Preliminary Study of Allelopathy of Root Aqueous Extracts from Populus tomentosa

We adopted root aqueous extracts from Populus tomentosa of different age( 8 years and 45years) at different concentrations( 0.001,0.020,0.050 and0.100 g·mL-1) to deal with the seed germination and seedling growth of three common agronomic crops( Wheat,Alfalfa,Radish) and Poplar. The results showed that the root aqueous extracts of P. tomentosa of both 8 years and 45 years had negative effects on seeds germination,seedlings and roots growth of Wheat,Alfalfa,Radish and poplar at higher concentration( 0.050 and 0.100 g·mL-1),and the inhibited effects decreased gradually with decreasing concentration of root aqueous extract. Occasionally their effects were not significant at lower concentration and even the root aqueous extracts increased seed germination and seedling growth. However,the root aqueous extract of 45 years had positive effects on the seedling growth of poplar,and had no effects on the seed germination of Wheat. Variables related to seed germination were more susceptible for Alfalfa,Radish than for Wheat and Poplar,while seeding height-related variables more susceptible for Wheat than others,and root height-related variables more susceptible for Poplar. In general,the inhibited effects of root aqueous extracts of 8 years on both seeds germination and seedlings growth of plants tested were more intensive than root aqueous extracts of 45 years. The effects of different age root aqueous extracts on seeds germination and seedlings growth of Wheat and Poplar were significantly different,as well as on seeds germination of Alfalfa.