Effects of Rare Earth Lanthanum and Cerium on Key Enzyme Activi-ties of Soybean Nitrogen Metabolism

In this study, the typical northeast soybean varieties Dongnong 42 (high protein), Dongnong 47 (high fat) and Dongnong 52 (mixed-use) were used as experimental materials and planted in pots. Foliar spraying 100, 150 and 200 mg · L-1 LaCl3 solution, 30, 60 and 90 mg · L-1 CeCl3 solution and 40, 60 and 70 mg · L-1 LaCl3+CeCl3 mixed solution. To study the effects of different types and concentrations of rare earth on nitrate reductase activity, glutamine synthetase activity of soybean leaves and protein content of soybean grains. The results showed that spraying appropriate concentration of rare earth solution on the leaves could increase the activities of nitrate reductase and glutamine synthase in soybean functional leaves and the protein content of soybean grains. The protein content of the three types of soybean grains was significantly positively correlated with the activity of nitrate reductase and glutamine synthetase in the leaves.