Study on salt tolerance of different winter wheat genotypes and their physiological mechanism under sterile condition

The seed vigor,seedling biomass,protective enzyme activity and compatible osmolytes as well as Na+ and K+ content of four wheat genotypes seedling under salt stress were studied in vitro.The results indicated that the seed germination and seedling growth were inhibited under the salt stress.The germination rate,single root length,bud length and biomass decreased significantly as the increase of salt concentration,and there were significant differences among genotypes.The biomass of Xiaoyan 6 and NR9405 were significantly greater than Shaan229 and RB6 under salt stress.SOD activity of Xiaoyan and NR9405 increased with the increase of salt concentration.SOD activity of RB6 and Shaan229 increased under the salt concentration of 0～150 mmol/L;however,it decreased sharply under the 200 mmol/L salt concentration.As the increase of salt concentration,the free proline content in four different wheat genotypes increased,and the accumulation in RB6 was significantly higher than others under the 200 mmol/L salt concentration.The Na+ content and Na+/K+ in wheat seedlings rose but K+ content dropped owing to the increase of salt concentration.Overall,Xiaoyan6 and NR9405 were better than Shaan229 and RB6 in salt tolerance.