Studies on the systematics of ectomycorrhizal fungi in axenic culture. IV. The effect of some selected fungitoxic compounds upon linear growth

摘要

When cultures of ectomycorrhizal fungi were grown on potato dextrose agar supplemented with either benomyl (10ensp;mu;g/mL), cycloheximide (2ensp;mu;g/mL), rose bengal (10ensp;mu;g/mL), malachite green (2ensp;mu;g/mL), or sodium chloride (10ensp;mg/mL), characteristic differences in linear growth rate reduction were exhibited. These fungitoxic compounds were able to differentiate ectomycorrhizal fungi into three growth-response categories, namely sensitive, semitolerant, and tolerant, which reflected taxonomic affinity. Linear growth of the Russulaceae and species ofHebeloma, for example, was inhibited by benomyl (10ensp;mu;g/mL), whereas members of the Boletaceae and most species ofCortinariuswere tolerant and species ofTricholomawere semitolerant at this concentration.Lactarius,Leccinum, and mostSuillusspecies were sensitive to cycloheximide (2ensp;mu;g/mL);Laccaria,Rhizopogon, and mostHebelomaspecies showed tolerance.Hygrophorusand mostLactariusspecies showed sensitivity to rose bengal (10ensp;mu;g/mL), whereasCortinarius,Laccaria,Suillus, and someLactariusspecies (section Dapetes) exhibited tolerance. Malachite green (2ensp;mu;g/mL) inhibited species ofLactarius, whereas species ofSuillusandTricholomawere tolerant.Xerocomus,Rhizopogon,Hygrophorus, and mostTricholomaspecies were sensitive to sodium chloride (10ensp;mg/mL), whereas tolerance was exhibited by most species ofSuillus,Laccaria, andHebeloma. The results reveal that growth responses to these fungitoxic compounds have potential as taxonomic characters for the differentiation and identification of isolates of ectomycorrhizal fungi.Key words: ectomycorrhizal fungi, fungitoxic compounds, cultures, identification, systematics.