Abstract: Since making full use of salinized soil is one of the important ways to increase grain output, it is of great significance to study exogenous substances to improve salt tolerance of winter wheat. In this study, the effects of proline seed soaking at different concentrations on seed vigor and organic osmolyte contents in seedlings of winter wheat under salt stress were investigated. The results showed that seed soaking with 250 μmol/L proline significantly increased germination energy, germination percentage, germination index, vigor index, seedling height, and root length under 50 mmol/L NaCl stress. Under 90 mmol/L NaCl stress, proline soaking increased the contents of proline, soluble sugar, and soluble protein in winter wheat seedlings, with the 250 μmol/L treatment showing the overall greatest effect. Seed soaking with 350 μmol/L proline significantly increased only the germination index under 50 mmol/L NaCl stress, whereas 450 μmol/L proline showed inhibitory effects on some germination and growth traits. These results indicate that an appropriate concentration of proline, particularly 250 μmol/L, can improve seed germination and seedling growth of winter wheat under low salt stress.

Key words: winter wheat, salt stress, proline, seed vigor, organic osmolyte