Abstract: Taking cucumber cultivars‘Jinlv No.5’ (salt-tolerant) and ‘Jinyou No.1’ (salt-sensitive) as test materials, a pot experiment was conducted to study the effects of applying cinnamic acid on the accumulation of applied cinnamic acid in cucumber seedling-soil system under NaCl (585 mg·kg^-1 soil) stress. The concentration of applied cinnamic acid was the main factor affecting the accumulation of the exogenous cinnamic acid in the cucumber plant and soil. With the increasing concentration of applied cinnamic acid, except in the treatment of highest concentration (200 mg·kg^-1 soil) cinnamic acid, the total content of cinnamic acid in cucumber plant was increased. NaCl stress enhanced the toxicity of cinnamic acid. In the treatments of low and medium concentration cinnamic acid, the cinnamic acid content in cucumber plant increased; whereas in the treatments of high concentration cinnamic acid, the decline of the seedlings growth was observed, and led to the decrease of the cinnamic acid content in the plant. The  content of cinnamic acid in ‘Jinlv No.5’ plant  decreased at the concentration of applied cinnamic acid being >200 mg·kg^-1 soil, while that in ‘Jinyou No.1’ started to decrease when the concentration of applied cinnamic acid was >100 mg·kg^-1 soil, reflecting the discrepancy in salt tolerance of the two cultivars. For the cucumber plant, its leaf had the highest content of cinnamic acid. In the cucumber seedling-soil system, most of applied cinnamic acid was mainly accumulated in soil.

Key words: salt stress, cinnamic acid, plant-soil system