Effect of rare earth elements on peroxidase activity in tea shoots

Rare earth microelement fertiliser (REMF) can increase the yield and quality of crops and has been widely applied in Chinese agriculture. However, relatively little is known about the physiological effects of rare earth ions. In this study the effects of REMF on the biomass and peroxidase (POD) activity of tea plants were investigated. The possible inductive mechanism of POD was also analysed. The results showed that REMF could promote POD activity in tea shoots and enhance the tea shoot biomass. The POD protein in tea shoots was found to bind rare earth elements, mainly La, Nd and Ce. It was also proved that La^3+ and Nd^3+ increased POD activity in vitro. The POD activity induced by La^3+ and Nd^3+ is possibly related to partial replacement of the metals in POD by La^3+ and Nd^3+.