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: Understanding the Concept:
The question asks to identify the plant hormone responsible for increasing the rate of respiration in fruits during storage, a process associated with ripening.

Step 2: Detailed Explanation:
In climacteric fruits (like bananas, mangoes, apples), the ripening process is marked by a sharp increase in the rate of respiration, known as the "climacteric rise". This rise is triggered by the plant hormone ethylene. Ethylene acts as a signaling molecule that initiates a cascade of events leading to ripening, including color change, softening, and aroma development, all of which are energy-intensive processes fueled by respiration. \[\begin{array}{rl} \bullet & \text{GA3 (Gibberellin) and Cytokinin are generally known to delay senescence.} \\ \bullet & \text{IBA (an auxin) is primarily used for promoting root growth.} \\ \bullet & \text{Ethylene is famously known as the "ripening hormone" and directly stimulates respiration.} \\ \end{array}\]

Step 3: Final Answer:
Ethylene is the hormone that increases the respiration rate during storage.