Mycorrhizal fungi supply nitrogen to host plants in Arctic tundra and boreal forests : 15N is the key signal
Hobbie, John E.
Hobbie, Erik A.
Conte, Maureen H.
Weber, John C.
MetadataShow full item record
Symbiotic fungi’s role in providing nitrogen to host plants is well-studied in tundra at Toolik Lake, Alaska, but little-studied in the adjoining boreal forest ecosystem. Along a 570 km north–south transect from the Yukon River to the North Slope of Alaska, the 15N content was strongly reduced in ectomycorrhizal and ericoid mycorrhizal plants including Betula, Salix, Picea mariana (P. Mill.) B.S.P., Picea glauca Moench (Voss), and ericaceous plants. Compared with the 15N content of soil, the foliage of nonmycorrhizal plants (Carex and Eriophorum) was unchanged, whereas content of the ectomycorrhizal fungi was very much higher (e.g., Boletaceae, Leccinum and Cortinarius). It is hypothesized that similar processes operate in tundra and boreal forest, both nitrogen-limited ecosystems: (i) mycorrhizal fungi break down soil polymers and take up amino acids or other nitrogen compounds; (ii) mycorrhizal fungi fractionate against 15N during production of transfer compounds; (iii) host plants are accordingly depleted in 15N; and (iv) mycorrhizal fungi are enriched in 15N. Increased N availability for plant roots or decreased light availability to understory plants may have decreased N allocation to mycorrhizal partners and increased δ15N by 3‰–4‰ for southern populations of Vaccinium vitis-idaea L. and Salix. Fungal biomass, measured as ergosterol, correlated strongly with soil organic matter and attained amounts similar to those in temperate forest soils.
Author Posting. © NRC Research Press, 2009. This article is posted here by permission of NRC Research Press for personal use, not for redistribution. The definitive version was published in Canadian Journal of Microbiology 55 (2009): 84-94, doi:10.1139/W08-127.
Suggested CitationArticle: Hobbie, John E., Hobbie, Erik A., Drossman, Howard, Conte, Maureen H., Weber, John C., Shamhart, Julee, Weinrobe, Melissa, "Mycorrhizal fungi supply nitrogen to host plants in Arctic tundra and boreal forests : 15N is the key signal", Canadian Journal of Microbiology 55 (2009): 84-94, DOI:10.1139/W08-127, https://hdl.handle.net/1912/2902
Showing items related by title, author, creator and subject.
Hobbie, John E.; Hobbie, Erik A. (Ecological Society of America, 2006-04)When soil nitrogen is in short supply, most terrestrial plants form symbioses with fungi (mycorrhizae): hyphae take up soil nitrogen, transport it into plant roots, and receive plant sugars in return. In ecosystems, the ...
Depleted 15N in hydrolysable-N of arctic soils and its implication for mycorrhizal fungi–plant interaction Yano, Yuriko; Shaver, Gaius R.; Giblin, Anne E.; Rastetter, Edward B. (2009-08)Uptake of nitrogen (N) via root-mycorrhizal associations accounts for a significant portion of total N supply to many vascular plants. Using stable isotope ratios (δ15N) and the mass balance among N pools of plants, ...
Microbes in nature are limited by carbon and energy : the starving-survival lifestyle in soil and consequences for estimating microbial rates Hobbie, John E.; Hobbie, Erik A. (Frontiers Media, 2013-11-12)Understanding microbial transformations in soils is important for predicting future carbon sequestration and nutrient cycling. This review questions some methods of assessing one key microbial process, the uptake of labile ...