Effect of coumarin on some biochemical and physiological responses of canola, Hyola 401 cultivar

Some plant phenolics as allelochemicals take part in allelopathy and affect seed germination and seed growth, thereby reduce plant productivity. On the other hand, these allelochemicals maybe used to control pests, plant pathogens and eradication of weeds. In the present study, the effects of different concentrations of coumarin (0, 0.05, 0.5, 5 and 10 Mm) on seed germination, seedling growth, pigments content, activity of catalase and guiacol peroxidase were investigated. Pigments content was measured spectrophotometrically, catalase and guiacol peroxidase activities were determined at 240 and 436 nm. Coumarin reduced seed germination and seedling growth of canola Hyola 401 cultivar. Cholorophyll content was also decreased in the presence of this phenolic compound. Low molecular weight antioxidants, such as carotenoids and anthocyanins, were increased by coumarin. At higher concentrations of coumarin, catalase activity was not decreased significantly. Guaicol peroxidase, an antioxidant enzyme showed a significantly increase in activity in the presence of this phenolic compound. We concluded that this allelochemicals investigation could result in the development of herbicides with less adverse effect on environment and ecosystem. The presence of some phenolic compounds can reduced canola yield therefore, elimination of weeds, containing these compound are very important, from allelopathic point of view, to enhance canola production.