【摘要】 以结瘤和非结瘤近等位基因大豆品系为材料,利用砂培方式,分析了不同供氮水平对大豆生长、碳氮代谢、结瘤和固氮的影响。结果表明:供氮水平直接影响大豆生物量,结瘤大豆在N2水平(54 mg尿素·kg-1砂)时生物量达到最大(9.16 g·株-1);非结瘤大豆在N4水平(216 mg尿素·kg-1砂)时生物量达到最大(6.36 g·株-1)。植株体内碳氮含量与生物量的变化趋势相同。此外,结瘤品系N2水平大豆根瘤数最多(205个.株-1),极显著高于除N4以外的其它处理(P<0.01),该水平的共生固氮量最大,为275.92 mg·株-1,且与N3、N4、N5处理间差异极显著(P<0.01)。因此,结瘤和非结瘤大豆对外源氮的需求存在显著差异,该试验条件下的氮阻遏阈值为N2水平,即54 mg尿素·kg-1砂。更多还原

【Abstract】 To illustrate the influence of nitrogen fertilizer application on the growth and nitrogen fixation in soybean,the study on the effect of the different N application levels on growth,carbon and nitrogen metabolism,nodulation and nitrogen fixation in soybean under sand culture condition,was carried out with nodulation and non-nodulation soybean isolines.The results showed that N application levels directly impacted soybean biomass.The biomass of nodulation soybean reached the maximum value of 9.16 g·plant-1 at N2 level(54 mg urea·kg-1 sand),while the non-nodulation soybean reached the maximum of 6.36 g·plant-1 at N4 level(216 mg urea·kg-1 sand).There was similar trend of carbon and nitrogen metabolism affected by N level.In addition,nodule number reached the largest number(205 per plant)at N2 level,and there were significant differences between N2 and other treatment,exception of N4 level(P<0.01).The amount of symbiotic nitrogen fixation reached the maximum of 275.92 mg·plant-1 at N2 level,and there were significant differences between N2 and N3(N4 or N5)(P<0.01).These results showed that there was obvious difference between nodulation and non-nodulation soybean isoline to the demand of exogenous nitrogen.To take full advantage of symbiotic nitrogen fixation of soybean,nitrogen repression threshold was N2 level(54 mg·kg-1 sand)under this experiment conditions.更多还原