Suaeda salsa L. seedlings grown in Hoagland nutrient solution were treated with different concentrations of NaCl combined with two levels of K+ (12 μmol/L and 6 mmol/L) to study the K+ nutrition effect on plant growth and leaf tonoplast V H+ ATPase and V H+ PPase activity. Increase of K+ supply in the culture solution markedly increased the fresh weight, dry weight and K+ content of S. salsaplants. Western blot analysis showed that the leaf V H+ ATPase of S. salsa was at least composed of A,B,C,D,E and c subunits, and their expression decreased with the increase of NaCl concentration under K+ starvation （12 μmol/L K+）, but increased under normal K+ application (6 mmol/L K+）. Leaf V H+ PPase molecular weight was about 72.6 kD and its expression increased as NaCl concentration increased under both high or low levels of K+ concentration in nutrient solution. There was a positive correlation between of V H+ ATPase or V H+ PPase activity and the amounts of their expression. Results in this study suggest that K+ nutrition plays an important role in the salt tolerance of S. salsa, and K+ is involved in the regulation of V H+ ATPase or V H+ PPase activity under salt stress.
K+
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