Effect of Powdery Mildew on Physiological and Biochemical Indexes of Different Melon Varieties

In order to study the effect of melon powdery mildew on physiological indexes different varieties, high resistant variety ‘16-6’, medium ‘04-38’, and highly susceptible ‘15B-42’ were used as materials. The activities antioxidant defense system enzymes, contents of malondialdehyde (MDA), soluble protein chlorophyll, photosynthetic indicators in leaves seedlings assayed after inoculated with 1 d, 3 5 7 d 9 d. results showed that inoculation mildew, except for superoxide dismutase (SOD) activity, enzyme activities, including peroxidase (POD), catalase (CAT), ascorbic acid (APX), phenylalanine ammonialyase (PAL) polyphenol oxidase (PPO) MDA content three varieties a trend first increase then decrease, increment amplitude lines was larger than ; chlorophyll protein, five indicators, net rate (Pn), stomatal conductance (Gs), intercellular CO 2  concentration (Ci), transpiration (Tr) limitation (Ls) decreased , decrement smaller lines.