Impact of axial root growth angles on nitrogen acquisition in maize depends on environmental conditions
Impact of axial root growth angles on nitrogen acquisition in maize depends on environmental conditions
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DOI：
10.1093/aob/mcw112
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发表时间：
2016-09-01
期刊：
影响因子：
4.2
通讯作者：
Lynch, J. P.
中科院分区：
文献类型：
--
作者：
Dathe, A.;Postma, J. A.;Lynch, J. P.
背景和目的减少氮肥需要量的作物将给发达国家带来巨大的利益，同时改善发展中国家的粮食安全。本研究采用植物功能结构模型SimRoot来验证玉米（Zea mays L.）中轴根生长角度的变化是氮捕获的重要决定因素的假设。方法在10 ~ 250 kg ha（-1）的7种土壤硝态氮水平、0 ~ 1中心点5x的5种降雨模式下，对6种轴根生长角度的表型进行了42 d的模拟。将模型结果与粉壤土和壤土样地的土壤氮测量值进行了比较。为了获得最佳的硝酸盐吸收，根系觅食必须与土壤剖面中的硝酸盐有效性一致，这取决于土壤类型和降水情况。特定根系构型对氮素有效吸收的效益随土壤氮含量的降低而增加，土壤类型的影响随土壤氮水平的增加而增加。极端的根结构在极端的环境条件下是有益的。极浅根系在降水减少的情况下表现良好，但在环境和较大降水条件下表现不佳。具有正常或浅种子和非常陡峭的节根的二态表型在所有情况下都表现良好，并且始终优于陡峭表型。在减少淋滤和低降水条件下，淤泥壤土的硝态氮吸收量增加。结论根系生长角度是玉米氮素获取的主要决定因素。随着土壤氮素状况的降低，最佳角度在42 d内的氮素获取量增加了15- 50%。根系氮素捕获的最佳表型因土壤和降水制度而异，这表明根系表型的遗传选择可以根据特定环境进行调整。
Backgrounds and Aims Crops with reduced requirement for nitrogen (N) fertilizer would have substantial benefits in developed nations, while improving food security in developing nations. This study employs the functional structural plant model SimRoot to test the hypothesis that variation in the growth angles of axial roots of maize (Zea mays L.) is an important determinant of N capture.Methods Six phenotypes contrasting in axial root growth angles were modelled for 42 d at seven soil nitrate levels from 10 to 250 kg ha(-1) in a sand and a silt loam, and five precipitation regimes ranging from 0 center dot 5x to 1 center dot 5x of an ambient rainfall pattern. Model results were compared with soil N measurements of field sites with silt loam and loamy sand textures.Key Results For optimal nitrate uptake, root foraging must coincide with nitrate availability in the soil profile, which depends on soil type and precipitation regime. The benefit of specific root architectures for efficient N uptake increases with decreasing soil N content, while the effect of soil type increases with increasing soil N level. Extreme root architectures are beneficial under extreme environmental conditions. Extremely shallow root systems perform well under reduced precipitation, but perform poorly with ambient and greater precipitation. Dimorphic phenotypes with normal or shallow seminal and very steep nodal roots performed well in all scenarios, and consistently outperformed the steep phenotypes. Nitrate uptake increased under reduced leaching conditions in the silt loam and with low precipitation.Conclusions Results support the hypothesis that root growth angles are primary determinants of N acquisition in maize. With decreasing soil N status, optimal angles resulted in 15-50 % greater N acquisition over 42 d. Optimal root phenotypes for N capture varied with soil and precipitation regimes, suggesting that genetic selection for root phenotypes could be tailored to specific environments.