scholarly journals Resistance of thermo-hygro-mechanically (THM) densified wood to degradation by white rot fungi

Holzforschung ◽  
2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Oleksandr Skyba ◽  
Peter Niemz ◽  
Francis W.M.R. Schwarze
Keyword(s):  
Norway Spruce ◽  
Cell Walls ◽  
Treated Wood ◽  
White Rot Fungi ◽  
Hyphal Growth ◽  
White Rot ◽  
Densified Wood ◽  
Weight Losses ◽  
Spruce Wood ◽  
Different Temperatures

AbstractColonisation and degradation by the white rot fungi,Trametes versicolorandT. pubescens, were studied in wood of Norway spruce and beech subjected to three different treatments: (1) hygro-thermal treatment (160°C and 180°C), (2) mechanical densification, and (3) thermo-hygro-mechanical (THM) treatment including densification and post-treatment at different temperatures (140°C, 160°C and 180°C). The weight losses induced by the fungi were lowest in THM-densified woods. However, volume related numerical indicators for decay susceptibility did not show any significant improvements of THM-densified woods against both fungi. Analysis of the chemical composition of treated wood species revealed slight alterations in the content of polysaccharides and lignin. White rot fungi circumvented conditions restricting hyphal growth within the occluded tracheid lumina by hyphal tunnelling in the secondary walls of fibre tracheids in beech or by forming bore holes that transversally penetrated cell walls of earlywood tracheids in THM-densified spruce. The studies indicate that THM-densified beech and Norway spruce wood may have some potential in utility class 3 but are inappropriate for use in utility class 4.

scholarly journals Resistance of thermo-hygro-mechanically densified wood to colonisation and degradation by brown-rot fungi

Holzforschung ◽  
2005 ◽  
Vol 59 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Francis W.M.R. Schwarze ◽  
Melanie Spycher
Keyword(s):  
Large Diameter ◽  
Treated Wood ◽  
Brown Rot ◽  
Hyphal Growth ◽  
Saturated Steam ◽  
Densified Wood ◽  
Brown Rot Fungi ◽  
Weight Losses ◽  
Poria Placenta ◽  
Different Temperatures

Abstract Colonisation and wood degradation by three brown-rot fungi, Coniophora puteana, Gloeophyllum trabeum and Poria placenta, were studied in wood of Norway spruce (Picea abies) subjected to three different treatments: hygro-thermal (TH) (160 and 180°C), mechanical densification and thermo-hygro-mechanical (THM) treatment including densification and post-treatment under saturated steam conditions at different temperatures (140, 160 and 180°C). The weight loss induced by all three fungi was lowest in THM-densified wood post-treated at 180°C. Highest weight losses were recorded for controls and TH-treated wood. Fungal colonisation varied in its intensity, depending on the treatment applied to the wood. Hyphal growth in controls and TH-treated wood was abundant, whereas in densified and THM-densified wood it was sparse and confined predominantly to the cell lumina of earlywood tracheids. Also, penetration of large-diameter hyphae and associated degradation in THM-densified wood was impeded by occlusion of the lumina, associated with irreversible compression (loss in shape memory). In contrast to C. puteana and P. placenta, which showed typical brown-rot behaviour, G. trabeum frequently showed hyphal tunnelling within the secondary walls of tracheids and xylem ray parenchyma of controls and thermally treated wood. Such growth was never observed in THM-densified wood post-treated at 180°C.

scholarly journals Degradation of thermo-hygro-mechanically (THM)-densified wood by soft-rot fungi

Holzforschung ◽  
2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Oleksandr Skyba ◽  
Peter Niemz ◽  
Francis W.M.R. Schwarze
Keyword(s):  
Lignin Content ◽  
Beech Wood ◽  
Treated Wood ◽  
Untreated Wood ◽  
Soft Rot ◽  
Saturated Steam ◽  
Densified Wood ◽  
Microscopical Examination ◽  
Weight Losses ◽  
Spruce Wood

Abstract Thermo-hygro-mechanical (THM)-densified wood is more resistant to colonisation and degradation by brown-rot fungi than untreated wood. Colonisation and degradation by soft-rot fungi was investigated in treated Norway spruce (Picea abies) and treated beech (Fagus sylvatica) to assess their suitability for utility class 4. Three different treatments were applied: thermal-hygro (TH) treatment, mechanical densification and THM-treatment including densification and post-treatment under saturated steam conditions at different temperatures. For comparison, additional wood specimens were treated with two concentrations of a chromium-copper (CC) wood preservative. After 32 weeks incubation, weight losses induced by soft-rot fungi were lowest in wood treated with CC. Highest weight losses were recorded from TH-treated wood, in which soft-rot erosion attack (type 2) was exclusively observed in spruce. In comparison to controls, significantly lower weight losses by soft-rot fungi were recorded in THM-treated spruce wood, but no such differences were found in beech wood. Microscopical examination showed that in THM-treated wood of spruce, soft-rot type 1 commenced from the outer wood surfaces and cavity formation was not found in deeper regions of the wood samples. THM-treated beech wood was more susceptible to degradation than that of spruce which can be partly explained by the higher syringyl lignin content in beech wood, which is more susceptible to all kinds of degradation. Hyphal colonisation and soft-rot was facilitated within deeper regions of beech wood mainly in the non-occluded lumina of parenchyma cells in multiseriate xylem rays. It can be concluded that TH-treated spruce wood and THM-treated beech wood is susceptible to soft-rot and therefore inappropriate for utility class 4.

A new method for evaluating decay: the effect of oxygen on Polyporuscompactus in red oak

1985 ◽  
Vol 15 (6) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. J. Hall ◽  
Curt Leben
Keyword(s):  
Weight Loss ◽  
Continuous Flow ◽  
Constant Pressure ◽  
White Rot Fungi ◽  
Dry Weight ◽  
Ambient Air ◽  
White Rot ◽  
Weight Losses ◽  
Soil Block ◽  
Effect Of Oxygen

The effects of oxygen decay (weight loss) incited by Polyporuscompactus Overh. was studied using small fresh and dried wood blocks containing both sapwood and heartwood of similar radial position and age. A manifold was used to deliver hydrated gas mixtures of 1.0, 4.2, or 21% (ambient air) oxygen at constant pressure and continuous flow to jars containing inoculated or noninoculated blocks. Means (P = 0.05) for dry weight losses in inoculated blocks at 1.0, 4.2, and 21% oxygen were 3.3, 8.9, and 21.4%, respectively; losses may be comparable to decay by other white rot fungi using the soil-block procedure. Losses in noninoculated blocks at the above oxygen levels were 2.0, 4.6, and 7.0%, respectively. Differences in dry weight losses between fresh and dry blocks were found. In particular, losses in inoculated fresh blocks were significantly less than losses in inoculated dry blocks in ambient air. Native inhabitants occurring in fresh wood appear to interfere with the decay processes of P. compactus. Losses in noninoculated fresh blocks were significantly greater than in noninoculated dry blocks at 21% oxygen but not at 1.0 or 4.2% oxygen; losses were attributed to natural inhabitants in fresh wood.

scholarly journals Combination of Pretreatment with White Rot Fungi and Modification of Primary and Secondary Cell Walls Improves Saccharification

2014 ◽  
Vol 8 (1) ◽  
pp. 175-186 ◽  
Author(s):  
Charis Cook ◽  
Fedra Francocci ◽  
Felice Cervone ◽  
Daniela Bellincampi ◽  
Paul G Bolwell ◽  
...  
Keyword(s):  
Cell Walls ◽  
White Rot Fungi ◽  
White Rot ◽  
Secondary Cell Walls

scholarly journals Detection and Identification of Decay Fungi in Spruce Wood by Restriction Fragment Length Polymorphism Analysis of Amplified Genes Encoding rRNA

2000 ◽  
Vol 66 (11) ◽  
pp. 4725-4734 ◽  
Author(s):  
Claudia A. Jasalavich ◽  
Andrea Ostrofsky ◽  
Jody Jellison
Keyword(s):  
Fragment Length ◽  
Internal Transcribed Spacer ◽  
White Rot Fungi ◽  
Wood Decay ◽  
Brown Rot ◽  
White Rot ◽  
Internal Transcribed Spacer Region ◽  
Decay Fungi ◽  
Spruce Wood ◽  
Restriction Fragment Length

ABSTRACT We have developed a DNA-based assay to reliably detect brown rot and white rot fungi in wood at different stages of decay. DNA, isolated by a series of CTAB (cetyltrimethylammonium bromide) and organic extractions, was amplified by the PCR using published universal primers and basidiomycete-specific primers derived from ribosomal DNA sequences. We surveyed 14 species of wood-decaying basidiomycetes (brown-rot and white-rot fungi), as well as 25 species of wood-inhabiting ascomycetes (pathogens, endophytes, and saprophytes). DNA was isolated from pure cultures of these fungi and also from spruce wood blocks colonized by individual isolates of wood decay basidiomycetes or wood-inhabiting ascomycetes. The primer pair ITS1-F (specific for higher fungi) and ITS4 (universal primer) amplified the internal transcribed spacer region from both ascomycetes and basidiomycetes from both pure culture and wood, as expected. The primer pair ITS1-F (specific for higher fungi) and ITS4-B (specific for basidiomycetes) was shown to reliably detect the presence of wood decay basidiomycetes in both pure culture and wood; ascomycetes were not detected by this primer pair. We detected the presence of decay fungi in wood by PCR before measurable weight loss had occurred to the wood. Basidiomycetes were identified to the species level by restriction fragment length polymorphisms of the internal transcribed spacer region.

scholarly journals Decay of oak Wood provoked by fungus Stereum hirsutum (Willd. ex Fr.) S. F. Gray. and its' essential physiological requirements

2005 ◽  
pp. 179-192
Author(s):  
Milenko Miric
Keyword(s):  
Cell Walls ◽  
Tension Wood ◽  
White Rot Fungi ◽  
White Rot ◽  
Pedunculate Oak ◽  
Nitrogen And Phosphorus ◽  
Wood Fibres ◽  
Parenchyma Cells ◽  
Stereum Hirsutum ◽  
Mycelial Mass

White rot fungi usually decompose cell walls of attacked wood destroying tissue elements (i.e. parenchyma cells, wood fibres, tension wood, tracheas etc) in different amount, depending to wood-species as well as to its' zones. Different fungi secrete specific enzymes that are responsible for certain damages. As consequence, the wood structure use to be significantly and unfixable decomposed and changed. Microscopical analyses that have been run provided clear and indicative information relating to effects of fungal activity on wood tissue. Physiological requirements of fungi are for shore of the highest importance in understanding of mechanism of decaying process in the wood. The most important factors as like temperature and concentration of H ions, as well as main nutrients as sources of carbon, nitrogen and phosphorus can affect the behaviour of wood decaying fungi. The impacts of these factors on the growth and production on mycelial mass of Stereum hirsutum (Willd. ex Fr.) S.F. Gray., have been investigated. This fungus is one of the most frequent appearing on the Sessile- and Pedunculate Oak weakened trees or felled logs, behaving as parasite as well as saprophyte. As a causer of Oak sapwood white rot S. hirsutum causes significant damages of wood at forest- as well as at industrial storages.

EM and microspectrophotometric analysis of biological delignification of plants

1995 ◽  
Vol 53 ◽  
pp. 986-987
Author(s):  
D. E. Akin ◽  
L. L. Rigsby ◽  
W. H. Morrison ◽  
A. Sethuraman ◽  
K.-E. L. Eriksson
Keyword(s):  
Gas Chromatography ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Biomass ◽  
White Rot Fungi ◽  
Uv Absorption ◽  
White Rot ◽  
Plant Cell Walls ◽  
Rumen Microorganisms ◽  
Cyathus Stercoreus

Aromatic constituents such as lignin bind to carbohydrates within plant cell walls and thus render the plant carbohydrates less utilizable as food and energy. Chemical methods used to upgrade the quality of plant biomass are costly, expensive, and unsafe. White rot fungi, which are the only known microorganisms that, to any extent, can remove lignin from plant cell walls, offer a biological solution to upgrading plant quality. Microscopic analyses provide information on the site of delignification that is strategically important in improving use of plant biomass.Stems of grasses and a legume were treated with the white rot fungi Ceriporiopsis subvermispora and Cyathus stercoreus for 6 weeks. Treated residues were analyzed for structural modifications using scanning and transmission electron microscopy and for aromatic constituents using ultraviolet (UV) absorption microspectrophotometry and gas chromatography. These modifications were related to improved utilization of cell walls by rumen microorganisms.UV absorption microspectrophotometry, in conjunction with gas-chromatography of alkali-treated plants, indicated that ester-linked ferulic and ρ-coumaric acids were particularly susceptible to removal by both fungal species.

scholarly journals Spatial Patterns in Hyphal Growth and Substrate Exploitation within Norway Spruce Stems Colonized by the Pathogenic White-Rot Fungus Heterobasidion parviporum

2009 ◽  
Vol 75 (12) ◽  
pp. 4069-4078 ◽  
Author(s):  
Ari M. Hietala ◽  
Nina E. Nagy ◽  
Arne Steffenrem ◽  
Harald Kvaalen ◽  
Carl G. Fossdal ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Norway Spruce ◽  
Reaction Zone ◽  
Hyphal Growth ◽  
White Rot ◽  
White Rot Fungus ◽  
Local Concentration ◽  
Enhanced Production ◽  
Hyphal Sheath ◽  
Pathogen Dna

ABSTRACT In Norway spruce, a fungistatic reaction zone with a high pH and enrichment of phenolics is formed in the sapwood facing heartwood colonized by the white-rot fungus Heterobasidion parviporum. Fungal penetration of the reaction zone eventually results in expansion of this xylem defense. To obtain information about mechanisms operating upon heartwood and reaction zone colonization by the pathogen, hyphal growth and wood degradation were investigated using real-time PCR, microscopy, and comparative wood density analysis of naturally colonized trees with extensive stem decay. The hyphae associated with delignified wood at stump level were devoid of any extracellular matrix, whereas incipient decay at the top of decay columns was characterized by a carbohydrate-rich hyphal sheath attaching hyphae to tracheid walls. The amount of pathogen DNA peaked in aniline wood, a narrow darkened tissue at the colony border apparently representing a compromised region of the reaction zone. Vigorous production of pathogen conidiophores occurred in this region. Colonization of aniline wood was characterized by hyphal growth within polyphenolic lumen deposits in tracheids and rays, and the hyphae were fully encased in a carbohydrate-rich extracellular matrix. Together, these data indicate that the interaction of the fungus with the reaction zone involves a local concentration of fungal biomass that forms an efficient translocation channel for nutrients. Finally, the enhanced production of the hyphal sheath may be instrumental in lateral expansion of the decay column beyond the reaction zone boundary.

Changes in cation concentrations in red spruce wood decayed by brown rot and white rot fungi

1997 ◽  
Vol 27 (4) ◽  
pp. 567-571 ◽  
Author(s):  
A Ostrofsky ◽  
J Jellison ◽  
K T Smith ◽  
W C Shortle
Keyword(s):  
White Rot Fungi ◽  
Brown Rot ◽  
Red Spruce ◽  
White Rot ◽  
Spruce Wood
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