Abstract: Different concentrations of aqueous extracts from Paris polyphylla var. Yunnanensis roots were used for allelopathic study on seed germination and seedling growth of Tagetes patula, Salvia japonica, Trifolium repens, Festuca arundinacea by the laboratory bioassay in order to provide certain scientific basis for reasonable utilization of Paris polyphylla var. Yunnanensis in garden. The results showed that aqueous extracts from Paris polyphylla var. Yunnanensis roots had significant effects on seed germination and seedling growth of four ornamental plants. But the effects of different concentrations of aqueous extracts on four garden plants were quite different. The aqueous extracts from Paris polyphylla var. Yunnanensis roots had inhibitory effects on seed germination and seedling growth of four ornamental plants. And when the concentration of aqueous extracts increased, the inhibition enhanced gradually. On the contrary, lower treatments (≤0.04 g·mL^-1) increased seed germination and seedling growth of Salvia japonica in a degree. The comprehensive sensitivity of the allelopathic effect on the four ornamental plants of aqueous extracts from Paris polyphylla var. Yunnanensis roots was in the order of Tagetes patula>Trifolium repens>Festuca arundinacea>Salvia japonica. The aqueous extracts from Paris polyphylla var. Yunnanensis roots had inhibitory effects on chlorophyll content of four ornamental plants. On the contrary, aqueous extracts at a concentration of 0.02 g·mL^-1 were found to be facilitated to chlorophyll content for Salvia japonica. When the concentration of aqueous extract increased, the activities of superoxide dismutase (SOD) and catalase (CAT) increased at first and decreased later, and peroxidase (POD) activity and malondialdehyde (MDA) content increased. On the contrary, lower treatments (≤0.04 g·mL^-1) increased malondialdehyde content of Salvia japonica in a degree. Therefore, aqueous extracts from Paris polyphylla var. Yunnanensis roots make four plants suffer from oxidative stresses firstly. Then, they show an allelopathic inhibition.

Key words: Paris polyphylla var. Yunnanensis, aqueous extracts of roots, receptor plant, allelopathy