Abstract: This research aimed to provide technical information relevant to the restoration of degraded grassland. We used a petri-dish method to study allelopathic effects of an extract of Stellera chamaejasme on the seed germination and seedling growth of three forage plant species: Medicago sativa, Elymus dahuricus and Agropyron cristatum. It was found that: 1) The germination rate of M. sativa seeds was inhibited in the presence of S. chamaejasme extract. With addition of 125 g·L^-1 of extract germination was deceased by 33.56% compared to CK. However, with the two grass species E. dahuricus and A. cristatum, addition of S. chamaejasme extract at low rates promoted germination, and addition at higher rates was inhibitory. Compared to CK, with addition of 25 g·L^-1 S. chamaejasme extract, the germination rate of the seeds of E. dahuricus was increased by 19.76%, and the germination rate of A. cristatum seeds was increased by 45.91%. 2) The seedling height of M. sativa was increased when exposed to S. chamaejasme extract concentrations ≤50 g·L^-1 and was decreased when exposed to extract concentration ≥75 g·L^-1, while the seedling height of E. dahuricus was increased when the extract concentration was ≤25 g·L^-1, and decreased at concentrations ≥50 g·L^-1. Finally, S. chamaejasme extract had an inhibitory effect on the root length of A. cristatum, with the root length decreased by 78.21% compared to CK. In summary, the seed germination and seedling growth of all three forage plant species tested were inhibited by treatment with S. chamaejasme extract, and the inhibition strength was enhanced with increasing concentration of the extract.

Key words: grassland degradation, allelopathy, Stellera chamaejasme