Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize    . Issue 2 (2nd June 2014)

• Record Type: Journal Article
• Authors: Saengwilai, Patompong; Nord, Eric A.; Chimungu, Joseph G.; Brown, Kathleen M.; Lynch, Jonathan Paul
• Is Part Of: Plant physiology. Volume 166:Issue 2(2014)
• Page Start: 726
• Page End: 735
• Publication Date: 2014-06-02
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.114.241711
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : Abundant root cortical aerenchyma improves plant growth under nitrogen-limiting conditions by decreasing root metabolic costs, enhancing soil exploration in deep soil strata, thereby increasing nitrogen acquisition at greater depths . 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.