Abstract
Many coumarins have been identified from natural sources, especially green plants. These compounds affect many plant activities and can also control growth processes. The effect of coumarin (COU) on germination, early growth, nutrient mobilization, and some physiological parameters of faba bean (Vicia faba L.) was researched. Seeds of faba bean were primed with different concentrations of COU (0.5, 1.0, 2.0, and 4.0 mM) to elucidate the effect on germination and nutrient mobilization. Accordingly, a greenhouse pot experiment was conducted to study the effect of 1.0 mM COU, as a seed priming treatment alone or in combination with foliar application, on the growth parameters, some biochemical constituents from primary and secondary metabolism and phytohormones of faba bean. The impact of COU was more pronounced on growth than germination, and was dependent on concentration and the mode of application. Both COU treatments significantly improved the level of primary and secondary metabolites as well as phytohormones. These data suggest that COU can affect the growth and physiology of faba bean either directly, as an active growth substance, or indirectly by its interaction with the metabolism of phytohormones.