Plant organic nitrogen nutrition: costs, benefits, and carbon use efficiency

Abstract

Differences in soil mobility and assimilation costs between organic and inorganic nitrogen (N) compounds would hypothetically induce plant phenotypic plasticity to optimize acquisition of, and performance on, the different N forms. Here we evaluated this hypothesis experimentally and theoretically. We grew Arabidopsis in split-root setups combined with stable isotope labelling to study uptake and distribution of carbon (C) and N from l-glutamine (l-gln) and NO3- and assessed the effect of the N source on biomass partitioning and carbon use efficiency (CUE). Analyses of stable isotopes showed that 40-48% of C acquired from l-gln resided in plants, contributing 7-8% to total C of both shoots and roots. Plants grown on l-gln exhibited increased root mass fraction and root hair length and a significantly lower N uptake rate per unit root biomass but displayed significantly enhanced CUE. Our data suggests that organic N nutrition is linked to a particular phenotype with extensive growth of roots and root hairs that optimizes for uptake of less mobile N forms. Increased CUE and lower N uptake per unit root growth may be key facets linked to the organic N phenotype.

Keywords

amino acids; Arabidopsis thaliana; carbon use efficiency; glutamine; organic nitrogen; root hair

Published in

New Phytologist
2025, volume: 245, number: 3, pages: 1018-1028

SLU Authors

• Tuennermann, Laura

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Aguetoni Cambui, Camila

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Franklin, Oskar

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    
  • International Institute for Applied Systems Analysis (IIASA)

• Merkel, Patrizia

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Näsholm, Torgny

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    
  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Gratz, Regina

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany

Publication identifier

• DOI: https://doi.org/10.1111/nph.20285

Permanent link to this page (URI)

https://res.slu.se/id/publ/139409