Impact of cadmium and hydrogen peroxide on ascorbate-glutathione recycling enzymes in barley root

Abstract

We analyse the effect of Cd and H<sub>2</sub>O<sub>2</sub> short-term treatments on the activity of ascorbate-glutathione recycling enzymes in barley root tip. Even a short transient exposure of barley roots to low 15 µmol Cd concentration caused a marked approximately 70% root growth inhibition. Higher Cd concentrations caused root growth cessation during the first 6 h after short-term Cd treatment. Similarly, a marked root growth inhibition was also detected after the short-term exposure of barley seedlings to H<sub>2</sub>O<sub>2</sub>. Our results indicate that root ascorbate pool is more sensitive to Cd treatment than glutathione pool. Rapid activation of dehydroascorbate reductase and monodehydroascorbate reductase is the important component of stress response to the Cd-induced alterations in barley root tips. H<sub>2</sub>O<sub>2</sub> is probably involved in the Cd-induced activation of monodehydroascorbate reductase, but it is not involved in the Cd-induced increase of dehydroascorbate reductase activity.