Effect of dimethoate and UV-B irradiation on the response of antioxidant defense systems in cowpea (Vigna unguiculata L.) seedlings

To understand the effect of pesticide and UV-B on plant non-enzymatic antioxidant system, Vigna unguiculata was exposed to different concentration of dimethoate and UV-B (30 min) alone and in combination. Negative impact on V. unguiculata due to generation of superoxide radical (O-2(center dot-)), hydrogen peroxide (H2O2), electrolyte leakage (EC) and lipid peroxidation (MDA) was observed. Combined exposure to UV-B and dimethoate led to further increase in these parameters. The content of non-enzymatic antioxidants such as proline and flavonoids increased whereas the ascorbic acid content showed a decrease. The results suggested the role of proline and flavonoids in scavenging reactive oxygen species generated due to stress. (C) 2011 Elsevier Inc. All rights reserved.