Abstract: Cinnamic acid and vanillin are the allelochemicals commonly existed in eggplant root exudates. With pot culture experiment, the regulation effects of grafting on the cinnamic acid and vanillin in eggplant root exudates were studied, and the results showed that grafting decreased the amount of the two substances, especially of vanillin, in eggplants root system. The maximum reduction amount of cinnamic acid reached 68.96%, and that of vanillin reached 100%. Under the stress of exotic cinnamic acid and vanillin, especially of exotic cinnamic acid, grafting relieved the autotoxicity of the two substances on eggplants. Compared with own-rooted eggplant, grafted eggplant had a higher plant height and a larger stem diameter, its leaf chlorophyll content increased by 5.26%-13.12%, root electric conductivity and MDA content decreased, and root SOD activity enhanced.

Key words: Loess Plateau: subsoiling, soil physical and chemical property, tillage alternation, spring maize, yield