Vrålstad T, Holst-Jensen A, Schumacher T
Department of Biology, University of Oslo, Norway.
Mol Ecol. 1998 May;7(5):609-16. doi: 10.1046/j.1365-294x.1998.00365.x.
The hypothesis that the postfire discomycete Geopyxis carbonaria (Ascomycota, Pezizales, Pyronemataceae) has a biotrophic association with roots of Norway spruce (Picea abies) in nature was tested by isolation of fungal strains from fresh, brown, smooth mycorrhiza-like root tips of Norway spruce collected from below the depth of detrimental heat penetration in a postfire site. The morphology of seven culture isolates originating from the smooth mycorrhiza-like root tips of two different spruce trees was congruent with the morphology of axenic culture isolates obtained from ascospores of G. carbonaria. DNA sequences of the nuclear ribosomal internal transcribed spacers ITS1 and ITS2 from these root-derived cultures and the ascosporic G. carbonaria culture isolates were found to be identical, further supporting the conclusion that the isolates were conspecific. The extensive ascocarp and ascospore formation of G. carbonaria which succeeds a forest fire may be explained in terms of a fungal escape from a moribund tree associate. Possible ecological adaptations of G. carbonaria to the pre- and postfire community are discussed.
关于火灾后盘菌 Geopyxis carbonaria（子囊菌门，盘菌目，火丝菌科）在自然环境中与挪威云杉（Picea abies）根系存在生物营养关联的假说，通过从火灾后场地中有害热穿透深度以下采集的新鲜、褐色、光滑的类似菌根根尖中分离真菌菌株进行了验证。从两棵不同云杉树的类似菌根根尖分离得到的七个培养菌株的形态，与从 Geopyxis carbonaria 子囊孢子获得的无菌培养菌株的形态一致。发现这些源自根系的培养物以及 Geopyxis carbonaria 子囊孢子培养菌株的核糖体内部转录间隔区 ITS1 和 ITS2 的 DNA 序列相同，进一步支持了这些分离物为同种的结论。森林火灾后 Geopyxis carbonaria 广泛形成子囊果和子囊孢子的现象，或许可以用真菌从濒死的树木共生体中逃脱来解释。文中还讨论了 Geopyxis carbonaria 对火灾前后群落可能的生态适应性。
