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

Taking two melon cultivars 'DQ122'(Susceptible) and 'DQ21'(Resistance) as materials,the changes of physiological and biochemical indexes including SOD,CAT,POD,PPO,MDA content and electrolytic permeability of two melon seedlings infected by the powdery mildew were studied.The results showed that the resistant cultivar 'DQ21' made SOD activity,CAT activity and MDA content returned to normal levels in basically,and its capacities of self-regulating and returning to normal status were significantly greater than the susceptible 'DQ122'.The susceptible cultivar maintained higher activity of POD than the resistant cultivar;the resistant cultivar maintained higher activity of PPO than the susceptible cultivar.The susceptible cultivar maintained higher electrolytic permeability than the resistant cultivar.