Fluctuation Of Secondary Metabolites Of Castanea Henryi(Skan)Rehd.et Wils.Damaged By Dryocosmus Kuriphilus Yasumatus(Hymenoptera:Cynipidae)

The tests were conducted in 2003~2004 in the forest areas of Wenyang village located in Jian'ou county, Fujian Province. In order to prove up the difference between different varieties, and the mechanism of resistance of Castanea henryi to Dryocosmus kuriphilus Yasumatus, the induced variation of some secondary metabolites in the body of C. henryi, injured by D. kuriphilus, was studied. The main results were summarized as follows:1. Under the conditions of damaged by D. kuriphilus, flavone contents in all the studied varieties showed fluctuation that was in synchronization with the pest phenology while in undamaged plants, the fluctuation of these compounds was independent of the pest phenology. The amount of flavones varied according to the degree of resistance, with higher amounts found in more resistant varieties. Flavone contents of leaves varied reciprocally with those of phloem. Under the condition of pest damage, flavones could be transported from undamaged parts of the plant to the damaged leaves.2. Like the flavones, tannin contents in all the damaged genotypes also fluctuated with the pest phenology while such fluctuations were independent of pest phenology in the undamaged plants. Tannin contents of the leaves declined form April to May and then exhibited a sharp increase with the onset of injury by the early instar pest larvae. The rate of decrease in the first phase was closely related to the degree of resistance in the genotypes. The rate of increase in the second phase (after the onset of injury by the pest) was higher in the highly resistant genotypes but did not differ significantly in the rest of genotypes.3. Phenolic compounds also showed a variation that was in synchronization with the pest activity in the damaged plants. Undamaged plants also exhibited a fluctuation in the amounts of phenolic compounds but such changes did not seem to be related to the pest activity. With the onset of larval damage, the contents of phenolic compounds showed an increase in all the varieties but the rate of increase differed with the degree of resistance.