title: Organic nitrogen uptake by arbuscular mycorrhizal fungi in a boreal forest.
abstract: The breakdown of organic nitrogen in soil is a potential rate-limiting step in nitrogen cycling. Arbuscular mycorrhizal (AM) fungi are root symbionts that might improve the ability of plants to compete for organic nitrogen products against other decomposer microbes. However, AM uptake of organic nitrogen, especially in natural systems, has traditionally been difficult to test. We developed a novel quantitative nanotechnological technique to determinein situthat organic nitrogen uptake by AM fungi can occur to a greater extent than has previously been assumed. Specifically, we found that AM fungi acquired recalcitrant and labile forms of organic nitrogen. Moreover, N enrichment of soil reduced plot-scale uptake of these compounds. Since most plants host AM fungi, AM use of organic nitrogen could widely influence plant productivity, especially where N availability is relatively low.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, 321 Steinhaus, Irvine, CA 92697-2525, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Whiteside
authors.affiliation: Laboratory for Fluorescent Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA 92697-2525, USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Digman
authors.affiliation: Laboratory for Fluorescent Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA 92697-2525, USA.
authors.forename: Enrico
authors.initials: E
authors.lastname: Gratton
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, 321 Steinhaus, Irvine, CA 92697-2525, USA.
authors.forename: Kathleen K
authors.initials: KK
authors.lastname: Treseder
keywords: Arbuscular mycorrhizal fungi; Boreal forest; Chitosan; Emission fingerprinting; Glycine; Organic nitrogen; Quantitative confocal microscopy; Quantum dots; Raster image correlation spectroscopy