Effect of Exogenous Proline on Growth of Salt-Stressed Rice at Tillering Stage

To explore the application value of exogenous proline in agricultural production, the effect of exogenous proline at different concentration (5 mmol/L, 15 mmol/L, 30 mmol/L, 45 mmol/L) on the morphological index, biomass, chlorophyll and antioxidant enzymes of salt-stressed rice were investigated by pot test. The result showed that salt stress significantly reduced the morphological index (e.g. plant height, tillers and number of green leaves per plant) biomass, the content of chlorophyll (Chl a, Chl b and total chlorophyll) and carotenoid. Moreover, the activity of superoxide dismutase (SOD) under salt stress was significantly higher than that in control (P<0.05), while the activity of peroxidase (POD) had no significantly change. However, except the little effect on morphological index, exogenous application of proline mitigated the adverse effects by increasing root fresh weight and dry weight of each part of the plant, improving chlorophyll and carotenoid content, and enhancing the activity of SOD and POD. Application of 30 mM proline proved to be more effective in inducing salt stress tolerance as compared to other levels