EFFECTS OF N-NO3- N-NH4+ AND GA(3) ON THE VEGETATIVE GROWTH PERIOD OFSPINACH LEAVES

The effects of N-NO3-, mM/N-NH4+, mM at 45/0, 90/0, 22.5/22.5 and 45/4 5; and leaf spray of GA(3) at 5 and 10 ppm, on the vegetative growth p eriod of spinach (Spinacia oleracea L. cv. known-you 902 F1 hybrid) le aves are shown as follow : 1. Leaf fresh weight, blade area, leaf numb er, the longest petiole length, and the contents of chlorophyll, N-nit rate, N-ammonium and organic nitrogen, are all affected by the nutrien t ratios; whereas, petiole fresh weight and the longest petiole length are significantly increased by the leaf spray of GA(3). 2. Leaf fresh weight, blade area, and the longest petiole length are increased sign ificantly by the nutrient of 22.5/22.5, but above growth items of thos e treated by other three nutrients of 45/0, 90/0 and 45/45 have no sig nificant difference among them. Leaf number and the longest petiole le ngth are slightly affected by the nutrient ratios. 3. The chlorophyll contents of blades are about 0.16-0.30% of their fresh weight, and inc reased significantly by the nutrient of 45/45; but the chlorophyll con tents of those treated by the other three nutrients of 45/0, 90/0, 22. 5/22.5 have no significant difference among them. 4. The N-nitrate con tents of blades and petioles are about 0.1-0.3% and 1.7-2.3% of their dry weights, respectively. And the N-nitrate contents of those treated by the nutrients of 22.5/22.5 and 45/45 are significantly higher than the N-nitrate contents of those treated by the nutrients of 45/0 and 90/0. 5. The N-ammonium contents of blades are only about 0.04% of the ir dry weights, and do not affected by the nutrient ratios; the 0.04% N-ammonium contents of their dry weights in petioles treated by the nu trients of 22.5/22.5 and 45/45, are significantly higher than the 0.02 % N-ammonium contents of those treated by the nutrients of 45/45 and 9 0/0. 6. The organic nitrogen contents of blades are about 0.07% of the ir dry weights, and are not affected by the nutrient ratios.