Abstract: Taking the seeds of invasive plant Solidago canadensis and native plant Phramites australis from their mono- and co-dominant communities as allelopathic acceptors, this paper analyzed the differences in the seed germination rate and sprout length after treated with five level (12.5, 25, 50, 100, and 200 mg·mL^-1) S. canadensis and P. australis extracts, aimed to understand the allelopathic interactions between the two species. The 1000-grain weight and seed germination rate under distilled water treatment of the two species in co-dominated community were greater than those in mono-dominant community. Low level (12.5 and 25 mg·mL^-1) S. canadensi extracts slightly promoted the seed germination rates of S. canadensis in both mono- and co-dominant communities, but high level (50, 100, and 200 mg·mL^-1) S. canadensi extracts had strong inhibition effect, especially for the S. canadensis in co-dominated community. No significant patterns were observed about the effects of P. australis extract on S. canadensis seed germination. The sprout length of S. canadensis seeds in both mono- and co-dominant communities decreased with increasing level of S. canadensis extract, but decreased in a fluctuation way with increasing level of P. australis extract. After treated with the extracts of P. australis or S. canadensis, the seed germination rate of P. australis in mono-dominant community was significantly greater than that in co-dominant community (P<0.05), but there was no significant difference between these two extracts.

Key words: plant invasion, allelopathy, community restoration, Solidago canadensis, Phragmites australis