摘要

We identified the bioactive flavonoids from the aqueous leachates of Conyza canadensis and investigated their allelopathic potential on the seed germination and seedling growth of two recipient spp. Agrostis stolonifera and Lactuca sativa. In bioassay-directed isolation of phytotoxic constituents in the aqueous leachates of C. canadensis, it was extracted with various organic solvents (n-hexane, chloroform, ethyl acetate and n-butyl alcohol). The ethyl acetate and n-butyl alcohol extracts from the aqueous leachates of C. canadensis inhibited the seed germination and seedling growth of both recipient spp. Agrostis stolonifera and Lactuca sativa. Besides, two flavonoids (luteolin and eriodictyol) were identified from the ethyl acetate and n-butyl alcohol extracts of C. canadensis via HPLC-PDA/ESI-MS2 and spectral characteristics analysis. The luteolin and eriodictyol significantly decreased the seed germination and seedling growth of A. stolonifera and L. sativa at 15.8 mg/L and 20.3 mg/L, respectively. Furthermore, the lueolin at 40 mg/L and eriodictyol at 60 mg/L significantly inhibited the growth of plant pathogenic fungi Rhizoctonia solani. Our results suggested that luteolin and eriodictyol from C. canadensis allelochemicals, may help to suppress the tested organisms.