Mention some physiological changes occuring during senescence.

Explanation

1. Cells undergo changes in structure.
2. Vacuole of the cell acts as lysosome and secretes hydrolytic enzymes.
3. The strach content is decreased in the cells.
4. Photosynthesis is reduced due to loss of chlorophyll accompanied by synthesis and accumulation of anthocyanin pigments, therefore the leaf becomes red.