PHOTOSYNTHETIC AND BIOCHEMICAL CHANGES OF MELON LEAVES DURING SENESCENCE

Shortage of assimilate supply due to leaf senescence often limits melon yield and quality potential especially for late mature cultivars. We determined the net photosynthetic rates (Pn) and antioxidative enzyme activities in a field experiment with three cultivars to understand the physiological process in leaf senescence under natural condition. The results showed that the Pn decreased rapidly during senescence of melon leaves, along with lowered chlorophyll and soluble protein contents, lowered activities of SOD, CAT and APX, but gradually increased POD activity and MDA content. Difference existed in these proprieties among melon cultivars.