Research On Nitrogen Assimilation And Protein Accumulation Characters Of Different Soybean Types

The research utilized twelve soybean varieties which have big planting areas in Heilongjiang Province as experiment material, by the method of pot and field experiments. It was carried on the Northeast Agricultural University gardening experiment field and XiangFang experiment field in 2008. We studied the differences of nitrogen accumulation rules, the change rule, the key enzyme in nitrogen assimilation and protein accumulation rule in the seeds of different soybean types. Hope to provide the theoretical basis and technical support for high quality and efficiency of soybean in our province.The main conclusions of this experiment are as follows:The dynamics change of nitrogen content of different soybean types in the leaves and the stems showed a falling-rising-falling trend, but the pods showed a decreased and then an increased one. At part growth stages, the nitrogen content in each organ of different soybean types had a significantly difference(F=3.08*-98.24**), and the average nitrogen content in each organ showed: the high-protein varieties soybean had the highest average nitrogen content, the middle soybean varieties took the second place, and high-oil variety owned the lowest content. At part growth stages, there was a significantly positive correlation between the nitrogen content of every organ and the final protein content in seeds(r=0.56*-0.75**).The dynamics change of nitrogen accumulation of different soybean types in the leaves and the stems showed a single-peak curve, the peaks appeared at R2 and R6, but the pods showed an uninterrupted increased trend. At part growth stages, the average nitrogen accumulation of the every organ showed: the high-protein varieties soybean had the highest average nitrogen accumulation, the middle soybean varieties took the second place, and high-oil variety had the lowest average nitrogen accumulation. At part growth stages, there was a significantly positive correlation between the nitrogen accumulation in each organ and the final protein content in seeds(r=0.58*-0.72**).All the peak value of nitrogen accumulation,transportation quantity,transportation rate and contribution rate for seeds nitrogen in the leaves and the stems of different soybean types showed: leaves > stems. At part growth stages, there was a significantly positive correlation between the peak value of nitrogen accumulation, transportation quantity in the leaves and the stems and the final protein content in seeds(r=0.57*-0.65*). The enNRA and exNRA of different soybean types had the same tend, appeared two peaks in whole growth stage, the peaks appear at V4 and R2, and the first peak is more higher than the second peak, and the NR reducing potentiality had different tends. At part growth stages, the enNRA and exNRA of different soybean types had a significantly difference (F=4.27*-833.14**). The high-protein varieties soybean had the highest average enNRA,average exNRA and average NR reducing potentiality, the middle soybean varieties took the second place, and high-oil variety had the lowest average enNRA and exNRA at part growth stages. At part growth stages, there was a significantly positive correlation between the enNRA,exNRA,NR reducing potentiality in leaves and the final protein content in seeds(r=0.57*-0.95**).The GSA in the leaves,the stems and the roots of different soybean types had the same trend, and showed a double-peak curve. The peaks appeared at R2 and R5, and the pods of different soybean types had different trends. At part growth stages, the GSA in each organ of different soybean types had a significantly difference (F=3.04*-36.88**), the average GSA in each organ showed: the high-protein varieties soybean had the highest average GSA in each organ. The middle soybean varieties took the second place, and high-oil variety had the lowest average GSA in each organ. At part growth stages, there was a significantly positive correlation between the GSA in each organ and the final protein content in seeds (r=0.56*-0.91**).In part sampling times, the protein content in seeds of different soybean types had a significantly difference (F=5.86*-98.12**). In the middle or later period of the seeds formation, the average protein content of high-protein soybean seeds kept the highest during the later period of the seeds formation, the middle soybean varieties took second place, and high-oil variety kept the lowest,and there was a significantly positive correlation between the protein content in seeds and the final protein content in seeds (r=0.57*-r=0.96**). The final protein content depended on the protein content in the middle or later period of the seeds formation, the middle or later period of the seeds formation play a main role in protein synthesis. So the soybean growth in the middle or later period of the seeds formation can not be ignored.