To evaluate glycine betaine (GB) application on dry weight, leaf area, and some osmolyte compounds of cucumber plants under salinity stress a greenhouse experiment was conducted based on a completely randomized design (CRD) as factorial with two factors of salt stress at three levels (0, 50 and 100 mM of NaCl and glycine betaine at three levels (0, 50 and 100 mM). The results indicated that salinity treatments had significant effects on total dry weight and leaf area but exogenously applied GB improved these traits under salinity conditions. A positive growth response due to foliar application with GB was observed in all cucumber plants. The results also showed that soluble sugar, proline, and GB content increased by increasing salinity levels but the application of GB led to a higher amount of these traits. Soluble sugar, proline, and GB increased in saline treatment in comparison with the control treatment. The highest content of these compounds was observed in plants treated by GB under the high level of salinity (100 mM) treatment and the lowest soluble sugar, proline, and GB content were recorded in plants grown under control treatment without GB application. According to the results of this study, it can be concluded that GB application as an organic osmolyte regulator can improve the dry weight, leaf area, osmolyte compounds, and tolerance of cucumber plants to severe conditions.
