The performance of isolates of the ectomycorrhizal fungi Coltricia
perennis, Laccaria bicolor, Lactarius hepaticus
and
Paxillus involutus
originating from Scots pine stands was studied on solid media with different
concentrations of ammonium, glycine and glucose as
inorganic nitrogen, organic nitrogen and carbon source. Laccaria bicolor
was able to grow on both ammonium- and glycine-containing
media. Biomass and growth rate of L. hepaticus and P. involutus
on media with ammonium were generally higher than on media with
glycine as nitrogen source. Coltricia perennis did not clearly
show
preference for either ammonium or glycine. Fractal dimensions,
calculated from the biomass and radii of the fungi, were in the range 1–3.
Fractal dimensions provided extra information about the
foraging strategy of mycelia not obtained from growth rate and biomass
production measurements, but cannot replace those because
the use of fractal dimensions alone may lead to misinterpretation.