, Volume 146, Issue 2, pp 258–268 | Cite as

Foliar and fungal 15 N:14 N ratios reflect development of mycorrhizae and nitrogen supply during primary succession: testing analytical models

  • Erik A. HobbieEmail author
  • Ari Jumpponen
  • Jim Trappe
Ecosystem Ecology


Nitrogen isotopes (15N/14N ratios, expressed as δ15N values) are useful markers of the mycorrhizal role in plant nitrogen supply because discrimination against 15N during creation of transfer compounds within mycorrhizal fungi decreases the 15N/14N in plants (low δ15N) and increases the 15N/14N of the fungi (high δ15N). Analytical models of 15N distribution would be helpful in interpreting δ15N patterns in fungi and plants. To compare different analytical models, we measured nitrogen isotope patterns in soils, saprotrophic fungi, ectomycorrhizal fungi, and plants with different mycorrhizal habits on a glacier foreland exposed during the last 100 years of glacial retreat and on adjacent non-glaciated terrain. Since plants during early primary succession may have only limited access to propagules of mycorrhizal fungi, we hypothesized that mycorrhizal plants would initially be similar to nonmycorrhizal plants in δ15N and then decrease, if mycorrhizal colonization were an important factor influencing plant δ15N. As hypothesized, plants with different mycorrhizal habits initially showed similar δ15N values (−4 to −6‰ relative to the standard of atmospheric N2 at 0‰), corresponding to low mycorrhizal colonization in all plant species and an absence of ectomycorrhizal sporocarps. In later successional stages where ectomycorrhizal sporocarps were present, most ectomycorrhizal and ericoid mycorrhizal plants declined by 5–6‰ in δ15N, suggesting transfer of 15N-depleted N from fungi to plants. The values recorded (−8 to −11‰) are among the lowest yet observed in vascular plants. In contrast, the δ15N of nonmycorrhizal plants and arbuscular mycorrhizal plants declined only slightly or not at all. On the forefront, most ectomycorrhizal and saprotrophic fungi were similar in δ15N (−1 to −3‰), but the host-specific ectomycorrhizal fungus Cortinarius tenebricus had values of up to 7‰. Plants, fungi and soil were at least 4‰ higher in δ15N from the mature site than in recently exposed sites. On both the forefront and the mature site, host-specific ectomycorrhizal fungi had higher δ15N values than ectomycorrhizal fungi with a broad host range. From these isotopic patterns, we conclude:(1) large enrichments in 15N of many ectomycorrhizal fungi relative to co-occurring ectomycorrhizal plants are best explained by treating the plant-fungal-soil system as a closed system with a discrimination against 15N of 8–10‰ during transfer from fungi to plants, (2) based on models of 15N mass balance, ericoid and ectomycorrhizal fungi retain up to two-thirds of the N in the plant-mycorrhizal system under the N-limited conditions at forefront sites, (3) sporocarps are probably enriched in 15N by an additional 3‰ relative to available nitrogen, and (4) host-specific ectomycorrhizal fungi may transfer more N to plant hosts than non-host-specific ectomycorrhizal fungi. Our study confirms that nitrogen isotopes are a powerful tool for probing nitrogen dynamics between mycorrhizal fungi and associated plants.


Nitrogen concentration Isotope ratios Mycorrhizal Nitrogen cycling Primary succession Soil 



Our thanks to personnel of the Chelan Ranger District, Wenatchee National Forest for greatly facilitating this study, to the Oregon State University herbarium for loan of archived specimens, to Matt Trappe, Casey Corliss, Rauni Ohtonen, Goetz Palfner, and Kei Fujimora for assistance with field work, and to Steve Trudell for comments on an earlier manuscript draft. Casey Corliss, Bill Griffis, Willi Brand, Heike Geilmann, Steve Macko, and Marshall Otter assisted with sample processing and isotopic analyses. Funding was provided through the National Research Council (cooperative agreement CR-824072), the National Park Service, the U.S. National Science Foundation (DEB-0235727), and the U.S. Forest Service, Pacific Northwest Research Station.


  1. Bago B, Pfeffer P, Shachar-Hill Y (2001) Could the urea cycle be translocating nitrogen in the arbuscular mycorrhizal symbiosis? New Phytol 149:4–8CrossRefGoogle Scholar
  2. Caldwell BA, Jumpponen A, Trappe JM (2000) Utilization of major detrital substrates by dark-septate, root endophytes. Mycologia 92:230–232CrossRefGoogle Scholar
  3. Carrillo JH, Hastings MG, Sigman DM, Huebert BJ (2002) Atmospheric deposition of inorganic and organic nitrogen and base cations in Hawaii. Glob Biogeochem Cycle 16:24, 1–16Google Scholar
  4. Cázares E, Trappe JM, Jumpponen A (2005) Mycorrhiza-plant colonization patterns on a subalpine glacier forefront as a model system of primary succession. Mycorrhiza (DOI: 10.1007/s00572-004-0342-1)Google Scholar
  5. Deacon JW (1997) Modern mycology, 3rd edn. Blackwell, LondonGoogle Scholar
  6. Evans RD, Belnap J (1999) Long-term consequences of disturbance on nitrogen dynamics in an arid ecosystem. Ecology 80:150–160CrossRefGoogle Scholar
  7. Evans RD, Bloom AJ, Sukrapanna SS, Ehleringer JR (1996) Nitrogen isotope composition of tomato (Lycopersicon esculentum Mill. cv. T-5) grown under ammonium or nitrate nutrition. Plant Cell Environ 19:1317–1323CrossRefGoogle Scholar
  8. Fogel ML, Cifuentes LA (1993) Isotope fractionation during primary production. In: Macko SA, Engel MH (eds) Organic geochemistry. Plenum, New York, pp 73–98Google Scholar
  9. Handley LL, Brendel O, Scrimgeour CM, Schmidt S, Raven JA, Turnbull MH, Stewart GR (1996) The 15N natural abundance patterns of field-collected fungi from three kinds of ecosystems. Rapid Commun Mass Spec 10:974–978CrossRefGoogle Scholar
  10. Handley LL, Austin AT, Robinson D, Scrimgeour CM, Raven JA, Heaton THE, Schmidt S, Stewart GR (1999) The 15N natural abundance (15N) of ecosystem samples reflects measures of water availability. Aust J Plant Physiol 26:185–199CrossRefGoogle Scholar
  11. Hayes JM (2002) Fractionation of the isotopes of carbon and hydrogen in biosynthetic processes. In: Valley JW, Cole DR (eds) Stable isotope geochemistry. Mineralogical Society of America and the Geochemical Society, Washington, pp 225–277Google Scholar
  12. Helm DJ, Allen EB, Trappe JM (1996) Mycorrhizal chronosequence near Exit Glacier, Alaska. Can J Bot 74:1496–1506CrossRefGoogle Scholar
  13. Henn MR, Chapela IH (2001) Ecophysiology of 13 C and 15N isotopic fractionation in forest fungi and the roots of the saprotrophic-mycorrhizal divide. Oecologia 128:480–487CrossRefGoogle Scholar
  14. Hobbie EA (2005) Assessing functions of soil microbes with isotopic measurements. In: Buscot F, Varma A (eds) Micro-organisms in soils: roles in genesis and functions. Springer, Berlin, Heidelberg New York, pp 383–402CrossRefGoogle Scholar
  15. Hobbie EA, Colpaert JV (2003) Nitrogen availability and colonization by mycorrhizal fungi correlate with nitrogen isotope patterns in plants. New Phytol 157:115–126CrossRefGoogle Scholar
  16. Hobbie EA, Macko SA, Shugart HH (1999) Insights into nitrogen and carbon dynamics of ectomycorrhizal and saprotrophic fungi from isotopic evidence. Oecologia 118:353–360CrossRefGoogle Scholar
  17. Hobbie EA, Macko SA, Williams M (2000) Correlations between foliar δ15N and nitrogen concentrations may indicate plant-mycorrhizal interactions. Oecologia 122:273–283CrossRefGoogle Scholar
  18. Hobbie EA, Weber NS, Trappe JM (2001) Determining mycorrhizal or saprotrophic status of fungi from isotopic evidence: implications for element cycling and fungal evolution. New Phytol 150:601–610CrossRefGoogle Scholar
  19. Högberg P (1997) 15N natural abundance in soil-plant systems. New Phytol 137:179–203CrossRefGoogle Scholar
  20. Holloway JM, Dahlgren RA (2002) Nitrogen in rock: occurrences and biogeochemical implications. Glob Biogeochem Cycle 16:65, 1–17Google Scholar
  21. Jumpponen A, Trappe JM (1998) Dark septate endophytes: a review of facultative biotrophic root-colonizing fungi. New Phytol 140:295–310CrossRefGoogle Scholar
  22. Jumpponen A, Mattson K, Trappe JM, Ohtonen R (1998) Effects of established willows on primary succession on Lyman Glacier Forefront, North Cascade Range, Washington, U.S.A.: evidence for simultaneous canopy inhibition and soil facilitation. Arctic Alpine Res 30:31–39CrossRefGoogle Scholar
  23. Jumpponen A, Trappe JM, Cázares E (2002) Occurrence of ectomycorrhizal fungi on the forefront of retreating Lyman Glacier (Washington, USA) in relation to time since deglaciation. Mycorrhiza 12:43–49PubMedCrossRefGoogle Scholar
  24. Kohls SJ, Van Kessel C, Baker DD, Grigal DF, Lawrence DB (1994) Assessment of N2 fixation and N cycling by Dryas along a chronosequence within the forelands of the Athabasca Glacier, Canada. Soil Biol Biochem 26:623–632CrossRefGoogle Scholar
  25. Kohls SJ, Baker DD, van Kessel C, Dawson JO (2003) An assessment of soil enrichment by actinorrhizal N2 fixation using δ15N values in a chronosequence of deglaciation at Glacier Bay, Alaska. Plant Soil 254:11–17CrossRefGoogle Scholar
  26. Kohzu A, Yoshioka T, Ando T, Takahashi M, Koba K, Wada E (1999) Natural 13 C and 15N abundance of field-collected fungi and their ecological implications. New Phytol 144:323–330CrossRefGoogle Scholar
  27. Kohzu A, Tateishi T, Yamada A, Koba K, Wada E (2000) Nitrogen isotope fractionation during nitrogen transport from ectomycorrhizal fungi, Suillus granulatus, to the host plant, Pinus densiflora. Soil Sci Plant Nutr 46:733–739Google Scholar
  28. Lilleskov EA, Hobbie EA, Fahey TJ (2002) Ectomycorrizal fungal taxa differing in response to nitrogen deposition also differ in pure culture organic nitrogen use and natural abundance of nitrogen isotopes. New Phytol 154:219–231CrossRefGoogle Scholar
  29. Martinelli LA, Piccolo MC, Townsend AR, Vitousek PM, Cuevas E, McDowell W, Robertson GP, Santos OC, Treseder K (1999) Nitrogen stable isotopic composition of leaves and soil: tropical versus temperate forests. Biogeochemistry 46:45–65Google Scholar
  30. McKane RB, Johnson LC, Shaver GR, Nadelhoffer KJ, Rastetter EB, Fry B, Giblin AE, Kielland K, Kwiatkowski BL, Laundre JA, Murray G (2002) Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra. Nature 415:68–71PubMedCrossRefGoogle Scholar
  31. Michelsen A, Schmidt IK, Jonasson S, Quarmby C, Sleep D (1996) Leaf 15N abundance of subarctic plants provides field evidence that ericoid, ectomycorrhizal and non- and arbuscular mycorrhizal species access different sources of soil nitrogen. Oecologia 105:53–63CrossRefGoogle Scholar
  32. Michelsen A, Quarmby C, Sleep D, Jonasson S (1998) Vascular plant 15N natural abundance in heath and forest tundra ecosystems is closely correlated with presence and type of mycorrhizal fungi in roots. Oecologia 115:406–418CrossRefGoogle Scholar
  33. Molina R, Massicotte H, Trappe JM (1992) Specificity phenomena in mycorrhizal symbioses: community-ecological consequences and practical implications. In: Allen MF (ed) Mycorrhizal functioning. Chapman & Hall, New York, pp 357–423Google Scholar
  34. Nadelhoffer KJ, Fry B (1994) Nitrogen isotope studies in forest ecosystems. In: Lajtha K, Michener R (eds) Stable isotopes in ecology and environmental science. Blackwell, London, pp 22–44Google Scholar
  35. Nara K, Nakaya H, Hogetsu T (2003) Ectomycorrhizal sporocarp succession and production during early primary succession on Mount Fuji. New Phytol 158:193–206Google Scholar
  36. Read DJ (1991) Mycorrhizas in ecosystems. Experientia 47:376–391CrossRefGoogle Scholar
  37. Read DJ, Perez-Moreno J. (2003) Mycorrhizas and nutrient cycling in ecosystems - a journey towards relevance? New Phytol 157:475–492CrossRefGoogle Scholar
  38. Schmidt S, Stewart GR (1997) Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum). Plant Cell Environ 20:1231–1241CrossRefGoogle Scholar
  39. Simard SW, Durall D, Jones M (2002) Carbon and nutrient fluxes within and between mycorrhizal plants. In: van der Heijden MGA, Sanders IR (eds) Mycorrhizal ecology. Springer, Berlin, Heidelberg New York, pp 33–74Google Scholar
  40. Taylor AFS, Högbom L, Högberg M, Lyon AJE, Näsholm T, Högberg P (1997) Natural 15N abundance in fruit bodies of ectomycorrhizal fungi from boreal forests. New Phytol 136:713–720CrossRefGoogle Scholar
  41. Taylor AFS, Fransson PM, Högberg P, Högberg MN, Plamboeck AH (2003) Species level patterns in C-13 and N-15 abundance of ectomycorrhizal and saprotrophic fungal sporocarps. New Phytol 159:757–774CrossRefGoogle Scholar
  42. Trappe JM (1977) Selection of fungi for ectomycorrhizal inoculation in nurseries. Ann Rev Phytopath 15:203–222CrossRefGoogle Scholar
  43. Trowbridge J, Jumpponen A (2004) Fungal colonization of shrub willow roots at the forefront of a receding glacier. Mycorrhiza 14:283–293PubMedCrossRefGoogle Scholar
  44. Trudell SA, Rygiewicz PT, Edmonds RL (2004) Patterns of nitrogen and carbon stable isotope ratios in macrofungi, plants and soils in two old-growth conifer forests. New Phytol 164:317–335CrossRefGoogle Scholar
  45. Vitousek PM, Shearer G, Kohl DH (1989) Foliar 15N natural abundance in Hawaiian rainforest: patterns and possible mechanisms. Oecologia 78:383–388CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Complex Systems Research CenterUniversity of New HampshireDurhamUSA
  2. 2.Division of BiologyKansas State UniversityManhattanUSA
  3. 3.Department of Forest ScienceOregon State UniversityCorvallisUSA

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