Global ETD Search

1	Studies on Trametes species occurring in the indigenous forests of Zimbabwe Mswaka, Allen Yvon January 1994 (has links) No description available. 580 Wood decay fungi
2	Basidiomycota in forest reserves and plantation forests in Peninsular Malaysia Ujang, Salmiah January 1997 (has links) No description available. 620.11223 Wood decay fungi; Wood preservation
3	Effects of microbial interactions on gene expression during the wood decay process Mangum, Lee Christopher 08 August 2009 (has links) Real-time RT-PCR was used to assess the effects of interspecific microbial interactions on the expression of genes associated with lignin peroxidase, manganese peroxidase and alcohol oxidase production during the wood decay process. Expression levels of genes encoding the selected lignolytic enzymes were quantitated in one-, two- and multiple-organism interaction tests with the basidiomycetes Trametes elegans, Phanerochaete chrysosporium, Gloeophyllum sepiarium and Gloeophyllum trabeum. Compression strength loss was measured for each decay sample and correlated with gene expression data for each species. Soil microflora actively producing lignolytic enzymes during wood decay were also assessed and identified using degenerative PCR coupled with denaturing gradient gel electrophoresis, cloning and cycle sequencing. Differential expression was detected in three genes in the two-organism interaction tests: manganese peroxidase in T. elegans interactions, lignin peroxidase A in P. chrysosporium interactions and alcohol oxidase in G. sepiarium interactions. A positive linear correlation was observed between lignin peroxidase A expression and compression strength loss in P. chrysosporium interactions. Wood Decay Fungi DGGE Real-time RT-PCR Gene Expression
4	Factors that limit the occurrence of wood-decaying fungi / Gustafsson, Mårten. January 2001 (has links) (PDF) Lic.-avh. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 2 uppsatser.
5	Nano-Chitosan Wood Treatment : A Combined Fire-Retardant and Antifungal Treatment KhademiBami, Laya 03 May 2019 (has links) The feasibility of using modified nano-chitosan particles as an environmentally friendly wood preservative agent was investigated in this research. Chitosan nano-particles were prepared from commercially available low molecular weight (LMW) chitosan and its derivative, trimethyl chitosan (TMC). The specific amount of sodium nitrite added to LMW chitosan through depolymerization process indicated the desired chitosan oligomers. Thin layer chromatography (TLC) was done to confirm the formation of chitosan oligomers with degree of polymerization four. Preparation of TMC was done through a quaternization process and Fourier-transform infrared spectroscopy (FTIR) graphs proved the formation of TMC. Sodium tri-poly phosphate (TPP) as a commercial fire retardant was added to these nanoparticles (chitosan oligomers and TMC) to form nanochitosan-TPP particles based on the ionic gelation method. The viscosity of chitosan nanoparticles which were made by chitosan oligomers and TMC were measured by rheometer. The results showed very low viscosity in comparison to LMW chitosan. The final concentration of chitosan oligomers, TMC and TPP in the nano-chitosan-TPP solution to treat wood were 12, 12 and 4.8% respectively. Then, these particles were used to treat southern yellow pine wood through vacuum impregnation process. Mass and volume of samples increased after treatment which means the nano-chitosan-TPP particles penetrated into cell walls. To study the leaching of treated samples, they were soaked to water according to the E11 standard test (AWPA, 2016) and to investigate the fungi resistance of treated samples, they were exposed to brown rot fungus (Gloeophyllum trabeum) and white rot fungus (Trametes versicolor) according to the E10 standard test (AWPA, 2016). Mass loss of the samples was compared to untreated wood controls. The results of leaching and fungi indicated that non quaternized nanochitosan-TPP particles were more effective than quaternized nanochitosan-TPP particles. Measuring the fire resistance and water vapor sorption isotherm of treated samples revealed that there were not any differences among treated and control samples. Nanochitosan particles Southern yellow pine Wood preservatives Decay fungi Fire retardancy
6	Aspects of Management of Subterranean Termites in Queensland Peters, Brenton Charles Unknown Date (has links) i ABSTRACT I investigated aspects of the management of subterranean termites in the field by evaluating the protective values of preservative treated softwoods and evaluating the potential of softwoods conditioned by decay fungi or heat to produce termite monitoring and aggregating devices. As part of the investigation, it was necessary to: · develop assay techniques suitable for research into the natural resistance of timbers, the efficacy of wood preservatives and termite biology and foraging behaviour; and quantify variation in termite responses to untreated softwoods in various situations in the field using these techniques. Field bioassays were conducted with two Australian Coptotermes species to determine protection of pine sapwood afforded by borate compounds (Chapter 2). Coptotermes lacteus (Froggatt) was examined in winter and C. acinaciformis (Froggatt) in winter, spring and summer at two localities in Queensland. Hoop-(Araucaria cunninghamii Ait ex D. Don) and slash-pine (Pinus elliottii Engelm.)-sapwood blocks were placed in plastic containers and attached to termite mounds or infested trees. Termite response was determined by mass losses over five weeks and modelled. Coptotermes lacteus was relatively benign in winter and for 1.0 and 2.5% mass losses of hoop-pine sapwood, borate retentions of 0.20 and 0.06% mass/mass (m/m) boric acid equivalent (BAE), respectively, were derived. With C. acinaciformis, for 1.0 and 5.0% mass losses of hoop-pine sapwood, borate retentions ranged from 0.49 and 0.25% BAE, respectively, in winter to 0.76 and 0.47% BAE, respectively, in late summer. For 1.0 and 5.0% mass losses of slash-pine sapwood in summer, borate retentions of 0.58 and 0.14% BAE, respectively, were derived for C. acinaciformis. These results support conclusions from earlier laboratory studies conducted elsewhere. Prevention of damage by field populations of termites was not achieved. Marked intercolony variation in response to borate compounds was demonstrated, highlighting the usefulness of this rapid technique. The need for long-term field exposure trials to calibrate the lunch-box technique and to facilitate technology transfer to industry, is indicated. For comparison, termite response to white cypress (Callitris glaucophylla Thompson and Johnson), a naturally termite resistant timber, is also reported. A field bioassay was conducted to evaluate responses of C. acinaciformis to untreated southern-yellow-pine (Pinus spp.), hoop-pine and slash-pine blocks (Chapter 3). Sapwood blocks were placed in plastic containers and attached to trees infested with the termites during summer. Containers with a test block of each of the timber species were prepared. These and other containers were exposed to termites for 10 weeks. Termite feeding response (voracity) was assessed for all blocks by determining the mass of wood consumed. Termite voracity differed among trees. Variation in termite responses to individual hoop-pine feeder-blocks within a container was appreciable and consistent between containers. Variation in termite responses to the test blocks was appreciable, with hoop pine being significantly more susceptible to termite attack than either slash pine or southern yellow pine. Southern yellow pine is a generic name for five species of pine which are difficult to separate reliably. Therefore, caution should be exercised when using southern yellow pine to ensure that samples are at least from the same species of pine and preferably from the same length of timber. The sensitivity of both the bioassay and the statistical tests was demonstrated. Of particular interest was the similar level of termite response to the test timbers in the two sections of the experiment. The usefulness of feeder-blocks to initiate reliable attack rather than to promote sustained attack, is worth further attention. Sapwood stakes of Australian-grown hoop pine, slash pine, radiata pine and North American-grown southern yellow pine were exposed to subterranean termite attack in an in-ground bioassay (Chapter 4). Stakes in bait containers and bare stakes were attacked by C. acinaciformis and Schedorhinotermes intermedius (Brauer). Susceptibility of these timbers was evaluated with regard to potential for termite monitoring and aggregation. Variation between timbers and difference between termite species are described. The relevance of these data to suppressing foraging populations of subterranean termites, in Australia, using insect growth regulators, is discussed. Four field bioassays were conducted using two species of Australian subterranean termites, C acinaciformis and C. lacteus (Chapter 5). Hoop-pine blocks decayed using 14 fungi for four weeks and for 10 weeks were subsequently conditioned using dry heating, freezing or moist heating, and then exposed to termites. Blocks decayed by Gloeophyllum abietinum [Persoon: Fries] Murrill, Trametes lilacino-gilva (Berkeley) Wright & Deschamps, Schizophyllum commune Fries and Rigidoporus undatus (Persoon) Donk and subsequently oven dried, were attacked the most. Oven drying generally enhanced termite feeding responses in these two field bioassays. In a third bioassay, blocks of five softwood timber species conditioned with two high temperature regimes were exposed to C. acinaciformis. Slash pine was attacked the least. Mean mass losses for hoop pine, Caribbean pine (Pinus caribaea Morelet), radiata pine and the interspecific F1 hybrid between Caribbean and slash pine were not significantly different. For C. lacteus, slash and hoop-pine blocks were attacked the least while radiata pine was attacked the most. Additional heating at 105°C increased the susceptibility of most timber species. Relationships between heating duration and the consumption of hoop-pine-sapwood blocks were determined using results from a fourth bioassay. Heating the timber increased feeding responses for both termite species. The selective and rapid response of the termites highlights the usefulness of this field technique for multiple-choice bioassays. The cyclodiene termiticides were withdrawn from use, in Australia, as from 30 June 1995. Implications for the management of subterranean termites in Queensland are discussed. Community perceptions of the use of chemical pesticides and cost do not favour the widespread use of preservative treated timber in buildings. An integrated pest management approach to termite control is the likely direction for the future in Australia. A range of building techniques, regular inspections, and attention to factors that predispose existing buildings to termite attack can reduce the risk of damage from termites, but do not eliminate that risk. There will be an increased need for reliable preventative and remedial treatments involving bait technology. Much more work is needed on termite biology, foraging behaviour and bait toxicants before a baiting system can be confidently commercialised in Australia. Directions for research in Queensland are discussed. subterranean termites wood preservation borates bait technology Coptotermes Schedorhinotermes field bioassay softwood susceptibility decay fungi heat treatment
7	Effect of experimental warming and assembly history on wood decomposition Hagos, Saba January 2020 (has links) Sammanfattning: Wood decay fungi are the main decomposer of lignocellulose material stored in wood. Thus, all factors that affect them could affect their ecological function. This in return, may affect ecosystem functioning in terms of altered carbon emissions from dead wood. Increased temperature is one of the main factors influencing fungal decay. The aim of the current study is to explore the effects of temperature and assembly history (order of species arrival), two important regulators of fungal communities, on wood decomposition. I conducted a microcosm experiment with two temperature treatments and eight assembly histories where each species was allowed to colonize the wood two weeks ahead of the rest of the species. The temperature treatments were set to mimic the effect of climate induced warming. Therefore, I had one treatment with relatively high temperature, representing the expected temperatures year 2100 given the current emission trends of the northern inland of Sweden, and another treatment representing the current normal temperature (1961-1990). The temperature treatments had an average difference of 5°C. In order to see how climate induced warming and fungal assembly history influenced decomposition, I measured and analyzed initial fungal growth, fungal respiration and wood weight loss. Both temperature and assembly history had a significant influence on fungal growth, fungal respiration and wood decomposition. There was also strong interaction between the two factors. The average increase in mass loss under elevated temperature was 19% compared to 14% under normal temperature. The highest mass loss (25%) was when Phlebia centrifuga was the initial species under elevated temperature and the lowest (12%) was when Climacocystis borealis was initial species under normal temperature. All assembly histories had higher mass loss under elevated temperature, but the magnitude varied. For example, when C. borealis was the initial species, mass loss increased by 60% compared to only 7% when Antrodia sinuosa was the initial species. Six out of eight assembly histories had higher CO2 under elevated temperature, with the highest increase (88%) in P. centrifuga histories and the lowest (7%) in C. borealis histories. Even if the results need to be confirmed by field studies, my data illustrates that climate induced warming probably results in higher fungal respiration and deadwood decomposition and that the magnitude of this effect depends on fungal assembly history. wood decay fungi species composition assembly history warming temperature fungal growth decomposition carbon dioxide climate feedbacks species priority polypore microcosm Norway spruce Biological Sciences Biologiska vetenskaper
8	Actions of lignocellulolytic enzymes on Abies grandis(grand fir) wood for application in biofuel production Cherdchim, Banyat 27 October 2010 (has links) No description available. 000 Allgemeines Wissenschaft Forest Sciences and Forest Ecology Abies grandis Armillaria mellea Heterobasidion annosum Heterobasidion parviporum Pleurotus ostreatus Trametes versicolor Coniophora puteana biodegradation cell wall modification urea formaldehyde ammonium sulphate mass loss area fraction stained cell wall cell wall area latewood earlywood oxidative enzyme MBTH laccase-mediator manganese peroxidase butylhydroxytoluol carbon chromatography fraction Coprinopsis cinerea decay fungi 1 4-dihydroxybenzene p-benzochinone 3 5-di-tertbut-4-hydroxy-toluene GC-MS analysis gel electrophoresis growth inhibition 4-hydroxy cinnamic acid laccase induction nitrogen phenolic compounds p-coumaric acid wood extraction wood extractives biofuels chemical pretreatment physico-chemical pretreatment biological pretreatment microwave irradiation liquid acid rate of production of glucose kinetic curve of production of glucose influence of wood extractive influence of phenolic compound Abies grandis Armillaria mellea Heterobasidion annosum Heterobasidion parviporum Pleurotus ostreatus Trametes versicolor Coniophora puteana biodegradation cell wall modification urea formaldehyde ammonium sulphate mass loss area fraction stained cell wall cell wall area latewood earlywood oxidative enzyme MBTH laccase-mediator manganese peroxidase butylhydroxytoluol carbon chromatography fraction Coprinopsis cinerea decay fungi 1 4-dihydroxybenzene p-benzochinone 3 5-di-tertbut-4-hydroxy-toluene GC-MS analysis gel electrophoresis growth inhibition 4-hydroxy cinnamic acid laccase induction nitrogen phenolic compounds p-coumaric acid wood extraction wood extractives biofuels chemical pretreatment physico-chemical pretreatment biological pretreatment microwave irradiation liquid acid rate of production of glucose kinetic curve of production of glucose influence of wood extractive influence of phenolic compound 48.46 Holz YQ 000: Forstbotanik

Search results