Varietal differences in salt acclimation ability of rice

Soil salinity substantially decreases the productivity in rice (Oryza sativa L.). To elucidate the adaptive responses of salt acclimation, physiological parameters of two rice varieties were evaluated under control and salt stress conditions after acclimation. The results indicated that 50 mM NaCl salinity stress reduced the shoot dry weight in both varieties. However, Vandaran seedlings acclimated with 10 mM NaCl maintained shoot dry weight under 50 mM NaCl salinity stress, whereas acclimation treatment did not enhance the shoot dry weight in Deejiaohualuo. In addition, acclimated Vandaran seedlings maintained better physiological status as determined by enhanced water conservation, improved membrane stability, improved K+ accumulation, lower Na+ concentration, and lower Na+/K+, Na+/Ca2+, Na+/Mg2+ ratios in the leaf tissues compared to non-acclimated seedlings. However, acclimation did not enhance the above-mentioned physiological traits in Deejiaohualuo. Our results suggest that Vandaran possesses better salt acclimation ability as compared to Deejiaohualuo. The present study suggests that the salt acclimation ability of rice relies on the interaction between varieties and their response to acclimation treatment. Na+ exclusion from the shoot may be a key regulation mechanism involved in the salt acclimation process. The acclimation variety would be a better genetic resource to grow in a changing saline environment.