| 1. |
- Bhatt, Isha M, et al.
(författare)
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Anatomical changes in the cell-wall structure of Leucaena leucocephala(Lam.) de Wit as caused by the decay fungi Trametes versicolorandTrametes hirsuta
- 2015
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Ingår i: Southern Forests, a journal of forest science. - : National Inquiry Services Center (NISC). - 2070-2620 .- 2070-2639. ; 77:4, s. 297-303
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Tidskriftsartikel (refereegranskat)abstract
- The structural changes in the cell wall and delignification pattern caused by Trametes versicolor and Trametes hirsuta in the sap wood of Leucaena leucocephala were examined by light and confocal laser scanning microscopy. The in vitro decay test was conducted for 12 weeks. Both species of Trametes used in this study caused anatomical characteristics specific to simultaneous white rot. Formation of boreholes, erosion troughs, erosion channels with U-shaped notches in tangential sections and thinning of cell walls were evident in the wood inoculated with each of the fungal species. Cell separation due to removal of middle lamellae occurred at the early stages of infection (30 d) with T. versicolor. In contrast, middle lamellae remained intact in wood inoculated with T. hirsuta and showed cell separation due to degradation of the outer layer of the secondary wall and degradation of the middle lamellae observed only in severely decayed wood at late stages. Confocal microscopy revealed the delignification pattern particularly from cell corners and vessel walls at an advanced stage of decay, indicating strong ligninolytic activity of both species in the sapwood of L. leucocephala.
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| 2. |
- Bhatt, Isha M., et al.
(författare)
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Histological changes in the cell wall structure during wood decay by Trametes hirsuta and Trametes versicolor in neem (Azadirachta Indica A. Juss)
- 2016
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Ingår i: Journal of Sustainable Forestry. - : Informa UK Limited. - 1054-9811 .- 1540-756X. ; 35:8, s. 578-590
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Tidskriftsartikel (refereegranskat)abstract
- Structural alterations in the wood cell walls of neem inoculated with by Trametes hirsuta and T. versicolor were studied by microscopic methods. In vitro decayed wood showed extensive weight loss of test blocks (26.7 and 41.38% by T. versicolor and T. hirsuta, respectively) at the end of 3 months. Selective delignification in the initial phase followed by simultaneous removal of lignin was evident in test blocks inoculated with both the species. The separation of middle lamellae and patches of cellulosic polysaccharides stained blue with Astra blue in the delignified region of the fiber wall during early stages indicates selective mode of decay. In contrast, the occurrence of erosion troughs with characteristic U-notch in tangential sections is a characteristic feature of simultaneous rot that was apparent after 3 months of incubation. The decay pattern occurred concomitantly in all the xylem elements irrespective of general resistance pattern shown by vessel and axial parenchyma cells. At an advance stage, both species of Trametes showed formation of erosion channels along the microfibrils angle of cellulose which is considered as characteristics of soft rot decay type. The sharing of white rot and soft rot decay pattern by both the fungi suggest a phylogenetic link between both groups of fungi.
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| 3. |
- Koyani, Rina D., et al.
(författare)
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The Delignification Pattern of Ailanthus excelsaWood by Inonotus hispidus (Bull.: Fr.) P. Karst.
- 2015
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Ingår i: Journal of Sustainable Forestry. - : Informa UK Limited. - 1054-9811 .- 1540-756X. ; 34:5, s. 502-515
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Tidskriftsartikel (refereegranskat)abstract
- AbstractIn vitro laboratory decay tests on Ailanthus excelsa Roxb. wood revealed that I. hispidus exhibits a combination of both white-rot and soft-rot patterns of wood decay. Early stages of wood decay showed dissolution of the middle lamella as well as defibration and localized delignification of fiber walls; vessels, axial, and ray parenchyma remained unaltered. Delignification commenced from the middle lamellae at the cell corners without any marked effect on the primary and secondary wall layers. In later stages of growth, the species produces typical soft-rot decay pattern by forming erosion channels through the S2 layers of fiber walls, transverse bore holes in the cell walls, and erosion channels alongside/following the orientation of cellulose microfibrils. The rays showed signs of cell wall alterations only after the extensive damage to the fiber walls. After 120 days of incubation, the vessels also showed localized delignification, the erosion of pits, and separation from associated xylem elements. The extensive weight losses under natural and in vitro decayed wood as well as the very soft nature of severely degraded wood indicate that I. hispidus alters wood strength and stiffness.
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| 4. |
- Sivan, Pramod, 1984-, et al.
(författare)
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Histological and ultrastructural alterations in the Ailanthus excelsa wood cell walls by Bjerkandera adusta (Willd.) P. Karst
- 2015
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Ingår i: International Biodeterioration & Biodegradation. - : Elsevier. - 0964-8305 .- 1879-0208. ; 100, s. 124-132
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Tidskriftsartikel (refereegranskat)abstract
- Ailanthus excelsa Roxb. requires less care than other species and thrives in arid and semi-arid regions. Therefore, it becomes an important choice for forestry programs. Young branches of these trees are frequently invaded by the fungus Bjerkandera adusta (Willd.) P. Karst. The main aims of this study were to characterize the wood decay pattern and evaluate the extent of damage caused by the fungus. Infected samples were studied using light microscopy, confocal laser scanning microscopy, transmission electron microscopy, and scanning electron microscopy. Wood of the dead branches became pale white and very soft. In vitro decayed wood showed extensive weight loss of wood blocks (68.6%) at the end of three months. In the xylem, fibres were the most severely affected cell types, whereas wall structure of the axial parenchyma remained virtually unaltered. Unlike axial parenchyma, walls of the ray cells formed several boreholes and finally collapsed in the advanced stage of decay. By contrast, the middle lamella of all the xylem elements remained intact even at the end of three months. In the early stages of infection, vessels appeared to be resistant to the fungal action but they also became eroded at the advanced stage. The degradation pattern showed anatomical characteristics of both the white-rot and soft-rot type of decay. Thinning of walls from the lumen side and appearance of U-notches resembles white-rot decay, while tunnels through the S2 layer of the fibre wall added the characteristics of the soft-rot decay pattern. Extensive weight loss of wood blocks following infection suggests B. adusta is an aggressive wood-degrading fungus.
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