Hydrogen sulphide ameliorates hexavalent chromium toxicity in two cereal crops: Role of antioxidant enzymes and proline metabolism.

Chromium pollution in soils is a major threat as it reduces crop yields. Hence, researchers seek methods/strategies which could curtail such losses. We report the role of H 2 S in alleviating hexavalent chromium [Cr(VI)] stress in two cereals crops, i.e. wheat and rice seedlings, by estimating various physiological attributes. Cr(VI) reduced shoot and root length in both cereals through increased accumulation of Cr(VI) in root tips and increased in oxidative stress markers, i.e. superoxide radicals (SOR), H 2 O 2 and lipid peroxidation (as MDA equivalent). Supplementation with H 2 S alleviated Cr(VI) toxicity in both cereal crops. Application of H 2 S increased tolerance to Cr(VI) stress by protecting photosynthesis and enhancing activity of antioxidant enzymes, particularly glutathione-S-transferase and content of proline. Rice was more resistant to Cr(VI) than wheat seedlings.