Abstract: The nitrate content of 70 samples of 9 main vegetables varieties in Zhenjiang was investigated separately. The resultsshowed that the nitrate content of root, shoot and leaf vegetables was seriously higher than the standard level, such as Chinesecabbage, crowndaisy chrysanthemum, celery, radish, water spinach and three-colored amaranth. Lettuces were pollutedintermediately, while romaine lettuces and potatoes less. Nitrate reductase activity (NRA) in different tissues of differentvegetables increased with the inducement of 50mmol/L KNO3 solution, but the rule of variation was dissimilar. NRA in differentvegetable leaves was also enhanced after seedlings were dipped in various concentration of KNO3 solution for 2h, but the peakvalue’s concentration of KNO3 solution was different. The vegetable with higher NRA had better nitrate resistance, and the activitytime of high NRA was longer after being induced by nitrate.

Key words: vegetable, nitrate, nitrate reductase, activity