Question

Which of the following hormones increases the respiration rate during storage?

• A. GA3
• B. Cytokinin
• C. IBA
• D. Ethylene

Hint:

Remember the phrase "one bad apple spoils the bunch." This is because a ripening apple produces ethylene gas, which then triggers the ripening (and increased respiration) in the apples around it.

Answer 1

The Correct Option is D

Step 1: Core Concept:
The question requires identifying the plant hormone that accelerates fruit respiration during storage, a key part of ripening.

Step 2: Elaboration:
Climacteric fruits (e.g., bananas, mangoes, apples) exhibit a significant respiration increase during ripening, known as the "climacteric rise". This rise is driven by ethylene, a plant hormone. Ethylene triggers ripening through signaling, which includes changes in color, softening, and aroma development, all of which use energy produced by respiration. \[\begin{array}{rl} \bullet & \text{GA3 (Gibberellin) and Cytokinin typically delay senescence.} \\ \bullet & \text{IBA (an auxin) mainly promotes root growth.} \\ \bullet & \text{Ethylene is well-known as the "ripening hormone" and directly boosts respiration.} \\ \end{array}\]

Step 3: Conclusion:
Ethylene is the hormone that elevates respiration rates during storage.