2 results
1 - Imaging complex nutrient dynamics in mycelial networks
- from I - Imaging and modelling of fungi in the environment
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- By Daniel P. Bebber, Department of Plant Sciences, University of Oxford, Monika Tlalka, Department of Plant Sciences, University of Oxford, Juliet Hynes, Cardiff School of Biosciences, Cardiff University, Peter R. Darrah, Department of Plant Sciences, University of Oxford, Anne Ashford, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sarah C. Watkinson, Department of Plant Sciences, University of Oxford, Lynne Boddy, Cardiff School of Biosciences, Cardiff University, Mark D. Fricker, Department of Plant Sciences, University of Oxford
- Edited by Geoffrey Gadd, University of Dundee, Sarah C. Watkinson, University of Oxford, Paul S. Dyer, University of Nottingham
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- Book:
- Fungi in the Environment
- Published online:
- 03 November 2009
- Print publication:
- 12 April 2007, pp 3-21
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Summary
Introduction
Basidiomycetes are the major agents of decomposition and nutrient cycling in forest ecosystems, occurring as both saprotrophs and mycorrhizal symbionts (Boddy & Watkinson, 1995; Smith & Read, 1997). The mycelium can scavenge and sequester nutrients from soil, concentrate nutrients from decomposing organic matter, relocate nutrients between different organic resources, and ultimately make nutrients available to plants to maintain primary productivity. Hyphae of both saprotrophic and ectomycorrhizal basidiomycetes that ramify through soil often aggregate to form rapidly extending, persistent, specialized high-conductivity channels termed cords (Rayner et al., 1994, 1999; Boddy, 1999; Watkinson, 1999; Cairney, 2005). These cords form complex networks that can extend for metres or hectares in the natural environment. The distribution of resources is extremely heterogeneous and unpredictable in space and time, and these fungi have developed species-specific strategies to search for new resources and to capitalize on resources landing on their mycelial systems (Chapter 6, this volume). Thus the architecture of the network is not static, but is continuously reconfigured in response to local nutritional or environmental cues, damage or predation, through a combination of growth, branching, fusion or regression (Boddy, 1999; Watkinson, 1999; Chapter 6, this volume). At this stage it is not clear whether specific global mechanisms exist to couple local sensory perception and responses over different length scales specifically to maximize the long-term success of the whole colony, or whether such collective behaviour is an emergent property arising solely from local interactions of individual hyphae.
7 - The role of wood decay fungi in the carbon and nitrogen dynamics of the forest floor
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- By Sarah Watkinson, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, Dan Bebber, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, Peter Darrah, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, Mark Fricker, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, Monika Tlalka, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, Lynne Boddy, Cardiff School of Biosciences, Cardiff University, Main Building Park Place, Cardiff CF10 3TL, UK
- Edited by Geoffrey Michael Gadd, University of Dundee
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- Book:
- Fungi in Biogeochemical Cycles
- Published online:
- 10 December 2009
- Print publication:
- 04 May 2006, pp 151-181
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Summary
Introduction
The mycelium of woodland fungi can act both as a reservoir and as a distribution system for nutrients, owing to its physiological and developmental adaptations to life at the interface between organic and mineral soil horizons. The mobility of accumulated nitrogen and phosphorus within the mycelial networks of cord-forming wood decay fungi and ectomycorrhiza enables fungi to play key roles as wood decomposers and root symbionts. The dynamics of nitrogen movement have been less investigated than phosphorus owing to lack of a suitable tracer. We have developed a new technique for tracing nitrogen translocation in real time, using 14C as a marker for nitrogen by incorporating it into a non-decomposed amino acid that tracks the mycelial free amino acid pool. Its movement can be imaged by counting photon emissions from a scintillant screen in contact with the mycelial system. This method allows real-time imaging at high temporal and spatial resolution, for periods of weeks and areas up to 1 m2, in microcosms that mimic the mineral/organic soil interface of the forest floor. The results reveal a hitherto unsuspected dynamism and responsiveness in amino acid flows through mycelial networks of cord-forming, wood-decomposing basidiomycetes. We interpret these in the light of current understanding of the pivotal role of fungi in boreal and temperate forest floor nutrient cycling, and attempt to formulate key questions to investigate the effects of mycelial nitrogen translocation on forest floor decomposition and nitrogen absorption.