scholarly journals The Cell Wall Structure of Xylem Parenchyma

1952 ◽  
Vol 5 (2) ◽  
pp. 223 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Secondary Cell Wall ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xylem Parenchyma ◽  
Cell Axis ◽  
X Ray ◽  
Ray Methods ◽  
Longitudinal Cell

The fine structure of the cell wall of both ray and vertical parenchyma has been investigated. In all species examined secondary thickening had occurred. In the primary cell wall the micellar orientation was approximately trans"erse to the longitudiJ)aI cell axis. Using optical and X-ray methods the secondary cell wall was shown to possess a helical micellar organization, the micelles being inclined between 30� and 60� to the longitudinal cell axis.

scholarly journals The origin and early evolution of tracheids in vascular plants: integration of palaeobotanical and neobotanical data

2000 ◽  
Vol 355 (1398) ◽  
pp. 857-868 ◽  
Author(s):  
William E. Friedman ◽  
Martha E. Cook
Keyword(s):  
Cell Wall ◽  
Vascular Plants ◽  
Secondary Cell Wall ◽  
Early Evolution ◽  
Land Plants ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Cell Wall Formation ◽  
Wall Formation ◽  
Resistant Layer

Although there is clear evidence for the establishment of terrestrial plant life by the end of the Ordovician, the fossil record indicates that land plants remained extremely small and structurally simple until the Late Silurian. Among the events associated with this first major radiation of land plants is the evolution of tracheids, complex water–conducting cells defined by the presence of lignified secondary cell wall thickenings. Recent palaeobotanical analyses indicate that Early Devonian tracheids appear to possess secondary cell wall thickenings composed of two distinct layers: a degradation–prone layer adjacent to the primary cell wall and a degradation–resistant (possibly lignified) layer next to the cell lumen. In order to understand better the early evolution of tracheids, developmental and comparative studies of key basal (and potentially plesiomorphic) extant vascular plants have been initiated. Ultra–structural analysis and enzyme degradation studies of wall structure (to approximate diagenetic alterations of fossil tracheid structure) have been conducted on basal members of each of the two major clades of extant vascular plants: Huperzia (Lycophytina) and Equisetum (Euphyllophytina). This research demonstrates that secondary cell walls of extant basal vascular plants include a degradation–prone layer (‘template layer’) and a degradation–resistant layer (‘resistant layer’). This pattern of secondary cell wall formation in the water–conducting cells of extant vascular plants matches the pattern of wall thickenings in the tracheids of early fossil vascular plants and provides a key evolutionary link between tracheids of living vascular plants and those of their earliest fossil ancestors. Further studies of tracheid development and structure among basal extant vascular plants will lead to a more precise reconstruction of the early evolution of water–conducting tissues in land plants, and will add to the current limited knowledge of spatial, temporal and cytochemical aspects of cell wall formation in tracheary elements of vascular plants.

Fine structure in the red algae - II. The structure of the cell wall of Rhodymenia Palmata

1959 ◽  
Vol 150 (941) ◽  
pp. 447-455 ◽  
Keyword(s):  
Cell Wall ◽  
Chemical Treatment ◽  
Amorphous Matrix ◽  
Dry Weight ◽  
Wall Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Floridean Starch ◽  
Thin Sectioning ◽  
Paper Chromatographic Separation

The cell-wall structure of the red alga Rhodymenia palmata has been examined by the methods of X -ray diffraction analysis and electron microscopy, including ultra-thin sectioning. The cell wall is shown to consist of numerous lamellae each of which is made up of unoriented, crystalline microfibrils embedded in an amorphous matrix of other cell-wall constituents. The material can be stretched reversibly up to 100% when wet, and the stretching induces orientation of the microfibrils. The ‘∝ cellulose' fraction, which accounts for only 2 to 7 % of the original dry weight, was isolated chemically and was analyzed by means of hydrolysis and paper chromatographic separation of the resulting sugars, and it was found to be composed of approximately equal quantities of glucose and xylose residues. Chemical treatment of the cell wall was found to cause considerable variations in the X -ray diagrams, which are discussed. It is concluded that the microfibrils contain both glucose and xylose residues in approximately equal proportions and that chemical treatment in this case causes changes in crystallinity of the structural component of the wall. The importance of these findings for the meaning of the term cellulose is discussed. The X -ray diagram of older fronds was found to be complicated by the occurrence of extra rings due to the presence of floridean starch, and the highly elastic properties of the thallus enabled the diagrams of the starch and the cell wall to be separated.

scholarly journals Catalysts of plant cell wall loosening

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 119 ◽  
Author(s):  
Daniel J. Cosgrove
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Turgor Pressure ◽  
Wall Stress ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xyloglucan Endotransglycosylase ◽  
Growing Cell ◽  
Tensile Forces ◽  
Wall Loosening

The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyloglucan endotransglycosylase/hydrolase (XTH), and pectin methylesterases, and offer a critical assessment of their wall-loosening activity

Fine structure of tissue bordering lesions induced by wounding and virus infection

1978 ◽  
Vol 56 (23) ◽  
pp. 2990-2999 ◽  
Author(s):  
G. Faulkner ◽  
Warwick C. Kimmins
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Secondary Cell Wall ◽  
Wall Material ◽  
Wall Thickening ◽  
Pinto Bean ◽  
Local Lesions ◽  
Virus Localization ◽  
Similar Appearance ◽  
Secondary Cell Wall Thickening

Tissue in Phaseolus vulgaris L. cv. Pinto bean bordering local lesions induced by tobacco mosaic virus showed cell wall deposition associated with paramural body formation in a narrow ring of viable cells extending one to three cell diameters around the lesions. Deposition, which led to secondary cell wall thickening, was greatest 3–4 days after inoculation, the time when the lesion stopped expanding. Secondary cell wall thickening, of similar appearance but less pronounced, was seen in tissue bordering local lesions which continued to expand; no significant secondary cell wall thickening was observed in leaves with a nonlocalized infection. Cells bordering mechanical lesions differed markedly in fine structure from cells bordering virus and chemical lesions. It is suggested that the deposition of extra cell wall material in the wall regions of cells bordering fully expanded local lesions is associated with virus localization.

Fine structure in the red algae III. A general survey of cell-wall structure in the red algae

1959 ◽  
Vol 150 (941) ◽  
pp. 456-459 ◽  
Keyword(s):  
Cell Wall ◽  
Red Algae ◽  
Amorphous Matrix ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
General Survey ◽  
X Ray ◽  
Floridean Starch

A general survey of cell-wall structure in the red algae has been carried out using the methods of X -ray diffraction analysis and electron microscopy. The fifteen species all show a similar wall structure consisting of numerous lamellae each of which is made up of random micro-fibrils embedded in an amorphous matrix. The X -ray diagrams obtained from several species are complicated by the existence of crystalline floridean starch, but nevertheless reveal the absence of cellulose I.

scholarly journals Golgi-localized GALT7 and GALT8 participate in cellulose biosynthesis

2021 ◽  
Author(s):  
Pieter Nibbering ◽  
Romain Castilleux ◽  
Gunnar Wingsle ◽  
Totte Niittylä
Keyword(s):  
Cell Wall ◽  
Golgi Apparatus ◽  
Secondary Cell Wall ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Primary Cell Wall ◽  
Cellulose Content ◽  
Cellulose Biosynthesis ◽  
Cell Wall Assembly ◽  
Protein Levels

AbstractArabinogalactan protein (AGP) glycan biosynthesis in the Golgi apparatus contributes to plant cell wall assembly, but the mechanisms underlying this process are largely unknown. Here, we show that two putative galactosyltransferases -named GALT7 and GALT8 -from the glycosyltransferase family 31 (GT31) of Arabidopsis thaliana participate in cellulose biosynthesis. galt7galt8 mutants show primary cell wall defects manifesting as impaired growth and cell expansion in seedlings and etiolated hypocotyls, along with secondary cell wall defects, apparent as collapsed xylem vessels and reduced xylem wall thickness in the inflorescence stem. These phenotypes were associated with a ∼30% reduction in cellulose content, a ∼50% reduction in secondary cell wall CELLULOSE SYNTHASE (CESA) protein levels and reduced cellulose biosynthesis rate. CESA transcript levels were not significantly altered in galt7galt8 mutants, suggesting that the reduction in CESA levels was caused by a post-transcriptional mechanism. We provide evidence that both GALT7 and GALT8 localise to the Golgi apparatus, while quantitative proteomics experiments revealed reduced levels of the entire FLA subgroup B in the galt7galt8 mutants. This leads us to hypothesize that a defect in FLA subgroup B glycan biosynthesis reduces cellulose biosynthesis rate in galt7galt8 mutants.

Complete substitution of a secondary cell wall with a primary cell wall in Arabidopsis

Nature Plants ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 777-783 ◽  
Author(s):  
Shingo Sakamoto ◽  
Marc Somssich ◽  
Miyuki T. Nakata ◽  
Faride Unda ◽  
Kimie Atsuzawa ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Primary Cell ◽  
Primary Cell Wall
Sign in / Sign up

Export Citation Format

Share Document