作　　者： ; ; ; ;

机构地区： 兰州大学草地农业科技学院农业部草地农业生态系统学重点开放实验室

出　　处： 《西北植物学报》 2009年第3期574-579,共6页

摘　　要： 采用稳定性同位素15N自然丰度（15N natural abundance）技术,以小麦为参照植物,研究了盆栽条件下,在外源供氮0、0.8、2.0、4.0 mmol·L^-1水平下大豆的生物固氮百分率以及生物固氮数量对植物氮的贡献.结果显示：（1）0-2.0 mmol·L^-1外源供氮可显著提高大豆的生物量和固氮百分率,且于2.0 mmol·L^-1处理下地上生物量最高,达104 g·m^-2,比CK增加了48%;（2）在0.8 mmol·L^-1的供氮水平下大豆生物固氮量最高,为1.318 g·m^-2,占大豆植株总吸氮量的70.4%,而在4.0 mmol·L^-1供氮水平下生物固氮量仅占植株总吸氮量的44%;随供氮水平的升高,大豆生物固氮量占总吸氮量的比重下降,说明在高水平外源氮下,大豆生物固氮能力受到抑制;（3）大豆生物固氮百分率、固氮数量及吸氮数量与地上生物量间均呈显著正相关关系.结果表明,应用稳定性15N同位素技术可以定量大豆的生物固氮效率,根瘤菌接种配合低浓度外源氮有利于大豆生物固氮潜能的释放,对提高大豆产量、减少化肥投入有积极的指导意义. A pot experiment was conducted to determine the BNF （biological nitrogen fixation） ability of soybean [Glycinemax （Linn.） Merr.] under 0,0.8,2.0,4.0 mmol N · L^-1 levels nitrogen supply. The percentage nitrogen fixation rate （% Ndfa） was tested by MAS isotope spectrometer. Spring wheat was used as reference plant. The results showed that soybean biomass was significantly increased with the supplied N level at range 0 to 2.0 mmol · L^-1. The aboveground biomass at 2.0 mmol · L^-1 nitrogen supplied was up to 104 g · m^-2 ,48% increase than that of CK;The N2 fixation amount in soybean was the highest when the supplied N concentration was at 0.8 mmol · L^- 1 ,some 1. 318 g · m^-2 was fixed, amounted to 70% of total soybean N uptake,BNF ability was shown to be restricted at supplied N levels above 4.0 mmol · L^-1. Significantly positive linear relationships among % Ndfa, amount of N fixed, plant N uptake and aboveground biomass were found. It conclude that N2 fixation amount in soybean can be assessed using 1aN natural abundance method,the BNF ability was weaken when additional N supply increased.

关 键 词： 自然丰度 生物固氮百分率 生物固氮数量 根瘤菌

领　　域： [生物学]