Salt tolerance of four proline accumulation variant lines come from diploid grape callus was studied under different concentration of NaCl. The results showed that the NaCl tolerance of four proline accumulation variant lines was high. Under 240 mmol·L -1 NaCl stress, the control line callus didnt grew but four variant line callus could grow well. Under control conditions, contents of the free proline and the soluble proteins in four variant lines were significantly higher than those of control and t...