Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize
Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize
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DOI：
10.1104/pp.114.241711
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发表时间：
2014-10-01
期刊：
影响因子：
7.4
通讯作者：
Lynch, Jonathan Paul
中科院分区：
文献类型：
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作者：
Saengwilai, Patompong;Nord, Eric A.;Lynch, Jonathan Paul
次优的氮（N）可用性是发展中国家作物生产的主要限制因素，而在富裕国家，密集的N施肥带来了巨大的环境和经济成本。因此，了解根表型，提高氮的收购是相当重要的。结构功能模型预测，根皮层通气组织（RCA）可以提高玉米（玉米）的氮吸收。我们评估的实用性RCA的N收购玉米重组自交系的生理比较，在RCA生长下的次优和充足的N供应量在温室中围生态系统和在美国和南非的领域。氮胁迫增加RCA形成的200%，在围隔和90%至100%，在外地。RCA的形成显著降低了根系呼吸和根系含氮量。在低氮条件下，RCA的形成增加了15%至31%的生根深度，增加了28%至81%的叶片N含量，增加了22%的叶片叶绿素含量，增加了22%的叶片CO2同化，增加了31%至66%的营养生物量，并增加了58%的籽粒产量。我们的研究结果是一致的假设，即RCA改善植物生长在氮限制条件下，通过降低根系代谢成本，从而提高土壤勘探和N收购在深层土壤地层。虽然RCA形成的潜在的健身权衡知之甚少，增加RCA形成似乎是一个有前途的育种目标，以提高作物氮的收购。
Suboptimal nitrogen (N) availability is a primary constraint for crop production in developing nations, while in rich nations, intensive N fertilization carries substantial environmental and economic costs. Therefore, understanding root phenes that enhance N acquisition is of considerable importance. Structural-functional modeling predicts that root cortical aerenchyma (RCA) could improve N acquisition in maize (Zea mays). We evaluated the utility of RCA for N acquisition by physiological comparison of maize recombinant inbred lines contrasting in RCA grown under suboptimal and adequate N availability in greenhouse mesocosms and in the field in the United States and South Africa. N stress increased RCA formation by 200% in mesocosms and by 90% to 100% in the field. RCA formation substantially reduced root respiration and root N content. Under low-N conditions, RCA formation increased rooting depth by 15% to 31%, increased leaf N content by 28% to 81%, increased leaf chlorophyll content by 22%, increased leaf CO2 assimilation by 22%, increased vegetative biomass by 31% to 66%, and increased grain yield by 58%. Our results are consistent with the hypothesis that RCA improves plant growth under N-limiting conditions by decreasing root metabolic costs, thereby enhancing soil exploration and N acquisition in deep soil strata. Although potential fitness tradeoffs of RCA formation are poorly understood, increased RCA formation appears be a promising breeding target for enhancing crop N acquisition.