Abstract: This research used a bioassay method to evaluate the effects of a range of concentrations (2.5, 5.0, 10.0, 20.0, 40.0 g·L^-1) of extracts of aboveground and underground parts of Vicia villosa on seed germination of four important forage species: Avena sativa, Lolium multiflorum, Medicago sativa and Trifolium repens. The results showed that in the concentration range tested, the V. villosa extracts of aboveground parts significantly inhibited the seed germination of M. sativa and T. repens. The inhibitory effect of T. repens increased with increasing concentration and the germination rate of T. repens seeds reduced by 62.5% compared with the control under the 40 g·L^-1 treatment. The extract of underground parts of V. villosa inhibited the root length of L. multiflorum, M. sativa and T. repens. Among the tested species, the M. sativa root length under 40 g·L^-1 treatment displayed the largest inhibitory effect (64.94%) compared with the control. With respect to the effects of the underground extract on seedling heights, the height of M. sativa seedlings under the 40 g·L^-1 treatment was significantly reduced, compared to the control. In some cases, the extracts reduced the chlorophyll content of L. multiflorum, M. sativa and T. repens. However, for A. sativa, treated with underground extracts at 20 g·L^-1, the chlorophyll content was increased by 144.23% compared to the control. Treatment with the underground extract significantly increased the peroxidase activity of M. sativa and T. repens. Treatment with the aboveground and underground extract of V. villosa enhanced the catalase (CAT) activity of T. repens and decreased the CAT activity of M. sativa.

Key words: Vicia villosa, water extract, forage plant species, seeds germination, allelopathy