Effect of different rates of Cd and Cu on growth and chemical composition of spinach

In order to study the effects of different levels of soil available Cu and Cd on growth and chemical composition of spinach, a factorial experiment with completely randomized design and three replications was conducted in greenhouse of Zanjan Agricultural Research Center. In this experiment factorial combinations of five levels of Cu (0, 5, 10, 20 and 40 mg/kg soil) and five levels of Cd (0, 10, 20, 40 and 80 mg/kg soil) were used as 25 treatments using cadmium and copper sulfate to artificially contaminate soil samples.The results of the experiment showed that with increase in available form of soil copper up to 10 mg/kg the fresh and dry weights of plants increased but when the concentration of soil Cu increased to 20 or 40 mg/kg the fresh and dry weights of spinach decreased significantly. Increase in available form of soil cadmium up to 20 mg/kg increased the dry weight of aerial parts in spinach but higher concentrations of this element decreased the spinach biomass significantly. The Cu concentration of leaf increased as the available form of soil Cu increased. Increase in soil available form of Cu up 10 mg/kg increased Cd content of leaf but higher concentrations of soil Cu decreased leaf concentration of Cd significantly. With increase in available form of soil Cu the leaf concentrations of Zn and Mn decreased. The Fe concentration of leaf increased when the concentration of soil Cu increased up to 20 mg/kg but at higher concentrations of soil Cu it decreased significantly. With increase in available form of soil Cd up to 40 mg/kg the Cd content of leaf increased but at higher concentrations of soil Cd the concentration of Cd in leaf decreased significantly. With increase in concentration of soil Cd the leaf concentrations of Cu, Zn, Mn and P decreased but that of Fe increased significantly.