Hydrogen sulfide (H2S) was identified as a novel signalling molecule that plays roles in plant growth and responses to abiotic stresses. However, information regarding its role in cadmium (Cd) detoxification and possible beneficial effects against oxidative damage in garlic plants is lacking. In this study, garlic (Allium sativum) seedlings were grown hydroponically at 0, 10-4, 10-3 and 10-2 M of cadmium chloride (CdCl2) and 0, 200 µM concentrations of sodium hydrosulfide (NaHS). Cadmium stress caused growth inhibition and biomass reduction, which was related to high accumulation of cadmium in roots and shoots, depletion of chlorophyll contents, decrease of photosynthetic parameters and imbalanced in essential elements. These changes were accompanied by increasing activities of superoxide dismutase and ascorbate peroxidase enzymes while catalase enzyme activity decreased. The treatment with H2S ameliorator reduced Cd accumulation in seedling and improved photosynthetic rate of plants. This conclusion was supported by the increase of superoxide dismutase and ascorbate peroxidase activities as well as the balanced to mineral element uptake. Based on the results, it can be concluded that exogenous H2S has a positive effect on reducing Cd oxidative damages by adjusting antioxidant enzyme system and balances in nutrient element uptake, thus proposing H2S as a candidate for managing toxicity of cadmium in garlic plants.
