Physiological and Biochemical Mechanism of Exogenous Spermidine Improving Drought Resistance in Melon Seedlings Under Drought Stress

‘Tiancuiwang’ melon seedlings was used as experimental matireials by nutrient solution culture experiments.The regulation mechanism of 1 mmol· L^-1 spermidine（Spd） on drought resistance of melon seedlings under 20% PEG 6000 osmotic stress was studied,in order to provide reference for the study of polyamines in drought resistance.The results showed that spraying 1mmol·L^-1 Spd under drought stress,activities of SOD,POD and CAT could be significantly increased.The contents of chlorophyll,proline,soluble sugar and soluble protein were improved.The content of MDA was reduced content.It indicated that exogenous Spd treatment could alleviate the damage caused by drought stress and enhance the tolerance of melon seedlings to drought environments.