Arctic and temperate strains of Hebeloma spp. were grown
in axenic culture on glutamic acid, alanine, lysine and NH4+
as sole
sources of nitrogen (N), with excess carbon (C) or deficient C (supplied
as glucose). Their ability to utilize seed protein as a natural
N source was also assessed. All strains tested had the capacity to assimilate
amino acids and generally utilized alanine and glutamic
acid more readily than NH4+. Some strains were able
to utilize amino C when starved of glucose C, and could mineralize amino-N
to NH3-N. Arctic strains, in particular, appeared to be pre-adapted
to the utilization of seed protein N and glutamic acid N, which is
often liberated in high concentrations after soil freezing. The results
are discussed in relation to their possible ecological importance.