Allelopathic effect of Sesamum indicum L. extract on growth parameters, photosynthetic system and proline osmolite in Glycine max (L.) Merrill and Ipomoea sp.

The aim of this study was to investigate the effect of sesame aqueous extract on growth parameters, proline, chlorophyll pigments, and soluble sugars of leaves and roots of soybean and morning-glory (Ipomoea sp.). To this end, an experiment was conducted as a split plot in a randomized complete block design with three replications in the Research Farm of Golestan Agricultural and Natural Resources Research and Education Center. The main plot included 5 different concentrations of sesame extract (0, 2.5, 5, 10, and 10% with surfactant) and the sub-plot included the target plants at two levels (Soybean and Ipomoea sp). Results showed that the effects of different concentrations of sesame on growth parameters such as root length, fresh and dry weight of shoots and roots, and number of leaves of soybeans and Ipomoea sp were significant different while photosynthetic pigments of these two plants were not influenced by the allelopathic effects of sesame crop extract. Based on the obtained data, increasing the concentration of sesame extract led to increases in the amount of soluble sugars in soybean leaves and roots while decreasing this parameter in Ipomoea sp. Also, the amount of proline in the roots and shoots of soybean and Ipomoea plants increased under effect of sesame extract, in which the increase in the proline content of soybean leaves was significant in comparison with Ipomoea plants. Generally, based on the obtained results, the allelopathic effect of aqueous extract of sesame on morphophysiological parameters of Ipomoea sp. weed in this study was more than those in soybeans, and a complementary research on seed and crop yield, may make it possible to suggest application of sesame extract as a natural herbicide in soybean fields.