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Intensity of Physisporinus vitreus activity on bordered pits, half bordered pits and tracheid cell wall after different incubation periods. The values of sapwood/heartwood and earlywood/latewood were combined for more explicit illustration. The error bars reflect the overall standard deviation. (*) ¼ significant difference of the data from seven and nine weeks compared to the data of three and five weeks (n ¼ 1505).
Source publication
Bioincising is a biotechnological method to enhance the permeability of refractory wood species such as Norway spruce (Picea abies (L.) Karst) by incubation with the white rot fungus Physisporinus vitreus. Increase in wood permeability is supposedly induced by the selective degradation of pit membranes in the bordered and half bordered pits, entail...
Contexts in source publication
Context 1
... the three categories, the intensity of P. vitreus activity was moderate during the first five weeks of incubation (Fig. 2). Only very few strongly degraded cells or pit structures were detected Table 2 Classification of typical decay patterns in half bordered pits in crossfields (radial longitudinal ...
Context 2
... cell wall thinning and localized soft rot was apparent in strongly degraded tracheids and xylem ray cells after seven and nine week's incubation. Here, cavities (soft rot Type I), erosion notches (soft rot Type II) and hyphal tunneling developing in local clusters of high fungal activity were predominantly apparent within the latewood ( Fig. 5.2 and 5.3). Hyphal tunneling was mostly t-branched, since the hyphae formed branches in the secondary walls growing perpendicular to the main growth ...
Citations
... P. Karst. (Schwarze 2006, Lehringer 2010, Thaler 2012) and the bacterium Bacillus subtilis (Ehrenberg 1835) Cohn 1872 (Pánek andReinprecht 2011, Sajitha et al. 2018) are two examples of the most widely used organisms in wood and cellulose biotechnology. One of their most important applications is to increase the permeability of wood that has undergone pit aspiration. ...
... The industrial-scale application of bioincising will not be feasible until advancements in biotechnological control of fungal activity enable homogeneous and controlled permeability enhancement in wood substrates (Stange and Wagenführ 2022). To effectively utilize these organisms for wood modification and achieve consistent and controlled wood degradation, it is essential to understand their influence on wood's anatomical structure and elucidate the wood-fungus interactions (Lehringer 2010, Fuhr 2012, Bari et al. 2015, Bakir 2021. Many studies have explored methods for enhancing the permeability of wood species that naturally resist impregnation. ...
... Physisporinus vitreus is a type of white-rot fungus that selectively destroys the membrane of bordered pits in tracheids and simple pits in the parenchyma of softwood rays in a controlled and timely manner Landmesser 2000, Schwarze 2006). Other studies have found that the activity of this fungus results in the destruction of the pit membrane, creating holes and cracks in the wall of the tracheids (Lehringer 2010). Fungal hyphae extensively search food in parenchymal cells and rays, and from there, they are transported to the adjacent tracheids through the pit apertures (Fang 2023). ...
The fungus Physisporinus vitreus and the bacterium Bacillus subtilis are commonly used organisms in wood biotechnology to increase wood permeability. However, comparative researches on wood destruction by these biological wood decomposers are scarce, particularly from microscopic and chemical perspectives. This study aimed to compare the fungal and bacterial wood destruction patterns over time. Loblolly pine (Pinus taeda L.) heartwood samples were exposed to both organisms for six and nine weeks; microscopic and spectroscopic analyses of the incubated wood were performed, and mass loss of samples was calculated. Both organisms initially destroyed the pit tori and ray parenchyma cells, but B. subtilis was more selective in its consumption of wood components. It exclusively consumed hemicelluloses and free carbohydrates in wood, whereas the fungus destroyed all chemical components simultaneously. The digestion of bordered pits by B. subtilis was more selective than that by P. vitreus, making it a better choice for controlled wood destruction. By extending the exposure duration, the bacterial destruction pattern remained consistent, whereas fungal destruction spread to the secondary wall of the tracheids. Understanding the interactions between microbes and wood can lead to a more effective and efficient use of this natural resource.
... However, the use of them is not always desired due to operating costs and qualities of treated wood [17,23]. The biological method is a potential technique to improve wood treatability by the application of enzymes [24][25][26], bacteria [27][28][29], and fungi [30][31][32][33][34][35][36][37][38][39][40][41][42][43]. An increase in wood permeability is supposedly induced by the selective degradation of pit membranes in the bordered and halfbordered pits, entailing only negligible changes in the tracheid cell wall [33,38]. ...
... The biological method is a potential technique to improve wood treatability by the application of enzymes [24][25][26], bacteria [27][28][29], and fungi [30][31][32][33][34][35][36][37][38][39][40][41][42][43]. An increase in wood permeability is supposedly induced by the selective degradation of pit membranes in the bordered and halfbordered pits, entailing only negligible changes in the tracheid cell wall [33,38]. Bacteria, enzymes, and fungi have all been studied for their ability to improve permeability without having excessively negative effects on other wood properties. ...
Desired retention and depth into wood are necessary for wood preservatives to provide long-term durability. In general, heartwood of wood is difficult to treat, and bioincising was investigated as a potential technique to improve the treatability of refractory wood and heartwood. In order to study the effects of bioincising treatment with white-rot fungus Trametes versicolor on the pore structure and treatability of radiata pine heartwood, this research conducted tests of mass loss, microscopic structures, pore structure parameters, uptake, and penetration of preservative of radiata pine heartwood specimens incubated by T. versicolor for 4, 8, and 12 weeks. The results showed that the optimal inoculation time of T. versicolor bioincising on radiata pine heartwood was 4 to 8 weeks. At this time, the retention of injected preservatives increased by 5.01%–17.73%, the penetration depth of preservatives increased significantly, and the corresponding mass loss was 3.04%–6.45%. The results of microstructure and pore structure showed that T. versicolor entered the adjacent tracheids via apertures, with less impact on the cell wall, mainly degrading pit membranes and ray parenchyma cells early in the inoculation of radiata pine heartwood. As the structures impeding fluid flow were connected, the porosity of the wood and the range of the main pore size distribution increased significantly, thus increasing the treatability of radiata pine heartwood.
... It is very important to protect the wood by impregnation in areas of use where longer service life is required, such as poles, fences, wood sidings used outdoors, and wooden structural elements in buildings and bridges. The effectiveness of the protective treatment is determined by considering the penetration and retention values governed by the permeability of the wood (Wang and DeGroot 1996;Watanabe et al. 1998;Lehringer et al. 2010;Ahmed et al. 2012;Panigrahi et al. 2018). The permeability is low in refractory woods, and parts of the wood (e.g., heartwood) affect preservative penetration, retention, and distribution. ...
... In other words, it was understood that P. vitreus fungal activity is similar in the spruce and larch sapwood samples. Lehringer et al. (2010) reported that P. vitreus, a basidiomycetes class fungus, causes both selective delignification and soft rot of types I and II in tracheid cell walls, which have a high heterogeneity during wood colonization. Decay patterns produced by this fungus resulted in selective degradation of the pit membranes in the bordered and semibordered pits. ...
... To better understand this case, extensive wood chemistry analyses are needed for the type and amount of wood chemical components degraded after P. vitreus fungal activity. Although many studies have been conducted on the effects of P. vitreus fungus on the permeability, physical, mechanical, and anatomical properties of wood (Lehringer et al. 2010;Lehringer 2011;Lehringer et al. 2011;Fuhr et al. 2012;Gilani et al. 2014;Emaminasab et al. 2016;Bakir et al. 2021;Tajrishi et al. 2021;Bakir et al. 2022aBakir et al. ,b, 2022a, studies on wood chemical components seem to be limited. ...
The anatomical structure of wood and the application of three different incision pretreatments affect the distribution of preservatives in refractory woods. This study focused on Picea orientalis (L.) Peterm.) and Larix decidua Mill. and investigated the distribution of copper-based preservatives in the wood microstructure. Different incision pretreatments were applied before impregnation to increase the permeability of spruce and larch sapwood samples. After the incision pretreatments, transverse cross-sectional surfaces of the samples were sealed with polyurethane-based paint to prevent excessive preservative uptake into open ends of longitudinal tracheid lumens. The samples were then impregnated with Celcure C4, by applying a vacuum method. The structure of wood samples with preservatives before and after the incision pretreatments were observed. Copper microdistribution was observed to increase significantly in refractory wood species after different incision pretreatments, especially in larch wood. The degradation of pits caused by biological incision effectively increased the microdistribution of copper. The difference in the microdistribution of increased copper with the laser and mechanical incision pretreatments-following the same incision model-was attributed to the different anatomical structure and density of spruce and larch wood species and the fact that the hole depth and geometry were different in the laser and mechanical incision processes.
... In living trees, pits account for at least 50% of the overall hydraulic resistance [14]. In the industrial use, wood drying causes irreversible pit aspirations and results in a low permeability to fluids [15]. Therefore, the degradation of pit membranes will increase the permeability of wood to the concrete pore water. ...
This study aims to measure the pit torus and border to monitor the immediate and short-term degradation of wood surfaces after the concrete is cast and the cement hydration releases heat. The surface morphology and adhesion force curves were measured by atomic force microscopy during the treatments in saturated calcium hydroxide solutions ranging from 1 h to 27 days. The results showed that the pit torus and pit border showed different degradation processes. The adhesion force was sensitive to the type of the surface chemical components exposed during the degradation, while the surface modulus, deformation and jump-off force ratio were sensitive to the surface structural strength. The surface modulus of the pit torus degraded to 0.61–0.66 of the untreated original (95% CI) after 7-h treatments, and degraded almost completely after 48-h treatments. The surface modulus of the pit border degraded to 0.83–0.95 of the untreated original (CI) after 10 days and to 0.20–0.23 of the untreated original (95% CI) after 27 days of treatments. The treatment temperature 50 °C caused a 10-times faster degradation in the torus modulus compared to the temperature 20 °C.
... High permeability is desirable when applying preservatives and wood-modification substances to protect wood against fungi, wood-boring insects, marine-boring organisms, and other harmful factors or to increase specific wood properties. For many product and applications, the penetration of preservative solutions and modification substances into wood should be deep and homogeneous (Lehringer et al. 2010;Dale et al. 2019;Nath et al. 2020a,b). Therefore, it is very important for the forestry industry to increase the permeability of wood species that are resistant to impregnation. ...
... Bacteria (Ünligil 1972;Clausen 1995;Kobayashi et al. 1998a,b;Hansmann et al. 2002;Pánek and Reinprecht 2011;Yıldız et al. 2012;Tajrishi et al. 2021), enzymes (Durmaz et al. 2015), and blue stain fungi (Lehringer et al. 2010;Danihelová et al. 2018) have also been used to increase the permeability of wood. In the forest products industry, the impact of controlled decay by wood rot fungi has been studied for years. ...
... This first pretreatment was bioincising. The biotechnological method of bioincising increases the uptake of impregnation in low-permeability wood species such as spruce by incubating Physisporinus vitreus, a white rot fungus that belongs to the Basidiomycetes class (Lehringer et al. 2009b;Lehringer et al. 2010;Schubert and Schwarze 2011). The second pretreatment was mechanical incising, where small slits are opened in the wood by running toothed rollers parallel to the fibers (Perrin 1978;Winandy et al. 1995;Morris 1995). ...
For many product and applications, the penetration of preservatives or modification substances into wood species should be deep and homogeneous. Caucasian spruce and European larch are resistant to impregnation. This study compared how different incising pre-processes increased the retention of impregnation materials and the depth of their penetration into the structures of these refractory wood species. Mechanical, biological, and laser incising pretreatments were applied to increase the permeability of sapwood samples before the impregnation. To compare the uptake of the wood preservatives transverse and longitudinal to the axial tracheids in the samples, the cross-sections of some of the samples that had been subjected to different incising pretreatments were covered with a polyurethane-based paint. All wood samples were impregnated using a vacuum method with Celcure C4 new generation preservatives. The study compared the possible effects of these different incising pretreatments on the uptake of preservatives into the tracheids in the spruce and larch woods in both longitudinal and transverse directions. The results showed that the copper (Cu) uptake levels increased in these refractory wood species, especially in the transverse direction, after the different incising pretreatments. Moreover, the results showed it is very important to choose the most suitable pretreatment method for the refractory tree species before impregnation.
... Mechanical incising and biotechnological procedures are also available for bioincising of refractory wood species. Enzymes (Durmaz et al. 2015), bacteria (Kobayashi et al. 1998, Hansmann et al. 2002, Yıldız et al. 2012, and blue-stain fungi (Lehringer et al. 2010, Danihelová et al. 2018 have been applied to improve the permeability of wood. For years, wood-decaying fungi in biotechnological applications have been studied for their effects on increasing wood permeability in the forest products industry. ...
... For years, wood-decaying fungi in biotechnological applications have been studied for their effects on increasing wood permeability in the forest products industry. Although some of these studies have discussed hyphal growth rate, fungal hyphae penetration velocity-capacity, and effects of Physisporinus vitreus in wood using different technological systems or models , Lehringer et al. 2010, Fuhr et al. 2012a, Fuhr et al. 2012b, Fuhr et al. 2013, Schubert et al. 2013, Gilani et al. 2014, Schubert et al. 2014, Gilani and Schwarze 2014, some studies (Schwarze et al. 2006, Lehringer et al. 2009, Lehringer et al. 2010, Volkmer et al. 2010, Humar et al. 2012, Emaminasab et al. 2016, Chang et al. 2020) also focused on increasing the permeability in wood portions (sapwood/heartwood) of refractory tree species. Lehringer et al. (2010) have revealed that improvement in the permeability and activity of P. vitreus was higher in the sapwood of Norway spruce (Picea abies); however, a notable effect was also recorded in the heartwood. ...
... For years, wood-decaying fungi in biotechnological applications have been studied for their effects on increasing wood permeability in the forest products industry. Although some of these studies have discussed hyphal growth rate, fungal hyphae penetration velocity-capacity, and effects of Physisporinus vitreus in wood using different technological systems or models , Lehringer et al. 2010, Fuhr et al. 2012a, Fuhr et al. 2012b, Fuhr et al. 2013, Schubert et al. 2013, Gilani et al. 2014, Schubert et al. 2014, Gilani and Schwarze 2014, some studies (Schwarze et al. 2006, Lehringer et al. 2009, Lehringer et al. 2010, Volkmer et al. 2010, Humar et al. 2012, Emaminasab et al. 2016, Chang et al. 2020) also focused on increasing the permeability in wood portions (sapwood/heartwood) of refractory tree species. Lehringer et al. (2010) have revealed that improvement in the permeability and activity of P. vitreus was higher in the sapwood of Norway spruce (Picea abies); however, a notable effect was also recorded in the heartwood. ...
Since the treatability of Oriental spruce wood (Picea orientalis) with preservative solutions is difficult and considered as a refractory wood species, this study was intended to bring its treatability class by a bioincising process to the level of sapwood of Scots pine (Pinus sylvestris), a desirable wood species for the forest products industry. Bioincising process by Physisporinus vitreus fungus was applied to wood samples from sapwood and heartwood portions of spruce wood. The samples with two different weight loss groups (5–10 % and 10–15 %) in the bioincising process were used to detect changes in treatability with wood preservative solutions caused by the fungus. The bioincised and unincised control samples were treated with either micronized copper quat (MCQ) or alkaline copper quat type D (ACQ-D) wood preservative solutions by either dipping or vacuum methods. Following impregnation with the preservative solutions, the effects of the bioincising process on CuO (copper oxide) retention, and the leaching of Cu (copper) element were determined. The results showed that CuO retention levels increased after the bioincising process. Moreover, there was greater CuO retention in the spruce heartwood samples compared to the spruce and Scots pine sapwood samples. Amount of Cu element released from the Scots pine sapwood samples was found to be lower than that from the spruce sapwood and heartwood samples after the bioincising. process. The results suggest that the bioincising process by P. vitreus in refractory wood species might improve the treatability of wood by Cu-based wood preservatives.
... Impregnation by various chemical agents is a common method to protect and extend the service life of wood and wood products against such factors. High permeability of wood is a required feature for better penetration and high retention levels of preservatives (Wang and DeGroot 1996, Lehringer et al. 2010, Ahmed et al. 2012, Panigrahi et al. 2018. Sapwood portions of most tree species can be successfully impregnated (with some exceptions, such as Norway spruce wood), whereas heartwood is more difficult to treat by conventional impregnation methods (Wang and DeGroot 1996). ...
... Sapwood portions of most tree species can be successfully impregnated (with some exceptions, such as Norway spruce wood), whereas heartwood is more difficult to treat by conventional impregnation methods (Wang and DeGroot 1996). In softwoods such as Norway spruce (Picea abies (L.) Karst), bordered pits constitute the pathways for fluid transport between adjacent tracheids (Lehringer et al. 2010). The impregnation process becomes difficult because of aspiration of the bordered pits in the tracheid cell walls in spruce wood (Matsumura et al. 1999, Messner et al. 2003, Yıldız et al. 2012, Durmaz and Yıldız 2016, Panigrahi et al. 2018. ...
... For refractory wood species, various attempts to increase permeability and treatability, such as immersing in water, steaming, applying solvent, treating with enzymes (Durmaz and Yıldız 2016), mechanically incising, and incubating with blue-stain fungi (Lehringer et al. 2010, Danihelová et al. 2018 or bacteria (Kobayashi et al. 1998, Hansmann et al. 2002, Yıldız et al. 2012) have been made. Among these applications, bioincising using various organisms is a process aiming to increase the permeability of wood without adverse effects on its properties. ...
ABSTRACT
Bioincising is a biotechnological process to improve the permeability of wood by biological organisms. In recent years, there has been a great interest to determine the changes in the
anatomical structure of wood as a result of bioincising process. In this study, the effects of
bioincising by Physisporinus vitreus on the pit structure and permeability of Picea orientalis
L. sapwood and heartwood were studied. Bioincised and non-bioincised samples were then
treated with micronized copper quaternary and Celcure AC-500 wood preservatives by either
dipping or vacuum method. The copper distribution and amount of copper retained in treated
wood were evaluated by SEM-EDX and ICP-OES, respectively. The area of copper fixation in treated
wood was also measured by the ArcGIS software package. The effects of P. vitreus activity were
examined in the wood microstructure after bioincising by light microscope and SEM analyses on
radial sections. After the bioincising, a significant increase was observed in the uptake of wood
preservatives by vacuum, particularly in heartwood. The measurements on bordered pit, crossfield
pit, and ray tracheid bordered pit dimensions in the microstructure of wood indicated that the
degradation of pits was the most important factor in improved penetration and uptake of
preservative solutions employed.
... Impregnation by various chemical agents is a common method to protect and extend the service life of wood and wood products against such factors. High permeability of wood is a required feature for better penetration and high retention levels of preservatives (Wang and DeGroot 1996, Lehringer et al. 2010, Ahmed et al. 2012, Panigrahi et al. 2018. Sapwood portions of most tree species can be successfully impregnated (with some exceptions, such as Norway spruce wood), whereas heartwood is more difficult to treat by conventional impregnation methods (Wang and DeGroot 1996). ...
... Sapwood portions of most tree species can be successfully impregnated (with some exceptions, such as Norway spruce wood), whereas heartwood is more difficult to treat by conventional impregnation methods (Wang and DeGroot 1996). In softwoods such as Norway spruce (Picea abies (L.) Karst), bordered pits constitute the pathways for fluid transport between adjacent tracheids (Lehringer et al. 2010). The impregnation process becomes difficult because of aspiration of the bordered pits in the tracheid cell walls in spruce wood (Matsumura et al. 1999, Messner et al. 2003, Yıldız et al. 2012, Durmaz and Yıldız 2016, Panigrahi et al. 2018. ...
... For refractory wood species, various attempts to increase permeability and treatability, such as immersing in water, steaming, applying solvent, treating with enzymes (Durmaz and Yıldız 2016), mechanically incising, and incubating with blue-stain fungi (Lehringer et al. 2010, Danihelová et al. 2018 or bacteria (Kobayashi et al. 1998, Hansmann et al. 2002, Yıldız et al. 2012) have been made. Among these applications, bioincising using various organisms is a process aiming to increase the permeability of wood without adverse effects on its properties. ...
Bioincising is a biotechnological process to improve the permeability of wood by biological organisms. In recent years, there has been a great interest to determine the changes in the anatomical structure of wood as a result of bioincising process. In this study, the effects of bioincising by Physisporinus vitreus on the pit structure and permeability of Picea orientalis L. sapwood and heartwood were studied. Bioincised and non-bioincised samples were then treated with micronized copper quaternary and Celcure AC-500 wood preservatives by either dipping or vacuum method. The copper distribution and amount of copper retained in treated wood were evaluated by SEM-EDX and ICP-OES, respectively. The area of copper fixation in treated wood was also measured by the ArcGIS software package. The effects of P. vitreus activity were examined in the wood microstructure after bioincising by light microscope and SEM analyses on radial sections. After the bioincising, a significant increase was observed in the uptake of wood preservatives by vacuum, particularly in heartwood. The measurements on bordered pit, crossfield pit, and ray tracheid bordered pit dimensions in the microstructure of wood indicated that the degradation of pits was the most important factor in improved penetration and uptake of preservative solutions employed.
... In coniferous woods, such as Norway spruce (Picea abies (L.) Karst.), the liquid transfer is realized through mainly bordered pits. Sealing of these valve-like structures is called "pit aspiration" (Matsumura et al. 1999, Lehringer et al. 2010, which generally occurs in the wood drying process (Dvinskikh et al. 2011, Schwarzkopf 2021. Because of the pit aspiration, the permeability and treatability of wood are declined. ...
... High permeability is a desired property of wood to effectively increase its specific characteristics and the penetration of preservative solutions (Wang and DeGroot 1996, Tripathi and Poonia 2015, Panigrahi et al. 2018, Dale et al. 2019, Messaoudi et al. 2020. Enzymes (Durmaz and Yıldız 2015), bacteria (Kobayashi et al. 1998, Hansmann et al. 2002, Yıldız et al. 2012, and blue-stain fungi (Lehringer et al. 2010, Danihelová et al. 2018 have been used to increase the permeability of wood. The promise of wood-decaying fungi for this purpose has also been tested for years (Schwarze et al. 2006, Lehringer et al. 2009a, Lehringer et al. 2010, Volkmer et al. 2010, Fuhr et al. 2012, Humar et al. 2012, Emaminasab et al. 2016, Chang et al. 2020. ...
... Enzymes (Durmaz and Yıldız 2015), bacteria (Kobayashi et al. 1998, Hansmann et al. 2002, Yıldız et al. 2012, and blue-stain fungi (Lehringer et al. 2010, Danihelová et al. 2018 have been used to increase the permeability of wood. The promise of wood-decaying fungi for this purpose has also been tested for years (Schwarze et al. 2006, Lehringer et al. 2009a, Lehringer et al. 2010, Volkmer et al. 2010, Fuhr et al. 2012, Humar et al. 2012, Emaminasab et al. 2016, Chang et al. 2020. Lehringer et al. (2010) investigated the effects of Physisporinus vitreus used for biotechnological purposes in the microstructure of Norway spruce wood. ...
Even though oriental spruce (Picea orientalis L.), a common species in the East Black Sea Region of Turkey, is used in a wide range of applications, its wood has low permeability. This study investigated the degradation effects of the bioincising process to improve its treatability with wood preservatives on the microstructure of oriental spruce wood. Test samples were previously subjected to bioincising by Physisporinus vitreus fungus, and the bioincised samples were examined under both a light microscope and scanning electron microscope to observe the effects of the bioincising on the anatomical properties. Bordered pits on the longitudinal tracheid radial walls, piceoid-type cross-field pits, ray tracheid bordered pits, and ray tracheid cell walls in the earlywood and latewood regions within a growth ring were particularly subjected to anatomical evaluations. In the study, the degradation intensity in the samples after the bioincising was well correlated with the weight losses occurred. Splits and factures were determined on the tori of bordered pits on the tracheid cell walls while tears and cracks were present on the pit apertures. The results also show that P. vitreus, a Type I and II white rot fungus, may cause a Type I soft rot.
... Similarly, other species that resemble brown-rot fungi due to their lack of lignin peroxidases (PODs), may be found possessing a carbohydrate-degrading apparatus typical of white-rot fungi (Riley et al. 2014). Moreover, there are species appear as intermediates between white-rot and brown-rot fungi which demonstrate also characteristics of decay that resembles soft rot (Lehringer et al. 2010;Floudas et al. 2015). Therefore, it had become apparent that other functional considerations, beyond the gene content or the possession of PODs and CAZymes, may be important for a biologically reliable descriptive classification of wood fungal decay modes (Riley et al. 2014;Cragg et al. 2015;Floudas et al. 2015). ...
... An example of a peculiar selective white rot mechanism is the one produced by the fungus Physisporinus vitreus. This fungus causes both selective delignification and simultaneous degradation of lignin and polysaccharides and demonstrates ultrastructural characteristics of white rot and soft rot type I and type II (Fig. 6.31) (Lehringer et al. 2010(Lehringer et al. , 2011. Physisporinus vitreus degrades pit membranes and at the same time forms bore holes, cavities and notches in tracheid cell walls (Lehringer et al. . ...
... Physisporinus vitreus degrades pit membranes and at the same time forms bore holes, cavities and notches in tracheid cell walls (Lehringer et al. . This fungus appears to be selective during early stages of colonization, but this selectivity turns into non-selective with time (Lehringer et al. 2010). ...
In terrestrial ecosystems the microbial decomposition of wood is caused principally by fungi, opposed to aquatic ecosystems where bacteria degradation predominates. This chapter discusses the deterioration of wooden Cultural Heritage caused by terrestrial basidiomycetes and in particular the decay types of brown and white rot.
The various overlapping terms of terrestrial fungal decay, such as “red rot”, “destruction rot”, “wet rot” or “marble rot” are initially clarified. Following, brown- and white-rot fungi are introduced and several examples of their decay on historical and archaeological timbers are
given. Elements of their biology are provided and their distinctly different enzyme systems, which had resulted as a consequence of their evolutionary relationships, are described. Their niche is also considered, with special reference to environmental factors influencing decay, such as wood moisture content, oxygen, temperature and pH.
The residual chemistry of rotted wood is also examined and the different decay mechanisms employed by brown- and white-rot fungi are explicated. The two independent systems of
brown rotters, the hydrolytic and the oxidative via Fenton reactions are presented, elucidating the selective removal of wood polysaccharides and the pathways of lignin modification. Similarly, the preferential and the simultaneous delignification of wood caused by white rotters are described and the key enzymatic activities of lignin breakdown, involving LiPs, MnPs, VPs, and laccases, or of cellulose decomposition, engaging enzymatic and nonenzymatic pathways are explored.
Ultrastructural aspects of decay are also investigated, where hyphae invasion, penetration and spreading via the radial and the longitudinal cell systems of softwoods and hardwoods, and decay progression within the cell wall layers, is demonstrated.
Finally macroscopic diagnostic features, like the cubical cracks of brown rot or the fibrous texture and demarcation lines of white rot are provided and microscopic features related to the topochemistry of decayed wood along with several diagnostic patterns of decay such as loss of cell walls’ birefringence, erosion zones, pits enlargement and bore holes expansion are illustrated.
