Effect of Aphid Invasion on Protective Enzyme Activities of Different Watermelon Varieties

Taking 6varieties of watermelon which have different resistance to aphid as materials,the effect of aphid invasion on activities of polyphenol oxidase(PPO),peroxidase(POD),catalase(CAT),superoxide dismutase(SOD)and ascorbate oxidase(AsA-POD)of watermelon were studied using spectrophotometry.The results showed that there was significant difference in activities of PPO,POD,CAT,SOD and AsA-POD in watermelon leaf between the susceptible and the resistant varieties.The activities of PPO,POD,CAT,SOD and AsA-POD of resistant varieties were significantly increased.Then no significant changes were found in PPO,POD,CAT,SOD and AsA-POD activities of susceptible varieties.All the results suggested that PPO,POD,CAT,SOD and AsA-POD activities had relevance with the aphis resistant of watermelon.