developing embryo.

• Auxin (B - III):
The primary effect of auxin (IAA) is to promote cell elongation by increasing the plasticity of the cell wall (Acid Growth Hypothesis). This is the basis for its role in phototropism.

• Cytokinin (C - II):
As the name implies, cytokinins are essential cell division factors. They stimulate the process of cytokinesis and are used in tissue culture to induce shoot formation.

• Ethylene (D - I):
Ethylene is a gaseous hormone. Its characteristic effect on etiolated seedlings is the Triple Response: 1. Inhibition of stem elongation, 2. Promotion of lateral swelling (thickening), and 3. Horizontal growth habit.

Step 2: Final Answer:
The correct matching is A-IV, B-III, C-II, D-I, which is Option (A).