Effects of drought stress and rewatering on antioxidant systems and relative water content in different growth stages of maize (Zea mays L.) hybrids

Drought is a problem of the expanding universe which seriously influences crop production and quality. Approximately one-third of the cultivated area of the world suffers from constantly inadequate supplies of water. The present study aimed to determine the effects of drought and rewatering on activities of antioxidant enzymes, chlorophyll, proline, and relative water contents (RWC). In this experiment, six maize hybrids (Sc260, Sc370, Sc500, Sc647, Sc700, and Sc704) were examined in a pot study during the maize-growing season of 2011. Results indicated that the growth of hybrids was retarded under drought stress conditions and regained growth speed during rewatering. RWC, chlorophyll, and carotenoid contents were markedly decreased by the water deficit and reached normal values during rewatering in Sc647, Sc704, and Sc700. Our findings also indicated significantly higher activity levels of peroxidase and catalase and proline content in water-stressed plants than in well-watered plants, which decreased when the plants were rewatered, showing an inverse relationship to gluthatione reductase activity. According to the results, the better upregulation of the protective mechanism in Sc704 and Sc647 probably induced higher drought resistance. We concluded that antioxidant enzyme activity could provide a useful tool for depicting drought tolerance in maize hybrids in arid and semiarid regions.