Abstract: This study investigated the effect of exogenous salicylic acid （SA） on physiological characteristics of Gardenia jasminoides seedlings under salt stress. G. jasminoides seedlings were cultured with 150 mmol·L-1 NaCl and different concentrations（0， 05， 1， 2 and 4 mmol·L-1）of SA， physiological and biochemical indexes were studied， including osmolytes content and antioxidant system. The results showed that 150 mmol·L-1 NaCl significantly inhibited the physiological and biochemical indexes of G.jasminoides seedlings. Appropriate concentration of SA could improve chlorophyll， soluble sugar， soluble protein， free proline（Pro） contents， and superoxide（SOD）， peroxidase（POD） and catalase（CAT） activities of G.jasminoides seedlings under 150 mmol·L-1 NaCl， meanwhile reduced their relative electric conductivity and malondialdehyde（MDA） content， especially the SA concentration of 0.5-1 mmol·L-1 showed the best effect. In conclusion， it was shown that SA with concentration of 0.5-1 mmol·L-1 could markedly reduce the physiological damages to G.jasminoides seedlings exposed to salt stress， and increase its salt resistance， but 2-4 mmol·L-1 SA were likely to exacerbate the salt stress.

Key words: Gardenia jasminoides, salt stress, salicylic acid, antioxidant system