The effect of nitrogen nutrition on growth, primary and secondary metabolits and nitrate reductase enzyme activity of Hyoscyamus pusillusL.

Hyoscyamus is one of the medicinal plants, rich of tropane alkaloids. In this research the effects of nitrate and ammonium on secondary metabolite and other physiological parameters, were investigated. he results indicated that when nitrate and ammonium both were present in nutrient solution and ammonium concentration was lower than nitrate, dry and fresh weight of root and shoot increase but by increasing ammonium concentration, plant growth decrease. R/S ratio and root and shoot soluble carbohydrate, significantly decrease in plants treated with higher ammonium concentration. Shoot and root chlorophyll content and protein content were increased. Assay of nitrate reductase activity (NRA) showed that in presence of low ammonium concentration, as well as nitrate, NRA increased. By increasing of ammonium concentration, it will be decreased. Alkaloid content was increased in both nitrate and ammonium fed plant, on condition that, ammonium concentration was lower than nitrate