Resistant Function Of Polyphenol Oxidase Against Ectropis Oblique Prout

Camellia sinensis(L) O. Ktze and larvae of Ectropis obliqua Prout were investigated in the present study. Polyphenol oxidase activity induced by mechanical damage and exogenous application of jasmonic acid was measured by spectrophotometer method. Then, feeding tests were carried out to determine the resistant function of PPO against Ectropis obliqua Prout larvae. The main conclusions are as follows:Results showed that mechanical damage could be significantly induced the increase of the free PPO activity, and the inducement is systmetic. The inducible time in systmetic leaves were shorten than damaged leaves. The activity of free PPO could also be significantly induced by exogenous application of jasmonic acid in different concentrations. There is almost positive linear relationship between PPO activity and jasmonic acid concentrations, which were tested in the present study. Whereas, bound PPO activity could not be indcued by mechanical damage and exogenous application of jasmonic acid .Bioassay results showed that E. obliqua weight of larvae t and survival numbers were decreased with the concentration of JA, which exogenous applied to the tea plants. When E. obliqua larvea were fed with artificial diet mixed with PPO, we found that the larvae's weight, survival numbers, eclosion rate, amount of spawned egg were all decreased with the increase of specific activity of PPO in artificial diet, and larvae stage and pupa period were all prolonged. The same phenomena were found in the second generation as well. In order to verify the impact of PPO on the development of E. obliqua, RGR,RCR,AD,ECI, and ECD was investigated with the PPO activity in 0.6U, then we found that larvae growth slower, body smaller, less eat and less excrement than contro.