Cell wall and plasmalemma modifications in diseased and injured plant tissues

1974 ◽  
Vol 52 (5) ◽  
pp. 1005-1009 ◽  
Author(s):  
Harry Wheeler
Keyword(s):  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Structural Changes ◽  
Uranyl Acetate ◽  
Plant Roots ◽  
Plant Tissues ◽  
Diseased Plant ◽  
Localized Structures ◽  
Electrolyte Loss

Pathological modifications in structure at the cell wall – plasmalemma interface are common in diseased plant tissues. These modifications vary from small, localized structures which invaginate the protoplast to large, irregularly contoured elaborations which envelop haustoria. Some published electron micrographs suggest that the plasmalemma may be discontinuous in areas adjacent to modified cell walls. Structural changes in cell walls, similar to those in diseased plants, are common in plant roots exposed to uranyl acetate. In such roots, the plasmalemma appeared distinctly discontinuous in cells with highly modified walls, whereas it was continuous in adjacent cells with little or no wall modification. In both types of cells, internal membranes and organelles appeared normal. This suggests that the breaks seen in the plasmalemma were not fixation artifacts. In untreated roots, apparent discontinuities in the plasmalemma were observed only in secretory outer root cap cells which contained masses of mucilaginous material between the wall and protoplast. Since uranyl treatment does not increase the rate of electrolyte loss from tissue, these observations suggest that modified cell walls may assume some of the permeability functions usually attributed to the plasmalemma.

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

Conversaziones 1974

1975 ◽  
Vol 29 (2) ◽  
pp. 163-171
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Walls ◽  
Structural Changes ◽  
Vascular Tissue ◽  
Root Systems ◽  
Plant Roots ◽  
Tracer Studies ◽  
Water Move ◽  
Intact Root

CONVERSAZIONES were held this year on 9 May and 27 June. At the first conversazione twenty-seven exhibits and two films were shown. The fine structure of plant roots in relation to transport of nutrient ions and water was demonstrated by Dr D. T. Clarkson of the A.R.C. Letcombe Laboratory, Wantage and Dr A. W. Robards of the Department of Biology, University of York. Two major pathways by which nutrients and water move radially across the cortex towards the central vascular tissue have been distinguished by the use of tracer studies of adsorption by different zones of intact root systems, microautoradiography and electron microscopy. Movement can be apoplastic through cell walls, or symplastic between cells joined by plasmodesmata. As the root ages, structural changes in the endodermis reduce movement in the former pathway but the symplast is not interrupted by the elaboration of endodermal walls because plasmodesmatal connexions remain intact. These observations help explain the contrasting extent to which different ions and water reach the shoot from young and mature parts of root systems.

The Structure of the Macromolecular Units on the Cell Walls of Bacillus Polymyxa

1967 ◽  
Vol 2 (4) ◽  
pp. 587-591
Author(s):  
J. T. FINCH ◽  
A. KLUG ◽  
M.V. NERMUT
Keyword(s):  
Cell Wall ◽  
Electron Micrographs ◽  
Electron Scattering ◽  
Cell Walls ◽  
Single Layer ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Bacillus Polymyxa ◽  
Optical Filtering ◽  
Diffraction Patterns

Electron micrographs of negatively stained preparations of cell walls of Bacillus polymyxa have been investigated by optical diffraction and optical filtering techniques. Images of single layers of the cell wall, from which the ‘noise’ has been filtered optically, show hollow, square-shaped morphological units arranged on a square lattice of side 100 Å. Single-layer images showing the same pattern have been filtered from moiré patterns arising from two overlapping single layers. The morphological units are composed of four smaller subunits. The optical diffraction patterns from regions of two overlapping layers show extra reflexions which are attributed to multiple electron scattering.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

Étude cytochimique ultrastructurale de la dégradation des lignines dans les résidus pariétaux de bois d'épicéa et de peuplier par le Reticulitermes lucifugus var. santonensis (Rhinotermitidae, Isoptera)

1992 ◽  
Vol 70 (5) ◽  
pp. 933-941 ◽  
Author(s):  
E. Garnier-Sillam ◽  
I. Grech ◽  
Y. Czaninski ◽  
M.-T. Tollier ◽  
B. Monties
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Periodic Acid ◽  
Mechanical Action ◽  
Free Cell ◽  
Uranyl Acetate ◽  
Picea Sitchensis ◽  
Wall Material ◽  
Before And After ◽  
Acetate Lead

Free cell-wall residues were prepared by extracting wood samples of spruce (Populus euramericana cv. Fidzi Pauley) and poplar (Picea sitchensis). These species were chosen for their lignin types: guaiacyl in spruce and guaiacyl–syringyl in poplar. The parietal residues obtained were used as the sole food for the xylophagous termite Reticulitermes lucifugus var. santonensis and were compared before and after ingestion and transit in the digestive tracts. Differences due to the mechanical action of the gizzard were found in association with chemical changes. Polysaccharides were unmasked after digestion and could clearly be observed after reaction with periodic acid – thiocarbohydrazide – silver proteinate. A fibrillary meshwork was also observed inside the lignified cell walls. Biodegradation of cell wall material was particularly clear in poplar where granules formed an electron-dense plasma when uranyl acetate – lead citrate or periodic acid – thiocarbohydrazide – silver proteinate was used as a contrast medium. A selective biodegradation of syringyl monomers in poplar parietal residues was indicated by thioacidolysis but requires confirmation. Breakdown of lignified cell walls begins with a biodegradation of the lignin network associated with or followed by the digestion of polysaccharides. Syringyl-rich lignin fractions seemed to break down faster. Whether the enzymic pathway leading to ligninolysis originates from the termite digestive cells or from the endosymbionts present in their digestive tract lumen remains to be defined. Key words: Isoptera, Reticulitermes lucifugus var. santonensis, wood, lignin, spruce, poplar.

scholarly journals Rearrangement of the Cellulose-Enriched Cell Wall in Flax Phloem Fibers over the Course of the Gravitropic Reaction

2020 ◽  
Vol 21 (15) ◽  
pp. 5322
Author(s):  
Nadezda Ibragimova ◽  
Natalia Mokshina ◽  
Marina Ageeva ◽  
Oleg Gurjanov ◽  
Polina Mikshina
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Structural Changes ◽  
Plant Cell Wall ◽  
Complex Structure ◽  
Fiber Cell ◽  
Vertical Position ◽  
Cell Wall Polysaccharides ◽  
Cellulose Structure ◽  
Phloem Fibers

The plant cell wall is a complex structure consisting of a polysaccharide network. The rearrangements of the cell wall during the various physiological reactions of plants, however, are still not fully characterized. Profound changes in cell wall organization are detected by microscopy in the phloem fibers of flax (Linum usitatissimum) during the restoration of the vertical position of the inclined stems. To characterize the underlying biochemical and structural changes in the major cell wall polysaccharides, we compared the fiber cell walls of non-inclined and gravistimulated plants by focusing mainly on differences in non-cellulosic polysaccharides and the fine cellulose structure. Biochemical analysis revealed a slight increase in the content of pectins in the fiber cell walls of gravistimulated plants as well as an increase in accessibility for labeling non-cellulosic polysaccharides. The presence of galactosylated xyloglucan in the gelatinous cell wall layer of flax fibers was demonstrated, and its labeling was more pronounced in the gravistimulated plants. Using solid state NMR, an increase in the crystallinity of the cellulose in gravistimulated plants, along with a decrease in cellulose mobility, was demonstrated. Thus, gravistimulation may affect the rearrangement of the cell wall, which can enable restoration in a vertical position of the plant stem.

Tropospheric ozone-induced structural changes in leaf mesophyll cell walls in grapevine plants

Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Nikola Ljubešić ◽  
Mihaela Britvec
Keyword(s):  
Cell Wall ◽  
Tropospheric Ozone ◽  
Cell Walls ◽  
Structural Changes ◽  
Mesophyll Cell ◽  
Ambient Air ◽  
Vitis Vinifera L ◽  
Mesophyll Cells ◽  
Ozone Concentrations ◽  
Leaf Mesophyll

AbstractThe structural changes in leaves of grapevine plants (Vitis vinifera L.) exposed to different ozone concentrations were investigated. Ozone fumigations were performed in open-top chambers at four different ozone levels (charcoal-filtered air (F), ambient air (N), ambient air + 25 mm3m−3 ozone (O-25) and ambient air + 50 mm3m−3 ozone (O-50)).The leaves of plants from chambers with increased ozone concentrations (O-25 and O-50) were significantly thicker than the controls (F), owing to increased thickness of the mesophyll layer. Observing O-50 leaves, it was found that the mesophyll cell wall displayed structural changes. In some places cell wall thickness increased up to 1 µm. We found callose deposits on the inner side of the cell walls of mesophyll cells. These data are in accord with the concept that the mesophyll cell wall acts as a barrier against the penetration of tropospheric ozone into the cells.

scholarly journals Mathematical modelling of the cellular mechanics of plants

2003 ◽  
Vol 358 (1437) ◽  
pp. 1437-1444 ◽  
Author(s):  
David M. Bruce
Keyword(s):  
Cell Wall ◽  
Mechanical Behaviour ◽  
Cell Walls ◽  
Single Cells ◽  
Tissue Mechanics ◽  
Plant Tissues ◽  
Cellular Mechanics ◽  
Applied Loading ◽  
Wall Cell ◽  
Wall Ultrastructure

The complex mechanical behaviour of plant tissues reflects the complexity of their structure and material properties. Modelling has been widely used in studies of how cell walls, single cells and tissue respond to loading, both externally applied loading and loads on the cell wall resulting from changes in the pressure within fluid–filled cells. This paper reviews what approaches have been taken to modelling and simulation of cell wall, cell and tissue mechanics, and to what extent models have been successful in predicting mechanical behaviour. Advances in understanding of cell wall ultrastructure and the control of cell growth present opportunities for modelling to clarify how growth–related mechanical properties arise from wall polymeric structure and biochemistry.

The toughness of plant cell walls

1995 ◽  
Vol 348 (1325) ◽  
pp. 363-372 ◽  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Volume Fraction ◽  
Plant Tissues ◽  
Individual Plant ◽  
Plant Cell Walls ◽  
A Value ◽  
Cracking Process

All plant tissues and plant-based materials are composites and therefore, during standard fracture mechanics tests, cracks within them tend to arrest and deflect because of crack-stopping mechanisms at cell boundaries or in air-spaces. Due to this change of direction cracks do not cross the toughest structures, frustrating both their measurement and the understanding of the cracking process. Accordingly, there are no accurate values for the toughness of plant cell walls. We have attempted to solve this problem here by driving the crack with blades. We show from cutting experiments on twenty individual plant tissues and plant-based materials that the intrinsic toughness of plant cell wall, independent of cell form, is between 3.4—4.2 kj m -2 ; for any tissue it is directly proportional to the volume fraction that the cell wall occupies. Plastic work, which is dependent on cellular geometry, can increase toughness to a value of at least 30 kj m -2 in woody tissues, but this capacity is probably not linearly related to cell wall volume fraction.

Thickened cell walls of Bacillus cereus grown in the presence of chloramphenicol: their fate during cell growth

1971 ◽  
Vol 17 (12) ◽  
pp. 1561-1565 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Bacillus Cereus ◽  
Cell Walls ◽  
Structural Changes ◽  
Synthetic Medium ◽  
Wall Material ◽  
Partial Removal ◽  
Daughter Cells ◽  
Thickened Wall

Bacillus cereus incubated for 4 h in a synthetic medium containing chloramphenicol was observed to form cell walls 2 to 3 times as thick as those from control cells growing in the same medium containing no antibiotic. Then the cells were washed and reincubated in fresh synthetic medium and the ultra-structural changes in the thickened walls during cell growth and elongation were examined by electron microscopy. After incubation for 20 min, multiple ruptured sites and internal fractures appeared randomly on the surface of the thickened cell wall. Large and small pieces of thickened wall fragments soon "peeled off" from the surface, leaving behind a deeper layer of wall material. Normal cell growth and elongation resumed after partial removal of the thickened cell wall. After several generations, thickened wall fragments were not observed on the surface of daughter cells.

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