Abstract: With three wheat varieties (99-1, Chuanmai 45 and Wenmai No. 8) grown in Panax notoginsengproducing region as receptor materials, the allelopathic effects of different concentrations of stem and leaf aqueous extracts, root aqueous extracts, hair root and hair root rotted liquids from P. notoginseng were measured. The results showed that: (1) Stem and leaf aqueous extracts had obvious inhibition on the germination potential, germination rate, germination index, mean germination days, seedling height, root number, the length of longest root, shoot dry weight, root dry weight, ratio of root to shoot, and total dry weight of the tested wheat varieties, while root aqueous extracts inhibited only the length of longest roots. (2) Hair root showed significant inhibitory effects on the wheat cultivars. With the increase of concentration, the inhibition effects increased. (3) With the increase of concentration, hair root rotted liquids showed bidirectional effects of “promotion at low concentration and suppression at high concentration” on Chuanmai 45 and Wenmai No. 8, and inhibitory effects on variety 991. (4) The allelopathic sensitivity of 99-1 and Wenmai No. 8 to P. notoginseng was stronger compared with Chuanmai 45, and thus the latter would be more suitable for rotation with P. notoginseng.

Key words: soil-vegetable system, transfer function, risk threshold, species sensitivity distribution, Cd contamination