Allelopatic effect of medicinal plants on emergence uniformity and seedling vigor of weed plants case study: fennel, velvetleaf, bindweed

摘要

In sustainable agricultural strategies there is a world-wide effort to reduce the amount of herbicides used in production by introducing modern biological and ecological methods. Essential oils were reported as inhibitors of seed germination and plant growth. In order to evaluating emergence and stand establishment of weeds as affected by allelopatic effect of fennel extract an experiment was conducted at the Research Station of Islamic Azad University of Tabriz, Iran during 2013. The velvetleaf (Abutilon theophrastii) and field bindweed (Convolvulus arvensis) seeds were obtained from weed institute of Iran, Tehran. Studied treatments were essence concentrations as 100, 200, 300 and 400 ppm. LSD test was used to compare the differences among treatment means. Both weeds studied responded positively and similarly to studied treatments. When pots irrigated with lower dose of essence, time to start emergence, time taken to 50 % of emergence of seedling and mean emergence time were statistically same as control. All the treatments also decreased the coefficient of uniformity of emergence compared with non-treated seeds; however, minimum coefficient of uniformity of emergence was recorded from 300 and 400 ppm essence concentrations. Maximum seedling dry weight (0.49 g.plant-1) was noticed in control (0.96 g.plant-1) followed by 100 ppm treatment (0.90 g.plant-1), and the lowest from treatments of 200, 300 and 400 ppm treatments. The data shows that seedling vigor index can be decreased by essential oil concentrations with the same trend of seedling dry weight. In the present study a further reduction in essential oil concentration from 200 ppm could restrict seedling vigor index significantly. As a conclusion, higher essence concentration of fennel essential oil could be potentially effective in controlling of the weeds studied.