Secondary Metabolic Response Of Chinese Tallow(Triadica Sebifera) To Multiple Herbivory

Secondary metabolites of plants have played an important role in plants' defense against the feeding of insects.The feeding of insects can induce plants to produce metabolic defense response,activate the metabolic synthesis network of plants,and then,resist the harm of insects.In recent years,most of the researches on plants' secondary metabolism are limited to single-factor greenhouse control experiments.However,plants in natural states often suffer feeding of a variety of insects at the same time,and how plants' secondary metabolism response to different herbivory is still reminding in unclear.In this paper,the responses of plants' secondary metabolism to different herbivory were studied by field investigation and controlled experiment with Chinese tallow tree as the object of study to explore:(1)How does the secondary metabolism of Tallow tree respond to different herbivory under natural conditions?(2)What changes will be produced in the secondary metabolic response of Tallow trees in the face of simultaneous feeding pressures from a variety of herbivores? In order to solve the two problems,we investigated the secondary metabolism of Tallow in the field.(2)Two experiments including insect feeding laboratory control experiment were carried out to explore.(1)We conducted an extensive field survey to explore the different response of secondary metabolism of tallow tree under natural conditions when it was fed by different above-ground herbivores communities.We found that the secondary metabolic responses of the above-ground and below-ground parts of tallow tree to herbivory were different from each other,and the plants' secondary metabolic responses induced by different feeding types of insects were also different when different above-ground insect communities fed on tallow tree.The secondary metabolic response of tallow tree increased with the increasing of feeding pressure,and the secondary metabolism of tannin components in the leaves of tallow was more sensitive than that in the roots,while that of flavonoids did the opposite.During the survey,the most seriously damage form was the “Chewing scar”,which also made this damage type become the main factor that dominated the changes of tannins in the leaves(with the rate of contribution 8.3%,R2=0.134),and flavonoids in the roots(with the rate of contribution 19.76%,R2=0.230)of tallow tree.(2)It was found that the feeding of Cnidocampa flavescens Walker significantly increased the content of flavonoids and tannins in tallow leaves through the homogenous garden experiment which the feeding of insects was controlled.The herbivory from Bikasha collaris significantly inhibited the concentration of flavonoids in the leaves of tallow tree,and greatly increased the concentration of tannin in the leaves of tallow tree.The concentration of tannin in the leaves of tallow tree was significantly increased,but the concentration of tannin in the roots of tallow tree was not significantly affected by the feeding of Heterapoderopsis bicallosicollis.When different species of herbivores feeding on the same plant simultaneously,the plant secondary metabolism induced by different feeding types of insects was antagonistic to each other.The above results indicate that the above-ground insect community made an important difference on the secondary metabolism of plants' aboveground and below-ground parts,which lays a foundation for the exploring of the mechanism of plant insect resistance and provides a theoretical basis for the management of below-ground pests.