scholarly journals In situ observation of shrinking and swelling of normal and compression Chinese fir wood at the tissue, cell and cell wall level

2021 ◽  
Author(s):  
Tianyi Zhan ◽  
Jianxiong Lyu ◽  
Michaela Eder
Keyword(s):  
Cell Wall ◽  
Compression Wood ◽  
Chinese Fir ◽  
Fine Tuning ◽  
Tissue Cell ◽  
In Situ Observation ◽  
Normal Wood ◽  
Moisture Variation ◽  
Hierarchical Levels

AbstractThe shrinking and swelling of wood due to moisture changes are intrinsic material properties that control and limit the use of wood in many applications. Herein, hygroscopic deformations of normal and compression wood of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) were measured during desorption and absorption processes. The dimensional changes were observed in situ by an environmental scanning electron microscope and analyzed at different hierarchical levels (tissue, cell and cell wall). The relationship between moisture variation and hygroscopic deformation was measured. During initial desorption periods from 95 to 90 or 75% RH, an expansion of the lumen and a shrinkage of the cell wall were observed, revealing a non-uniform and directional deformation of single wood cells. The variation of shrinking or swelling at different hierarchical levels (tissue, cell and cell wall) indicates that the hygroscopic middle lamella plays a role in the deformation at the tissue level. Higher microfibril angles and helical cavities on the cell wall in compression wood correlate with a lower shrinking/swelling ratio. Normal wood showed a more pronounced swelling hysteresis than compression wood, while the sorption hysteresis was almost the same for both wood types. This finding is helpful to elucidate effects of micro- and ultrastructure on sorption. The present findings suggest that the sophisticated system of wood has the abilities to adjust the hygroscopic deformations by fine-tuning its hierarchical structures.

Lignin distribution in mild compression wood of Pinus radiata

1999 ◽  
Vol 77 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Lloyd A Donaldson ◽  
Adya P Singh ◽  
Arata Yoshinaga ◽  
Keiji Takabe
Keyword(s):  
Cell Wall ◽  
Fluorescence Microscopy ◽  
Pinus Radiata ◽  
Compression Wood ◽  
Middle Lamella ◽  
Confocal Fluorescence Microscopy ◽  
Interference Microscopy ◽  
Normal Wood ◽  
Lignin Distribution ◽  
Confocal Fluorescence

Lignin distribution in the tracheid cell wall of mild compression wood in Pinus radiata D. Don was examined by interference microscopy, confocal fluorescence microscopy, and ultraviolet (UV) microscopy. Two anatomically different samples of mild compression wood were compared with a sample of normal wood using quantitative interference microscopy and microdensitometry combined with confocal fluorescence microscopy to estimate the quantitative or semiquantitative lignin distribution in the S2 and S2L regions of the secondary cell wall and of the cell corner middle lamella (CCML). One of these samples was briefly examined by UV microscopy for comparison. Quantitative interference microscopy provided information on lignin concentration in different regions of the cell wall with values of 26, 46, and 57%, respectively, for the S2, S2L, and CCML regions of sample 1 and 20, 29, and 46%, respectively, for the same regions of sample 2. Microdensitometry of confocal fluorescence images provided semiquantitative information on the relative lignin distribution based on lignin autofluorescence. Comparison between the two compression wood samples using autofluorescence gave results that were in partial agreement with interference microscopy with respect to the relative lignification levels in the S2, S2L, and CCML regions. Some improvement was achieved by using calibration values for hemicellulose rather than holocellulose for interference data in the S2L region. Results for UV microscopy performed on sample 1 indicated that the lignification of the CCML region was comparable with that of the S2L region in this sample but with some variation among cells. All three techniques indicated significant variation in lignification levels of the S2L and CCML regions among adjacent cells and a significant reduction in the lignification of the CCML region compared to normal wood.Key words: lignin distribution, interference microscopy; confocal fluorescence microscopy, UV microscopy, mild compression wood, Pinus radiata D. Don.

scholarly journals The Nature of Reaction Wood III. Cell Division and Cell Wall Formation in Conifer Stems

1952 ◽  
Vol 5 (4) ◽  
pp. 385 ◽  
Author(s):  
ABW Ardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Secondary Wall ◽  
Compression Wood ◽  
Normal Wood ◽  
Reaction Wood ◽  
Primary Wall ◽  
Wall Formation ◽  
Tracheid Length ◽  
Secondary Wall Formation

Cell division, the nature of extra-cambial readjustment, and the development of the secondary wall in the tracheids of conifer stems have been investigated in both compression wood and normal wood. It has been shown that the reduction in tracheid length, accompanying the development of compression wood and, in normal wood, increased radial growth after suppression, result from an increase in the number of anticlinal divisions in the cambium. From observations of bifurcated and otherwise distorted cell tips in mature tracheids, of small but distinct terminal canals connecting the lumen to the primary wall in the tips of mature tracheids, and of the presence of only primary wall at the tips of partly differentiated tracheids, and from the failure to observe remnants of the parent primary walls at the ends of differentiating tracheids, it has been concluded that extra-cambial readjustment of developing cells proceeds by tip or intrusive growth. It has been further concluded that the development of the secondary wall is progressive towards the cell tips, on the bases of direct observation of secondary wall formation in developing tracheids and of the increase found in the number of turns of the micellar helix per cell with increasing cell length. The significance of this in relation to the submicroscopic organization of the cell wall has been discussed. Results of X-ray examinations and of measurements of� tracheid length in successive narrow tangential zones from the cambium into the xylem have indicated that secondary wall formation begins before the dimensional changes of differentiation are complete.

In situ detection of laccase activity and immunolocalisation of a compression-wood-specific laccase (CoLac1) in differentiating xylem of Chamaecyparis obtusa

2016 ◽  
Vol 43 (6) ◽  
pp. 542 ◽  
Author(s):  
Hideto Hiraide ◽  
Masato Yoshida ◽  
Saori Sato ◽  
Hiroyuki Yamamoto
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
Compression Wood ◽  
Laccase Activity ◽  
Outer Part ◽  
Chamaecyparis Obtusa ◽  
Wall Layer ◽  
Wall Thickening ◽  
Lignin Concentration

The secondary cell wall of compression wood tracheids has a highly lignified region (S2 L) in its outermost portion. To better understand the mechanism of S2 L formation, we focussed on the activity of laccase (a monolignol oxidase) and performed in situ studies of this enzyme in differentiating compression wood. Staining of differentiating compression wood demonstrated that laccase activity began in all cell wall layers before the onset of lignification. We detected no activity of peroxidase (another monolignol oxidase) in any cell wall layer. Thus, laccase likely plays the major role in monolignol oxidisation during compression wood differentiation. Laccase activity was higher in the S2 L region than in other secondary wall regions, suggesting that this enzyme was responsible for the high lignin concentration in this region of the cell wall. Immunolabelling demonstrated the expression of a compression-wood-specific laccase (CoLac1) immediately following the onset of secondary wall thickening, this enzyme was localised to the S2 L region, whereas much less abundant in the S1 layer or inner S2 layer. Thus, the CoLac1 protein is most likely localised to the outer part of S2 and responsible for the high lignin concentration in the S2 L region.

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.

Juvenile and Compression Wood Cell Wall Layers Differ in Lignin Structure in Norway Spruce and Scots Pine

IAWA Journal ◽  
2008 ◽  
Vol 29 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Eija Kukkola ◽  
Pekka Saranpää ◽  
Kurt Fagerstedt
Keyword(s):  
Cell Wall ◽  
Norway Spruce ◽  
Scots Pine ◽  
Cell Walls ◽  
Compression Wood ◽  
Wood Cell Wall ◽  
Outer Part ◽  
Wall Layer ◽  
Mature Wood ◽  
Normal Wood

Dibenzodioxocin, an 8-ring substructure of lignin identified in the mid- 1990's, is known to occur in softwood cell walls especially in the S3-layers of normal wood. In this study the lignin substructure was immunolocalised in juvenile and mature wood as well as in different degrees of compression wood of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.). In juvenile wood of Norway spruce, dibenzodioxocin was hardly present in the tracheid cell wall, while in Scots pine some dibenzodioxocin was found evenly distributed in the S2-layers. In mature normal wood, dibenzodioxocin was localised in the S3-layers in both Scots pine and Norway spruce. In contrast, in compression wood tracheids of Scots pine, where the S3-layer is not present, dibenzodioxocin was found in the S1-layers and in the outer part of the S2-layers, while in Norway spruce the innermost cell wall layer showed a strong signal. These findings support the idea that in mature wood the condensed dibenzodioxocin structure is formed in Norway spruce at the end of lignification, when the supply of monolignols and probably also hydrogen peroxide is diminishing. The reasons for Scots pine juvenile and compression wood showing a different pattern of dibenzodioxocin labelling is discussed.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In Situ Observation of Catalyzed Gasification of Graphite by Nickel

1981 ◽  
Vol 39 ◽  
pp. 76-77
Author(s):  
R. T. K. Baker ◽  
R. D. Sherwood
Keyword(s):  
Objective Lens ◽  
In Situ Observation ◽  
Gas Flows ◽  
Catalytic Gasification ◽  
Television Camera ◽  
Viewing Screen ◽  
Fuels And Chemicals ◽  
Gasification Of Carbon ◽  
Transmission Microscope

The catalytic gasification of carbon at high temperature by microscopic size metal particles is of fundamental importance to removal of coke deposits and conversion of refractory hydrocarbons into fuels and chemicals. The reaction of metal/carbon/gas systems can be observed by controlled atmosphere electron microscopy (CAEM) in an 100 KV conventional transmission microscope. In the JEOL gas reaction stage model AGl (Fig. 1) the specimen is positioned over a hole, 200μm diameter, in a platinum heater strip, and is interposed between two apertures, 75μm diameter. The control gas flows across the specimen and exits through these apertures into the specimen chamber. The gas is further confined by two apertures, one in the condenser and one in the objective lens pole pieces, and removed by an auxiliary vacuum pump. The reaction zone is <1 mm thick and is maintained at gas pressure up to 400 Torr and temperature up to 1300<C as measured by a Pt-Pt/Rh 13% thermocouple. Reaction events are observed and recorded on videotape by using a Philips phosphor-television camera located below a hole in the center of the viewing screen. The overall resolution is greater than 2.5 nm.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

In-Situ Observation of Clay Minerals Hydrated and Intercalated With Liquid Chemicals Using Film-Sealed Environmental Cell

1980 ◽  
Vol 38 ◽  
pp. 208-209 ◽  
Author(s):  
K. Fukushima ◽  
N. Kohyama ◽  
A. Fukami
Keyword(s):  
Carbon Film ◽  
Resolving Power ◽  
In Situ Observation ◽  
Interlayer Water ◽  
Saturated Water ◽  
Structure Changes ◽  
Environmental Cell ◽  
Gas Layer ◽  
20 Nm

A film-sealed high resolution environmental cell(E.C) for observing hydrated materials had been developed by us(l). Main specification of the E.C. is as follows: 1) Accelerated voltage; 100 kV. 2) Gas in the E.C.; saturated water vapour with carrier gas of 50 Torr. 3) Thickness of gas layer; 50 μm. 4) Sealing film; evaporated carbon film(20 nm thick) with plastic microgrid. 5) Resolving power; 1 nm. 6) Transmittance of electron beam; 60% at 100 kV. The E.C. had been successfully applied to the study of hydrated halloysite(2) (3). Kaolin minerals have no interlayer water and are basically non-expandable but form intercalation compounds with some specific chemicals such as hydrazine, formamide and etc. Because of these compounds being mostly changed in vacuum, we tried to reveal the structure changes between in wet air and in vacuum of kaolin minerals intercalated with hydrazine and of hydrated state of montmori1lonite using the E.C. developed by us.

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