Objective The effects of 2, 4-epibrassinolide (EBR) on the growth and flower stalk nutritional quality of flowering Chinese cabbage (Brassica parachinensis Bailey) were studied in order to screen out optimal application concentration and spraying period.

Method With the cultivar "Sijiu Youqing" as tested material, the effects of exogenous EBR at different concentrations and spraying periods on the growth and flower stalk nutritional quality of flowering Chinese cabbage were analyzed.

Result Spraying EBR could affect the growth and nutrition indicators of flowering Chinese cabbage. Spraying low concentrations (0.01-0.05 mg/L) of EBR significantly increased the flower stalk length and diameter and the contents of Vc, chlorophyll, total soluble sugar, soluble protein, total nitrogen and total potassium, while reduced the cellulose content. However, spraying high concentrations of EBR (0.14-0.17 mg/L) significantly increased the total nitrogen, total phosphorus and total potassium contents of flowering stalk. Based on the plant growth and nutritional quality after treatments with EBR at three growth periods, spraying low concentrations (0.01-0.05 mg/L) of EBR at seedling stage had the best effect on improving the growth and nutrition indicators of flowering stalks, and spraying 0.05 mg/L of EBR had the largest reduction in the cellulose content, which reduced from 5.71% of the control to 3.88%. Spraying 0.05 mg/L of EBR at the stages of seedling and before-bolting had the largest increase effect on the total nitrogen content, which increased from 0.75% of the control to 1.19%; while the flowering stalks sprayed with 0.14 mg/L of EBR at before-bolting stage had the highest contents of total phosphorus and potassium, reaching 0.36% and 7.00%, respectively.

Conclusion The suitable concentration of EBR used in flowering Chinese cabbage was 0.01-0.05 mg/L, and the spraying period was better at the seedling stage or at the stages of both seedling and before-bolting.