Harper, Carla , Taylor, Thomas , Krings, Michael .
Antarctic wood-decay fungi in glossopteridalean roots and stems.
One of the most significant and recognized roles of fungi in modern environments is as saprotrophic entities involved with nutrient cycling. One of the most prevalent hosts for fungal degradation is woody plants, in the form of wood rot. Wood rot is of three principal types: white, brown, and soft rot. In extant ecosystems, white-rot decay is caused by either a basidiomycete or ascomycete fungus. The most important diagnostic character of white-rot decay is the delignification of the plant cell wall. Thus, this type of rot produces enzymes to degrade lignin, cellulose, and hemicellulose. White-rot decay can also produce a degradational pattern of large "pockets" wherein secondary xylem is destroyed and termed white pocket rot. Through the use of thin-sectioning techniques, we present the first evidence of wood-decaying fungi in stems (Araucarioxylon/Dadoxylon-type wood) of Glossopteridales and will further detail the wood-decaying fungi in the woody roots of Vertebraria. The fungus is represented by vegetative septate hyphae that are present in tracheids, ray parenchyma cells, and when preserved, the pith. These hyphae branch at right angles and possess simple, medallion, and putative whorled clamp connections; these features are characters of basidiomycetous fungi. The fungus progresses through the pit apertures and can directly penetrate the wood cells radially and tangentially. In certain infected cells, the wall layers separate and form possible appositions. The wood in both roots and stems contain numerous pockets, however, fungal remains are absent in pockets. We therefore interpret this type of fungal interaction as a white-rot wood decay. One of the most interesting aspects of this investigation is the co-occurrence of fungal remains at multiple stages of fungal decay in multiple specimens. As a result it is possible to delineate and follow the degradational pattern caused by these fungi by examining the wood cell walls. These wood-decaying fungi may have played a major role as decomposers in Permian peat forming environments. With these data, we can further elucidate wood-fungal relationships and build a more complete understanding of the ecological processes that sustained late Paleozoic terrestrial ecosystems.
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1 - University Of Kansas, Ecology And Evolutionary Biology, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
2 - University Of Kansas, Department Of Ecology And Evolutionary Biology, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, KS, 66045-2106, USA
3 - Department für Geo- und Umweltwissenschaften, Paläontologie und Geobiologie, Ludwig- Maximilians-Universität, Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, Munich, 80333, Germany
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Monday, July 9th, 2012
Time: 9:15 AM