Root contraction in hyacinth IV. Orientation of cellulose microfibrils in radial longitudinal and transverse cell walls

PROTOPLASMA ◽  
1990 ◽  
Vol 154 (2-3) ◽  
pp. 161-171 ◽  
Author(s):  
Nancy L. Smith-Huerta ◽  
Judith A. Jernstedt
Keyword(s):  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Root Contraction

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

scholarly journals Thermal degradation of hemicellulose and cellulose in ball-milled cedar and beech wood

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Mohd Asmadi ◽  
Haruo Kawamoto
Keyword(s):  
Thermal Degradation ◽  
Ball Milling ◽  
Cell Walls ◽  
Uronic Acid ◽  
Beech Wood ◽  
Cellulose Microfibrils ◽  
Homogeneous Distribution ◽  
Japanese Beech ◽  
Temperature Range ◽  
The Matrix

AbstractThe thermal degradation reactivities of hemicellulose and cellulose in wood cell walls are significantly different from the thermal degradation behavior of the respective isolated components. Furthermore, the degradation of Japanese cedar (Cryptomeria japonica, a softwood) is distinct from that of Japanese beech (Fagus crenata, a hardwood). Lignin and uronic acid are believed to play crucial roles in governing this behavior. In this study, the effects of ball milling for various durations of time on the degradation reactivities of cedar and beech woods were evaluated based on the recovery rates of hydrolyzable sugars from pyrolyzed wood samples. The applied ball-milling treatment cleaved the lignin β-ether bonds and reduced the crystallinity of cellulose, as determined by X-ray diffraction. Both xylan and glucomannan degraded in a similar temperature range, although the isolated components exhibited different reactivities because of the catalytic effect of uronic acid bound to the xylose chains. These observations can be explained by the more homogeneous distribution of uronic acid in the matrix of cell walls as a result of ball milling. As observed for holocelluloses, cellulose in the ball-milled woods degraded in two temperature ranges (below 320 °C and above); a significant amount of cellulose degraded in the lower temperature range, which significantly changed the shapes of the thermogravimetric curves. This report compares the results obtained for cedar and beech woods, and discusses them in terms of the thermal degradation of the matrix and cellulose microfibrils in wood cell walls and role of lignin. Such information is crucial for understanding the pyrolysis and heat treatment of wood.

scholarly journals Structure of Cellulose Microfibrils in Primary Cell Walls from Collenchyma

2012 ◽  
Vol 161 (1) ◽  
pp. 465-476 ◽  
Author(s):  
Lynne H. Thomas ◽  
V. Trevor Forsyth ◽  
Adriana Šturcová ◽  
Craig J. Kennedy ◽  
Roland P. May ◽  
...  
Keyword(s):  
Cell Walls ◽  
Primary Cell ◽  
Cellulose Microfibrils

High-Resolution Field Emission Scanning Electron Microscopy (FESEM) Imaging of Cellulose Microfibril Organization in Plant Primary Cell Walls

2017 ◽  
Vol 23 (5) ◽  
pp. 1048-1054 ◽  
Author(s):  
Yunzhen Zheng ◽  
Daniel J. Cosgrove ◽  
Gang Ning
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
High Resolution ◽  
Field Emission ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Critical Point Drying ◽  
Sputter Coating ◽  
Scanning Electron

AbstractWe have used field emission scanning electron microscopy (FESEM) to study the high-resolution organization of cellulose microfibrils in onion epidermal cell walls. We frequently found that conventional “rule of thumb” conditions for imaging of biological samples did not yield high-resolution images of cellulose organization and often resulted in artifacts or distortions of cell wall structure. Here we detail our method of one-step fixation and dehydration with 100% ethanol, followed by critical point drying, ultrathin iridium (Ir) sputter coating (3 s), and FESEM imaging at a moderate accelerating voltage (10 kV) with an In-lens detector. We compare results obtained with our improved protocol with images obtained with samples processed by conventional aldehyde fixation, graded dehydration, sputter coating with Au, Au/Pd, or carbon, and low-voltage FESEM imaging. The results demonstrated that our protocol is simpler, causes little artifact, and is more suitable for high-resolution imaging of cell wall cellulose microfibrils whereas such imaging is very challenging by conventional methods.

scholarly journals Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants

2016 ◽  
Vol 113 (40) ◽  
pp. 11348-11353 ◽  
Author(s):  
Shundai Li ◽  
Logan Bashline ◽  
Yunzhen Zheng ◽  
Xiaoran Xin ◽  
Shixin Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Cellulose Synthase ◽  
Cellulose Microfibrils ◽  
Critical Component ◽  
Distinct Structure ◽  
Secondary Cell Walls ◽  
Composition Structure ◽  
Membrane Spanning

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana. This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

THE ABSENCE OF ELASTIC DEFORMATION IN DRIED BENT CELLULOSE MICROFIBRILS IN PLANT CELL WALLS

1965 ◽  
Vol 43 (3) ◽  
pp. 339-343
Author(s):  
J. Ross Colvin
Keyword(s):  
Elastic Deformation ◽  
Plant Cell ◽  
Cell Walls ◽  
Cold Water ◽  
Hot Water ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls ◽  
Avena Coleoptile ◽  
Parenchyma Cells ◽  
Embedding Medium

A small fraction of individual cellulose microfibrils in plant cell walls show appreciable bending along a portion of their length in a plane tangential to the cell surface. Segments of such curved microfibrils from transverse sections of Avena coleoptile epidermal or parenchyma cells do not straighten when they are freed from the constraints imposed by adjacent microfibrils, amorphous cell wall constituents, or the embedding medium. The curvature of these segments is not affected by immersion in cold water for 30 minutes, in hot water for 10 minutes, or in steam at 100° for 10 minutes. The results indicate that there is no elastic deformation of bent cellulose microfibrils in dried plant cell walls. The curvature of the microfibrils in the absence of elastic deformation suggests either (a) that cellulose microfibrils may be synthesized in a bent strain-free condition or (b) that cellulose microfibrils are synthesized in a straight form, followed by elastic deformation with subsequent release of strain by recrystallization on drying.

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