Abstract: In this study, the technology of inducing mutants by tissue culture was used to establish the screening system of salt-tolerant mutants in rice to provide a new method for obtaining new rice breeding materials. Four japonica rice lines（Nipponbare, C418, C34 and C210）as materials were used to induce rice callus by culturing of N6+2.0 mg/L 2,4-D and four different NaCl concentrations, and to screen rice mutants by differentiation. At the same time, the physiological indexes of regenerated plants were determined. The results showed that with the increase of NaCl concentration, the rate of callus induction and subculture survival among different rice lines showed an overall decline trend, and reached the lowest at 150 mmol/L NaCl, and the rate of callus differentiation also showed the same trend, and was 0% at 150 mmol/L NaCl. By means of physiological index determination in the leaves of regenerated plants, peroxidase（POD）activity showed a significant upward trend, the content of malondialdehyde（MDA）showed a significant downward trend, and the content of proline（Pro）showed a significant upward trend. Therefore, based on the above results, 100 mmol/L NaCl was considered the optimal concentration which was the most beneficial for screening salt-tolerant mutants in rice. The results lay a foundation for the establishment of salt-tolerant mutant induction system in rice.

Key words: rice, tissue culture, salt tolerance, mutant screening