Allelopathic Effect of Aqueous Extracts of Mentha longifolia on Seed Germination of Two Cultivars of barley and a Weed

This research is an attempt to analyze the allelopathic effect of aqueous extracts of Mentha longifolia on germination of two cultivar of barley (Zarjo and Valfajr) and a weed (Portulaca oleracea) experimentally and in a quiet accidentally frame of 5 treatments and 4 replications. The treatments of the experiment included aqueous extract of M. longifolia (in concentrations of 6, 12, 25 and 50 percent) and distilled water (control). The results showed the strong allopathic effect of the extract of M. longifolia on germination of barley and Portulaca oleracea seeds in such a way that the statistical comparison indicates the reduction of germination percentage of seeds in treating the aqueous extracts in comparison with control in the level of 5 percent.