Abstract :
Allelochemical compounds are known as a phenomenon for ecological control of weeds. in order to investigation of inhibitory potential of six allelochemicals on barnyardgrass (Echinochloa crus-galli L.) germination and seedling parameters an experiment was conducted in factorial arrangement based on completely randomized design . These allelochemicals consist of ferulic acid, m- coumaric acid, p-coumaric acid, vanillic acid, p-hydroxybanzoic acid and cinnamic acid. The results of analysis of variance showed highly significant differences among allelochemicals and concentrations (10-3, 10-4 and 10-5M). Allelochemicals showed high inhibitory activity compared to control. Results indicated that, cinnamic acid had the highest inhibitory activity in terms of root and shoot length, total fresh weight and chlorophyll content (67.93, 25.41, 33.32 and 73.12% respectively). In term of total dry weight, germination rate and germination percentage the highest inhibitory activity was related to m-coumaric acid by 33.75, 55.68 and 41%, respectively. Root elongation was sensitive to allelopathic compounds rather than shoot elongation. Generally, the inhibitory effects of mentioned allelochemicals were increased with increasing of their concentrations from 10-5 to 10-3 M.
