Physiological Responses of Creeping Bentgrass Cultivars to Carbonate, Chloride, and Sulfate Salinity

Abstract

ABSTRACTEvaluation of creeping bentgrass (Agrostis stolonifera L.) salt tolerance often showed inconsistent results. The objective of this study was to investigate the reactions of ‘Seaside II’ and ‘T‐1’ to NaCl, Na2CO3, Na2SO4, and CaCl2, each at concentrations of 0, 25, 75, 125, 175, and 225 mM. Chlorophyll a (Chla) content was the lowest in the CaCl2 treatment followed by Na2CO3 and Na2SO4 and highest in NaCl whereas chlorophyll b (Chlb) content was lowest in Na2CO3 followed by CaCl2 and Na2SO4 and highest in NaCl. Turfgrass visual quality and green density were reduced the most by the Na2CO3 and CaCl2 treatments. Evapotranspiration (ET) decreased in the order of treatments CaCl2, Na2SO4, Na2CO3, and NaCl at 1 wk after treatment (WAT), but at 4 WAT there were no difference among CaCl2, Na2SO4, and Na2CO3. Significant salt type × concentration interaction existed, and the first order or second order coefficient of regression equation ranked the changing rate of physiological parameters differently in different salts. Leaf K+:Na+ ratio was affected differently by salts and a threshold of 1 appeared at different salt concentrations depending on salt types and cultivars. The pH, osmotic potential, and electrical conductivity of salt solutions were confounded making the interpretation of mechanisms of physiological stress difficult. Nevertheless, this study showed that different salts rank creeping bentgrass salt tolerance differently.