The seeds of C.florida in pretreatment 1 (T1) were soaked with 500 mg/L gibberellin acid (GA₃) , which was prepared with water. The seeds of pretreatment 2 (T2) were soaked with 500 mg/L gibberellin acid (GA₃), which was prepared with four concentrations of salt solution(0.20%, 0.30%, 0.40% and 0.45%) .All the seeds were soaked for three days, followed by moist chilling for two months, then the germination testing, measurements of seedling growth and biochemical indexes were carried out. Germinating substrate (sand) and water management were as follows： five salt concentrations [0(CK), 0.20%, 0.30%, 0.40% and 0.45%] were used in T1 treatment seeds, while the corresponding to pretreatment salt concentrations were used in T2 treatment seeds.

Salt stress extremely significantly decreased the germination rate and germination energy. Moreover, the effect of salt stress in T2 was considerably greater than that in T1； especially, germination indexs of salt concentrations ≥0.30% were significantly different between T1 and T2. The effects of salt stress on seedling indexes are mainly reflected in seedling height, followed by root length, relative water content, fresh weight, and dry weight. Furthermore, malondialdehyde content, superoxide dismutase activity, and proline content increased significantly with increasing salt concentration, whereas soluble sugar content was the highest at a salt concentration of 0.40%. K⁺ content in the roots significantly decreased with increasing salt concentration, but the response of Na⁺ content was not significant (P<0.05).

Salt stress inhibited the germination of C. florida seeds, and pre?treatment with salt enhanced the inhibition. Moreover, the growth indicators, biochemical indicators, and ion absorption of seedlings significantly differed with increasing salt concentration. Comprehensively, seed germination and seedling growth of C. florida were normal under a salt concentration of 0.30%. Thus, C. florida is a candidate species for ornamental use in salt?rich coastal areas, but further field cultivation is needed before extensive application.