Effects of Aqueous Extract from Ageratum conyzoide L. on Seed Germination and Seedling Growth of Two Vegetable Seeds

[Objective] The research aimed to explore the allelopathy of invasive plant——Ageratum conyzoide. L and the influence on crop growth. [Method] The aqueous extracts from Ageratum conyzoide L. with different concentrations on the seed germination and seedling growth of Brassica oleracea L. and Brassica campestris L. were studied by the method of laboratory germination. [Result] Allelopathy of aqueous extracts from Ageratum conyzoide L. could inhibit germination rate,germination index of Brassica oleracea L. and Brassica campestris L. seed,and its effects increased with the increase of extracts concentration. It showed same influencing pattern on root length,bud length,root / shoot rates as seed germination speed,while it stimulated the stem and root fresh weight. In contrast,it had more influence on Brassica oleracea L,and the root was more sensitive to aqueous extracts from Ageratum conyzoide. L than the overground part. [Conclusion] The aqueous extracts from Ageratum conyzoide L. on the seed germination and seedling growth had different degrees of allelopathy.