Abstract: The effects of salicylic acid（SA）on the content of Na+，K+，Ca 2+ and Mg 2+ and activities of plasma membrane H+-ATPase，tonoplast H+-ATPase and H+-PPase of roots of chrysanthemum under salt stress were studied with the methods of spraying exogenous SA on leaves of chrysanthemum. The results showed that salt stress increased the contents of Na+，but reduced the contents of K+，Ca2+ ，Mg 2+ of the roots of chrysanthemum. Exogenous SA treatment decreased Na+ contents，increased K+，Ca 2+ and Mg 2+ contents in the roots of chrysanthemum under salt stress conditions. The activities of plasma membrane H+-ATPase，vacuolar H+-ATPase and H+ -PPase of the roots of chrysanthemum decreased respectively under the salt stress，but exogenous SA treatments inhibited the scopes of decreasing of the activities. And at 10th day after stress treatments，they increased by 17.67%，16.47% and 18.65% respectively in SA treated plants compared with those in NaCl treated plants. These results indicated that exogenous SA may alleviate the damage of chrysanthemum seedlings from salt stress via improvement activities of proton pump of root systems and increasing of contents of K+，Ca2+ and Mg2+，but decreasing contents of Na+ in the roots of chrysanthemum and then reduce damage from salt stress.

Key words: chrysanthemum, salt stress, salicylic acid, ions content, proton pump activity