Effects of different concentrations of NO3- on the growth,quality and antioxidant activities in pakchoi

Pakchoi was used as materials for investigating the effects of different concentrations of NO3- on the growth, quality and antioxidant activities using nutrient solution. The results indicated that the leaf number, root volume and the shoot fresh weight showed a trend of first increase and then decrease as the concentrations of NO3- increased. In the leaves and petioles, the nitrate, soluble sugar and soluble protein contents showed a trend of first increase and then decrease. Total soluble phenols and flavonoids contents decreased. POD and SOD activities increased obviously, while CAT activitydecreased obviously. The contents of nitrate and soluble sugar in petioles were higher than those in leaves, the contents of soluble protein, soluble total phenols and flavonoids in leaves were higher than those in petioles, and the activities of POD,SOD and CAT in leaves were higher than those in petioles.