Gaseous plant hormone responsible for fruit ripening is which of the following?

Gaseous plant hormone responsible for fruit ripening is which of the following?

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

Answer: (D)

Ethylene is the gaseous plant hormone that triggers fruit ripening. It is produced by fruit tissues (and other parts of the plant) and increases as ripening begins, initiating a cascade that raises respiration and activates enzymes that soften the fruit and alter color and aroma. Its gaseous nature allows it to diffuse through tissues and even promote further ripening in an autocatalytic way, which is why applying ethylene after harvest can force ripening and why inhibitors can delay it. Other hormones like auxin, cytokinins, and gibberellins influence growth, development, and aging in different ways—auxin mainly drives cell elongation and fruit set, cytokinins promote cell division and delay senescence, and gibberellins promote stem growth and seed germination. They do not serve as the primary gaseous signal that initiates the ripening process, which is why ethylene is the correct answer.

Ethylene is the gaseous plant hormone that triggers fruit ripening. It is produced by fruit tissues (and other parts of the plant) and increases as ripening begins, initiating a cascade that raises respiration and activates enzymes that soften the fruit and alter color and aroma. Its gaseous nature allows it to diffuse through tissues and even promote further ripening in an autocatalytic way, which is why applying ethylene after harvest can force ripening and why inhibitors can delay it.

Other hormones like auxin, cytokinins, and gibberellins influence growth, development, and aging in different ways—auxin mainly drives cell elongation and fruit set, cytokinins promote cell division and delay senescence, and gibberellins promote stem growth and seed germination. They do not serve as the primary gaseous signal that initiates the ripening process, which is why ethylene is the correct answer.