Effects of several chemicals on nitrate accumulation and nutritive quality of Chinese cabbage

The optimum mixed design, 311-A, was adopt to study the effects of different combinations of gibberellin (GA), ammonium molybdate (Mo) and dicyandiumide (DCD) on the yield and nitrate in leaf and nutritive quality of Chinese cabbage(Brassica chinensis). The results indicated that the effects of three chemicals on yield and nitrate content of Chinese cabbage could be quantitatively described by a regression equation with three factors. When GA, Mo and DCD were used reasonably, the yield of Chinese cabbage was increased, the nitrate in leaf at three growth stages was decreased obviously, and the content of Vc and amino acid were improved significantly. The accumulation of Mo in leaf directly correlated with the spraying concentration of ammonium molybdate, but it didn't exceed the heath limit to Mo. Under the experimental conditions, the optimum combinations of 3 chemicals applied to Chinese cabbage were GA 46.3 mg/L + Mo 441mg/L + DCD 8.3 mg/pot, GA 28.7 mg/L + Mo 159 mg/L + DCD 8.3 mg/pot and GA 37.5 mg/L + Mo 300 mg/L + DCD 2.55 mg/pot respectively.