Dynamic changes in cinnamic acid content in cucumber-soil system under salt stress

The dynamics of transfer and distribution of cinnamic acid were investigated in cucumber plant and cucumber-soil under salt stress. Two cucumber cultivars (Jinlv No. 5 and Jinyou No.1) with different salt resistance were grown in salt prepared soil (585 NaCl mg·kg⁻¹soil), seedlings at first-leaf stage were treated with cinnamic acid solution at doses of 0, 25, 50, 100 and 200 mg·kg⁻¹ dry soil. Plant and soil samples were taken at 7, 14, 21 days after application. Cinnamic acid concentration in each organ of cucumber and in soil was determined by HPLC. Under salt stress, cinnamic acid content in cucumber plants of ‘Jinlv No.5’ (Salt tolerant) were increased at doses of 0, 25, 50 and 100 mg·kg⁻¹ soil, but decreased at 200 mg·kg⁻¹soil, while the cinnamic acid content of ‘Jinyou No.1’ (Salt sensitive) were increased at doses of 0, 25 and 50 mg·kg⁻¹ soil, but decreased from dose of 100 mg·kg⁻¹soil. The cinnamic acid contents in soil increased with increasing applied doses and showed dynamic changes of ‘high-low-high’ with time except the control. In cucumber plant-soil system, most of the cinnamic acid remained mainly in soil than in cucumber plants.