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1.
Haustoria of the haploid stage (n stage) of Cronartium ribicola in bark cells of Pinus monticola were studied with the aid of the scanning electron microscope. The morphology of mature haustoria in all kinds of bark cells was consistently filamentous or elongate (hyphalike). Only immature haustoria are short and globose or reniform. Immature and mature haustoria are constricted at the point of passage through the host cell wall. N stage C. ribicola hyphae are characterized as having haustoria that are morphologically similar to intercellular hyphae. 相似文献
2.
The hyphal sheath is a morphological feature of many kinds of fungi. Although the fine structures of the sheath have been
studied in detail by a number of electron microscopy techniques, the function and physiology of the hyphal sheath are not
yet clarified. One reason for this is that the hyphal sheath is a colorless, mucilaginous, and delicate material so that it
is not easily identified. We developed a simple method to visualize and identify the hyphal sheath of the white-rot fungus
Phanerochaete crassa WD1694. The small mycelial pellets in shaken liquid cultures of P. crassa WD1694 were stained directly with phloxine B. Both the hyphae and the hyphal sheath that filled the gaps between each of
the hyphae were visualized and observed by light microscopy. The stained hyphae were further studied by transmission electron
microscopy, atomic force microscopy, and fl uorescence microscopy. Based on these observations, we confirmed that the staining
of the hyphae was also due to the presence of the hyphal sheath that closely covered the fungal cell wall. These results clearly
showed that the hyphal sheath was selectively stained with phloxine B and could be observed and identified by conventional
light microscopy.
Part of this report was presented at the 50th Lignin Symposium, Nagoya, October 2005 相似文献
3.
Adya P. Singh Uwe Schmitt Ralf Möller Bernard S.W. Dawson Gerald Koch 《Wood Science and Technology》2006,40(1):16-25
A visual decay assessment of Pinus radiata wood, which was part of a framing timber in a house in the North Island of New Zealand, indicated the presence of surface
decay. Microscopic observations, employing confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and
transmission electron microscopy (TEM), provided evidence of decay by cavity-forming soft rot (SR) fungi. A comparison of
ray tracheids (RT) with axial tracheids (AT) indicated that RT were considerably more resistant to SR than AT. In the heavily
degraded regions of wood, where axial tracheid walls contained abundant SR cavities, the walls of RT contained only a few
or no cavities. An assessment of lignin concentration in the cell walls by a combination of TEM, confocal fluorescence and
UV microscopy provided evidence of greater lignin concentration in the secondary wall of RT as compared to AT, which may explain
the observed greater resistance of RT to soft rot.
Dedicated to Professor Dr. Dr. h.c. mult. Walter Liese on the occasion of his 80th birthday. 相似文献
4.
Fibre morphology, anatomy and ultrastructure in cell wall of Salix gordejecii normal wood were examined by transmission electron microscopy (TEM). S. gordejecii tension wood can be recognized anatomically by the presence of gelatinous (G) fibres, which contain a conspicuously thickened inner cell wall layer. TEM images showed that cell wall of S. gordejecii normal wood was typically divided into three layers including the primary wall (P), the middle lamellar (ML) and the secondary wall (S1, S2 and S3). Lignin distribution was determined by using confocal laser scanning microscopy (CLSM) and transmission electron microscopy with energy dispersive X-ray analysis (TEM-EDXA). Confocal images (530 nm) of S. gordejecii normal wood showed strongly lignified CCML, and weakly lignified ML and S2 layer. Weakly lignified fibres (F) and strongly lignified vessels (V) were also detected by using CLSM. Results obtained from confocal microscopy were further confirmed by using TEM-EDXA, indicating that the ratio of lignin concentration in CCML, ML and S2 is 1.72 (1321):1.31 (1006):1 (768). Lignin distribution in tension wood is similar to that in normal wood, except for the non-lignified G layer. 相似文献
5.
A fraction containing low-molecular-weight peptides that catalyzes redox reactions between electron donors and O2 to produce ·OH, was partially purified from wood-decaying cultures of the brown-rot fungusTyromyces palustris. Polyclonal antibodies raised to the fraction were used for immunogold labeling of transverse sections of sapwood of spruce in various stages of degradation byT. palustris to demonstrate the cellular localization of the ·OH-producing substance. Initially, the wood cell wall was attacked primarily by fungal hyphae growing in the cell lumen. During the early stages of degradation, the gold label was localized in the fungal cytoplasm and cell wall and in the extracellular slime sheath surrounding the fungal cell wall. The gold label also was found throughout the wood cell wall, although the cell wall remained almost intact so long as the fungal hyphae remained in the lumen. Thus, the ·OH-producing substance is secreted by the hyphae into the lumen, and it diffuses through the S3 layer into the S2 layer and the middle lamella. The role of this ·OH-producing system in wood degradation byT. palustris is discussed. 相似文献
6.
Sooty moulds on crape myrtle leaves were investigated using light and electron microscopy. The adaxial leaf surface was distinctly covered with soot‐like masses of dark brown hyphae and conidia. The main characteristics of the sooty moulds included stauroconidia, conidial clusters, hyphal degeneration and extracellular melanin depositions. Some conidia were round, measured ~10 μm in diameter, and mostly one‐septate; others were branched and multiseptate (stauroconidia). Based on their morphology, the sooty moulds were determined to consist of several component fungal species belonging to genera such as Antennaria, Metacapnodium and Tripospermum. Enclosed in electron‐dense melanin layers, hyphae and conidial clusters had concentric bodies exhibiting electron‐transparent cores and electron‐dense shells with fibrillar sheaths. Concentric bodies are hypothesized to function as multilayer lipid‐encapsulated nanobubbles or eukaryotic gas vesicles for cytoplasmic volume control. Intrahyphal hyphae possessed electron‐dense cytoplasm and lipid globules. These results suggest that sooty moulds are equipped with melanized cell walls, multicelled resting structures, hyphal regeneration, intrahyphal growth and gas vesicles to adapt to their xeric phylloplane environment. Condensed and elongated starch granules in the chloroplasts of mesophyll tissues may indicate the acclimation of the sooty leaf regions to light reduction and temperature increase. 相似文献
7.
Infection and Deterioration of Spruce Root Bark by Fomes Annosus . The paper describes the mode of infection and consequent deterioration of spruce root bark by the root rot fungus, Fomes annosus using light and electron microscope observations. Spread of fungal hyphae occurs through bore holes produced by enzymatic activity. Although a definte loss of wall substance occurs, the bark tissues primarily represent merely a pathway for the fungus before it colonieses the xylem. 相似文献
8.
The presence of basidiomes of wood-decay fungi on living lenga (Nothofagus pumilio) was investigated in seven forest stands in Patagonia (Argentinia). The following species accounted for 85% of the rots: Postia pelliculosa, Phellinus andinopatagonicus, Piptoporus portentosus, Aurantioporus albidus, and Serpula himantoides. Ph. andinopatagonicus and A. albidus cause characteristic white rots, while the other tree species cause unspecific, cubical brown rots. S. himantoides was associated with cords among the decayed wood fragments. One stand was investigated in detail. The volume of decayed timber on this plot was 75%. Postia pelliculosa and Ph. andinopatagonicus probably infected the trees through the roots as well as through the canopy, and accounted for 70% of the wood-rots. Piptoporus portentosus probably infected only through the canopy, while A. albidus and S. himantoides did so through the roots. Only 12% of the trees showed no decay. From trees with decay, 36% were attacked by one fungal species, 35% by two species. 相似文献
9.
Maximilian Wentzel Tim Koddenberg Holger Militz 《Wood material science & engineering》2020,15(4):223-228
ABSTRACT Eucalyptus nitens specimens were thermally modified under open and closed systems. The anatomical characteristics from selected modifications that presented similar mass losses were investigated by analyzing images taken from scanning electron microscopy, transmission light microscopy, and X-ray micro-computed tomography. Wood cell wall thickness, fiber, and lumen area were measured and compared to unmodified specimens, and the crack formation after modification was also analyzed. There was only a slight decrease in the measured characteristics when compared to unmodified specimens. The wood cell wall thickness was less affected than the fiber and lumen areas, and both modifications presented similar crack formations. Overall, there were no significant differences between open and closed system modifications in the anatomical structure. 相似文献
10.
A histological investigation of Oriental beech wood decayed by Pleurotus ostreatus and Trametes versicolor 
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下载免费PDF全文 Chemical, light and electron microscopic studies were carried out on wood of Oriental beech (Fagus orientalis Lipsky) decayed by the white‐rot fungi Pleurotus ostreatus and Trametes versicolor for 30, 60 and 120 days according to the modified European standard EN 113. Mass loss as well as lignin, cellulose and carbohydrate content were determined before and after fungal attack. There were no significant differences of wood mass loss and chemical composition between both fungi at the end of incubation. After each incubation period, small specimens were stained for microscopic studies. The micromorphology of fungal cell wall degradation was rather similar for both fungi. Both decreased the cell wall thickness to the same extent. The accumulation of hyphae as well as the rupture of cell walls was also similar. The occurrence of hyphae, cavities in the pits and vessel walls followed nearly the same patterns. The parenchyma cells were completely destroyed. Altogether, both fungi produced a simultaneous white rot in Oriental beech wood. 相似文献
11.
Erwin Shuhei Takemoto Won-Joung Hwang Miyuki Takeuchi Takao Itoh Yuji Imamura 《Journal of Wood Science》2008,54(3):233-241
To further our understanding of wood decay in living light red meranti (Shorea smithiana) trees, microscopic characteristics of the cell and cell wall degradations of S. smithiana wood in the presence of the decay fungi, the identity of the causal fungi, and the decay potential and pattern by an isolated
fungus were investigated. Cell wall degradations, including cell wall thinning, bore holes formation, rounded pit erosion,
and eroded channel opening were clearly observed under light and scanning electron microscopy. In transverse view, many large
voids resulting from a coalition of degraded wood tissue appeared in the decayed canker zone. All these observations suggest
the well-known simultaneous decay pattern caused by white-rot fungi. By phylogenetic analysis based on the sequences of internal
transcribed spacer region of ribosomal DNA, a basidiomycete fungus isolated from the decayed wood was identified as Schizophyllum commune. The degradation caused by this fungus on sound S. smithiana wood in an in situ laboratory decay test was classified as the early stage of simultaneous decay, and showed a similar pattern
to that observed in the wood samples naturally decayed. 相似文献
12.
Summary A new type of soft rot of southern pine longitudinal tracheids is described. In this type, soft-rot cavities form by diffuse degradation of the S2 cell wall layer by hyphae growing within the cell wall. Cavity formation is diffuse and irregular as opposed to the restricted, periodic cavity formation typical of type 1 soft rot. Proboscis hyphae are small (diameter 0.6 to 0.9 m) and rapidly autolyse. These proboscis hyphae are not easily recognizable with light microscopy, especially at later stages of decay, but require transmission electron microscopy to confirm their presence. This may be an alternative interpretation of the type 2 soft rot of softwoods described previously as being caused by lumenal hyphae through an intact S3. Chemical analysis of pine test blocks revealed a greater loss of glucose and an increase of galactose with diffuse type 1 species compared to typical type 1 soft rot species. The term diffuse type 1 is suggested to describe this soft rot.The authors thank the Electric Power Research Institute (EPRI) and the USDA Competitive Research Grants Program for financial support, Kathy M. Anderson for technical assistance and The N.C. Brown Center for Ultrastructure Studies at the SUNY College of Environmental Science and Forestry for use of their facilities. 相似文献
13.
《Wood material science & engineering》2013,8(1-2):1-11
Abstract Growing markets for chopped firewood have created alternative uses for the by-products of sawmills. Based on empirical data and simulated results, the potential of birch (Betula pendula Roth, Betula pubescens Ehrh.) from commercial thinnings for combined industrial production of sawn timber and firewood billets was investigated. In the simulations, different sawing patterns were used for logs intended to combine production of sawn timber and billets for chopped firewood (‘sawlogs’), and for logs intended only to firewood production (‘firewood logs’). Finally, economical feasibility analysis was done concerning the differences between the sawmills’ traditional business concept and the novel concept combining sawn wood and firewood production. The bucking results for the volume yield of different timber assortments varied only slightly between the different bucking options, i.e. the combinations of timber assortments. The main differences in the volumes of timber assortments were due to the stand type where the birch trees were sampled (planted, naturally regenerated, mixed birch–spruce). In the sawing procedure, the output of sawn timber varied between 24% and 42% of the log volume in the sawlogs, depending on the log diameter class. As the volume yield of sawn timber and firewood billets was counted together in the case of sawlogs, the log consumption was c. 1.75 m3 of roundwood per 1 m3 of sawn timber and firewood billets. In the case of the firewood logs, the log consumption rate was considerably lower, only c. 1.35. The economic calculations showed that using the firewood approach in sawing may increase the net added value of products by €1.9–5.4 m?3 of logs, depending on their diameter class. As a conclusion, parallel production of sawn timber and firewood from logs from the first and second commercial thinning of birch-dominated stands is a concept that could work as an alliance between a sawmiller and a firewood entrepreneur. The concept could be competitive compared with both traditional sawmilling and production of chopped firewood. 相似文献
14.
The decay pattern in bamboo fibers caused by a brown rot fungus, Gloeophyllum trabeum, was examined by microscopy. The inner part of the polylaminate secondary wall was degraded, while the outer part of the
secondary wall remained essentially intact. Degradation in bamboo fiber walls without direct contact with the fungal hyphae
was similar to wood decay caused by brown rot fungi. Degradation in polylaminate walls was almost confined to the broad layers
whereas the narrow layers appeared resistant. The p-hydroxylphenyl unit lignin in middle lamella, particularly in the cell corner regions, was also degraded. The degradation
of lignin in bamboo fibers was evidenced by Fourier transform infrared spectra. The present work suggests that the decay of
bamboo fiber walls by G. trabeum was influenced by lignin distribution in the fiber walls as well as the polylaminate structures. 相似文献
15.
Anatomical studies on the infection biology of Scleroderris lagerberii (Brunchorstia pinea) . Infection of Pinus nigra shoots by B. pinea was studied by means of both ordinary light and fluorescent microscopy. Following spore germination, the mycelium lives under and between the leaf scales, subsequently invading the leaf scales directly. The hyphae can grow through periderms, later invading the xylem via the rays. 相似文献
16.
Rina D. Koyani Isha M. Bhatt Hiral R. Patel Ajit M. Vasava 《Wood material science & engineering》2016,11(1):46-56
Lignin biodegradation potential of Schizophyllum commune Fr. is studied by using sound wood blocks of Ailanthus excelsa, Azadirachta indica, Tectona grandis, Eucalyptus sp. and Leucaena leucocephala. Initially, in vitro wood decay test showed minor weight loss, but it became rapid after one month. After 120 days of incubation, weight loss was minimum in T. grandis (24.05%) whereas it was maximum in A. excelsa (34.44%). Treated test blocks were characterised by enlargement of pits on ray cell wall, formation of additional boreholes in rays, separation of fibres and cell wall thinning and formation of ‘U’-shape notches. Fungal hyphae moved through the xylem cell lumen, and intercellular spaces formed in response to separation of fibres. Hyphae traverse in adjacent cell through the cell wall pits or by making additional boreholes. In all the species studied, xylem fibres and parenchyma (axial and ray) cells were more susceptible while vessels were resistant to fungal attack. In advanced stage of decay, fibres and axial parenchyma lost their rigidity while vessel walls showed uneven thinning. In the tension wood, G-fibres remained unaffected initially but loosening and separation of gelatinous layer facilitated fungal action and showed similar pattern of cell wall deterioration. Among the wood of different species studied, Tectona was more resistant whereas Ailanthus was more susceptible to fungal attack. 相似文献
17.
The current study attempts to verify secretion of a callose hollow fiber from plant protoplasts, which was previously reported in woody plants, as a common stressed culture-induced phenomenon among plants, by re-examining herbaceous plant cultured cells of tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yellow 2) and Arabidopsis thaliana allowing inhibition of cell wall formation. Then, inhibition of cell wall formation was found to induce the secretion of callose fibers by adding isoxaben, an inhibitor of cellulose synthesis, into the stressed culture medium. The inducing period for the secretion from both tobacco BY-2 and A. thaliana was shorter than that previously reported in Betula platyphylla (white birch). The secreted fibers were observed by confocal laser scanning microscopy and atomic force microscopy. The microscopic images indicated that the callose fibers from herbaceous plants did not necessarily possess a similar structure to hollow fibers from white birch. Eventually, it has been demonstrated that the secretion of callose fibers from protoplasts can be a stress-induced phenomenon commonly occurring in plants, but their hierarchical 3D-fiber structures are likely to depend on species. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(3):256-262
Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands. 相似文献
19.
Degradation of cell walls in elm wood tissue (Ulmus americand) by aggressive and non-aggressive isolates of Ophiostoma ulmi was studied by scanning electron microscopy. Xylem vessel walls were much more affected after infection with the aggressive isolate than after infection with the non-aggressive one. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(5):570-578
In order to obtain a more precise prediction of the distribution of each timber grade or log grade with regard to the volume of birch (Betula pendula Roth., B. pubescens Ehrh.) in models for long-term planning, ordered probit models were developed. These models were developed by using data from three mixed birch and Norway spruce stands in Norway. The data consisted of 168 stems. In Norway, three ordinary birch saw log grades are commonly used, with pulpwood as a fourth grade. In this study, these four grades were applied in addition to waste timber, which was treated as a fifth grade. The developed models showed that the grade distribution of birch trees of mixed birch and spruce stands was highly correlated with tree height (p<0.01) and height to first visible dry branch (p=0.081). The statistical significance of both models was good (p<0.0001), as measured by log likelihood test statistics. Classifying the 168 stems by saw timber or pulpwood in butt log led to greatly improved estimates (p<0.01). The developed models would allow the incorporation of timber grade in stand simulators, enabling more precise predictions regarding the economic implications of alternative management strategies for birch trees. 相似文献