Growth responses and ion regulation of Agrostis stolonifera L. to trinexapac-ethyl under salinity stress

Plant growth regulators can improve plant growth under environmental stress conditions. Effect of trinexapac-ethyl (TE) on growth response, soluble sugars content (SSc), proline and ion regulation were investigated in creeping bentgrass (Agrostis stolonifera L.) under salinity stress. The four salinity levels were applied at rte of control, 5, 10, and 15 dS/m with NaCl and TE treatments were applied with a hand sprayer on three times, biweekly at rate of 0, 60, 120, and 240 mg/100 m-2. Salinity, significantly increased SSc, proline content, leaf and root Na+, leaf K+, leaf Na/K and root Na/K rates but root K+, root length density and relative water content (RWC) decreased. Also, Foliar application of TE increased RWC, root length density, SSc, proline, leaf and root Na+ and K+ concentration, leaf and root Na/K rates. The results indicate that taking up more of the K+, maintaining a high K+ concentration in the leaves and reducing the Na+ being transferred from the roots to the shoots could be the mechanisms for Na+ and K+ regulation for salinity tolerance in creeping bentgrass.