scholarly journals Properties of chemically and mechanically isolated fibres of spruce (Picea abies [L.] Karst.). Part 1: Structural and chemical characterisation

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Ingo Burgert ◽  
Notburga Gierlinger ◽  
Tanja Zimmermann
Keyword(s):  
Cell Wall ◽  
Picea Abies ◽  
Environmental Scanning Electron Microscopy ◽  
Middle Lamella ◽  
Solid Wood ◽  
Wall Structure ◽  
Environmental Scanning ◽  
Cell Wall Assembly ◽  
Ir Microscopy ◽  
Mechanical Isolation

Abstract Single fibres of spruce (Picea abies [L.] Karst.) were isolated both chemically and mechanically from a solid wood sample. Mechanical isolation was carried out using very fine tweezers to peel out fibres, thereby taking advantage of the low shear strength between them. Chemical isolation was achieved using hydrogen peroxide and glacial acetic acid. Fibres were examined with Fourier-transform infrared (FT-IR) microscopy, and field-emission environmental scanning electron microscopy (FE-ESEM) in low-Vacuum mode to compare the isolation techniques with respect to their influence on cell wall structure and polymer assembly. The chemical treatment led to degradation of lignin and hemicelluloses, significantly influencing the cell wall assembly and structure. The cell wall polymers of mechanically isolated fibres remained in their natural constitution. As expected, the peeling process caused separation of cell wall layers. Our examinations indicate that delamination predominately took place at the interface between the secondary cell wall and the compound middle lamella. However, fracture between the S1 and S2 layers was examined as well. With respect to fibre quality, it was of particular importance that transverse crack propagation in the secondary cell walls (S2) was not observed.

Properties of chemically and mechanically isolated fibres of spruce (Picea abies[L.] Karst.). Part 2: Twisting phenomena

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 247-251 ◽  
Author(s):  
Ingo Burgert ◽  
Klaus Frühmann ◽  
Jozef Keckes ◽  
Peter Fratzl ◽  
Stefanie Stanzl-Tschegg
Keyword(s):  
Cell Wall ◽  
Picea Abies ◽  
Microfibril Angle ◽  
Cell Wall Assembly ◽  
Opposite Wood ◽  
Wood Compression ◽  
Mechanical Isolation ◽  
Wall Assembly ◽  
S2 Layer ◽  
Lateral Cell

Abstract The twisting behaviour of chemically and mechanically isolated fibres of spruce (Picea abies[L.] Karst.) was examined. Mechanical isolation was carried out using very fine tweezers to obtain fibres with an unmodified cell wall assembly. Chemical isolation was achieved using hydrogen peroxide and glacial acetic acid, leading to partial degradation of lignin and hemicelluloses. Besides normal adult wood, compression wood and opposite wood fibres were investigated. Fibre twisting while drying increased with higher microfibril angles in the S2 layer, and was significantly less pronounced for mechanically isolated compared to chemically macerated fibres. A simple model is introduced that takes into account the interdependency between lateral cell-wall shrinkage and the microfibril angle in the S2 cell wall.

Ripening-Associated Microstructural Changes in Antisense ACC Synthase Tomato Fruit

2001 ◽  
Vol 7 (1) ◽  
pp. 59-71 ◽  
Author(s):  
G. O. Sozzi ◽  
A. A. Fraschina ◽  
M. A. Castro
Keyword(s):  
Cell Wall ◽  
Tomato Fruit ◽  
Environmental Scanning Electron Microscopy ◽  
Middle Lamella ◽  
Acc Synthase ◽  
Ethylene Biosynthesis ◽  
Environmental Scanning ◽  
High Electron ◽  
Exogenous Ethylene ◽  
Transgenic Tomatoes

The ultrastructural impact of low ethylene biosynthesis (less than 0.5% of normal levels) was evaluated in transgenic (A11.1) tomatoes ( Lycopersicon esculentumMill.) expressing an antisense 1-aminocyclopropane-1-carboxylic acid synthase (ACC-S) transgene by means of transmission and environmental scanning electron microscopy. In 48-day mature green fruit, no significant ultrastructural differences were found between transgenic and control tomatoes. In 78-day control fruit, which were overripe and showed deteriorated texture, many areas of the cytoplasm were devoid of structures, and micrographs showed cell collapse with folding and dissolution of the cell wall. On the other hand, in 90-day transgenic fruit, which were firm and not ripe, the cytoplasm showed a relatively high electron density. Plastids retained remnants of chloroplast thylakoids along with significant amounts of osmiophylic plastoglobuli, but lycopene was not detected. Conspicuous starch granules were observed in mature green transgenic tomatoes, but were not detected in 90-day chlorochromoplasts. Electron-dense regions reflecting the integrity of the middle lamella alternated with other partially degraded regions. This incipient dissolution of the middle lamella pectic polymers may be attributable to nonenzymatic deaggregation or to cell-wall hydrolases which could be ethylene independent or responsive to very low levels of ethylene. Besides, cells were attached along extended contact areas and appeared turgid. This feature may provide an explanation of firmness retention that does not solely involve cell walls. Disruption of the middle lamella and development of lycopene crystalloids were observed when exogenous ethylene (12 ppm) was applied.

Acetyl Group Distribution in Acetylated Wood Investigated by Microautoradiography

Holzforschung ◽  
2001 ◽  
Vol 55 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Marie Rosenqvist
Keyword(s):  
Cell Wall ◽  
Weight Gain ◽  
Acetic Anhydride ◽  
Wood Cell Wall ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Accurate Information ◽  
Concentration Gradients ◽  
Good Opportunity ◽  
Acetyl Group

Summary Sapwood of Scots pine (Pinus silvestris L.) was acetylated with 14C- and 3H-labelled acetic anhydride. The distribution of acetyl groups was investigated with microautoradiography and microautoradiographs were evaluated with ESEM, Environmental Scanning Electron Microscopy. The investigation showed that the impregnation of wood with radioisotope-labelled substances provides a good opportunity to investigate the location of substances covalently bonded to the wood material. Introduced 14C-labelled acetyl groups show an even distribution in the wood cell wall, with no discernible concentration gradients at acetylation levels of about 5, 15 and 20% weight gain. 3H-labelled acetyl groups show an even distribution in the wood cell wall at 15 and 20% weight gain, with no discernible concentration gradients. At the 5% weight gain level, however, an uneven distribution of 3H-labelled acetyl groups over the cell wall is observed. Nevertheless, the unevenness is random and no concentration gradient is discernible at this level. 3H with a relatively high resolution, 0.5–1 μm, compared to 14C with a resolution of 2–5 μm, gives more accurate information about where exactly the acetyl groups are situated in the wood cell wall. Acetic anhydride was evenly distributed when a full impregnation procedure was used. The chemical and physical properties of acetic anhydride allow a uniform penetration into the pine cell wall and a complete acetylation takes place when the specimens are heated.

scholarly journals Chilling Injury in Peaches: A Cytochemical and Ultrastructural Cell Wall Study

1992 ◽  
Vol 117 (1) ◽  
pp. 114-118 ◽  
Author(s):  
J.G. Luza ◽  
R. van Gorsel ◽  
V.S. Polito ◽  
A.A. Kader
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Prunus Persica ◽  
Periodic Acid ◽  
Chilling Injury ◽  
Middle Lamella ◽  
Wall Structure ◽  
Positive Staining ◽  
Intercellular Matrix ◽  
Parenchyma Cells

Fruits of mid- (`O'Henry'), late (`Airtime'), and extra-late-season (`Autumn Gem') peach [Prunus persica (L.) Batsch] cultivars were examined for changes in cell wall structure and cytochemistry that accompany the onset of mealiness and leatheriness of the mesocarp due to chilling injury. The peaches were stored at 10C for up to 18 days or at SC for up to 29 days. Plastic-embedded sections were stained by the Schiff's-periodic acid reaction, Calcofluor white MR2, and Coriphosphine to demonstrate total insoluble carbohydrates, ß-1,4 glucans, and pectins, respectively. Mealiness was characterized by separation of mesocarp parenchyma cells leading to increased intercellular spaces and accumulation of pectic substances in the intercellular matrix. Little structural change was apparent in the cellulosic component of the cell walls of these fruits. In leathery peaches, the mesocarp parenchyma cells collapsed, intercellular space continued to increase, and pectin-positive staining in the intercellular matrix increased greatly. In addition, the component of the cell walls that stained positively for ß-1,4 glucans became thickened relative to freshly harvested or mealy fruit. At the ultrastructural level, dissolution of the middle lamella, cell separation, irregular thickening of the primary wall, and plasmolysis of the mesocarp parenchyma cells were seen as internal breakdown progressed.

scholarly journals Inhibitory Effects of CaCl2 and Pectin Methylesterase on Fruit Softening of Raspberry during Cold Storage

Horticulturae ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Ran Yan ◽  
Cong Han ◽  
Maorun Fu ◽  
Wenxiao Jiao ◽  
Weihao Wang
Keyword(s):  
Cell Wall ◽  
Cold Storage ◽  
Middle Lamella ◽  
Free Water ◽  
Pectin Methylesterase ◽  
Wall Structure ◽  
Rapid Decline ◽  
Fruit Softening ◽  
Cell Wall Degrading Enzymes

Quality of raspberry fruit experiences a rapid decline after harvest due to its vulnerable texture and high moisture content. Application of calcium chloride (CaCl2) combined with pectin methylesterase (PME) is efficient in delaying fruit softening. In this study, the effects of exogenous CaCl2 alone or in combination with PME on the structure of the cell wall, the molecular properties of pectin, and the amount of free water of raspberry during postharvest storage were investigated. The results showed that CaCl2 combined with PME treatment could maintain fruit firmness and inhibit weight loss. The treatment of CaCl2+PME maintained the cell wall structure via sustaining middle lamella integrity and reducing the activities of cell wall-degrading enzymes, such as polygalacturonase, pectin methylesterase, β-galactosidase, α-L-arabinofuranosidase, and β-xylosidase. In addition, CaCl2+PME treatment could effectively increase the content of chelate-soluble pectin (CSP) and develop a cross-linked structure between Ca2+ and CSP. Moreover, CaCl2+PME treatment was of benefit in maintaining free water content. CaCl2 in combination with PME treatment could be a promising method for inhibiting softening and maintaining the quality of postharvest raspberry during cold storage.

scholarly journals Calcium-mediated Postharvest Changes in Texture and Cell Wall Structure and Composition in `Golden Delicious' Apples

1990 ◽  
Vol 115 (6) ◽  
pp. 962-968 ◽  
Author(s):  
Gregory M. Glenn ◽  
B.W. Poovaiah
Keyword(s):  
Cell Wall ◽  
Cortical Cell ◽  
Middle Lamella ◽  
Outer Wall ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Cell Contact ◽  
Wall Region ◽  
Control Fruit ◽  
Golden Delicious

Changes in texture, cell wall structure and composition during storage of Ca-treated and untreated `Golden Delicious' apple fruit (Malus domestics Borkh.) were investigated. The cell wall region of Ca-treated fruit showed no swelling during storage and cell-to-cell contact was maintained, whereas regions of the middle lamella in untreated tissue stained lightly, appeared distended, and eventually separated. In control fruit, microfibril orientation was lost in distended regions of the cell wall, especially in the outer wall region adjacent to the middle lamella. Furthermore, the middle lamella was fenestrated and in some cases was completely degraded. These changes during storage of control fruit were accompanied by a decrease in arabinose and galactose moieties of the cell wall and an increase in soluble pectin. Calcium treatment of fruit inhibited solubilization of polyuronide and arabinose moieties and reduced the loss in galactose content during storage. Tensile strength and firmness were positively correlated to Ca content of the fruit cortex. Excessive tensile stress caused tissue failure in control fruit when cells of the cortical tissue separated at the middle lamella. In contrast, cylinders of Ca-treated fruit fractured through cortical cell walls.

scholarly journals Macroscopic and Microscopic Characteristics of 2- and 4-Year-Old Schizostachyum brachycladum

2019 ◽  
pp. 62-69
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Vascular Bundle ◽  
Middle Lamella ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Transmission Electron ◽  
Scanning Electron

Anatomical of cell wall structure on Schizostachyum brachycladum examined. The harvested two-year-old and four-year-old bamboo culms segregated into the bottom, middle and top portions. The samples then undergo the Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) to determine their structure such as a vascular bundle, parenchyma, and sclerenchyma. Results show the surface of bamboo was visualized by LM to decide on their structural figure. In this part, 2-year age indicated that higher numbers of vascular bundle and average of mean compared to the 4-year S. brachycladum. Followed by a specific study of cell wall structure using SEM with highlighted 4-year S. brachycladum had more complex of morphology structure compared to the 2-year-old. Later on, TEM illustrated to shows most depth anatomically structure of bamboo such as middle lamella, primary and secondary walls.

Ultrastructural and biochemical effects of endopectate lyase on cell walls from cell suspension cultures of bean and rice

1980 ◽  
Vol 58 (8) ◽  
pp. 867-880 ◽  
Author(s):  
Con J. Baker ◽  
James R. Aist ◽  
Durward F. Bateman
Keyword(s):  
Cell Wall ◽  
Cell Suspension ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Middle Lamella ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Cell Wall Integrity ◽  
Wall Material ◽  
Wall Structure

Cell walls prepared from suspension cell cultures of bean and rice in log-phase growth were used to examine the effects of endopectate lyase (PL) on the solubilization of cell wall carbohydrates and concomitant ultrastructural alterations. Cell wall preparations from both plant sources were heterogeneous and contained a range of wall types from primary walls to xylem elements with spiral, secondary wall thickenings. Marked differences in wall thickness and number of wall laminations typified both preparations.Bean cell walls were more susceptible to degradation by PL than were those of rice. Upon treatment of the former with 2.3 × 10−3 units/mL of PL (1 unit released 1 μmol of unsaturated uronide/min at 30 °C from polygalacturonic acid at pH 8.5), 27% of the noncellulosic wall carbohydrate was solubilized in 1 h. This represented 50% of the PL susceptible carbohydrate in the preparation. Only 3% of the noncellulosic carbohydrate was released from rice cell walls in 1 h when treated with 115 × 10−3 units of PL/mL. This accounted for 60% of the PL susceptible wall fractions. Only uronic acid, rhamnose, galactose, and arabinose were solubilized from both preparations by PL.Cell walls in the bean and rice preparations were affected differentially by the PL. Those walls with secondary thickenings did not appear to be degraded, while the distinct fibrillar appearance of both bean and rice walls tended to fade or disappear. The middle lamella tended to dissolve to varying degrees in the presence of PL. Bean walls were more severely degraded than were the rice walls and many exhibited swelling, separation of wall layers, markedly reduced staining intensity, and (or) a granular ultrastructure.This study has demonstrated that as PL acts on susceptible cell walls there are major changes evoked in cell wall structure which suggest that the rhamnogalacturonan fraction of the higher plant cell wall contributes significantly to cell wall integrity. This study also emphasizes the need for cell wall material of proven uniformity for investigations of both cell wall composition and effects of specific polysaccharide degrading enzymes on cell wall integrity. Preliminary studies indicate that tobacco pith may provide more uniform cell walls than do cell suspension cultures.

scholarly journals Bacterial and abiotic decay in waterlogged archaeological Picea abies (L.) Karst studied by confocal Raman imaging and ATR-FTIR spectroscopy

Holzforschung ◽  
2015 ◽  
Vol 69 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Nanna Bjerregaard Pedersen ◽  
Notburga Gierlinger ◽  
Lisbeth Garbrecht Thygesen
Keyword(s):  
Cell Wall ◽  
Picea Abies ◽  
Middle Lamella ◽  
Raman Imaging ◽  
Attenuated Total Reflection ◽  
Archaeological Wood ◽  
Residual Material ◽  
Polysaccharide Composition ◽  
Confocal Raman ◽  
Strong Depletion

Abstract Waterlogged archaeological Norway spruce [Picea abies (L.) Karst] poles were studied by means of confocal Raman imaging (CRI) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis to determine lignin and polysaccharide composition and distribution in the cell wall. The waterlogged archaeological wood (WAW) was submerged under anoxic conditions for approximately 400 years and solely decayed by erosion bacteria (EB). CRI showed that decayed tracheids contain a residual material (RM) with heterogeneous lignin distribution; within the same tracheid RM often contained regions with intensities lower than sound S2 layers up to intensity values as high as the compound middle lamella (CML). CRI revealed strong depletion of carbohydrates in RM which indicated that EB are able to utilise the carbohydrate fraction of the cell wall effectively. Raman bands assigned to lignin did not show any difference between RM and sound S2. This is a hint that EB do not modify the lignin structure. Sound WAW free from EB decay showed evidence of loss of acetyl groups in glucomannan, loss of un-conjugated ester linkages in the lignin-carbohydrate complexes between xylan and lignin, and minor oxidation of the lignin polymer compared to recent reference material. This is evidence for abiotic decay in the course of waterlogging.

Formation of 13C-Enriched Cell-Wall DHP Using Isolated Soft Xylem from Picea abies

Holzforschung ◽  
2002 ◽  
Vol 56 (6) ◽  
pp. 585-591 ◽  
Author(s):  
J. Hafrén ◽  
U. Westermark ◽  
H. Lennholm ◽  
N. Terashima
Keyword(s):  
Cell Wall ◽  
Picea Abies ◽  
Glucose Oxidase ◽  
Solid Wood ◽  
Coniferyl Alcohol ◽  
Side Chain ◽  
Acetone Water ◽  
Dehydrogenation Polymers

Summary Cell-wall dehydrogenation polymers (CW-DHP) were prepared by incubating a mixture of soft xylem (differentiating xylem) from Picea abies, coniferin 13C-enriched at the side-chain β-carbon and unenriched coniferin, both with and without the addition of β-glucosidase and glucose oxidase, which causes an in situ polymerisation of the coniferyl alcohol in the cell wall. From difference solid state 13C-NMR spectra between 13C-enriched CW-DHP and unenriched CW-DHP, the bond frequencies involving specifically 13C-enriched carbon can be quantitatively determined. The sub-structures in CW-DHP prepared without the addition of β-glucosidase and glucose oxidase showed more similarity to protolignin than CW-DHP prepared with the addition of extraneous enzymes. The CW-DHP obtained without the addition of enzymes contained 36% β-O-4-derived sub-structures, 44% combined β-β, β-5 and β-1 sub-structures and 20% coniferyl alcohol/coniferaldehyd end groups. After acetone/water extraction of the CW-DHP, the content of β-β, β-5 and β-1 structures decreased by 4%, and the β-O-4 dominating peak increased by 4%. The 13C-enriched CW-DHP material can be used to study lignin reactions in a solid wood matrix, and is also a powerful system for detailed studies on in vivo lignification mechanisms and the effects on lignification conditions on lignin structure.

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