Evaluation of germination characteristics and growth of barley)Hordeum vuIgare (under the allelopathic effects of aqueous extracts of leaves and roots of weed Pipperweed (Lepidium draba L.)

This experiment was conducted to evaluate the effect of aqueous extract from different parts of Pipperweed , namely aerial, underground and mixes of them, on germination and growth of barley seedlings in a randomized complete blocks design with four replications in 2015 and 2017 in the Seed Research Laboratory of Mohaghegh Ardebili University. Treatments included the aqueous extract of Pipperweed, including underground parts, aerial organs and their mixture in equal proportions and at five concentrations of 0 (distilled water as check), 5, 10, 20, 40 and 80% volumetric. Based on the results, different concentrations of aqueous extract of different organs of Pipperweed had a significant effect on germination and seedling growth of barley compared to the control (p>0.01). By increasing the concentration of the Pipperweed extract of the aqueous extract, there were significantly reductions in germination percentage, germination rate, radicle length, coleoptile length and fresh weight of radicle and coleoptile as well as the number of secondary roots. Most reviewed traits in this experiment was observed in the control of treatment and then, on the application of the concentration of 5 percent extracts of various organs of Pipperweed and the lowest amount of the aforementioned traits was obtained at concentration of 80, and 40% different organs extract of Pipperweed. Application of volumetric concentration of 80% of the extract air organs, under ground and mix it, could reduced to zero the amount of all the studied traits. Based on the results of the three-parameter...