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 culti-vars 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 |imol/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 |imol/l Cd stress. In addition, GSH also significantly enhanced chlorophyll a and b contents of Bing 97252 in both 5 and 50 |imol/l Cd, and Xiushui 63 in 50 |imol Cd.