The Insect-resistance And Protective Enzymes Activities Responses Of Morus Alba Induced By Apriona Germari Feeding-infestation Or Exogenous Jasmonic Acid

Morus alba L. is planted widely in China,but which is seriously restricted for plant diseases and insect pests. In order to clarify the insect-resistance mechanism in M. alba induced by Arpiona germari infestation, Experiments were designed based on understanding biological characteristics of M. alba,Arpiona germari and Aprostocetus prolixus. Feeding area of A. germari on different treated branches were measured, and several protective enzymes activities in cortex or leaves from different treated branches were investigated,and the attractiveness of volatiles from different treated branches Aprostocetus prolixus was determined. The concrete results of the research are shown as follow:1. The effects of Apriona germari feeding-infestation on induced-resistance in M. alba were investigated using choice tests. It was demonstrated that the feeding-area of A. germari on M. alba branches 3 days after infested was remarkably smaller than that on the intact branches, but which on the system branches was not significantly different with that on the healthy ones. The attractiveness of M. alba branches 1 day after infestation to Aprostocetus prolixus was significantly higher than that of intact branches. After that, the attractiveness of the infested branches decreased, and the differences in attractiveness to the parasitoid between infested and intact branches disappeared within 3 days.2. The feeding-area of A. germari on M. alba branches 1 day after jasmonic acid (JA) application significantly higher compared with that on intact branches. The attractiveness of the branches 2 days after JA treatment was extremely significantly higher than that of control branches, and the differences in the attractiveness to the parasitoid between JA treated and control branches were not significant 3 d after JA application. Neither infestation nor JA application affected the number of A. germari eggs laid on the branches. All data showed that feeding-infestation or exogenous JA application can induce the direct defense against herbivore, which was only limited to the infested branch, by reducing the feeding-area of A. germari on M. alba branches and indirect defense by enhancing the attractiveness to A. prolixus.3. The activities of LOX in cortex and leaves on the branches 8 or 48 hours after feeding-damaged by A. germari was remarkably higher than that on the intact branches, but the LOX activities on the system branches were remarkably higher only 8 hours after feeding-damaged. The temporal changes of LOX were consistent with that of direct or indirect defensive responses of M. alba to A. germari infestation experiment. It was shown that LOX was an important protective enzyme in the induced resistance of M. alba in response to A. germari infestation, but the activities of POD and CAT were not involved with the induced-resistance of M. alba.4. The LOX activities in cortex of the branches were significantly higher than that the intact branches and there was no significant differences between branches treated by water and intact branches 8 h or 48 h after treated by JA 8 h after treatment. The LOX activities in leaves of the branches treated by JA were not significantly different with those of branches treated by water or intact branches in 48 hours after treatment. The POD or CAT activities of cortex or leaves of the branches treated by JA were not signicantly different with those of branches treated by water or intact branches 48 h after treatment, except that the POD activities in the leaves of branches treated by JA were higher than that of intact branches 24 h after treatment. It was demonstrated that JA may be one of signal molecular inducing insect-resistance in M. alba.