Positive correlation between potassium uptake and salt tolerance in wheat

The aim of our study was to answer whether any positive correlation exists between K+ uptake and salt tolerance in wheat. We carried out a sand-culture experiment with salt-tolerant, DK961 (ST), and salt-sensitive, JN17 (SS), wheat cultivars, where photosynthesis, the K+/Na+ ratio, growth, and the biomass yield were examined. The seeds were exposed for four weeks to six NaCl concentrations (50, 100, 150, 200, 250, and 300 mM), which were embodied in the Hoagland solution. Salinity-induced decrease of K+ or increase in the Na+ content was much smaller in ST than that in SS. The reductions in the light-saturated photosynthetic rate (P (Nmax)) and chlorophyll content caused by salinity were smaller in the ST compared to SS. Stomatal conductance decreased in both cultivars under saline conditions; nevertheless, it was lower in SS than in ST. The antioxidative capacity was higher in ST than that in SS under saline conditions. Significant positive correlations were observed in both cultivars between K+ contents and P (Nmax)/biomass yields. We suggest that higher-affinity K+ uptake might play a key role in higher salt tolerance and it might be a reliable indicator for breeding new species of salt-tolerant wheat.