为明确黄芪根瘤象取食胁迫对黄芪叶片主要防御酶活性的影响及对黄芪药效物质的可能影响，以黄芪根瘤象及其寄主膜荚黄芪为试验材料，测定了不同取食诱导时间的苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和多酚氧化酶(PPO)活性变化。结果表明，取食24、48、72 h后，叶片PAL和POD的活性均显著增加；取食24 h后PPO活性达到峰值，然后有所下降。表明黄芪根瘤象的取食胁迫激活了黄芪的化学防御，对黄芪的诱导抗性及次生代谢物质产生一定的影响，现有的黄芪根瘤象防治策略有待于更加科学的评估。

In order to clarify the effects of Sitonasimillimus feeding stress on the activities of main defense enzymes in leaves and the possible effects on the active substances of Astragalus membranaceus， the activities of phenylalanine ammonia-lyase (PAL)， peroxidase(POD)， and polyphenol oxidase(PPO) were measured at different feeding induction timesin the laboratory， by using Sitonasimillimus and its host Astragalus membranaceus as experimental materials. Theresults showed that the activities of PAL and POD in leaves increased significantly after 24， 48， and 72 hours， and the activity of PPO increased to the peak after 24 hours of feeding and then decreased. This study shows that the feeding stress of Sitonasimillimus activates the chemical defense of Astragalus membranaceus and triggers a certain effect on the induced resistance and secondary metabolites of Astragalus membranaceus. The existing prevention and control strategies of Sitonasimillimus need to be evaluated more scientifically.

S567

国家自然科学基金(31760520)。