Question

Which of the following is the only gaseous plant growth regulator?

• A. ABA
• B. Cytokinin
• C. Ethylene
• D. Gibberellin

Hint:

Ethylene is the only gaseous plant growth regulator and plays a crucial role in processes such as fruit ripening and leaf abscission.

Answer 1

The Correct Option is C

Step 1: Understanding plant growth regulators.
Plant growth regulators (PGRs) include various hormones that regulate plant growth. Ethylene is the only gaseous plant growth regulator among the options provided.
Step 2: Analyzing the options.
(1) ABA: Incorrect. Abscisic acid (ABA) is a plant hormone but is not gaseous.
(2) Cytokinin: Incorrect. Cytokinins are plant hormones but are not gaseous.
(3) Ethylene: Correct. Ethylene is a gaseous plant hormone that regulates processes like fruit ripening and stress responses.
(4) Gibberellin: Incorrect. Gibberellins are plant hormones but are not gaseous.
Step 3: Conclusion.
The correct answer is (3) Ethylene, as it is the only gaseous plant growth regulator among the listed options.