Hydrogen sulfide alleviates chromium stress on cauliflower by restricting its uptake and enhancing antioxidative system.

The present study evaluated the physiological and biochemical mechanisms through which exogenous sodium hydrosulfide (H2 S donor) mitigates chromium (Cr) stress in cauliflower. The different levels of Cr included 0, 10, 100 and 200 µM. Results reported that Cr exposure reduced growth and biomass, chlorophyll (Chl) contents, gas exchange parameters and enzymatic antioxidants. Chromium stress enhanced the production of electrolyte leakage (EL), hydrogen peroxide (H2 O2 ) and malondialdehyde (MDA) contents and increased Cr content in the roots, stem, leaf and flowers. Exogenous H2 S improved the physiological and biochemical attributes of Cr-stressed cauliflower. Hydrogen sulfide decreased Cr content in different parts of Cr-stressed plants, whereas it increased the Chl contents and gas exchange attributes. H2 S reduced the EL, H2 O2 and MDA concentrations, enhancing the antioxidant enzymes activities in Cr-stressed roots and leaves compared to the Cr treatments alone. Collectively, our results provide an insight into the protective role of H2 S in Cr-stressed cauliflower and suggest H2 S as a potential candidate in reducing Cr toxicity in cauliflower and other crops.