Effect of nano zinc oxide on some growth and physiology parameters of Catharantus roseus

The effects of different concentrations of ZnO nanoparticles on some growth parameters، the amounts of proline and alkaloids and changes in activity of some antioxidant enzymes were investigated. Experiments were performed under controled greenhouse conditions and completely randomized design with three replications. Plants were exposed to different concentrations (2، 4، 5، 10 and 15 mM) of nano zinc oxideand the effect of these concentrations were compared with the plants that used a complete nutrient solution containing zinc Sulfate. Treatment of the plant with concentration of 0 to 2 micromolar caused increased and higher concentrations significantly reduced dry weight as well as root length. The results showed that the antioxidant enzymes activities in the treated plants increased with increasing concentration of nano zinc oxidein the nutrient solution compared to the control plants. As the level of stress was elevated، the amount of proline and total alkaloids also increased. With increasing concentrations of zinc oxide nanoparticles، Zn absorptionraised. Due to this toxicity، plant growth parameters were affected and oxidative stress in plants was induced. To overcome free radical production، plants have increased their antioxidant enzyme activities and proline.