title: Reduced frequency of lateral root branching improves N capture from low-N soils in maize.
abstract: Suboptimal nitrogen (N) availability is a primary constraint for crop production in developing countries, while in developed countries, intensive N fertilization is a primary economic, energy, and environmental cost for crop production. We tested the hypothesis that under low-N conditions, maize (Zea mays) lines with few but long (FL) lateral roots would have greater axial root elongation, deeper rooting, and greater N acquisition than lines with many but short (MS) lateral roots. Maize recombinant inbred lines contrasting in lateral root number and length were grown with adequate and suboptimal N in greenhouse mesocosms and in the field in the USA and South Africa (SA). In low-N mesocosms, the FL phenotype had substantially reduced root respiration and greater rooting depth than the MS phenotype. In low-N fields in the USA and SA, the FL phenotype had greater rooting depth, shoot N content, leaf photosynthesis, and shoot biomass than the MS phenotype. The FL phenotype yielded 31.5% more than the MS phenotype under low N in the USA. Our results are consistent with the hypothesis that sparse but long lateral roots improve N capture from low-N soils. These results with maize probably pertain to other species. The FL lateral root phenotype merits consideration as a selection target for greater crop N efficiency.
authors: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA.
authors: Ai
authors: A
authors: Zhan
authors: Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA jpl4@psu.edu.
authors: Jonathan P
authors: http://orcid.org/0000-0002-7265-9790
authors: JP
authors: Lynch
mesh_terms: D018533:Biomass; D009584:Nitrogen / Q000378:metabolism*; D010641:Phenotype; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D003313:Zea mays / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: Branching; frequency; lateral root; maize (Zea mays); nitrogen (N); respiration.