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Jonas Brändström - One of the best experts on this subject based on the ideXlab platform.
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MICRO- AND ULTRASTRUCTURAL ASPECTS OF NORWAY SPRUCE TracheidS: A REVIEW
Iawa Journal, 2020Co-Authors: Jonas BrändströmAbstract:Norway spruce, Picea abies (L.) Karsten, is one of the most commercially important wood species in northern Europe. Wood from Norway spruce consists mainly (> 90%) of Tracheids and the micro- and ultrastructure of these Tracheids have a considerable effect on the wood and its manufactured products. This literature review presents current knowledge on some important aspects of the micro- and ultrastructural morphology of Norway spruce Tracheids. At the microstructural level, variation and general trends within the tree are given for Tracheid length, Tracheid diameter and cell wall thickness. At the ultrastructural level, the architecture of the secondary cell wall, and particularly its lamellation and microfibril orientation are considered. Where information on Norway spruce Tracheids was lacking, Tracheids of other conifers are reviewed. Thus, this review also gives an insight on the structure of other conifer Tracheids since there are many similarities in structure between different conifer species.
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Hydraulic and anatomical properties of light bands in Norway spruce compression wood.
Tree physiology, 2006Co-Authors: Stefan Mayr, Stig Bardage, Jonas BrändströmAbstract:Compression wood (CW), which is formed on the underside of conifer branches, exhibits a lower specific hydraulic conductivity (k(s)) compared with normal wood. However, the first-formed Tracheids of an annual ring on the underside of a conifer branch often share several properties with normal Tracheids, e.g., thin cell walls and angular cross sections. These first-formed Tracheids appear bright when observed by the naked eye and are therefore called light bands (LB). In this study, hydraulic and related anatomical properties of LBs were characterized and compared with typical CW and opposite wood (OW). Measurements were made on branches of Norway spruce (Picea abies (L.) Karst.). Specific hydraulic conductivity was measured with fine cannulas connected to microlitre syringes. Micro- and ultrastructural analysis were performed on transverse and radial longitudinal sections by light and scanning electron microscopy. Xylem areas containing both typical CW and LBs had a k(s) 51.5% that of OW (7.95 +/- 0.97 m(2) s(-1) MPa(-1) x 10(-4)), whereas k(s) of pure CW was only 26.7% that of OW. The k(s) of LBs (6.38 +/- 0.97 m(2) s(-1) MPa(-1) x 10(-4); 80.3% of OW) was estimated from these k(s) values because the cannulas were too wide to measure the k(s) of LBs directly. Mean lumen area of first-formed Tracheids on the underside of branches was 65.7% that of first-formed Tracheids in OW and about three times that of CW. Light-band Tracheids exhibited a bordered pit frequency of 42.7 +/- 1.3 pits mm(-1), which was three times that in CW and 1.6 times that in OW. Bordered pit apertures in LB Tracheids (9.15 +/- 0.60 microm(2)) were 1.7 times wider than those in CW and similar in aperture to those in OW. The high k(s) of LBs was correlated with their wide Tracheid lumina, high pit frequency and wide pit apertures. We therefore suggest that LBs have a primarily hydraulic function within the mechanically optimized CW region. This might be important for supplying water to living tissues on the underside of branches, as well as to other distal areas along water transport pathways following the spiral grain of wood.
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Morphology of Norway spruce Tracheids with emphasis on cell wall organisation
2002Co-Authors: Jonas BrändströmAbstract:Wood from Norway spruce and other conifers consists mainly (>90%) of one cell type called Tracheids. The morphology of these Tracheids has a profound effect on wood industrial processes and products made from wood. A more in-depth understanding of Tracheid morphology is therefore required in order to improve wood industrial processes and products derived from conifer wood. The aim of this thesis was to study the morphology of Norway spruce (Picea abies (L.) Karst) Tracheids with emphasis on cell wall organisation, especially microfibril orientation in the secondary cell wall. A literature review provided an overview of the micro- and ultrastructure of Norway spruce Tracheids. The use of cavities from soft rot fungi was discussed and evaluated as a way of determining microfibril angles (MFA) in the secondary cell wall of Tracheids. Soft rot fungi were shown to be a useful tool for ultrastructural research and results correlated well with polarisation confocal microscopy when measuring microfibril angles of the middle layer of the secondary cell wall (S2). Both methods showed a decreasing trend in S2 microfibril angle, from the beginning of earlywood (MFA ca. 30°) and towards the end of earlywood (MFA ca. 5°). The low microfibril angles continued into the latewood. No direct correlation was found between Tracheid microstructure (i.e. cell length, cell width and cell wall thickness) and the microfibril angle in the S2 layer. Several methods were used to investigate the structural organisation of the outer layer of the secondary wall (S1). It was concluded that the S1 layer is rather homogenous layer being primarily comprised of microfibrils oriented approximately perpendicular to the Tracheid axis. No evidence could be found for a crossed fibrillar structure with microfibrils in alternate S and Z helices. The transition of microfibril orientation from the S1 to the S2 layer appeared abrupt. Cell wall models illustrating microfibril orientation in the cell wall layers were discussed from a historical perspective. Three new cell wall models, based on results obtained in this thesis and from the literature were presented in order to visualise the microfibril orientation in the cell wall layers of Norway spruce Tracheids.
Harri Makinen - One of the best experts on this subject based on the ideXlab platform.
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effect of thinning on wood density and Tracheid properties of scots pine on drained peatland stands
Forestry, 2015Co-Authors: Harri Makinen, Jari Hynynen, Timo PenttilaAbstract:The properties of wood and wood Tracheids from trees growing in peatland stands are still insufficiently known. The long-term effects of thinning on wood and Tracheid properties of Scots pine (Pinus sylvestris L.) were investigated in two thinning experiments on peatland sites in central Finland. The two sites were ditched for the first time in 1958 and 1973, and thinning experiments were established in 1987 and 1993, respectively. Thinning increased the basal area increment of the remaining trees by 20 per cent. No differences between the trees that were growing on the thinned plots and those that were growing on the unthinned control plots were found in the latewood proportion, wood density, Tracheid diameter, cell wall thickness and Tracheid length. Moreover, the wood and Tracheid properties did not differ markedly from those of corresponding material originating from mineral soil sites. The results confirm the previous results on mineral soils, which showed that an increasing availability of resources primarily increases the rate of Tracheid production but has no major effects on wood and Tracheid properties.
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intra annual Tracheid production of norway spruce and scots pine across a latitudinal gradient in finland
Agricultural and Forest Meteorology, 2014Co-Authors: Tuula Jyske, Harri Makinen, Tuomo Kalliokoski, Pekka NojdAbstract:Abstract Considerable changes in tree growth are projected due to the expected climate change. The expected changes of climate call for a better insight into the growth responses of trees to varying environmental conditions over large geographical regions. The aim of this study was to analyse the intra-annual Tracheid production of Norway spruce ( Picea abies (L.) Karst.) and Scots pine ( Pinus sylvestris L.) across a latitudinal gradient in Finland (60–68°N). The number of Tracheids and the day of the year for the onset, fastest rate, and cessation of Tracheid production were determined from microcores repeatedly collected in nine stands during growing seasons of 2001–2009. The onset of Tracheid production varied from late May in southern Finland to mid-June in northern Finland. On all stands, Tracheid production initiated earlier and ceased later for Scots pine than for Norway spruce. On average, the fastest Tracheid production rate occurred slightly after the summer solstice, but variation between sites and years was high. In the northernmost Scots pine stand, the length of the growing season was less than two months and the onset of Tracheid production required clearly lower TS than elsewhere. The results imply that within Finland, year-to-year weather variation has a marked impact on the timing of Tracheid production. However, the results indicate that the Norway spruce and Scots pine have adapted and are able to adjust their Tracheid production according to the local conditions.
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intra annual Tracheid formation of norway spruce provenances in southern finland
Trees-structure and Function, 2012Co-Authors: Harri Makinen, Tuomo Kalliokoski, Mehedi Reza, Tuula Jyske, Pekka NojdAbstract:We studied the intra-annual wood formation in a Norway spruce provenance experiment in southern Finland from 2004–2008. Two Finnish provenances, northern and southern, as well as German and Hungarian provenances were included. Timing of Tracheid formation and differentiation, and Tracheid dimensions were determined from periodically extracted microcores. The aim was to determine the differences between the years and provenances in the timing of the xylogenesis and in the xylem characteristics. Year-to-year variation was high both in timing of Tracheid formation and xylem characteristics, while between-provenance differences were small. The onset of Tracheid formation varied from early May to late June in different trees in different years. The onset of Tracheid formation was not closely related to the annual variations of temperature sum. In all the years, daily temperatures exceeded the threshold +5°C for several weeks before the onset of Tracheid formation. The highest Tracheid formation rate occurred after the summer solstice in all years and generally coincided with the highest daily temperatures during the growing season. Tracheid production ceased early in 2006 due to a mid-summer drought. Cell differentiation continued late in autumn as non-mature Tracheids were still observed around mid-September. No clear differences between the provenances in the timing of Tracheid formation were observed, although the Finnish provenances tended to initiate Tracheid formation slightly earlier than the other provenances. The tree-ring widths of the Finnish provenances were also wider, while Tracheid diameter of the German provenance was slightly smaller. Our results indicate that between-tree variation in the timing of wood formation is high compared with the latitude effect of seed source.
Feng Xu - One of the best experts on this subject based on the ideXlab platform.
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dilute acid pretreatment differentially affects the compositional and architectural features of pinus bungeana zucc compression and opposite wood Tracheid walls
Industrial Crops and Products, 2014Co-Authors: Xia Zhou, Zhe Ji, Xun Zhang, Shri Ramaswamy, Feng XuAbstract:Compression wood represents a unique challenge for biochemical processing of sustainable biomass to produce biofuels and bioproducts on account of its highly lignified Tracheids relative to opposite wood. In the current work, differentiating response of Pinus bungeana Zucc. compression wood and opposite wood Tracheid walls to dilute acid pretreatment was elucidated by combining chemical and microscopic approaches. Dilute acid pretreatment released greater amount of hemicelluloses from opposite wood (91.0%) than from compression wood (31.2%). The dissolution of hemicelluloses was not uniform and varied across the Tracheid wall. In addition, for both compression wood and opposite wood the heterogeneity in lignin distribution was enhanced, probably attributed to the lignin migration and relocalization. The ultrastructural arrangement of the cell wall was also altered with the pretreated opposite wood Tracheid wall exposing more apparent cellulose microfibril bundles and less abundant globular structures compared to compression wood. The dilute acid pretreatment demonstrated that the greater recalcitrance of compression wood probably originated from the higher lignin content and the resulting more compact structure of the cell wall.
Keiji Takabe - One of the best experts on this subject based on the ideXlab platform.
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immunolocalization and structural variations of xylan in differentiating earlywood Tracheid cell walls of cryptomeria japonica
Planta, 2010Co-Authors: Tatsuya Awano, Arata Yoshinaga, Keiji TakabeAbstract:We investigated the spatial and temporal distribution of xylans in the cell walls of differentiating earlywood Tracheids of Cryptomeria japonica using two different types of monoclonal antibodies (LM10 and LM11) combined with immunomicroscopy. Xylans were first deposited in the corner of the S1 layer in the early stages of S1 formation in Tracheids. Cell corner middle lamella also showed strong xylan labeling from the early stage of cell wall formation. During secondary cell wall formation, the innermost layer and the boundary between the S1 and S2 layers (S1/S2 region) showed weaker labeling than other parts of the cell wall. However, mature Tracheids had an almost uniform distribution of xylans throughout the entire cell wall. Xylan localization labeled with LM10 antibody was stronger in the outer S2 layer than in the inner layer, whereas xylans labeled with LM11 antibody were almost uniformly distributed in the S2 layer. In addition, the LM10 antibody showed almost no xylan labeling in the S1/S2 region, whereas the LM11 antibody revealed strong xylan labeling in the S1/S2 region. These findings suggest that structurally different types of xylans may be deposited in the Tracheid cell wall depending on the developmental stage of, or location in, the cell wall. Our study also indicates that deposition of xylans in the early stages of Tracheid cell wall formation may be spatially consistent with the early stage of lignin deposition in the Tracheid cell wall.
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temporal and spatial immunolocalization of glucomannans in differentiating earlywood Tracheid cell walls of cryptomeria japonica
Planta, 2010Co-Authors: Tatsuya Awano, Arata Yoshinaga, Keiji TakabeAbstract:We investigated the deposition of glucomannans (GMs) in differentiating earlywood Tracheids of Cryptomeria japonica using immunocytochemical methods. GMs began to deposit at the corner of the cell wall at the early stages of S1 formation and showed uneven distribution in the cell wall during S1 formation. At the early stages of S2 formation, limited GM labeling was observed in the S2 layer, and then the labeling increased gradually. In mature Tracheids, the boundary between the S1 and S2 layers and the innermost part of the cell wall showed stronger labeling than other parts of the cell wall. Deacetylation of GMs with mild alkali treatment led to a significant increase in GM labeling and a more uniform distribution of GMs in the cell wall than that observed before deacetylation, indicating that some GM epitopes may be masked by acetylation. However, the changes in GM labeling after deacetylation were not very pronounced until early stages of S2 formation, indicating that GMs deposited in the cell wall at early stages of cell-wall formation may contain fewer acetyl groups than those deposited at later stages. Additionally, the density of GM labeling increased in the cell wall in both specimens before and after GM deacetylation, even after cell-wall formation was complete. This finding suggests that some acetyl groups may be removed from GMs after cell-wall formation is complete as part one of the Tracheid cell aging processes.
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cell wall formation of conifer Tracheid as revealed by rapid freeze and substitution method
Journal of Electron Microscopy, 1992Co-Authors: Fumie Inomata, Keiji Takabe, Hiroshi SaikiAbstract:Cell wall formation of conifer Tracheid was studied by rapid-freeze and substitution method. Small thin strips cut from differentiating conifer Tracheids were plunged into liquid propane, and then substituted in acetone with 2% OsO 4 . Sections prepared by this method gave improved images of ultrastructures of the developing cell wall. The most outstanding feature of the developing cell wall is a non-fibrillar, homogeneous thin layer immediately outside of the plasma membrane which appeared to be composed of newly-deposited polysaccharides containing a great deal of water
Parviz Navi - One of the best experts on this subject based on the ideXlab platform.
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Microfibril angle non-uniformities within normal and compression wood Tracheids
Wood Science and Technology, 2005Co-Authors: Marjan Sedighi-gilani, Homeira Sunderland, Parviz NaviAbstract:The pattern and extent of variation of microfibril angle (MFA) in normal and compression Tracheids of softwood were investigated by using confocal laser scanning microscopy technique. All measurements support the idea that the orientation of microfibrils in single wood Tracheids is not uniform. MFA of the radial wall of earlywood Tracheids was highly non-uniform and had an approximately circular form of arrangement around the bordered pits (inside the border). Between the bordered pits the measured MFAs were less than the other parts of the Tracheid. In the latewood Tracheids MFA was less variable. The average orientation of simple pits in the crossfield region was consistent with the mean MFA of the Tracheids; however some of the measurements showed a highly variable arrangement in the areas between the simple pits. In many cases the local measured MFAs of compression wood Tracheids agreed with the orientation of natural helical cavities of compression wood. Comparing the measured results in different growth rings showed that MFAs in juvenile wood are generally larger than in perfect wood.
