关键词: 白三叶, 狗牙根, 浸提液, 化感作用, GC-MS分析

Abstract: To explore the allelopathic effects of Trifolium repens，and clarify its mechanism and pathway of action on Cynodon dactylon，different parts of Trifolium repens（stem and leaf，root）were used to make up of four concentrations（0，30，60，120 g/L）of their extracts. The indoor bioassay method was used to study the changes in seed germination（germination rate，germination potential，germination index，vitality index）and seedling growth（seedling height，root length，dry and fresh weight）of Cynodon dactylon under different treatments. GC‑MS analysis was conducted on the extracts from different parts to analyze their chemical composition and differences. The results showed that treatment with 30 g/L stem and leaf extract promoted the germination and seedling growth of Cynodon dactylon seeds，while treatment with 120 g/L had an inhibitory effect.Among them，the inhibitory effects on seed germination potential，vitality index，and seedling root length were more significant（p<0.05），with inhibition rates of 85%，81%，and 95%.The root extract treatment also showed a trend of low concentration promotion and high concentration inhibition.The comprehensive effect analysis showed that the allelopathic effect of stem and leaf extract（21.84%）on Cynodon dactylon was stronger than that of root extract（13.92%）.Chemical composition analysis was conducted on the extraction solutions of three parts，revealing a total of six different components.Among them，4‑chlorobutyryl chloride，3，4‑dimethylpyridine，2，4‑dimethylpyridine，and 3‑ethylpyridine were only detected in the leaf extraction solution，while methyl mercaptoacetate and 1，1‑difluoro‑1‑isocyanate were only detected in the stem extraction solution.In conclusion，the release of alkaloids through leaves of Trifolium repens may the main reason that affect the seed germination and growth of Cynodon dactylon.

Key words: Trifolium repens, Cynodon dactylon, Extract, Allelopathy, GC?MS analysis