Printer-friendlyIrving K. Barber School of Arts and Sciences /  > Biology > Research > FAME > Projects > Physiological diversity of ectomycorrhizal fungi

Physiological diversity of ectomycorrhizal fungi in the field

As part of a major study on N transformations in high elevation spruce/fir forests following logging, we compared uptake of 15N-labeled nitrate, 15N-labeled ammonium or 15N/13C-labeled aspartate by 15 month-old Picea engelmannii seedlings that had become naturally colonized by ectomycorrhizal fungi after growing on the site for 12 months. 15N from all N sources was detected in roots after 24 hours, and in shoots after 72 hours. There was no difference in the amount of 15N accumulated from nitrate, ammonium or aspartate. When we accounted for the specific activity of the label, it was apparent that much more ammonium was absorbed in total, because soil solution levels of ammonium were much higher than those of nitrate. Because colonization rates varied, some seedlings were still non-mycorrhizal and most others were colonized by one fungus only. There was no difference in the amount of 15N accumulated when all mycorrhizal plants were compared with non-mycorrhizal plants. Interestingly, however, there were differences amongst plants ectomycorrhizal with different fungi. Furthermore, seedlings colonized with different fungi had different ratios of 13C to 15N from aspartate, suggesting that the mycorrhizas and associated rhizobacteria differed in their accumulation of intact aspartate.

This study was part of the PhD project of Heather Peat. Other collaborators include Leanne Philip, Frank Grenon, Michele Fitzgerald, Leigh Holt, Carl Redmond, Robert Bradley, Cindy Prescott and Tony Glass.

Unresolved questions

Do the dominant ectomycorrhizal fungi in clearcuts differ physiologically in a consistent way from fungi dominant in developed forests?

Last reviewed shim4/8/2015 12:33:32 PM