Reduced frequency of lateral root branching improves N capture from low-N soils in maize

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 (Ze...

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Bibliographic Details
Published in:	Journal of experimental botany 2015-04, Vol.66 (7), p.2055-2065
Main Authors:	Zhan, Ai, Lynch, Jonathan P.
Format:	Article
Language:	eng
Subjects:	Biomass Nitrogen - metabolism Phenotype Photosynthesis Plant Leaves - genetics Plant Leaves - growth & development Plant Leaves - metabolism Plant Roots - genetics Plant Roots - growth & development Plant Roots - metabolism Plant Shoots - genetics Plant Shoots - growth & development Plant Shoots - metabolism RESEARCH PAPER Soil - chemistry Zea mays - genetics Zea mays - growth & development Zea mays - metabolism
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Summary:	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.
ISSN:	0022-0957 1460-2431