Abstract:In order to probe the impact of water extraction from roots of Carya illinoensis for Triticum aestivum L. and Glycine max(L.) Merr, we studied the effects of different levels(0.025, 0.05 and 0.1 g·mL-1) of water extraction from roots of C.illinoensis on the seeds and seedling growth of T.aestivum L. and G.max(L.) Merr with indoor bio-assay. The water extract prominently inhibited the seed germination and seedling growth of T.aestivum L. and G.max(L.) Merr with concentration effect(weak inhibition in low concentration, high inhibition in high concentration). The descending order of inhibition of water extract for germination rate, germination energy, germination index and vigor index of T.aestivum and G.max(L.) Merr were vigor index, germination energy, germination index, germination rate, and vigor index, germination energy, germination rate, germination index, respectively. The descending order of allelopathic effects of water extract on shoot height, root length, fresh weight and dry weight of T.aestivum and G.max(L.) Merr were both root length, shoot height, fresh weight, dry weight. The water extract prominently decreased the seedling root length, but had different impacts on the dry and fresh weight of receptor due to the different species. The order of the synthesis effects of water extraction from roots of C.illinoensis on two crops is T.aestivum L.>G.max(L.) Merr. The activity of SOD in the 7 d seedings was decreased, but the content of MDA, the activity of POD and CAT were increased with the increasing of concentration. Comprehensively, the inhibition of the water extraction from roots of C.illinoensis is higher for T.aestivum L. than for G.max(L.) Merr.