Abstract:Allelopathy is one of the important factors that affect the relationship between forest and grass intercropping species.To explore the possible mechanism of Zanthoxylum bungeanum allelopathic effect,so as to fully understand the interspecies relationship of Zanthoxylum bungeanum forest and grass intercropping,and provide a theoretical basis for agroforestry management and scientific cultivation.The effects of different concentrations(5 g/L,10 g/L,20 g/L,40 g/L) of the extract from Zanthoxylum bungeanum leaves on seed germination,seedling root length and physiology and biochemistry of the tested plant Astragalus sinicus were studied.The results showed that:1) The extract from Zanthoxylum bungeanum leaves had varying degrees of inhibition on the seed germination and seedling root length of Astragalus sinicus,and the strength of the action was generally positively correlated with the concentration(P＜0.05); 2) With the concentration of the extract increased the concentration of the extract superoxide dismutase(SOD) activity in Astragalus sinicus,seedlings was significantly reduced,and catalase(catalase,CAT) and superoxide anion free radical(O2-) activities both decreased first and then increased,malondialdehyde(MDA),proline(proline,Pro) and soluble sugar content increased significantly,while the activity of phenylalanine ammonia-lyase(PAL) increased first and then decreased.According to the above,The extract from Zanthoxylum bungeanum leaves exerts its allelopathic effect mainly by inhibiting the activity of defensive enzymes in Astragalus sinicus and causing damage to its cell structure and function.