Enhancement of rhizosphere citric acid and decrease of NO3−/NH4+ ratio by root interactions facilitate N fixation and transfer.
Enhancement of rhizosphere citric acid and decrease of NO3−/NH4+ ratio by root interactions facilitate N fixation and transfer.
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通过根部相互作用增强根际柠檬酸并降低NO3-/NH4比，促进氮的固定和转移。
DOI：
10.1007/s11104-018-03918-6
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发表时间：
2020
期刊：
影响因子：
4.9
通讯作者：
高强
中科院分区：
文献类型：
--
作者：
王新宇;高英志;张华亮;邵泽强;孙宝茹;高强
目的通过竞争土壤矿质氮来促进豆科植物固氮。此外，根际有机酸还能调动外界养分，有助于根际土壤的同化。然而，多少NO3-和NH4+竞争和有机酸在间作作物的根际有助于固氮仍不清楚，需要研究。MethodsField和温室实验进行了量化的影响，氮竞争和有机酸对氮固定在玉米/苜蓿间作system.ResultsIntercropping增加氮来自大气（% Ndfa），根瘤数，和血红蛋白含量分别提高43.66%、85.53%、141.05%，显著提高了总氮吸收量和产量。% Ndfa的提高不仅是由于NO3-的消耗，还与苜蓿根际NO3-/NH4+比值的降低和柠檬酸的增加显著相关，这可以在不加氮的情况下调动可溶性固氮资源。总的来说，15.4%-21.5%的苜蓿固定的N转移到相关的玉米，提高固氮增强N transfer.ConclusionsOur研究结果提供了一种机制，根相互作用如何促进固氮，突出的重要性NO3 −/NH4+比和柠檬酸在养分动员固氮。
AimsCereal can stimulate legume N fixation through competition for soil mineral N. In addition, organic acids in the rhizosphere can mobilize external nutrients, which may help nodulation. However, how much NO3−and NH4+competition and organic acids in the rhizosphere of intercropped crops contribute to N fixation remains unclear and requires study.MethodsField and greenhouse experiments were conducted to quantify effects of N competition and organic acids on N fixation in a maize/alfalfa intercropping system.ResultsIntercropping increased nitrogen derived from the atmosphere (%Ndfa), nodules number, and leghemoglobin content by 43.66%, 85.53%, 141.05%, respectively, leading to significantly improved total N uptake and yield, compared to monoculture. The improved %Ndfa was not only due to the depletion of NO3−, but also significantly correlated with the decrease of NO3−/NH4+ratio and the increase of citric acid in rhizosphere of alfalfa, which could mobilize soluble resources for N fixation under no N addition. Overall, 15.4%–21.5% of N fixed by alfalfa was transferred to associated maize, and the improved N fixation enhanced N transfer.ConclusionsOur findings provide a mechanism for how root interactions facilitate N fixation, highlighting the importance of NO3−/NH4+ratio and citric acid in nutrient mobilization for N fixation.