[Objective] To study the effect of exogenous salicylic acid on root growth and physiological characteristics of Brassica chinensis L.seedlings under salt stress. [Method]Wuyue Man seedlings were used as research object and sand culture was used to study the effect of exogenous salicylic acid on root dry weight,root length,root surface area and the activities of superoxide dismutase( SOD),and peroxidase( POD) of Brassica chinensis L. seedlings under salt stress. [Result]During the water soaking of seed,with ...