施氮对大豆根系形态和氮素吸收积累的影响

Root morphology and nitrogen accumulation in soybean (Glycnie max L.) under different nitrogen application levels

  • 摘要: 采用框栽试验方法研究了不同施氮水平对大豆根系形态和氮素吸收积累的影响, 结果表明: 不同施氮水平对大豆植株生物量、氮素吸收积累量及根系形态有显著影响, 随施氮量增加, 植株干重、氮素积累量、单株产量等均呈先增加后降低趋势, 其中以N100 100 kg(N)·hm-2处理效果最佳, 总体表现为N100>N200>N50>N25>N0。无N (N0)和适量偏低的氮(N25、N50)增加了大豆的根冠比, 但过多的氮(N200)反而降低了大豆的根冠比, 说明低氮胁迫促进了大豆根系的生长。大豆根长、根表面积和根体积随施氮量的增加表现为先降后增而后又降低的规律, 不施氮(N0)情况下, 根长、根表面积和根体积均高于低氮处理 (N25、 N50), 之后随施氮量增加而增加, 当超过一定施氮量(N200)时又呈降低趋势。不同生育时期植株生物量、氮素积累、根长、根表面积和根体积等表现为花期>苗期>鼓粒期。因此施用一定量氮肥对大豆植株生物量、氮素积累以及根系形态等产生显著影响, 进而影响大豆氮素转运量和转运效率, 最终影响大豆籽粒产量和品质。

     

    Abstract: A pot experiment was set up to study the effect of different nitrogen application levels on root morphology and nitrogen accumulation in soybean (,Glycnie max L.). The results show that nitrogen application level significantly influences soybean biomass, nitrogen accumulation and root morphology. Plant dry weight, nitrogen accumulation and per plant yield increase to the maximum point first and then decrease with increasing N application. For all the treatments, of which 100 kg(N)·hm-2 treatment (N100) presents the best effect, the effects are in the following order: N100>N200>N50>N25>N0. Meanwhile, root to shoot ratio of soybean under N0 and N25, N50 is higher than that under N200, suggesting that low nitrogen stress enhances root development. However, root length, surface area and volume initially drop with increasing nitrogen dose, then increase and eventually decrease in the order as follows: N100>N200>N0>N50>N25. For different growth stages, plant biomass, nitrogen accumulatin and root morphology are as follows: flowering>seedling>podding. This implies that proper nitrogen application has significant effect on soybean biomass, nitrogen accumulation and root morphology. This influences transport and efficiency of nitrogen, which eventually influences the yield and quality of soybean.

     

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