BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Gibberelline Is a plant hormone known to delay senescence, induce parthenocarpy and break dormancy during germination.

Detailed explanation-2: -This suggests that cytokinin may delay leaf senescence not only as a result of exogenous treatment, but as part of an endogenous developmental program.

Detailed explanation-3: -Cytokinin production slows down the process of senescence. However, accumulation of sugars during senescence, due to the breakdown of accumulated starch or the preferential export of N2 from the leaf, can block the effect of cytokinin, especially in low light.

Detailed explanation-4: -Cytokinin is a plant hormone that delays leaf ageing (senescence). It promotes cell division in the presence of auxin (another type of plant growth hormone).

Detailed explanation-5: -So, the correct answer is ‘Cytokinins’.