[Allelopathic effects of on seed germination and seedling growth of three crops].

Allelopathic effects of at different growth stages on , , and were examined using six parameters of seed germination and seedling growth, including germination rate, germination speed index, germination index, root length, stem length, and biomass. The results showed that the allelopathic effects of leaf extract were stronger than that of stem extract, with the germination index and biomass of reci-pient plants treated by leaf extract being significantly lower than those treated by stem extract. The allelopathic effect of in the withering stage was stronger than that in the vigorous growth stage. There was a significant dose-effect relationship between the concentrations of leaf extract and the allelopathic effects on three different receptor plants. The higher the extract concentration was, the stronger the allelopathic inhibition was. Leaf extract of could completely inhibit all the germination indices of and at the concentrations of 0.075 and 0.10 g·mL, respectively. The inhibition rates of 0.10 g·mL leaf extract on germination rate, germination speed index, and germination index of were 13.8%, 27.2% and 19.3%, respectively. Leaf extract of could completely inhibit all the growth indices of and at the concentrations of 0.05 and 0.10 g·mL, respectively. However, the inhibition rates of 0.10 g·mL leaf extract on root length, stem length, and biomass of were 64.6%, 92.9% and 21.8%, respectively. In summary, according to the comprehensive allelopathy response index (SE) of seed germination and seedling growth, the susceptibility of the three tested species to the extracts of was (Cruciferae) > (Compositae) > (Gramineae).