Using radiocarbon to determine the mycorrhizal status of fungi
Measurements of 13 C in fungal sporocarps are useful in assessing mycorrhizal or saprotrophic status. Because 14 C measurements can indicate the age of fungal carbon (C) and mycorrhizal fungi depend closely on recent photosynthate, 14 C may provide additional insight into possible mycorrhizal status.
Sporocarps, needles, and litter from Woods Creek, OR, USA together with archived sporocarps were measured for 14 C content by accelerator mass spectrometry.
Known mycorrhizal fungi resembled current‐year needles ( Amanita , Cantharellus and Gomphidius ) or atmospheric CO 2 ( Tuber ) in 14 C and indicated an average age of 0–2 yr for incorporated C, whereas saprotrophic genera ( Pleurocybella , Lepiota and Hypholoma ) were composed of C at least 10 yr old. Of genera tentatively considered mycorrhizal from previous work with 13 C, only Otidia and Sowerbyella appeared mycorrhizal from 14 C measurements, whereas Aleuria , Clavulina , Paurocotylis and Ramaria (sensu lato ) consisted of older carbon and were presumably saprotrophic.
14 C clearly separated known mycorrhizal or saprotrophic fungi and indicated 13 C measurements should be interpreted cautiously on species of unknown status. 14 C results for needles and mycorrhizal fungi suggested that C sources other than atmospheric CO 2 may contribute small amounts of C. Possible sources include storage of carbohydrates and amino acids, organic nitrogen uptake, and incorporation of soil‐respired CO 2 by anaplerotic or photosynthetic pathways.
Earth Systems Research Center
Digital Object Identifier (DOI)
Hobbie, E.A., N.S. Weber, J.M. Trappe, and G.J. van Klinken. 2002. Using radiocarbon to determine mycorrhizal status in fungi. New Phytologist 156:129-136.