Phytotoxicity of Plant Materials on Seed Germination of Crownvetch, Coronilla varia L.1

Abstract

AbstractPhytotoxic potential of six crop and four weed species was determined on crownvetch. Water extracts of Virginia pepperweed, evening primrose, crabgrass, and crownvetch were most toxic to seed germination. Tall fescue and weeping lovegrass were least toxic. Extracts from aerial portions were more inhibitory than those from roots. Crown vetch was less tolerant of high osmotic pressure than was crimson clover, but this did not explain the strong inhibition of the former species by certain plant extracts. Pepperweed residues incorporated into soil for 10 weeks were toxic to crownvetch seed germination. Kobe lespedeza residues incorporated into soil did not affect percent germination but decreased seedling growth.Pepperweed extract inhibited seed germination of tall fescue, ball clover, sericea, and Kobe lespedeza. It was toxic to crownvetch at a dilute concentration of 1:150 (w/v). The toxic substance occurred in all parts of the plant and was not affected by drying temperature. Pepperweed extract was toxic to five fungi. The phyto‐ and fungitoxicity of pepperweed may be of significance in competition with other plant species.