Aerial root cap structure of an orchid, Epidendrum

1981 ◽  
Vol 59 (9) ◽  
pp. 1702-1708 ◽  
Author(s):  
Susan J. Blackman ◽  
Edward C. Yeung
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Cell Walls ◽  
Root Cap ◽  
Wall Material ◽  
Wall Thickening ◽  
Cell Wall Material ◽  
Random Orientation ◽  
Mitotic Figures ◽  
Distal Cell

The root cap of Epidendrum ibaguense has a rounded profile with a root cap junction present between the cap and meristem. A distinct columella region is lacking. Mitotic figures are infrequent in the root cap initial cells. The root cap initials and their immediate derivatives show few dictyosomes, little endoplasmic reticulum, plastids lacking starch, and few vacuoles. As the cells age they increase in size and show increasing vacuolation. Plastids increase by division and accumulate large starch grains. Throughout the root cap, amyloplasts maintain a random orientation in the cell. Endoplasmic reticulum also becomes more abundant as the cells age. In older cells, hypertrophied dictyosomes are evident and cell wall material begins accumulating between the distal cell wall and the plasmalemma. Wall thickening progresses with age though radial walls remain largely unthickened. Vacuolation progresses and is followed by complete senescence leaving only the cell walls.

Synchrotron infrared microspectroscopy reveals the response of Sphagnum cell wall material to its aqueous chemical environment

2018 ◽  
Vol 15 (8) ◽  
pp. 513
Author(s):  
Ewen Silvester ◽  
Annaleise R. Klein ◽  
Kerry L. Whitworth ◽  
Ljiljana Puskar ◽  
Mark J. Tobin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Chemical Environment ◽  
Wall Material ◽  
Organic Soils ◽  
Cell Wall Material ◽  
Acid Base ◽  
Widespread Species ◽  
Flowing Liquid ◽  
Infrared Microspectroscopy

Environmental contextSphagnum moss is a widespread species in peatlands globally and responsible for a large fraction of carbon storage in these systems. We used synchrotron infrared microspectroscopy to characterise the acid-base properties of Sphagnum moss and the conditions under which calcium uptake can occur (essential for plant tissue integrity). The work allows a chemical model for Sphagnum distribution in the landscape to be proposed. AbstractSphagnum is one the major moss types responsible for the deposition of organic soils in peatland systems. The cell walls of this moss have a high proportion of carboxylated polysaccharides (polygalacturonic acids), which act as ion exchangers and are likely to be important for the structural integrity of the cell walls. We used synchrotron light source infrared microspectroscopy to characterise the acid-base and calcium complexation properties of the cell walls of Sphagnum cristatum stems, using freshly sectioned tissue confined in a flowing liquid cell with both normal water and D2O media. The Fourier transform infrared spectra of acid and base forms are consistent with those expected for protonated and deprotonated aliphatic carboxylic acids (such as uronic acids). Spectral deconvolution shows that the dominant aliphatic carboxylic groups in this material behave as a monoprotic acid (pKa=4.97–6.04). The cell wall material shows a high affinity for calcium, with a binding constant (K) in the range 103.9–104.7 (1:1 complex). The chemical complexation model developed here allows for the prediction of the chemical environment (e.g. pH, ionic content) under which Ca2+ uptake can occur, and provides an improved understanding for the observed distribution of Sphagnum in the landscape.

THE EFFECT OF PENICILLIN ON THE STRUCTURE OF STAPHYLOCOCCAL CELL WALLS

1959 ◽  
Vol 5 (6) ◽  
pp. 641-648 ◽  
Author(s):  
R. G. E. Murray ◽  
W. H. Francombe ◽  
B. H. Mayall
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Untreated Control ◽  
Osmium Tetroxide ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cell Wall Synthesis ◽  
Cell Wall Component ◽  
A Cell ◽  
Resistant Strains

Cultures of sensitive stains of Staphylococcus aureus were fixed with osmium tetroxide after 1–5 hours' exposure to various does of pencillin and were embedded in methacrylate for sectioning and electron microscopy. They were compared with untreated, control cultures. The contrast of the cell wall material was untreated, control cultures. The contrast of the cell wall material was increased, by cutting the section of lanthanum nitrate.The cells increased in size and the surrounding cell wall was thinner than normal. The main lesions appeared in the developing cell wall septa, which showed a loss in density and gross irregularity of shape. Some questionable inclusions were seen in the cytoplasm. Lysis was prevented in a medium containing 0.3 M sucrose and the stable spheroplasts retained a recognizable cell wall after 24 hours' exposure to penicillin. However, the septa could not be demonstrated in the cells treated in sucrose medium.Two resistant strains were exposed to penicillin. In one, the cells showed no morphological effects; in the other, there was temporary damage to the cell septa with complete recovery.The observations support the hypothesis that penicillin interferes with the synthesis of a cell wall component and indicate that the main point of cell wall synthesis is at the site of septum formation.

scholarly journals The amounts and rates of export of polysaccharides found within the membrane system of maize root cells

1974 ◽  
Vol 142 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Dianna J. Bowles ◽  
D. H. Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Golgi Apparatus ◽  
Cell Surface ◽  
Rough Endoplasmic Reticulum ◽  
Membrane System ◽  
Maize Root ◽  
Wall Material ◽  
Cell Wall Material ◽  
Root Cells

1. Maize seedling roots were incubated in vivo with d-[U-14C]glucose for 2, 5, 10, 15, 30 and 45min. The total incorporation of radioactivity into polysaccharide components in isolated fractions was investigated, and the pattern of incorporation into different polysaccharide components within the rough endoplasmic reticulum, Golgi apparatus and exported material was analysed. 2. The membrane compartments reached a saturation value of radioactivity in polysaccharide components by 30min incubation. Radioactivity in exported polysaccharide continued to increase after that time. The latter was formed and maintained by a steady-state turnover of polysaccharide synthesis and transport from the membrane system. 3. If the only access of the slime polysaccharide to the cell surface is via dictyosome-derived vesicles, the amount of slime components in the Golgi apparatus would have to be displaced every 0.3min in order to maintain the observed rates of increase in slime. This is in contrast with a displacement time of about 2.5min that is necessary for polysaccharide components in the Golgi apparatus to produce the observed increase in cell-wall material. The activity of the membrane system in the production of maize root slime is 8 times as great as that of the membrane system involved in cell-wall synthesis. 4. If the amount of polysaccharide material in the Golgi apparatus is maintained only by inflow of polymeric material from the rough endoplasmic reticulum the total amount of slime components in the rough endoplasmic reticulum would have to be displaced every 7min to maintain a constant amount in the Golgi apparatus. If the endoplasmic reticulum contributed directly to the cell surface in the synthesis of cell-wall material, displacement times necessary to maintain the observed rate of polymer production would be very slow.

In vitro fermentation characteristics of soya bean cell walls separated from hulls and endosperm

1998 ◽  
Vol 1998 ◽  
pp. 71-71
Author(s):  
H. van Laar ◽  
S. Tamminga ◽  
B.A. Williams ◽  
B. Diekema ◽  
W. Burgers ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Gas Production ◽  
Soya Bean ◽  
Wall Material ◽  
Cell Wall Material ◽  
In Vitro Fermentation

When analysing the fermentative breakdown of cell wall material in plants it is important to realize that it is not homogeneous. The cell walls are composed of different cell wall types which can differ in both their breakdown characteristics and composition. In this experiment in vitro cumulative gas production (Theodorou et al., 1994) was measured to study breakdown characteristics of cell walls from hulls and endosperm of soya beans.

scholarly journals Relative Contributions of Bacteria, Protozoa, and Fungi to In Vitro Degradation of Orchard Grass Cell Walls and Their Interactions

2000 ◽  
Vol 66 (9) ◽  
pp. 3807-3813 ◽  
Author(s):  
S. S. Lee ◽  
J. K. Ha ◽  
K.-J. Cheng
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Rumen Fluid ◽  
Wall Material ◽  
P System ◽  
Cell Wall Material ◽  
Cell Wall Degradation ◽  
Chemical Treatments ◽  
System A ◽  
Microbial Groups

ABSTRACT To assess the relative contributions of microbial groups (bacteria, protozoa, and fungi) in rumen fluids to the overall process of plant cell wall digestion in the rumen, representatives of these groups were selected by physical and chemical treatments of whole rumen fluid and used to construct an artificial rumen ecosystem. Physical treatments involved homogenization, centrifugation, filtration, and heat sterilization. Chemical treatments involved the addition of antibiotics and various chemicals to rumen fluid. To evaluate the potential activity and relative contribution to degradation of cell walls by specific microbial groups, the following fractions were prepared: a positive system (whole ruminal fluid), a bacterial (B) system, a protozoal (P) system, a fungal (F) system, and a negative system (cell-free rumen fluid). To assess the interactions between specific microbial fractions, mixed cultures (B+P, B+F, and P+F systems) were also assigned. Patterns of degradation due to the various treatments resulted in three distinct groups of data based on the degradation rate of cell wall material and on cell wall-degrading enzyme activities. The order of degradation was as follows: positive and F systems > B system > negative and P systems. Therefore, fungal activity was responsible for most of the cell wall degradation. Cell wall degradation by the anaerobic bacterial fraction was significantly less than by the fungal fraction, and the protozoal fraction failed to grow under the conditions used. In general, in the mixed culture systems the coculture systems demonstrated a decrease in cellulolysis compared with that of the monoculture systems. When one microbial fraction was associated with another microbial fraction, two types of results were obtained. The protozoal fraction inhibited cellulolysis of cell wall material by both the bacterial and the fungal fractions, while in the coculture between the bacterial fraction and the fungal fraction a synergistic interaction was detected.

Cell wall dynamics under conditions of diffuse growth in the thick-walled cortical tissue (prosoplectenchyma) of Ramalina usnea

2019 ◽  
Vol 51 (3) ◽  
pp. 269-280
Author(s):  
William B. SANDERS ◽  
Asunción DE LOS RÍOS
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Transverse Section ◽  
Tissue Expansion ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cortical Tissue ◽  
Transparent Material ◽  
Diffuse Growth ◽  
Wall Materials

AbstractA recent field study indicated that thalli of the beard lichen Ramalina usnea undergo diffuse (“intercalary”) growth throughout their length. We examined thallus sections with TEM to better understand how the highly thickened cell walls of the prosoplectenchymatous cortex behave under conditions of continued expansion. Cell protoplasts were surrounded by massive accumulations of structured electron-dense wall layers interspersed with amorphous, electron-transparent substances, visible as concentric rings in transverse section. Nearest the protoplast, electron-dense wall layers were distinct and more or less alternated with irregular deposits of electron-transparent material. With increasing distance from the protoplast, the electron-dense wall layers were increasingly disrupted and intermixed among the electron-transparent materials. New cell branches grew through the accumulated wall materials, interrupting the layers they penetrated while producing their own concentric wall layers. The differing amounts of cell wall material accumulated was further indication of the different relative ages of such neighbouring cells. These observations suggest that cell walls are disrupted by diffuse tissue expansion and continually replaced by new walls and wall materials deposited to their interior at the interface with the protoplast. This pattern of development, documented previously in R. menziesii and U. longissima, suggests that component cells of lichen prosoplectenchyma behave quite differently from those of diffusely expanding filaments studied in non-lichen-forming fungi, where a single, discrete cell wall is maintained throughout growth.

Comparative anatomy of colonization of cotton hypocotyls and roots by virulent and hypovirulent isolates of Rhizoctonia solani

1989 ◽  
Vol 67 (7) ◽  
pp. 2142-2149 ◽  
Author(s):  
B. Sneh ◽  
M. Ichielevich-Auster ◽  
I. Shomer
Keyword(s):  
Cell Wall ◽  
Rhizoctonia Solani ◽  
Outer Surface ◽  
Cell Walls ◽  
Comparative Anatomy ◽  
Close Contact ◽  
Wall Material ◽  
Cell Wall Material ◽  
Pith Parenchyma ◽  
Cuticular Layer

The hypovirulent (HV) isolate (No. 521) densely colonized the outer surface of the hypocotyls and roots of radish and cotton seedlings but did not penetrate into the cortical parenchyma, whereas the virulent (V) isolate (No. 82) penetrated the root and hypocotyl tissues (except for the xylem vessels) to the center of the pith parenchyma. The HV isolate did not cause any degradation of the cell wall material except for the cuticular layer that had disappeared in the regions of close contact between the hyphae and the epidermal outer surface. During the prepenetration stages of the V isolate, the cell walls of the seedlings underwent a significant, visible degradation. The cuticle between the hyphae and the epidermis was detached and degraded. The HV isolate seems to densely cover the outer surface of the seedlings, and it may occupy the possible infection sites, rendering recognition and occupation of such sites unavailable for the virulent pathogen.

scholarly journals Ultrastructural investigations of enzyme treated cell wall material from industrial by-products.

1992 ◽  
Vol 40 (2) ◽  
pp. 137-146
Author(s):  
F.M. Engels ◽  
N.A. Schalk
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Enzymic Activity ◽  
Wall Material ◽  
Cell Wall Material ◽  
Plant Materials ◽  
Carbohydrate Hydrolysis ◽  
Cell Layers ◽  
By Products ◽  
Wall Components

Ultrastructural investigations of glycanase treatments of cell wall material from industrial by-products was carried out with the enzyme-thiocarbohydrazide-silver protein technique (ETAg). Driselase, gamanase and an experimental enzyme preparation with a broad spectra of hemicellulase, cellulase and pectolytic activities were used. Carbohydrate hydrolysis was found in cell walls and cell contents in 1-2 cell layers at the surface of 0.2-mm plant particles. Enzyme activity was detected to some extent inside unlignified and lignified cell walls. The absence of any reaction in some sublayers of the cell wall was indicative for the absence of polysaccharide substrate or a very tied interaction of cell wall components preventing enzymic activity or the absence of typical enzymes in crude preparations. It was concluded that the ETAg-technique can be useful to provide information about structural limitations of poorly degradable plant materials. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Morphological aspects of starch and cell wall material mobilization in developing lupine cotyledons and the effect of kinetin on these processes

2015 ◽  
Vol 44 (4) ◽  
pp. 529-536 ◽  
Author(s):  
Fortunat Młodzianowski ◽  
Maria Wesołowska
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Wall Material ◽  
Cell Wall Material ◽  
Hemicellulose Hydrolysis ◽  
Seed Imbibition ◽  
Morphological Aspects ◽  
Hydrolysis Of

In the cotyledons of dry lupine seeds the presence of starch was not demonstrated. Its formation during seed imbibition in darkness is accompanied by a reduction in the thickness of cell walls containing hemicelluloses. It is believed that the products of hemicellulose hydrolysis, particullarily in isolated cotyledons, arę the main source of materials for the synthesis of starch, In the process of cell wall decomposition the invaginations of plasmalemma appear to be involved. Kinetin enhance the hydrolysis of cell walls and the mobilization of starch in isolated cotyledons.

Napropamide Binding in Corn (Zea mays) Root Tissue

Weed Science ◽  
1983 ◽  
Vol 31 (5) ◽  
pp. 712-719 ◽  
Author(s):  
Michael Barrett ◽  
Floyd M. Ashton
Keyword(s):  
Cell Wall ◽  
Zea Mays ◽  
Cell Walls ◽  
Wall Material ◽  
Cell Wall Material ◽  
Protease Treatment ◽  
Wall Components ◽  
Soluble Components ◽  
Soluble Fractions

Napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide]-binding in excised root segments of corn (Zea maysL. ‘NC + 59′) was confined to cell wall fractions (residue and 500gpellet) remaining after homogenization and to components of the 100 000gsupernatant. Binding increased in both the cell wall and soluble fractions with continued exposure to napropamide. Microautoradiographs revealed that the napropamide bound in the cell walls was located in epidermal, cortical, and stelar tissue. Various proteins were capable of binding napropamide in vitro; however, protease treatment did not liberate the radioactivity bound in the cell wall fragments. Carbohydrate release from the cell wall material with cellulase was not correlated with the solubilization of bound radioactivity and wall carbohydrate monomers did not appear to bind to napropamide in vitro. A portion of the radioactivity found in the soluble components (at 100 000g) was associated with a molecule of MW > 600. The continued influx of napropamide was due to binding to cell wall components and molecules within the cell.

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