不同氮肥用量下镁对大豆碳氮代谢的影响

试验采用框栽法,在N50kg/hm2,N75kg/hm2两个水平下施用MgO15kg/hm2,测定了大豆叶片可溶性蛋白、含氮量、可溶性糖、淀粉、植株酰脲以及产量和籽粒蛋白含量.结果表明,与N50相比,N50 Mg的产量增加了12.95%,但差异不显著;与N75相比,N75 Mg的各指标在各时期都有所增加,并达到了差异显著水平.其中可溶性蛋白含量在V4和R2期分别增加了68.04%和52.07%;酰脲含量在R2、R4、R6期分别增加了75.47%、21.04%和46.39%;淀粉含量在R4、R6期分别增加了59.34%和99.02%;产量和籽粒蛋白含量分别增加了28.67%和3.43%.与N50相比,N75的可溶性蛋白含量在V4、R2、R4期分别增加了36.67%、65.90%和19.70%,但酰脲含量在生殖生长期降低,淀粉含量在R4、R6期分别降低了22.34%和18.21%;而N75 Mg的酰脲含量比N50在R2、R4、R6期分别增加了59.81%、8.47%和25.67%,淀粉含量在R4、R6期也分别增加了23.60%和62.78%,差异显著,产量和籽粒蛋白含量各增加了34.38%,2.93%,均达到了5%的显著水平.这些结果表明,在较高氮肥用量下施用适量的镁可协调碳氮代谢平衡,促进光合产物向碳氮方向合理分配,实现优质高产.

EFFECTS OF MAGNESIUM ON CARBON AND NITROGEN METABOLISM OF SOYBEAN AT DIFFERENT NITROGEN LEVELS

Pot experiment was conducted to determine the soluble protein, total nitrogen,soluble sugar,starch content of soybean leaves,ureide content of plant,soybean yield and seeds protein content when applicating 15 kg/hm~2 MgO at N50 and N75 kg/hm~2.The results showed that compared with that of N50,the yield of N50+Mg increased by 12.95%,but not significant.All the indexes contents of N75+Mg increased at different growth stage,and significant,compared with that of N75.N75+Mg increased the soluble protein content by 68.04% and(52.07%) respectively at V_4 and R_2 stages,increased the ureide content by 75.47%,21.04% and 46.39% respectively at R_2,R_4,R_6 stages,increased the starch content by(59.34%) and 99.02% respectively at R_4 and R_6 stages,the yield and seeds protein content increased by 28.67% and 3.43% respectively.Compared with that of N50,the soluble protein content of N75 increased by 36.67%,65.90%,19.70% respectively at V_4,R_2,R_4 stages,significant at p=5%,but the ureide content decreased at reproductive stage,and the starch content decreased by(22.34%) and 18.21% respectively at R_4 and R_6 stage,significant at p=5%.However,compared with that of N50,the ureide content of N75+Mg increased by 59.81%,8.47% and 25.67% respectively at R_2,R_4,R_6 stage,the starch content increased by 23.60%,62.78% respectively at R_4 and R_6 stage,significant at p=5%,the yield and seeds content increased by 34.38% and 2.93% respectively,all significant at p=5%,which demonstrated that application of appropriate Mg at high nitrogen level could adjust the carbon and nitrogen metabolism to realize high yield and good quality.