Genotypic dependent effect of exogenous glutathione on Cd-induced changes in cadmium and mineral uptake and accumulation in rice seedlings (Oryza sativa)

A hydroponic experiment was performed using Cd-sensitive (cv. Xiushui63) and tolerant (cv. Bing97252) rice cultivars to evaluate the difference in their response to Cd toxicity in the presence of exogenous glutathione (GSH). The results showed that Cd stress (5 and 50 mu mol/l Cd) decreased plant fresh weight, contents of chlorophyll a, b and carotenoids, with Cd-sensitive genotype being more severely affected. Cd significantly decreased concentration and accumulation of Mn in roots/shoots, and Zn in shoots, but increased Cu concentration in roots/shoots. There was a significantly negative correlation between shoot Zn concentrations and shoot/root Cd concentrations, and between root Cd and Mn concentrations. Exogenous GSH significantly alleviated Cd-induced growth inhibition and markedly reduced Cd uptake in both genotypes. In addition, GSH induced a Cd-dose-and genotype-dependent effects on Cd-induced changes in mineral concentration/accumulation and chlorophyll content in rice seedlings. GSH alleviated Cd-induced decrease in root/shoot Zn and Ca concentrations and accumulation of Xiushui 63, while increased root Ca and Mn concentrations in Bing 97252 under 5 mu mol/l Cd stress. In addition, GSH also significantly enhanced chlorophyll a and b contents of Bing 97252 in both 5 and 50 mu mol/l Cd, and Xiushui 63 in 50 mu mol Cd.