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  • Cited by 13
  • Print publication year: 2006
  • Online publication date: December 2009

2 - Integrated nutrient cycles in boreal forest ecosystems – the role of mycorrhizal fungi

Summary

Introduction

Mycorrhizal fungi play a central role in biogeochemical cycles since they obtain carbon from their photosynthetic plant hosts and allocate this via their mycelia to the soil ecosystem. The mycelia interact with a range of organic and inorganic substrates, as well as with different organisms such as bacteria, fungi, soil micro- and meso-fauna and the roots of secondary hosts or non-host plants. Some of the carbon allocated to the mycelium is used to make compounds such as enzymes, organic acids, siderophores or antibiotics, which influence biotic or abiotic substrates through processes such as decomposition, weathering or antibiosis. Organic and inorganic nutrients mobilized from these substrates can be taken up by the mycorrhizal mycelia and translocated to their plant hosts, influencing plant growth, community structure and vegetation dynamics. Ultimately these changes have further impacts on biogeochemical cycles. Different types of mycorrhizal symbiosis have evolved as adaptations to different suites of edaphic parameters, resulting in the characteristic vegetation types that dominate different terrestrial biomes. Other chapters in this book consider specific contributions of ectomycorrhizal fungi to mineral dissolution (see Wallander, Chapter 14, this volume), carbon and nitrogen cycling (see Hobbie & Wallander, Chapter 5, this volume) and mineral tunnelling (see Smits, Chapter 13, this volume). In this chapter we concentrate on how these activities are integrated and on ways in which ectomycorrhizal hyphae may interact with other microorganisms to influence biogeochemical cycles.

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