Incorporating microbes into plant community ecology
Horton, Tom .
Structure and function of mycorrhizal networks: A complex foundation for plant communities.
In 1988 Newman outlined the ecological significance of mycorrhizal linkages in plant communities. Our understanding of the structure and function of mycorrhizal networks has developed further with the application of isotopic tracers and methods for identifying individuals and species of fungi. Fungal communities are species rich, and we are beginning to learn about the functional roles of those species. I define a common mycorrhizal network as a continuous thallus (mycelium of an individual) linking two or more plant individuals of the same or different species. The sum of multiple common mycorrhizal networks can be thought of as a complex mycorrhizal network, and with this complexity comes all the variations in structure and function that each species of fungus brings.The size of a fungal individual varies by species, but typically ranges from meters to tens of meters. Larger genetic individuals are likely made up of multiple ramets, but even if an individual is continuous, the scale of directin fluence on plants in a common network is likely centimeters to a few meters.Non-self fusions between thalli are rejected in Basidiomycota and Ascomycota (variously forming ecto-, ericoid, arbutoid, monotropoid and orchid mycorrhizae) through the vegetative incompatibility system. Species in Glomeromycota (forming arbuscular mycorrhizae) develop genetically mixed thalli. The fungi in a complex mycorrhizal network are a guild of organisms competing for resources. The fungi have enzymatic capacities for accessing forms of nutrients unavailable to plants such as organic nitrogen and recalcitrant forms of phosphorus. Competition for soil nutrients is likely a function of root-to-root competition for plant available forms and mycelial competition for plant unavailable forms. We have good evidence that C, N, and P move through networks, but we are in need of studies elucidating which species are moving them in these complex systems, how they interact with host species, and what molecules are transferred to the hosts.
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1 - SUNY-Environmental Science and Forestry, Environmental Biology, 241 Illick Hall, Syracuse, NY, 13210, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Westminster Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 8:45 AM