Effects of calcium nitrate on leaf senescence in fruiting nodes and yield and quality of fruits of muskmelon

In order to study the effects of calcium nitrate on the senescence of leave in fruiting nodes and the fruit yield of muskmelon, successive two foliage dressing experiments were conducted and three different spray concentrations of calcium nitrate (10 mmol/L, 20 mmol/L and 30 mmol/L) were tested at the bearingfruit flowering stage. The results show compared with CK, all the three Ca(NO3)2 spray concentrations can delay the decreases of the contents of chlorophyll and soluble protein, increase the activities of antioxidant enzymes and the net photosynthesis rate (Pn), and decrease the MDA content of leaves in the fruiting nodes. Both the plot yield and fruit quality are increased by the sparying ofCa(NO3)2, and the difference is significant between spraying 20 mmol/LCa(NO3)2 and CK. The research indicates that spraying 20 mmol/LCa(NO3)2 can be used to postpone the senescence of leaves in the fruiting nodes and increase the fruit yield and quality.