Topochemical Investigations on Delignification of Picea abies [L.] Karst. during Alkaline Sulfite (ASA) and Bisulfite Pulping by Scanning UV Microspectrophotometry

Holzforschung ◽  
2003 ◽  
Vol 57 (6) ◽  
pp. 611-618 ◽  
Author(s):  
G. Koch ◽  
B. Rose ◽  
R. Patt ◽  
O. Kordsachia.
Keyword(s):  
Picea Abies ◽  
Cell Walls ◽  
Lignin Content ◽  
Middle Lamella ◽  
Cellular Level ◽  
Analytical Technique ◽  
Compound Middle Lamella ◽  
Lignin Removal ◽  
S2 Layer ◽  
Uv Microspectrophotometry

Summary Delignification of spruce (Picea abies [L.] Karst.) during ASA (modified alkaline sulfite/anthraquinone pulping with alkali splitting) and magnesium bisulfite pulping was studied on a cellular level using scanning UV microspectrophotometry. This improved cellular analytical technique enables direct imaging of the topochemistry of lignin removal within the cell wall at different stages of cooking. The cooks were performed in a laboratory digester with forced liquor circulation. At 30 min intervals samples were taken for chemical and UV microscopic analyses. UV microscopy reveals that delignification during ASA pulping starts in the region of the pit canals and proceeds evenly across the entire S2 layer. As a specific feature of bisulfite pulping, a partial delignification of the radial compound middle lamella can be detected after 60 min of cooking. After 120 min, in both processes, the delignified cell walls show low UV absorbance values of both S2 and compound middle lamella. At this stage, approximately 90% of the initial lignin content is removed. At the end of both pulping processes, only parts of the cell corners can be distinguished by the new UV scanning technique.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

UV-microscopic analysis of acetylated spruce and birch cell walls

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 483-488 ◽  
Author(s):  
Christian Hansmann ◽  
Manfred Schwanninger ◽  
Barbara Stefke ◽  
Barbara Hinterstoisser ◽  
Wolfgang Gindl
Keyword(s):  
Cell Walls ◽  
Middle Lamella ◽  
Microscopic Analysis ◽  
Weight Percent ◽  
Cellular Level ◽  
Uv Spectrum ◽  
Spectral Shifts ◽  
Microscopy Analysis ◽  
Absorbance Peak ◽  
Absorbance Spectra

Abstract Spruce and birch earlywood was acetylated to different weight percent gains using three different acetylation procedures. The absorbance spectra of secondary cell wall and compound cell corner middle lamella were determined by means of UV microscopy. Analysis of the spectra showed that the characteristic lignin absorbance peak in the UV spectrum of wood around 280 nm shifted to shorter wavelengths in acetylated samples. A distinct relationship between achieved weight percent gains after acetylation and observed spectral shifts could be established revealing a certain potential to measure acetylation on a cellular level by means of UV microscopy.

Lignin distribution in waterlogged archaeological Picea abies (L.) Karst degraded by erosion bacteria

Holzforschung ◽  
2014 ◽  
Vol 68 (7) ◽  
pp. 791-798 ◽  
Author(s):  
Nanna Bjerregaard Pedersen ◽  
Uwe Schmitt ◽  
Gerald Koch ◽  
Claus Felby ◽  
Lisbeth Garbrecht Thygesen
Keyword(s):  
Picea Abies ◽  
Lignin Content ◽  
Middle Lamella ◽  
Uv Absorbance ◽  
Tem Analysis ◽  
Lignin Distribution ◽  
Transmission Electron ◽  
Residual Material ◽  
Ray Parenchyma Cells ◽  
Very High

Abstract The lignin distribution in poles of waterlogged archaeological Picea abies (L.) Karst, which was decayed by erosion bacteria (EB) under anoxic conditions for approximately 400 years, was topochemically identified by transmission electron microscopy (TEM) and high resolution UV-microspectrophotometry (UMSP). Lignin rich cell wall compartments such as cell corner (CC), compound middle lamella (CML), torus, initial pit border and mild compression wood (CW) appeared morphologically well preserved together with S1 and S3 layers and epithelial and ray parenchyma cells. Residual material (RM) from degraded S2 showed a varied lignin distribution as evidenced by the different local UV-absorbance intensities. However, evaluation of UV-absorbance line spectra of RM revealed no change in conjugation of the aromatic ring system. Presence of RM with both very low and very high lignin absorbances showed evidence for disassembly of lignin during degradation combined with aggregation of lignin fragments and physical movement of these fractions. In contrast to TEM analysis, locally decreasing lignin content was found by UMSP in CML regions.

Scanning UV microspectrophotometry as a tool to study the changes of lignin in hydrothermally modified wood

Holzforschung ◽  
2016 ◽  
Vol 70 (3) ◽  
pp. 215-221 ◽  
Author(s):  
Bruno Andersons ◽  
Guna Noldt ◽  
Gerald Koch ◽  
Ingeborga Andersone ◽  
Anete Meija-Feldmane ◽  
...  
Keyword(s):  
Cell Wall ◽  
Degradation Products ◽  
Middle Lamella ◽  
Temperature Range ◽  
Wood Protection ◽  
Lower Temperature Range ◽  
Lower Temperature ◽  
The One ◽  
S2 Layer ◽  
Uv Microspectrophotometry

Abstract Thermal modification (TM) of wood has occupied a relatively narrow but stable niche as an alternative for chemical wood protection. There are different technological solutions for TM and not all details of their effects on wood tissue have been understood. The one-stage hydrothermal modification (HTM) at elevated vapour pressure essentially changes the wood’s composition and structure. In the present paper, the changes in three hardwood lignins (alder, aspen, and birch) were observed within the cell wall by means of cellular UV microspectrophotometry. The lignin absorbances in the compound middle lamella (CML) of unmodified wood are 1.7- to 2.0-fold higher than those in the fibre S2 layer. The woods were modified in the temperature range from 140 to 180°C, while in the lower temperature range (140°C/1 h), the UV absorbances are little affected. Essential changes occur in the range of 160–180°C and the UV data reflect these by absorbtion changes, while the absorbances at 278 nm rise with factors around 2 more in the S2 layer than in the CML. The absorbance increments are interpreted as polycondensation reactions with furfural and other degradation products of hemicelluloses with the lignin moiety of the cell wall.

Ultrastructural Changes in the Cell Walls of Cambial Derivatives During Wood Formation in Indian ELM (Holoptelea Integrifolia)

IAWA Journal ◽  
2012 ◽  
Vol 33 (4) ◽  
pp. 403-416 ◽  
Author(s):  
Karumanchi S. Rao ◽  
Yoon Soo Kim ◽  
Pramod Sivan
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Middle Lamella ◽  
Ultrastructural Changes ◽  
Cell Wall Polysaccharides ◽  
Lignin Distribution ◽  
Parenchyma Cells ◽  
Ray Cells ◽  
Xylem Elements ◽  
S2 Layer

Sequential changes occurring in cell walls during expansion, secondary wall (SW) deposition and lignification have been studied in the differentiating xylem elements of Holoptelea integrifolia using transmission electron microscopy. The PATAg staining revealed that loosening of the cell wall starts at the cell corner middle lamella (CCML) and spreads to radial and tangential walls in the zone of cell expansion (EZ). Lignification started at the CCML region between vessels and associated parenchyma during the final stages of S2 layer formation. The S2 layer in the vessel appeared as two sublayers,an inner one and outer one.The contact ray cells showed SW deposition soon after axial paratracheal parenchyma had completed it, whereas noncontact ray cells underwent SW deposition and lignification following apotracheal parenchyma cells. The paratracheal and apotracheal parenchyma cells differed noticeably in terms of proportion of SW layers and lignin distribution pattern. Fibres were found to be the last xylem elements to complete SW deposition and lignification with differential polymerization of cell wall polysaccharides. It appears that the SW deposition started much earlier in the middle region of the fibres while their tips were still undergoing elongation. In homogeneous lignin distribution was noticed in the CCML region of fibres.

Ultrastructural Changes in the Compound Middle Lamella of Pinus thunbergii During Lignification and Lignin Removal

Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Jonas Hafrén ◽  
Takeshi Fujino ◽  
Takao Itoh ◽  
Ulla Westermark ◽  
Noritsugu Terashima
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Middle Lamella ◽  
Pinus Thunbergii ◽  
Ultrastructural Changes ◽  
Woody Tissue ◽  
Compound Middle Lamella ◽  
Lignin Removal ◽  
Transmission Electron ◽  
Early Phases

SummaryThe structure of the middle lamella inPinus thunbergiihas been studied by the rapid-freeze deep-etching (RFDE) technique in combination with transmission electron microscopy (TEM). The ultrastructure of the compound middle lamella was studied in the early phases of the development of woody tissue in the cambial and differentiating xylem, before the heavy incrustation with lignin had occurred. Lignified middle lamella in the xylem was studied both directly and after delignification. It was found that the structure of the unlignified middle lamella in the cambium/developing xylem consists of a fine irregular network probably containing pectin and hemicellulose. As a result of lignin incrustation, the middle lamella becomes increasingly dense and the surface structure of the fully lignified middle lamella appeared to be compact and partly covered with globular structures. After delignification of the lignified middle lamella a thin network with a different structure was revealed. This network probably mainly consists of hemicellulose. No microfibrils of the type that occurs in the primary and secondary walls were found in the middle lamella.

Anatomical and Topochemical Aspects of Japanese beech (Fagus crenata) Cell Walls After Treatment with the Ionic Liquid, 1-Ethylpyridinium Bromide

2015 ◽  
Vol 21 (6) ◽  
pp. 1562-1572 ◽  
Author(s):  
Toru Kanbayashi ◽  
Hisashi Miyafuji
Keyword(s):  
Ionic Liquid ◽  
Cell Walls ◽  
Middle Lamella ◽  
Morphological Characteristics ◽  
Fagus Crenata ◽  
Cellular Level ◽  
Chemical Components ◽  
Wood Fibers ◽  
High Concentration ◽  
Japanese Beech

AbstractChanges in the ultrastructure and chemical components, and their distribution in Japanese beech (Fagus crenata), during the ionic liquid 1-ethylpyridinium bromide ([EtPy][Br]) treatment were examined at the cellular level by light microscopy, scanning electron microscopy, and confocal Raman microscopy. Each of the tissues, including wood fibers, vessels and parenchyma cells treated with [EtPy][Br] showed specific morphological characteristics. Furthermore, lignin can be preferentially liquefied and eluted in [EtPy][Br] from the cell walls when compared to polysaccharides. However, the delignification was heterogeneous on the cell walls as lignin maintained a relatively high-concentration at the compound middle lamella, cell corners, inner surface of the secondary wall, and pits after [EtPy][Br] treatment.

Chemical and ultrastructural changes of ash wood thermally modified using the thermo-vacuum process: I. Histo/cytochemical studies on changes in the structure and lignin chemistry

Holzforschung ◽  
2015 ◽  
Vol 69 (5) ◽  
pp. 603-613 ◽  
Author(s):  
Jong Sik Kim ◽  
Jie Gao ◽  
Nasko Terziev ◽  
Ignazia Cuccui ◽  
Geoffrey Daniel
Keyword(s):  
Cell Walls ◽  
Lignin Content ◽  
Middle Lamella ◽  
Cell Types ◽  
Histochemical Staining ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
Native Cell ◽  
Different Response ◽  
Light Fluorescence

Abstract Changes in structure and lignin chemistry were investigated in ash wood thermally modified (TMW) by the thermo-vacuum (Termovuoto) process for 3 h at 190–220°C by means of light, fluorescence, and transmission electron (TEM) microscopy combined with histo/cytochemistry. Variation in changes in native cell color in TMWs was positively correlated with differences in lignin content between cell types and cell wall regions in the reference wood. Histochemical staining showed increasing amounts of acidic groups in TMWs with different response to ethanol extraction between secondary cell walls and CMLcc (compound middle lamella/middle lamella cell corner) regions. Fluorescence microscopy of TMWs and references showed a difference in intensity and color emission of lignin autofluorescence, reflecting modification of lignin in TMWs. Changes in histochemistry and fluorescence were prominent at and above 200°C. With TEM, increased intensity of lignin staining and distortion of fiber S1 layers were detected in TMW treated for 3 h at 220°C (TMW3 h, 220°C). TMW3 h, 220°C differed significantly in molecular ultrastructure of fiber cell walls compared to references, such as loss of the lamellar structure and size and distribution of lignin aggregates. The modification in CMLcc structure in ash TMW3 h, 220°C is different from that of softwoods.

Application of Scanning UV Microspectrophotometry to Localise Lignins and Phenolic Extractives in Plant Cell Walls

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 563-567 ◽  
Author(s):  
G. Koch ◽  
G. Kleist
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Individual Cell ◽  
Prunus Serotina ◽  
Plant Cell Walls ◽  
Phyllostachys Edulis ◽  
Woody Tissue ◽  
Analytical Technique ◽  
Uv Microspectrophotometry

Summary The localisation of lignin and phenolic extractives in woody tissue was determined using scanning UV microspectrophotometry. This improved cellular analytical technique enabled direct imaging of the topochemical lignin distribution within individual cell wall layers with a resolution of 0.25 μm2. Selected softwood (Picea abies), hardwood (Fagus sylvatica, Entandrophragma cylindricum, Prunus serotina) and monocotyledon (Phyllostachys edulis) sections of 1 μm thickness were scanned at a fixed wavelength and evaluated with the “APAMOS” software. This approach allowed the distribution pattern of lignins and aromatic extractives within the cell wall to be visualised simultaneously. The method was found to be ideally suited to the study of their subcellular distribution in plant cell walls.

The Effect of Varying Latewood Proportion on the Radial Distribution of Lignin Content in a Pine Stem

Holzforschung ◽  
2001 ◽  
Vol 55 (5) ◽  
pp. 455-458 ◽  
Author(s):  
W. Gindl
Keyword(s):  
Radial Distribution ◽  
Secondary Wall ◽  
Lignin Content ◽  
Middle Lamella ◽  
Individual Growth ◽  
Juvenile Growth ◽  
Growth Rings ◽  
Strong Negative Correlation ◽  
Compound Middle Lamella ◽  
The Difference

Summary The radial distribution of lignin content in a pine stem was compared to latewood proportion. With the exception of the innermost juvenile growth rings, a strong negative correlation was found. However, the cell-wall lignin content of low lignin growth rings was equal to that of high-lignin growth rings. Therefore, the difference in lignin content between individual growth rings was solely due to varying ratios of high-lignin compound middle lamella to low-lignin secondary wall in thin- and thick-walled tracheids.

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