Changes in the Chemical Composition of Wood Caused by Six Soft-Rot Fungi

摘要: Standardized blocks of alder, poplar, and pine wood were hemicellulose (xylan). Lignin, which was analyzed by the decayed six soft-rot fungi (Graphium sp., Monodictys “sulfuric acid” method, depleted all fungi. Pine Paecilomyces Papulospora Thielavia terrestris, not significantly three fungi, only Allescheria sp.), had been isolated from pulp chip to low weight losses (15% or less) other storage piles. Samples woods at different ( terrestris). for lignin, glucan (cellulose), xylan, Analysis that showed lignin mannan (hemicelluloses) allow calculation depletion faster than cellulose hemicelluloses in these major components caused sp. Carbohydrates alder usually Phytopathology 65:473-476 Additional key words: Alnus rubra, Populus balsamifera, Pinus monticola, decay, thermophilic Of types fungal decay (soft­ rot, brown-rot, white-rot) least studied is soft-rot, numerous members Fungi Imperfecti Ascomycetes 1 ) . Research has especially deficient elucidating chemistry wood. In fact, chemical effects one fungus, Chaetomium globosum, on kind wood, European beech (Fagus sylvatica), have investigated (5). globosum causer, extensive loss beech, depleting pentosans (mainly xylan) considerably (7, 9, 10). Working with polysaccharides rather whole Keilich et al. (4) Takahashi Nishimoto (11) found C. capable degrading xylans mannans, former being degraded a slightly greater rate latter. Soft-rot including large numbers piles recent years (2). laboratory studies, isolates considerable substance, particularly hardwood chips, thereby emphasizing importance as destructive organisms. However, it determined whether most cause changes similar those example, some attack cellulose, preferentially. Such information needed full assessment capabilities organisms, known be prevalent causing substantial The purpose this research, therefore, determine quantitatively structural during several wood-chip-inhabiting MATERIALS AND METHODS.-Wood samples decay.-Outer xylem blocks, 25.4 × 12.5 6.3 mm (1 1/2 1/4 in.), dimension fiber direction, cut single boards red (Alnus rubra Bong.), balsam poplar (Populus balsamifera L.), western white (Pinus monticola Dougl.). numbered, conditioned constant t 27 C 70% RH, then weighed. Eight replicate each species strung together, sterilized, subjected serial-block method (3). Following 12 weeks incubation mesophilic test 45 removed, reconditioned, weighed, their calculated. small size coupled relatively cross-sectional area, permitted rapid penetration uniform throughout blocks. used piles, shown previous tests appreciable Mesophilic included Graphium (MEBC-11), (ME-GC-18), (ME-PC-19). Thermophiles M E T B 0 , terrestris (Apinis) Mallock & Cain = (H-63­ 1), (ME-T-BC-9). roughly grouped according desired removed individual analysis. (The variation within same fungus reflects primarily intentional moisture contents among (3).) A block pine, well sectioned transversely tangentially examined microscopically typical both hardwoods softwoods. Analyses.-Decay control ground pass 0.50-mm (40-mesh) screen meal dried thoroughly under high vacuum. analyzed, without extraction, acid lignin” an adaptation published procedure (12) total reducing sugars hydrolysates (determined colorimetrically glucose) (8). Relative amounts glucose, xylose, mannose after paper chromatographic separation From values, glucan, mannan, calculated (6). Angiosperm composed mainly ofthe O-acetyl-4-O-methylglucuronoxylan type (approximately 75% plus smaller