Abstract: In order to explore allelopathic effects on cultivation of medicinal plants and its mechanism of natural regeneration of forestlands, allelopathy of extract solution of Castanopsis orthacantha on seed germination and seedling growth of Taraxacum mongolicum and Impatiens balsamina was studied. The results showed that seed germination, seedling height, content of chlorophyll of seedling, content of soluble protein of seedling, content of total saccharide of seedling of T. mongolicum and I. balsamina decreased with the increasing concentration of extract solution of C. orthacantha; but MDA content of seedling of T. mongolicum and I. balsamina increased with the increasing concentration of extract solution of C. orthacantha. It was found that allelopathy of extract solution of C. orthacantha on T. mongolicum and I. balsamina occurred with content of chlorophyll and seed germination and seedling growth inhibited and the degree of membrane lipid peroxidation and stress harm strengthened, and the allelopathic effects of extract solution of C. orthacantha on T. mongolicum and I. balsamina increased with higher concentration of extract solution of C. orthacantha. So the research can shed light on cultivation of medicinal plants and man-made regeneration of forestlands.

Key words: allelopathy, Castanopsis orthacantha, Taraxacum mongolicum, Impatiens balsamina