A hormone that prevents senescence In leaves is:

Explanation

Senescence is the aging of individual cells within an organism. The organism itself is still alive and metabolizing energy, but its cells no longer divide to create new cells, which is necessary for growth and repair. Hence, the individual cells remain alive but in a state of dormancy. Cytokinins are plant hormones that influence growth and the stimulation of cell division. Cytokinins also act in conjunction with auxin (another plant hormone) to retard senescence. During leaf senescence, cytokinins reduce sugar accumulation, increase chlorophyll synthesis, and prolong the leaf photosynthetic period.