Studies on the systematics of ectomycorrhizal fungi in axenic culture. V. Linear growth response to standard extreme temperatures used as a taxonomic character

摘要

Ectomycorrhizal fungi showed characteristic differences in linear growth rate reduction when grown on modified Melinndash;Norkrans agar at 7 and 30 deg;C. The two standard temperature extremes differentiated ectomycorrhizal fungi into three growth response categories which reflected taxonomic affinity: sensitive, semitolerant, and tolerant. At 7 deg;C, species ofLaccariaandHebelomagenerally exhibited tolerant or semitolerant growth, whereas at 30 deg;C growth tended to be restricted to species ofAmanita,Laccaria,Suillus, and a few gasteromycetous fungi (e.g.,Rhizopogon,Scleroderma, andPisolithus). The results reveal the potential value of standard extreme temperatures as a taxonomic character for differentiating species or genera of ectomycorrhizal fungiin vitro. Tolerance or sensitivity to 30 deg;C by ectomycorrhizal fungi may reflect their association with specific host trees.Key words: ectomycorrhizal fungi, temperature, sensitivity, tolerance, cultures, identification.