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PHYLOGENETIC AND ENVIRONMENTAL INFLUENCES ON NITROGEN STABLE ISOTOPE RATIOS IN SPOROCARPS OF ECTOMYCORRHIZAL FUNGI
Citation:
Trudell, S. A., P T. Rygiewicz, AND R. L. Edmonds. PHYLOGENETIC AND ENVIRONMENTAL INFLUENCES ON NITROGEN STABLE ISOTOPE RATIOS IN SPOROCARPS OF ECTOMYCORRHIZAL FUNGI. Presented at Third International Conference on Mycorrhizas, Adelaide, South Australia, July 8-13, 2001.
Description:
It has been suggested that nitrogen stable isotope ratios (expressed as d15N) of fungus sporocarps, in conjunction with d15N data from other ecosystem compartments, can be used to elucidate key processes in forest N-cycling. Although results of previous studies generally support this idea, they also show that the large number of factors that influence d15N can complicate interpretation of the data. To date, there has been no integrated study of the relative degree to which the different sources of variation contribute to the observed d15N of fungus sporocarp samples. Here, we report initial d15N measurements on a large number of sporocarp collections from two conifer forests located in contrasting environmental zones on the Olympic Peninsula, Washington. Based on these data, we provide estimates of variance in d15N for individual species and genera of ectomycorrhizal fungi and assess the degree to which phylogenetic and environmental factors appear to influence d15N values. The results of our overall study, of which this work is one component, will increase the usefulness of stable isotope ratios in understanding N-cycling and, hopefully, help draw greater attention to the critical ecosystem roles played by ectomycorrhizal fungi.