Effects of Soil Water Shortages on the Activity of Antioxidant Enzymes and the Contents of Chlorophylls and Proteins in Barley

Abstract

Water is a key factor influencing the yield and quality of crops. Plants mainly adapt to water deficits by biochemical changes and osmotic regulation. In the present study, the activities of catalase (CAT), guaiacol peroxidase (POX), ascorbate peroxidase (APX), superoxide dismutase (SOD) and as well as the levels of protein and chlorophyll were studied at maturity stage of barley (Hordeum vulgare L.) subjected to different soil water levels (without stress, moderate stress and severe stress). The results indicated that drought stress depended on drought intensity, with more severe drought stress creating more serious effects on barley. Water stress induced a decrease in total chlorophyll and total protein contents which was much more marked in severe stress than in moderate stress. The activities of antioxidant enzymes which include CAT, POX and SOD were significantly high in the water-stressed treatments. Furthermore, the activities of POX and SOD enzymes were significantly high in severe stress than in moderate stress. However, the activity of APX did not significantly change in the both of water-stressed levels compared with well-watered conditions. The present study possibly suggestd that antioxidant protection in barley plants under drought conditions could be attributed mainly to SOD and POX.