Chemical reactions of mantle pieces or rhizomorphs are mostly the method of choice, since frequently not enough material is available to use complete tips or ramified systems in order to test reactions. On the other hand colour changes of complete ectomycorrhizae are frequently influenced by reactions of root material. Chemical reagents should be applied and mixed as described by Agerer (1991): Methods in Microbiology 23: 25-73, or quoted by Agerer (1986): Mycotaxon 26: 473-492. The 17 commonly applied chemicals are not all of the same importance. Three groups can now be distinguished with respect to their significance regarding frequency and impressiveness of reactions. The following chemicals should always be used because they are very informative, as they cause striking changes, and the reactions are not infrequent: Melzer’s reagent, sulfo-vanillin, KOH 10%, guaiac, FeSO4, lactic acid, brillant-cresyl-blue. These reagents are arranged with respect to their relative importance (first to last). A second group of chemicals is characterized by the occurrence of infrequent and less pronounced reactions: toluidin blue, formol 40%, cotton-blue-lactic-acid, sudan III, ethanol 70%, phenole-aniline. These reagents are again arranged with respect to their relative importance (first to last). The third group of chemicals did not show any reactions up to now: phenole, anilin, acid fuchsin, ruthenium-red. But this does not imply that these reactions should always be omitted; possibly in the future these reagents might cause reactions in some ectomycorrhizae presently not described. Perhaps, also additional reagents should be applied by way of trial. When a reaction is positive, the kind of colour change should be noted separately, and can be looked up in text-fields. |
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