Development of Longitudinal Split Failure in White-Rotted Aspen (<i>Populus Tremuloides</i> Michx.)

Authors

  • John A. Akande
  • George H. Kyanka
  • Robert B. Hanna

Keywords:

Smooth, split, transwall, Populus tremuloides, Trametes versicolor, Bjerkandera adusta, parenchyma, SEM, TEM

Abstract

Longitudinal splits and associated smooth fracture planes were often noted along the growth ring boundaries of aspen, Populus tremuloides Michx., which were impact-loaded on the tangential plane, after decay by Trametes versicolor (L.: Fr.) Pilat, and Bjerkandera adusta (Willd.: Fr.) Karst. To characterize this failure pattern, scanning (SEM) and transmission (TEM) electron microscopy were employed. Results showed that this failure is a result of longitudinal fracture lines that cut through the parenchyma cell-wall layers (transwall failure) and opened the lumens. These parenchyma cells were preferentially invaded by fungal hyphae early (weight loss = 10%) in the degradation process. Prominent on the fracture planes was evidence of parenchyma cross walls perpendicular to the fiber axis, fungal hyphae, and associated hyphal sheaths. Localized fracturing along the parenchyma cells suggests that fungal invasion and degradation patterns influence the development and morphology of longitudinal fracture in wood.

References

Blanchette, R. A. 1984. Screening wood decayed by white-rot fungi for preferential lignin degradation. Appl. Environ. Microbiol. 48(3):647-653.nBlanchette, R. A., and C. G. Shaw. 1978. Association among bacteria, yeast and basidiomycetes during wood decay. Phytopathology 68:631-637.nBlanchette, R. A., L. Otjen, M. J. Effland, and W. E. Eslyn. 1985. Changes in structural and chemical components of wood delignified by fungi. Wood Sci. Technol. 19:35-46.nCôté, W. A., and R. B. Hanna. 1983. Ultrastructural characterization of wood fracture surfaces. Wood Fiber Sci. 15(2):135-163.nDebaise, G. R., A. W. Porter, and R. E. Pentoney. 1966. Morphology and mechanics of wood fracture. Materials Res. Stand. 6:493-499.nGove, P. B., ed. 1961. Webster's third new international dictionary of the English language unabridged. Copyright by G. & C. Merrian Co. 2,662 pp.nHarada, H., and W. A. Côté. 1985. Structure of wood. Ch. 1:1-42 in T. Higuchi, ed. Biosynthesis and biodegradation of wood components. Academic Press, Inc., Orlando, FL.nHighley, T. L., and T. K. Kirk. 1979. Mechanism of wood decay and the unique features of heart rots. Symposium on wood decay in living trees. Annual Meeting of the American Phytopathological Society, Tucson, AZ 69(10):1151-1157.nKarnovsky, M. H. 1965. A formaldehyde-glutaraldehyde fixative of high osmolarity for use in electron microscopy. J. Cell Biol. 21:137A.nKucera, L. J., and M. Bariska. 1982. On the fracture morphology in wood Part 1. A SEM-Study of deformations in wood of spruce and aspen upon ultimate axial compression load. Wood Sci. Technol. 16:241-259.nMurmanis, L., T. L. Highley, and J. G. Palmer. 1984. An electron microscopy study of Western Hemlock degradation by white-rot fungus Ganoderma applanatum.Holsforchung 28:11-18.nOtjen, L., and R. A. Blanchette. 1986. A discussion of microstructural changes in wood during decomposition by white-rot basidiomycetes. Scientific Journal Series Paper, Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA. 14330:905-911.nPanshin, A. J., and C. de Zeeuw. 1980. Textbook of wood technology. McGraw Hill Book Co. New York, NY. Pp. 358-404.nWood Handbook. 1974. Wood as an engineering material. Forest Service, Forest Products Laboratory. USDA Agric. Handbook No. 72. Washington, DC.n

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Published

2007-06-28

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Research Contributions