Root cortical aerenchyma enhances nitrogen acquisition from low-nitrogen soils in maize

Patompong Saengwilai, Eric A. Nord, Joseph G. Chimungu, Kathleen M. Brown, Jonathan Paul Lynch

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)726-735
Number of pages10
JournalPlant physiology
Volume166
Issue number2
DOIs
StatePublished - Oct 1 2014

All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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