Use of tannery effluent for irrigation: an evaluative study on the response of antioxidant defenses in maize (Zea mays)

The present study aimed at studying the effect of tannery effluent, which contained chromium beyond non-permissible limits, on the antioxidant defenses of Zea mays. The seeds were treated with diluted (50%) and undiluted tannery effluent and the alterations in the germination physiology and enzymic antioxidant levels were studied. The seed germination percentage and seedling growth remain unaltered in the treated seeds when compared to the controls. However, the levels of the enzymic antioxidants namely superoxide dismutase, catalase and glutathione peroxidase were significantly elevated. Zymogram analysis confirmed the enhanced activity of catalase in the seeds treated with undiluted effluent. There was also a significant increase in starch and protein content of the treated seeds. In conclusion, irrigation using tannery effluent exerted oxidative stress in maize seeds. Nevertheless, the diluted effluent proved to be less toxic. The study also proved that catalase can be used as a biomarker of chromium-induced oxidative stress.