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The Development of the Mycelium of Fomes Igniarius (fries) Kickx, in Culture and in Host Tissue

其他書名	(microfilm).
出版	National Library of Canada, 1971
URL	http://books.google.com.hk/books?id=SSNhtAEACAAJ&hl=&source=gbs_api

註釋The structure and development of the mycelium of Fomes igniavius (Fries) Kickx. is described on the basis of results obtained from comparative studies of the variety gogulinus occurring on aspen poplar and the variety laevigatus occurring on birch. It has been found that the mycelium has a distinctive morphology which is expressed in both the host tissue and in culture. The mycelium of F. igniavius consists of three kinds of hyphae; thin-walled hyphae, fiber hyphae and cuticular cells. The thin-walled hyphae are frequently branched and lack clamp connections. The type of branching is monopodial and branches form in acropetal succession. The branches arise mostly at acute angles, but branching at right angles and in whorls occurs occasionally. Hyphal anastomosis is frequent in thin-walled hyphae. Fiber hyphae and cuticular cells originate from the thin-walled hyphae with a septum at the differentiation point. The distinctive characters of the variety laevigatus are the presence of thin-walled, broad hyphae and development of hyphal rings. In variety -populinus, the presence of half septa, cell wall constrictions and invaginations are the distinguishing features. The maximum mycelial growth takes place at 27°C in both solid and liquid media. Diffusion zones are produced by F. igniavius on gallic and tannic acid agars. F. igniavius var. populinus is a slow growing fungus. The advancing zone becomes bayed after three to four weeks on malt-agar medium. The color of the mYcelium becomes dark brown at later stages of growth. The fungus produces a strong wintergreen'odor on malt-agar medium. On the same medium variety laevigatus, comparatively faster growing, is cinnamon-orange in color at later stages of growth. The advancing zone is hyaline with the hyphae well separated from each other. The wintergreen odor is mild in this variety. Ultrastructure studies of the hyphae have shown that there is dolipore type of septum in the various kinds of hyphae composing the mycelium. The hyphal cell wall in F. igniavius was observed to be either single or multilayered and was usually triple layered. Cell organelles such as endoplasmic reticulum, mitochondria and vesicles were found in abundance in the growing hyphae. As the fiber hyphae and cuticular cells developed, the cell organelles disintegrated and at maturity only diffuse cytoplasm was observed suggesting the possible utilization of these organelles in the thickening of the cell v/all. A characteristic feature of this fungus was the presence of complex concentric membranes. The lomasomes were seen to bud off from these membranes. The morphological and physiological characters of the mycelium are evaluated with respect to their usefulness in classification.