Abstract:To investigate the physiological and biochemical mechanisms of ricelow accumulation of cadmium(Cd) in rice, a low Cd accumulation mutant cadL-5 obtained from 500 strains of the Agrobacterium mediated rice T-DNA/Ds insertion mutant pool and wild type Zhonghua 11 as materials were used in this study. The mutant and WT plants were treated with different concentrations of CdCl2 for 10 d and sampling. The contents of proline and H2O2, and the ratios of AsA/DHA, GSH/GSSG and NADPH/NADP+and the corresponding enzyme activities were determined. Along with the increase of the external concentrations of Cd, results showed that the accumulation of Cd and hydrogen peroxide (H2O2) in cadL-5 was lower in the WT, while free proline content on the contrary; The ratios of reduced glutathione and oxidized glutathione, ascorbic acid and dehydrogenation ascorbic acid and reduced nicotinamide adenine dinucleotide phosphate and nicotinamide adenine dinucleotide phosphate in cadL-5 were higher than those in the WT. The activities of ascorbate oxidase, glutathione reductase, dehydroascorbate reductase and monodehydroascorbate reductase in cadL-5 were higher than in the WT. Based on the results, it can be proposed that the resistance of plants to Cd may depend on the oxidation protection system, in which ascorbate-glutathione (AsA-GSH) cycle plays a vital role. The results also shed lights on the future investigation to understand plant resistance to cadmium at the molecular level and provide some information of physiological and biochemical data.