Molecular xylem cell wall structure of an inclined Cycas micronesica stem, a tropical gymnosperm

IAWA Journal ◽  
2010 ◽  
Vol 31 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Clemens M. Altaner ◽  
Michael C. Jarvis ◽  
Jack B. Fisher ◽  
Thomas E. Marler
Keyword(s):  
Cell Wall ◽  
Compression Wood ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Picea Sitchensis ◽  
Wall Structure ◽  
Crystalline Cellulose ◽  
Cellulose Structure ◽  
Molecular Features ◽  
Cellulose Fibrils

The molecular structure of tracheid walls of an inclined eccentrically grown stem of Cycas micronesica K.D. Hill did not differ between the upper and lower side. The absence the typical molecular features of compression wood tracheids, i.e. an increased galactose and lignin content as well as an increased microfibril angle, indicated that cycads do not have the ability to form even very mild forms of compression wood, which lacks anatomical features commonly observed in compression wood. Analysis of the sugar monomers in Cycas micronesica tracheids did reveal a rather unique composition of the non-cellulosic polysaccharides for a gymnosperm. The low mannose and high xylose content resembled a cell wall matrix common in angiosperms. The crystalline cellulose structure in Cycas micronesica tracheids closely resembled those of secondary cell walls in Picea sitchensis (Bong.) Carr. tracheids. However, the spacing between the sheets of cellulose chains was wider and the cellulose fibrils appeared to form larger aggregates than in Sitka spruce tracheids.

Changes in Nanostructure of Wood Cell Wall during Deformation

2008 ◽  
Vol 599 ◽  
pp. 126-136 ◽  
Author(s):  
Marko Peura ◽  
Seppo Andersson ◽  
Ari Salmi ◽  
Timo Karppinen ◽  
Mika Torkkeli ◽  
...  
Keyword(s):  
Cell Wall ◽  
Poisson Ratio ◽  
Axial Strain ◽  
Microfibril Angle ◽  
Silver Birch ◽  
Wall Structure ◽  
Crystalline Cellulose ◽  
Tensile Behaviour ◽  
Angle Distribution ◽  
X Ray

The excellent mechanical properties of wood arise from its cellular and cell wall structure. X-ray scattering, ultrasound, and mechanical testing is combined to study the effects of strain on crystalline cellulose in wood. Results for dry and re-moistened softwood samples are reviewed and new results are presented for native, never-dried samples of Silver birch. When softwood is stretched parallel to the cell axis, the mean microfibril angle diminishes significantly in compression wood, but only slightly in clear wood. The cellulose chains in the crystallites elongate and their distance diminishes. In the never-dried Silver birch samples, axial strain caused the mode of the microfibril angle distribution to slightly decrease from the initial value of 14 degrees to 12 degrees. Unlike in softwood, in never-dried birch crystalline cellulose showed auxetic tensile behaviour. The distance of the chains increased and the X-ray Poisson ratio νca was negative, -0.3 ± 0.2. Dehydration of never-dried Silver birch caused no difference to the microfibril angle distribution.

Comparing Mechanical Properties of Normal and Compression Wood in Norway Spruce: The Role of Lignin in Compression Parallel to the Grain

Holzforschung ◽  
2002 ◽  
Vol 56 (4) ◽  
pp. 395-401 ◽  
Author(s):  
W. Gindl
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cell Wall ◽  
Mechanical Testing ◽  
Cell Walls ◽  
Compression Wood ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Compression Failure

Summary Cell-wall lignin content and composition, as well as microfibril angle of normal and compression wood samples were determined prior to mechanical testing in compression parallel to the grain. No effect of increased lignin content on the Young's modulus in compression wood was discernible because of the dominating influence of microfibril angle. In contrast, compressive strength of compression wood was not negatively affected by the high microfibril angle. It is proposed that the observed high lignification in compression wood increases the resistance of the cell walls to compression failure. An increased percentage of p-hydroxyphenylpropane units observed in compression wood lignin may also contribute to the comparably high compressive strength of compression wood.

scholarly journals Effect of Exogenously Applied 24-Epibrassinolide and Brassinazole on Xylogenesis and Microdistribution of Cell Wall Polymers in Leucaena leucocephala (Lam) De Wit

2021 ◽  
Author(s):  
S. Pramod ◽  
M. Anju ◽  
H. Rajesh ◽  
A. Thulaseedharan ◽  
Karumanchi S. Rao
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Leucaena Leucocephala ◽  
Higher Plants ◽  
Lignin Content ◽  
Wood Quality ◽  
Wall Structure ◽  
Vessel Element ◽  
Xylem Differentiation ◽  
Cell Wall Polymers

AbstractPlant growth regulators play a key role in cell wall structure and chemistry of woody plants. Understanding of these regulatory signals is important in advanced research on wood quality improvement in trees. The present study is aimed to investigate the influence of exogenous application of 24-epibrassinolide (EBR) and brassinosteroid inhibitor, brassinazole (BRZ) on wood formation and spatial distribution of cell wall polymers in the xylem tissue of Leucaena leucocephala using light and immuno electron microscopy methods. Brassinazole caused a decrease in cambial activity, xylem differentiation, length and width of fibres, vessel element width and radial extent of xylem suggesting brassinosteroid inhibition has a concomitant impact on cell elongation, expansion and secondary wall deposition. Histochemical studies of 24-epibrassinolide treated plants showed an increase in syringyl lignin content in the xylem cell walls. Fluorescence microscopy and transmission electron microscopy studies revealed the inhomogenous pattern of lignin distribution in the cell corners and middle lamellae region of BRZ treated plants. Immunolocalization studies using LM10 and LM 11 antibodies have shown a drastic change in the micro-distribution pattern of less substituted and highly substituted xylans in the xylem fibres of plants treated with EBR and BRZ. In conclusion, present study demonstrates an important role of brassinosteroid in plant development through regulating xylogenesis and cell wall chemistry in higher plants.

scholarly journals Changes in viscoelastic vibrational properties between compression and normal wood: roles of microfibril angle and of lignin

Holzforschung ◽  
2013 ◽  
Vol 67 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Iris Brémaud ◽  
Julien Ruelle ◽  
Anne Thibaut ◽  
Bernard Thibaut
Keyword(s):  
Cell Wall ◽  
Dynamic Modulus ◽  
Compression Wood ◽  
Microfibril Angle ◽  
Axial Direction ◽  
Vibrational Properties ◽  
Normal Wood ◽  
Time Frequency ◽  
Damping Characteristics ◽  
Frequency Domains

Abstract This study aims at better understanding the respective influences of specific gravity (γ), microfibril angle (MFA), and cell wall matrix polymers on viscoelastic vibrational properties of wood in the axial direction. The wide variations of properties between normal wood (NW) and compression wood (CW) are in focus. Three young bent trees (Picea abies, Pinus sylvestris and Pinus pinaster), which recovered verticality, were sampled. Several observed differences between NW and CW were highly significant in terms of anatomical, physical (γ, shrinkage, CIELab colorimetry), mechanical (compressive strength), and vibrational properties. The specific dynamic modulus of elasticity (E′/γ) decreases with increasing MFA, and Young’s modulus (E′) can be satisfactorily explained by γ and MFA. Apparently, the type of the cell wall polymer matrix is not influential in this regard. The damping coefficient (tanδ) does not depend solely on the MFA of NW and CW. The tanδ – E′/γ relationship evidences that, at equivalent E′/γ, the tanδ of CW is approximately 34% lower than that of NW. This observation is ascribed to the more condensed nature of CW lignins, and this is discussed in the context of previous findings in other hygrothermal and time/frequency domains. It is proposed that the lignin structure and the amount and type of extractives, which are both different in various species, are partly responsible for taxonomy-related damping characteristics.

scholarly journals Cell wall structure and formation of maturing fibres of moso bamboo ( Phyllostachys pubescens ) increase buckling resistance

2011 ◽  
Vol 9 (70) ◽  
pp. 988-996 ◽  
Author(s):  
Xiaoqing Wang ◽  
Haiqing Ren ◽  
Bo Zhang ◽  
Benhua Fei ◽  
Ingo Burgert
Keyword(s):  
Cell Wall ◽  
Mechanical Stability ◽  
Moso Bamboo ◽  
Wall Structure ◽  
Wall Thickening ◽  
Phyllostachys Pubescens ◽  
Vascular Bundles ◽  
Buckling Resistance ◽  
Cellulose Fibrils ◽  
Transverse Rigidity

The mechanical stability of the culms of monocotyledonous bamboos is highly attributed to the proper embedding of the stiff fibre caps of the vascular bundles into the soft parenchymatous matrix. Owing to lack of a vascular cambium, bamboos show no secondary thickening growth that impedes geometrical adaptations to mechanical loads and increases the necessity of structural optimization at the material level. Here, we investigate the fine structure and mechanical properties of fibres within a maturing vascular bundle of moso bamboo, Phyllostachys pubescens , with a high spatial resolution. The fibre cell walls were found to show almost axially oriented cellulose fibrils, and the stiffness and hardness of the central part of the cell wall remained basically consistent for the fibres at different regions across the fibre cap. A stiffness gradient across the fibre cap is developed by differential cell wall thickening which affects tissue density and thereby axial tissue stiffness in the different regions of the cap. The almost axially oriented cellulose fibrils in the fibre walls maximize the longitudinal elastic modulus of the fibres and their lignification increases the transverse rigidity. This is interpreted as a structural and mechanical optimization that contributes to the high buckling resistance of the slender bamboo culms.

scholarly journals Identifying transcription factors that reduce wood recalcitrance and improve enzymatic degradation of xylem cell wall in Populus

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chiaki Hori ◽  
Naoki Takata ◽  
Pui Ying Lam ◽  
Yuki Tobimatsu ◽  
Soichiro Nagano ◽  
...  
Keyword(s):  
Cell Wall ◽  
Populus Tremuloides ◽  
Cell Walls ◽  
Enzymatic Degradation ◽  
Plant Biomass ◽  
Lignin Content ◽  
Enzymatic Saccharification ◽  
Wall Structure ◽  
Xylem Cell

AbstractDeveloping an efficient deconstruction step of woody biomass for biorefinery has been drawing considerable attention since its xylem cell walls display highly recalcitrance nature. Here, we explored transcriptional factors (TFs) that reduce wood recalcitrance and improve saccharification efficiency in Populus species. First, 33 TF genes up-regulated during poplar wood formation were selected as potential regulators of xylem cell wall structure. The transgenic hybrid aspens (Populus tremula × Populus tremuloides) overexpressing each selected TF gene were screened for in vitro enzymatic saccharification. Of these, four transgenic seedlings overexpressing previously uncharacterized TF genes increased total glucan hydrolysis on average compared to control. The best performing lines overexpressing Pt × tERF123 and Pt × tZHD14 were further grown to form mature xylem in the greenhouse. Notably, the xylem cell walls exhibited significantly increased total xylan hydrolysis as well as initial hydrolysis rates of glucan. The increased saccharification of Pt × tERF123-overexpressing lines could reflect the improved balance of cell wall components, i.e., high cellulose and low xylan and lignin content, which could be caused by upregulation of cellulose synthase genes upon the expression of Pt × tERF123. Overall, we successfully identified Pt × tERF123 and Pt × tZHD14 as effective targets for reducing cell wall recalcitrance and improving the enzymatic degradation of woody plant biomass.

scholarly journals In situ detection of cell wall polysaccharides in sitka spruce (Picea sitchensis (Bong.) Carrière) wood tissue

BioResources ◽  
2007 ◽  
Vol 2 (2) ◽  
pp. 284-295
Author(s):  
Clemens Altaner ◽  
J. Paul Knox ◽  
Michael C. Jarvis
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Cell Walls ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Crystalline Cellulose ◽  
Carbohydrate Binding ◽  
Cell Wall Polysaccharides ◽  
Amorphous Cellulose ◽  
Carbohydrate Binding Modules

Wood cell wall polysaccharides can be probed with monoclonal antibodies and carbohydrate-binding modules (CBMs). Binding of monoclonal antibodies to β-1-4-xylan, β-1-4-mannan, β-1-3-glucan, and α-1-5-arabinan structures were observed in native Sitka spruce (Picea sitchensis (Bong.) Carrière) wood cell walls. Furthermore CBMs of different families, differing in their affinities for crystalline cellulose (3a) and amorphous cellulose (17 and 28), were shown to bind to the native wood cell walls with varying intensities. Resin channel forming cells exhibited an increased β-1-4-xylan and a decreased β-1-4-mannan content. Focusing on severe compression wood (CW) tracheids, β-1-3-glucan was found towards the cell lumen. In contrast, α-1-5-arabinan structures were present in the intercellular spaces between the round tracheids in severe CW, highlighting the importance of this polymer in cell adhesion.

scholarly journals Biosynthetic labeling with 3-O-propargylcaffeyl alcohol reveals in vivo cell-specific patterned lignification in loquat fruits during development and postharvest storage

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nan Zhu ◽  
Chenning Zhao ◽  
Yuqing Wei ◽  
Chongde Sun ◽  
Di Wu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lignin Content ◽  
Wall Layer ◽  
Wall Structure ◽  
Vascular Bundles ◽  
Precise Localization ◽  
In Planta ◽  
Cell Wall Modification ◽  
Fruit Flesh

AbstractLignification is a major cell wall modification that often results in the formation of sophisticated subcellular patterns during plant development or in response to environmental stresses. Precise localization of the spatiotemporal deposition of lignin is of great importance for revealing the lignification regulatory mechanism of individual cells. In loquat fruits, lignification typically increases the flesh lignin content and firmness, reducing their edibility and processing quality. However, the precise localization of the spatiotemporal active zones of lignification inside loquat fruit flesh remains poorly understood, and little is known about the contribution of patterned lignification to cell wall structure dynamics and the subsequent fruit-quality deterioration. Here, we performed an emerging bioorthogonal chemistry imaging technique to trace the in vivo patterned lignification dynamics in cells of loquat fruit flesh during development and storage. In developing fruits, lignified cells (LCs) and vascular bundles (VBs) were the zones of active lignification, and ring-like LCs deposited lignin at both the inner wall layer and the outer periphery sides. The domino effect of the generation of LCs was preliminarily visualized. In mature fruits, the newly formed lignin in the flesh of fruits during storage was specifically deposited in the corners and middle lamellae of parenchyma cells surrounding the VBs, resulting in the development of a reticular structure. Based on the findings, distinct spatiotemporal patterned lignification modes for different flesh cells in loquat fruits were proposed. These findings provide loquat lignification dynamics together with spatiotemporal data that can improve our understanding of the lignification process in planta.

scholarly journals Significant influence of lignin on axial elastic modulus of poplar wood at low microfibril angles under wet conditions

2019 ◽  
Vol 70 (15) ◽  
pp. 4039-4047 ◽  
Author(s):  
Merve Özparpucu ◽  
Notburga Gierlinger ◽  
Igor Cesarino ◽  
Ingo Burgert ◽  
Wout Boerjan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lignin Content ◽  
Construction Material ◽  
Linear Regression Analysis ◽  
Microfibril Angle ◽  
Tensile Tests ◽  
Multiple Linear Regression Analysis ◽  
Axial Stiffness ◽  
The Matrix ◽  
The Individual

Abstract Wood is extensively used as a construction material. Despite increasing knowledge of its mechanical properties, the contribution of the cell-wall matrix polymers to wood mechanics is still not well understood. Previous studies have shown that axial stiffness correlates with lignin content only for cellulose microfibril angles larger than around 20°, while no influence is found for smaller angles. Here, by analysing the wood of poplar with reduced lignin content due to down-regulation of CAFFEOYL SHIKIMATE ESTERASE, we show that lignin content also influences axial stiffness at smaller angles. Micro-tensile tests of the xylem revealed that axial stiffness was strongly reduced in the low-lignin transgenic lines. Strikingly, microfibril angles were around 15° for both wild-type and transgenic poplars, suggesting that cellulose orientation is not responsible for the observed changes in mechanical behavior. Multiple linear regression analysis showed that the decrease in stiffness was almost completely related to the variation in both density and lignin content. We suggest that the influence of lignin content on axial stiffness may gradually increase as a function of the microfibril angle. Our results may help in building up comprehensive models of the cell wall that can unravel the individual roles of the matrix polymers.

Microfiber Angle and its Effect on Wood Cell Behavior

2017 ◽  
Vol 1144 ◽  
pp. 88-93
Author(s):  
Vera Hlavata ◽  
Pavel Kuklik ◽  
Jiří Celler ◽  
Jan Vanerek
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Modulus Of Elasticity ◽  
Building Materials ◽  
Lignin Content ◽  
Strong Dependence ◽  
Complex Structure ◽  
Microfibril Angle ◽  
Cell Behavior ◽  
Main Task

The article continues the previous one “Coefficients of Transverse Contraction of the Wood Cell Constituents and their Effect on the Cell Behavior”. Wood, as being one of the most commonly used building materials, disposes of complex structure and basic building unit of a wood-cell. Each individual cell is composed of four distinct cell wall layers - the Primary, S1, S2, and S3. This work focuses on a closer examination of the relationship between microscopic and mechanical properties of wood. The main task was an effect of micro fibril angle (MFA) in the S2 layer of a wood on the cell wall parameters. This layer occupies more than 80% of the total thickness of the cell wall and thus has the greatest influence on the mechanical properties of wood cells. MFA values as well as values of bulk density has a strong dependence on the modulus of, elasticity in the longitudinal direction, as well as on the values of shrinkage. We tried to describe the dependence of the longitudinal modulus of elasticity on its. The proposed formula was partially validated using nanoindentation experiments performed in Norway spruce cell walls with highly variable cellulose microfibril angle and lignin content [5].

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