Effects of green and chemically synthesized ZnO nanoparticles on Capsicum annuum under drought stress

Abstract

Nanoparticle applications have recently become a popular method due to increase the tolerance levels of plants to environmental stresses. In this study, changes induced by exogenous application of green synthesized and commercially purchased zinc oxide nanoparticles (ZnO NPs) (100, 500, 1000 mg/L) to drought-stressed Capsicum annuum plants were studied through comprehensive morphologic, anatomic, physiological and biochemical analyzes. While drought decreased relative water content (RWC) and leaf water potential (LWP), it increased proline, thiobarbituric acid reactive substances (TBARS) content and antioxidant enzyme activities. Exogenous ZnO NPs increased RWC and LWP but they decreased TBARS and proline contents in drought-stressed plants. Furthermore, the data obtained in this study revealed that the response of the antioxidant enzyme varies depending on the concentration of the nanoparticles and the type of synthesis. However, green synthesized ZnO NPs applications (100 and 500 mg/L) were found to be much more effective in reducing the adverse effects of drought stress than those synthesized chemically. The results of this study indicated that although the response of Capsicum annuum plants to ZnO NPs applications varied according to the type and concentration under drought conditions, nanoparticle applications did not lead to a consistent stress response.