Differential response of antioxidant enzymes to water deficit stress in maize (Zea mays) hybrids during two leaf stage

Experiment was conducted to analyse maize (Zea mays L.) hybrids for antioxidant enzymes and non-enzyme compound at two leaf stages, under normal irrigation (IRR) and water deficit stress (WDS) condition. WDS was induced by withholding irrigation water for three days in seven-day old seedlings grown in pots. The hybrids exhibited wide variability in their antioxidant pools combined with activities of enzymes involved in defence against oxidative stress. The results showed that antioxidant activity was higher in tolerant hybrids than the susceptible hybrids. Superoxide dismutase activity was higher in susceptible hybrids under IRR, whereas it decreased significantly under WDS. On the other hand, peroxidase activity was increased almost two folds in all the tolerant hybrids. Under WDS, glutathione reductase activity increased in all the hybrids except VIVEKHYD-9, whereas the increase was highest, i.e.37.4% in tolerant than the susceptible hybrids. Catalase activity increased 56% in tolerant hybrid, whereas a decrease of about 30% was recorded in susceptible under WDS. Also, ascorbate peroxidase activity increased in tolerant hybrids and decreased in susceptible hybrids under WDS. In response to WDS, glutathione content (GSH) decreased 11% in tolerant while increased 55% in susceptible hybrids. Increase in GSH content was highest (100%) in HQPM-7 followed by NK-6240 (56%). In general, ascorbic acid content increased under WDS in both tolerant and susceptible hybrids, however the increase was higher in tolerant (80%) than susceptible (45%). Among the hybrids, highest increase was recorded in PRAKASH (99%) and lowest in VIVEKHYD-9 (29%), thus PRAKASH seems to be drought tolerant while VIVEKHYD-9 is drought susceptible. Thus status of antioxidant enzymes in maize hybrids could be evaluated with the drought tolerance during different stages of development and growth and could be used in developing climate resilient maize hybrids.