The interrelation between microfibril angle (MFA) and hygrothermal recovery (HTR) in compression wood and normal wood of Sugi and Agathis

Abstract Tree growth stress (GS) consists of an elastic component and a viscoelastic locked-in component. The elastic component is released instantaneously by cutting wood, whereas the locked-in component remains. The latter can be released by hot water treatment, which is known as hygrothermal recovery (HTR). In this paper the mechanism behind HTR is described and interpreted in terms of the microfibril angle (MFA) in the cell wall as follows: during cell-wall maturation, axial tensile stress is generated in the cellulose microfibrils (CMF), whereas isotropic compressive stress is generated in the matrix of lignin-hemicellulose (MT). Some amount of microscopic stresses remains following the removal of the wood from the living stem. Hygrothermal (HT) treatment induces recovery of remaining compressive stress in the MT, which causes its expansion. Axial tensile stress in the CMF are released by HT softening of the MT. This causes the CMF to contract along its length and to expand laterally. The combined effect of the expansions of the MT and contraction of the CMF causes the wood to deform anisotropically. This is the HTR of wood. The degree of anisotropy is determined by the MFA on the basis of reinforced-matrix theory.

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Microfibril Angle Distribution of Poplar Tension Wood

IAWA Journal ◽

10.1163/22941932-90000105 ◽

2012 ◽

Vol 33 (4) ◽

pp. 431-439 ◽

Cited By ~ 7

Author(s):

Silke Lautner ◽

Cordt Zollfrank ◽

Jörg Fromm

Keyword(s):

Electron Microscopy ◽

Tension Wood ◽

Microfibril Angle ◽

Cellulose Microfibrils ◽

Normal Wood ◽

Angle Distribution ◽

Transmission Electron ◽

Wood Fibres ◽

Characteristic Features ◽

Fibril Angle

Tension wood of poplar (Populus nigra) branches was studied by lightand electron microscopy. The characteristic features of tension wood such as wider growth rings, reduced vessel density and higher gross density were confirmed by our results. Based on a novel combination of transmission electron microscopy (TEM) imaging and image analysis, involving Fourier transformation, the orientation of cellulose microfibrils in the S2- and G-layer was determined. Within the G-layer microfibril angle (MFA) was parallel to the growth axis (0°). However, in the S2 it was 13° in tension wood fibres and 4° in normal wood fibres. With the exception of the relatively low fibril angle in the S2 of tension wood fibres (13°) the results are in good agreement with those of the literature.

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Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

Journal of The Royal Society Interface ◽

10.1098/rsif.2014.0126 ◽

2014 ◽

Vol 11 (95) ◽

pp. 20140126 ◽

Cited By ~ 29

Author(s):

Ahmad Rafsanjani ◽

Michael Stiefel ◽

Konstantins Jefimovs ◽

Rajmund Mokso ◽

Dominique Derome ◽

...

Keyword(s):

Cell Wall ◽

Growth Ring ◽

Ion Beam ◽

Microfibril Angle ◽

Cellulose Microfibrils ◽

Wall Material ◽

Neighbouring Cell ◽

Direction Parallel ◽

Hygroscopic Swelling ◽

S2 Layer

We document the hygroscopic swelling and shrinkage of the central and the thickest secondary cell wall layer of wood (named S2) in response to changes in environmental humidity using synchrotron radiation-based phase contrast X-ray tomographic nanoscopy. The S2 layer is a natural fibre-reinforced nano-composite polymer and is strongly reactive to water. Using focused ion beam, micropillars with a cross section of few micrometres are fabricated from the S2 layer of the latewood cell walls of Norway spruce softwood. The thin neighbouring cell wall layers are removed to prevent hindering or restraining of moisture-induced deformation during swelling or shrinkage. The proposed experiment intended to get further insights into the microscopic origin of the anisotropic hygro-expansion of wood. It is found that the swelling/shrinkage strains are highly anisotropic in the transverse plane of the cell wall, larger in the normal than in the direction parallel to the cell wall's thickness. This ultrastructural anisotropy may be due to the concentric lamellation of the cellulose microfibrils as the role of the cellulose microfibril angle in the transverse swelling anisotropy is negligible. The volumetric swelling of the cell wall material is found to be substantially larger than the one of wood tissues within the growth ring and wood samples made of several growth rings. The hierarchical configuration in wood optimally increases its dimensional stability in response to a humid environment with higher scales of complexity.

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Studies of the structure and chemical composition of the cell walls of Vaucheriaceae and Saprolegniaceae

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1963.0056 ◽

1963 ◽

Vol 158 (973) ◽

pp. 435-445 ◽

Cited By ~ 35

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Insoluble Fraction ◽

Water Soluble ◽

Hot Water ◽

Cellulose Microfibrils ◽

Wall Material ◽

Native Cellulose ◽

A Cell ◽

Crystalline Component

The cell walls of members of the Vaucheriaceae and Saprolegniaceae have been examined by X-ray analysis and electron microscopy, and their composition determined by hydrolysis and paper partition chromatography of the hydrolysates. Both differences and similarities between the members of these two species examined are found to supplement the comparative morphological and physiological information at present available. Saprolegnia , Achlya , Brevilegnia and Dictyuchus among the Saprolegniaceae possess hot-water soluble polysaccharides containing glucose residues only. This polysaccharide is not crystallographically identical with the polysaccharide found in Vaucheria sessilis with a similar solubility. The members of the Saprolegniaceae contain large amounts of alkali-soluble polysaccharides in contrast with the negligible amount found in V. sessilis . These polysaccharides are only weakly crystalline, but the indications are that the same polysaccharides may occur throughout the Saprolegniaceae. The alkali-insoluble wall material of Vaucheria species consists of highly crystalline native cellulose with large, apparently randomly arranged, microfibrils. The hydrolysate of this material contains ribose, xylose and arabinose in addition to glucose, presumably representing strongly bound pentosans. Native cellulose also occurs in the Saprolegniaceae but only in small proportion. The bulk of the alkali-insoluble fraction in the walls of these fungi appears amorphous in the electron microscope and is only weakly crystalline. It consists of one or m ore substances containing glucose, mannose, ribose and possibly other sugars together with traces of glucosamine. These substances presumably cover the cellulose microfibrils. The total quantity of non-cellulosic polysaccharide in the Saprolegniaceae approaches 85% of the total wall weight in contrast with the situation in Vaucheria where the cellulose alone approaches 90% of the total cell wall. Dichotomosiphon is unique among the organism s studied in this paper, in possessing a cell wall entirely soluble in alkali and composed of approximately equal quantities of glucose and xylose. The crystalline component is aβ-1,3-linked xylan, as already reported for some of the Siphonales (closely related algae) by Frei & Preston.

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

Holzforschung ◽

10.1515/hf-2011-0186 ◽

2013 ◽

Vol 67 (1) ◽

pp. 75-85 ◽

Cited By ~ 18

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.

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Application of Small-Angle X-Ray Scattering to Predict Microfibril Angle in Acacia mangium Wood

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.173.72 ◽

2010 ◽

Vol 173 ◽

pp. 72-77

Author(s):

Tabet A. Tamer ◽

Aziz Abdul Haji Fauziah ◽

Radiman Shahidan

Keyword(s):

Cell Wall ◽

Standard Deviation ◽

Intensity Distribution ◽

Small Angle ◽

Cell Walls ◽

Microfibril Angle ◽

Acacia Mangium ◽

Cellulose Microfibrils ◽

X Ray ◽

X Ray Scattering

Partially crystalline cellulose microfibrils are wound helically around the longitudinal axis of the wood cell. A method is presented for the measurement, using small-angle X-ray scattering (SAXS), of the microfibril angle, (MFA) and the associated standard deviation for the cellulose microfibrils in the S2 layer of the cell walls of Acacia mangium wood. The length and orientation of the microfibrils of the cell walls in the irradiated volume of the thin samples are measured using SAXS and scanning electron microscope, (SEM). The undetermined parameters in the analysis are the MFA, (M) and the standard deviation (σФ) of the intensity distribution arising from the wandering of the fibril orientation about the mean value. Nine separate pairs of values are determined for nine different values of the angle of the incidence of the X-ray beam relative to the normal to the radial direction in the sample. The results show good agreement. The curve distribution of scattered intensity for the real cell wall structure is compared with that calculated with that assembly of rectangular cells with the same ratio of transverse to radial cell wall length. It is demonstrated that for β = 45°, the peaks in the curve intensity distribution for the real and the rectangular cells coincide. If this peak position is Ф45, Then the MFA can be determined from the relation M = tan-1 (tan Ф45 / cos 45°), which is precise for rectangular cells.

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Wood microfibril angle variation after drying

Holzforschung ◽

10.1515/hf-2014-0334 ◽

2016 ◽

Vol 70 (5) ◽

pp. 485-488 ◽

Cited By ~ 3

Author(s):

Vinicius Lube ◽

Ciprian Lazarescu ◽

Shawn D. Mansfield ◽

Stavros Avramidis

Keyword(s):

Cell Wall ◽

Moisture Content ◽

Cell Walls ◽

Wood Cell Wall ◽

Microfibril Angle ◽

Cellulose Microfibrils ◽

Lateral Deformation ◽

Angle Variation ◽

Water Desorption

Abstract The change of microfibril angle (MFA) in wood cell wall was assessed after drying at 60°C and 70°C to a target moisture content (MC) of 8% or 15%. Despite literature contradictions about the effect of drying on MFA, this study showed that drying increased significantly the MFA, possibly as a result of lateral deformation of cellulose microfibrils during water desorption from wood cell walls. Moreover, MFA increased when target MC decreased.

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Synchrotron X-ray measurements of cellulose in wood cell wall layers of Pinus densiflora in the transmission and reflectance modes. Part 2: results with axial loading

Holzforschung ◽

10.1515/hf-2019-0222 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Chang-Goo Lee ◽

Mariko Yamasaki ◽

Erina Kojima ◽

Takanori Sugimoto ◽

Yasutoshi Sasaki

Keyword(s):

Cell Wall ◽

Mechanical Behavior ◽

Lattice Spacing ◽

Pinus Densiflora ◽

Microfibril Angle ◽

Compressive Load ◽

Axial Loading ◽

Cellulose Microfibrils ◽

Compressive Loads ◽

Almost All

AbstractThis study applied synchrotron radiation XRD to analyze the mechanical behavior of cellulose microfibrils in wood containing annual rings (thickness: 5 mm), for different layers of the secondary cell wall, under uniaxial load. Cellulose in S2 and in S1 and S3 layers were analyzed respectively, and the data were used to investigate for deformation behavior in the lattice spacing (d004). As a result, the mechanical behavior of cellulose sometimes differed from the behavior of bulk wood. The rigidity of cellulose in the S2 layer was larger than in S1 and S3 layers under both of tensile and compressive loads. However, once standardized with respect to estimated cellulose amount, this standardized rigidity was comparable across all layers and loading conditions. Variation in microfibril angle (MFA) and lattice spacing (d004) of cellulose barely changed at all under compressive load. Under tensile loads, there were both of positive and negative changes in MFA variation in both S2 layer and S1 and S3 layers, while d004 variation had little changes in almost all cases.

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Thickness-dependent stiffness of wood: potential mechanisms and implications

Holzforschung ◽

10.1515/hf-2019-0311 ◽

2020 ◽

Vol 74 (12) ◽

pp. 1079-1087 ◽

Cited By ~ 1

Author(s):

Fei Guo ◽

Clemens M. Altaner ◽

Michael C. Jarvis

Keyword(s):

Mechanical Properties ◽

Cell Wall ◽

Composite Materials ◽

Tensile Stress ◽

Single Cell ◽

Single Cells ◽

Axial Plane ◽

Cellulose Microfibrils ◽

Tensile Stiffness ◽

Thin Samples

AbstractWhen wood is split or cut along the grain, a reduction in tensile stiffness has been observed. The averaged mechanical properties of wood samples, veneers or splinters therefore change when their thickness is less than about 1 mm. The loss of stiffness increases as the thickness approaches that of a single cell. The mechanism of the effect depends on whether the longitudinal fission plane is between or through the cells. Isolated single cells are a model for fission between cells. Each cell within bulk wood is prevented from twisting by attachment to its neighbours. Separation of adjacent cells lifts this restriction on twisting and facilitates elongation as the cellulose microfibrils reorientate towards the stretching direction. In contrast when the wood is cut or split along the centre of the cells, it appears that co-operative action by the S1, S2 and S3 cell-wall layers in resisting tensile stress may be disrupted. Since much of what is known about the nanoscale mechanism of wood deformation comes from experiments on thin samples, caution is needed in applying this knowledge to structural-sized timber. The loss of stiffness at longitudinal fracture faces may augment the remarkable capacity of wood to resist fracture by deflecting cracks into the axial plane. These observations also point to mechanisms for enhancing toughness that are unique to wood and have biomimetic potential for the design of composite materials.

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Histochemical Structure and Tensile Properties of Birch Cork Cell Walls

10.21203/rs.3.rs-327370/v1 ◽

2021 ◽

Author(s):

Shingo Kiyoto ◽

Junji Sugiyama

Keyword(s):

Cell Wall ◽

Tensile Stress ◽

Cell Walls ◽

Middle Lamella ◽

Middle Layer ◽

Tensile Tests ◽

Cellulose Microfibrils ◽

Trunk Diameter ◽

Compound Middle Lamella ◽

Cork Cell

Abstract Tensile tests of birch cork were performed in the tangential direction. Birch cork in the wet state showed significantly higher extensibility and toughness than those in the oven-dried state. The histochemical structure of birch cork was investigated by microscopic observation and spectroscopic analysis. Birch cork cell walls showed a three-layered structure. In transmission electron micrographs, osmium tetroxide stained the outer and inner layers, whereas potassium permanganate stained the middle and inner layers. After chemical treatment to remove suberin and lignin, the outer and inner layers disappeared and Fourier-transformed infrared spectra showed the cellulose I pattern. Polarizing light micrographs indicated that molecular chains in the outer and inner layers were oriented perpendicular to suberin lamination, whereas those in the inner layer showed longitudinal orientation. These results suggested that the outer and inner layers mainly consist of suberin, whereas the middle layer and compound middle lamella consist of lignin, cellulose, and other polysaccharides. We hypothesized a hierarchical model of the birch cork cell wall. The lignified cell wall with helical arrangement of cellulose microfibrils is sandwiched between two suberized walls. Cellulose microfibrils in the middle layer act like a spring and bear tensile loads. In the wet state, water and cellulose in the compound middle lamella transfer tensile stress between cells. In the dried state, this stress-transferal system functions poorly and fewer cells bear stress. Suberin in the outer and inner layers prevents absolute drying to maintain mechanical properties of the bark and to bear tensile stress caused by trunk diameter growth.

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A survey of the natural variation in biomechanical and cell wall properties in inflorescence stems reveals new insights into the utility of Arabidopsis as a wood model

Functional Plant Biology ◽

10.1071/fp12386 ◽

2013 ◽

Vol 40 (7) ◽

pp. 662 ◽

Cited By ~ 9

Author(s):

Colleen P. MacMillan ◽

Philip J. O'Donnell ◽

Anne-Marie Smit ◽

Rob Evans ◽

Zbigniew H. Stachurski ◽

...

Keyword(s):

Tensile Strength ◽

Cell Wall ◽

Natural Variation ◽

Lignin Content ◽

Secondary Growth ◽

Microfibril Angle ◽

Biofuel Production ◽

Arabinogalactan Protein ◽

Cellulose Microfibrils ◽

Inflorescence Stems

The natural trait variation in Arabidopsis thaliana (L.) Heynh. accessions is an important resource for understanding many biological processes but it is underexploited for wood-related properties. Twelve A. thaliana accessions from diverse geographical locations were examined for variation in secondary growth, biomechanical properties, cell wall glycan content, cellulose microfibril angle (MFA) and flowering time. The effect of daylength was also examined. Secondary growth in rosette and inflorescence stems was observed in all accessions. Organised cellulose microfibrils in inflorescence stems were found in plants grown under long and short days. A substantial range of phenotypic variation was found in biochemical and wood-related biophysical characteristics, particularly for tensile strength, tensile stiffness, MFA and some cell wall components. The four monosaccharides galactose, arabinose, rhamnose and fucose strongly correlated with each other as well as with tensile strength and MFA, consistent with mutations in arabinogalactan protein and fucosyl- and xyloglucan galactosyl-transferase genes that result in decreases in strength. Conversely, these variables showed negative correlations with lignin content. Our data support the notion that large-scale natural variation studies of wood-related biomechanical and biochemical properties of inflorescence stems will be useful for the identification of novel genes important for wood formation and quality, and therefore biomaterial and renewable biofuel production.

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