Further Ultrastructural Observations on Polysaccharide Localization in Plant Cells

1968 ◽  
Vol 3 (1) ◽  
pp. 55-64
Author(s):  
J. D. PICKETT-HEAPS
Keyword(s):  
Cell Wall ◽  
Periodic Acid ◽  
Periodate Oxidation ◽  
Plant Cells ◽  
Primary Cell Wall ◽  
Root Tip ◽  
Root Tips ◽  
Golgi Bodies ◽  
Golgi Vesicles ◽  
Aldehyde Groups

Standard periodic acid/Schiff (PAS) techniques have not shown the existence of aldehyde groups in sections of glutaraldehyde-fixed, Araldite-embedded root-tip tissue; peroxidation of such sections resulted in a typical PAS staining pattern. Permanganate-fixed root tips also gave a weak PAS reaction which was intensified by prior peroxidation of the sections. At the ultrastructural level, silver hexamine was used to detect aldehyde groups produced in polysaccharide by permanganate and/or periodate oxidation. Golgi vesicles and slime material in root-cap cells always reacted strongly; the cell wall proper was less reactive. A marked increase in the stainability of the vesicles was evident, the further removed they were from Golgi bodies. This also occurred in root epidermal cells. In both these types of cells, smallersized vesicles and/or the contents of reticulate Golgi cisternae showed evidence of histochemical staining. In meristematic root tip cells, vesicles closely apposed to Golgi bodies did not stain convincingly, though cell walls stained readily. During cell-plate formation, however, both smaller (possibly Golgi) and larger vesicles (phragmoplasts) stained strongly. The walls of permanganate-fixed sieve-tube cells also stained quite strongly, but callose did not unless the tissue block had been treated with periodate before being embedded. In glutaraldehyde-fixed xylem cells, older wall thickenings reacted very strongly even when the sections had been blocked with iodoacetate and bisulphite (which rendered the rest of the section unreactive). If similar sections of younger xylem cells were peroxidized after such blocking reactions, the primary cell wall and the wall thickenings stained, as did many of the Golgi vesicles. The results are related to other experimental observations, both ultrastructural and histochemical, on plant cells.

scholarly journals PRELIMINARY ATTEMPTS AT ULTRASTRUCTURAL POLYSACCHARIDE LOCALIZATION IN ROOT TIP CELLS

1967 ◽  
Vol 15 (8) ◽  
pp. 442-455 ◽  
Author(s):  
J. D. PICKETT-HEAPS
Keyword(s):  
Cell Walls ◽  
Periodate Oxidation ◽  
Ultrastructural Localization ◽  
Epidermal Cells ◽  
Root Tip ◽  
Staining Reaction ◽  
Thin Sections ◽  
Golgi Bodies ◽  
Aldehyde Groups ◽  
Tip Cells

A basic method and many variations are described which initially appear to give good ultrastructural localization of polysaccharide material and also sulfhydryl groups in sections of plant tissues. Using permanganate fixation, alkaline silver hexamine solutions very strongly stained cell walls and starch grains (if they survived the treatment) in thin sections; in root cap and epidermal cells, Golgi bodies and associated vesicles also strongly reacted. The reaction was markedly reduced if sections were pretreated with aldehyde-complexing reagents (dimedone, etc.) and reintroduced after such blocking reactions by further periodate oxidation. Apart from a variable unspecific argentophilic reaction of manganese in the sections (which does not appear if the manganese is leeched out), other components of the cells showed very little staining in permanganate-fixed cells. Differences were noted between the reactivity of various polysaccharides. A strong generalized staining reaction was observed over sections of glutaraldehyde-fixed tissues, and this could be almost entirely blocked by pretreatment of the sections with iodoacetate; such treatment also indicated that there were comparatively few aldehyde groups present, either native and/or introduced by the fixative. Periodate oxidation then introduced staining groups in some Golgi bodies and cell walls, particularly in epidermal cells.

Immunocytochemical analysis of the secretory pathway of plant cells

1991 ◽  
Vol 49 ◽  
pp. 200-201
Author(s):  
L.A. Staehelin ◽  
T.H. Giddings ◽  
J.Z. Kiss ◽  
M.A. Lynch ◽  
P.J. Moore ◽  
...  
Keyword(s):  
High Pressure ◽  
Cell Wall ◽  
Cell Walls ◽  
Secretory Pathway ◽  
Plant Cells ◽  
Root Tip ◽  
Root Tips ◽  
Immunocytochemical Analysis ◽  
Culture Cells ◽  
Sycamore Maple

The Golgi apparatus of plant cells is the site of synthesis of complex polysaccharides and glycoproteins. Following their synthesis, the glycoproteins are sorted and then delivered either to vacuoles or to the plasma membrane or the cell wall, whereas all of the complex polysaccharides are secreted into the cell wall. Little is known about how these different synthetic pathways are organized within plant Golgi stacks, and where the secreted molecules are assembled into the cell walls. To address these problems, we have 1) reexamined the structure of plant Golgi stacks in high pressure frozen and freeze-substituted root tips of Arabidopsis and Nicotiana, as well as in sycamore maple suspension culture cells, and 2) used immunocytochemical methods to localize specific types of complex polysaccharides and glycoproteins in root tip cell walls and in Golgi stacks of high pressure frozen sycamore cells.

Ultrastructure of Medicago sativa rhizodermis cells over their early development

Biologia ◽  
2008 ◽  
Vol 63 (2) ◽  
Author(s):  
Lucia Mikolajová ◽  
Halina Vargová ◽  
Zora Hanáčková ◽  
Milada Čiamporová
Keyword(s):  
Cell Wall ◽  
Medicago Sativa ◽  
Root Hair ◽  
Phosphotungstic Acid ◽  
Root Tip ◽  
Cell Wall Polysaccharides ◽  
Golgi Bodies ◽  
Internalization Process ◽  
Subcellular Level ◽  
Root Hair Initiation

AbstractUltrastructure was investigated along the files of developing epidermal cells in the root tip of a model plant Medicago sativa, in which all rhizodermal cells are potential hair-forming trichoblasts. Differentiation at subcellular level was observed up to the stage of bulge initiation in the trichoblasts. Root hair initiation indicated by the emergence of bulges from trichoblasts was detected at various distances from the root tip and, it was independent of the trichoblast size.During rhizodermal cell differentiation, starch grains accumulated in the plastids. Nuclei located in the central part of the young, meristematic cells moved towards the inner periclinal wall as the central vacuole enlarged. The bulging region of the trichoblasts located opposite the nucleus and was rich in mitochondria, ER, ribosomes, and Golgi bodies, and contained also vesicles enclosing fibrillar material. This material responded positively to phosphotungstic acid, which was used for detection of cell wall polysaccharides. The cell wall thickness within the bulging domain was significantly lower than in other parts of trichoblasts. We suggest that internalization of cell wall polysaccharides occurs within the bulging area, contributing to local thinning of the cell wall and providing a source of osmotically active compounds for maintaining turgor in the trichoblast. Thus, the internalization process might be necessary for root hair outgrowth.

scholarly journals Structure and Biomechanics during Xylem Vessel Transdifferentiation in Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1715
Author(s):  
Eleftheria Roumeli ◽  
Leah Ginsberg ◽  
Robin McDonald ◽  
Giada Spigolon ◽  
Rodinde Hendrickx ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Turgor Pressure ◽  
Plant Cells ◽  
Building Blocks ◽  
Xylem Vessel ◽  
Primary Cell Wall ◽  
Individual Plant ◽  
Vessel Elements

Individual plant cells are the building blocks for all plantae and artificially constructed plant biomaterials, like biocomposites. Secondary cell walls (SCWs) are a key component for mediating mechanical strength and stiffness in both living vascular plants and biocomposite materials. In this paper, we study the structure and biomechanics of cultured plant cells during the cellular developmental stages associated with SCW formation. We use a model culture system that induces transdifferentiation of Arabidopsis thaliana cells to xylem vessel elements, upon treatment with dexamethasone (DEX). We group the transdifferentiation process into three distinct stages, based on morphological observations of the cell walls. The first stage includes cells with only a primary cell wall (PCW), the second covers cells that have formed a SCW, and the third stage includes cells with a ruptured tonoplast and partially or fully degraded PCW. We adopt a multi-scale approach to study the mechanical properties of cells in these three stages. We perform large-scale indentations with a micro-compression system in three different osmotic conditions. Atomic force microscopy (AFM) nanoscale indentations in water allow us to isolate the cell wall response. We propose a spring-based model to deconvolve the competing stiffness contributions from turgor pressure, PCW, SCW and cytoplasm in the stiffness of differentiating cells. Prior to triggering differentiation, cells in hypotonic pressure conditions are significantly stiffer than cells in isotonic or hypertonic conditions, highlighting the dominant role of turgor pressure. Plasmolyzed cells with a SCW reach similar levels of stiffness as cells with maximum turgor pressure. The stiffness of the PCW in all of these conditions is lower than the stiffness of the fully-formed SCW. Our results provide the first experimental characterization of the mechanics of SCW formation at single cell level.

scholarly journals Primary cell wall inspired micro containers as a step towards a synthetic plant cell

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Paulraj ◽  
S. Wennmalm ◽  
D.C.F. Wieland ◽  
A. V. Riazanova ◽  
A. Dėdinaitė ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Structural Integrity ◽  
Plant Cells ◽  
Lipid Vesicles ◽  
Primary Cell Wall ◽  
Living Plant ◽  
A Cell ◽  
Lipid Tubules

AbstractThe structural integrity of living plant cells heavily relies on the plant cell wall containing a nanofibrous cellulose skeleton. Hence, if synthetic plant cells consist of such a cell wall, they would allow for manipulation into more complex synthetic plant structures. Herein, we have overcome the fundamental difficulties associated with assembling lipid vesicles with cellulosic nanofibers (CNFs). We prepare plantosomes with an outer shell of CNF and pectin, and beneath this, a thin layer of lipids (oleic acid and phospholipids) that surrounds a water core. By exploiting the phase behavior of the lipids, regulated by pH and Mg2+ ions, we form vesicle-crowded interiors that change the outer dimension of the plantosomes, mimicking the expansion in real plant cells during, e.g., growth. The internal pressure enables growth of lipid tubules through the plantosome cell wall, which paves the way to the development of hierarchical plant structures and advanced synthetic plant cell mimics.

scholarly journals Identification of glycoproteins associated with elastin-associated microfibrils.

1985 ◽  
Vol 33 (4) ◽  
pp. 287-294 ◽  
Author(s):  
J C Fanning ◽  
E G Cleary
Keyword(s):  
Lectin Binding ◽  
Periodic Acid ◽  
Periodate Oxidation ◽  
Ruthenium Red ◽  
Elastic Tissue ◽  
Electron Microscopic ◽  
Periodic Acid Schiff ◽  
Mature Adult ◽  
Aldehyde Groups ◽  
Nuchal Ligament

The microfibrils associated with elastic tissue have been shown to be predominantly proteinaceous. On the basis of their affinity for cationic stains, including ruthenium red, they have been assumed to be glycoprotein, but more evidence to support this claim has not been adduced. Despite repeated investigation of glycoprotein materials obtained by extraction of elastic tissues with reagents that appear to remove microfibrils, the chemical composition of elastin-associated microfibrils remains obscure. An electron microscopic study of the microfibrils in two elastin-rich tissues (bovine nuchal ligament and aorta) during their development was pursued using more specific histochemical methods. The periodic acid-alkaline bismuth stain (analogous to the periodic acid-Schiff stain for glycoproteins in light microscopy) has been adapted for this study. Specific aldehyde groups (confirmed by blocking with m-aminophenol or sodium borohydride) were identified after periodate oxidation as fine granules of bismuth stain. These were shown to localize specifically along the elastin-associated microfibrils in a finely punctate form. Staining of the amorphous elastic component did not occur except for a fine rim adjacent to the microfibrils. Lectin binding with concanavalin A (with ferritin markers) confirmed that there are glucose- or mannose-containing proteins associated with the microfibrillar component of elastic tissue. This was true of these microfibrils in all layers of the aortic wall and throughout the ligament. It was also true of mature adult tissues in which there was a lesser proportion of microfibrils. It is concluded that elastin-associated microfibrils really are associated with glycoprotein(s).

Solid phase-solution-root interactions in soils subjected to acid deposition

1984 ◽  
Vol 305 (1124) ◽  
pp. 353-368 ◽  
Keyword(s):  
Field Experiments ◽  
Solid Phase ◽  
Primary Cell Wall ◽  
Root Decomposition ◽  
Root Tip ◽  
Silicate Weathering ◽  
Managed Forests ◽  
Root Tips ◽  
Root Interactions ◽  
Proton Production

In managed forests, biomass utilization means a discoupling of the otherwise closed ion-cycle. The rate of proton production caused by the utilization of the timber, however, is of the same magnitude as the rate of proton consumption during silicate weathering. Managed forests can thus be in a steady state and stable. The input of acidity in forest ecosystems due to air pollution will in most cases exceed the rate of proton consumption by silicate weathering and thus result in soil acidification. Acidity can be accumulated as organic acids (mainly phenoles) and as cationic acids, that is, ions of sparingly soluble oxides (Al, Fe, Mn and heavy metals). The lower the pH , the higher is the solubility and toxicity of the acids existing. Owing to its high concentration and solubility, AlOOH produces the most important cation acid. A soil is composed of microcompartments in which different reactions can occur at the same time. Also proton production can be spatially inhomogeneous for the following reasons: (i) a considerable fraction of the input of acidity due to dry deposition of SO 2 is buffered by the leaves of the trees. It reaches the soil via the roots during ion uptake and thus acidifies the soil close to the root tips. (ii) In acid soils, where the burrowing animals are missing, the soil organic matter formed from the root decomposition accumulates on the aggregate surfaces. It is thus in direct contact with the living roots. If during a temporal discoupling of the ion cycle (nitrification push) nitric acid is formed, this can acidify also, especially the soil close to the root surface. Thus in the direct vicinity of the roots, much higher Al-concentrations have to be expected than those which can be measured in equilibrium soil solution or in lysimeter solutions. A direct effect of Al-toxicity on the root system of trees is the die-back of the young roots, which has been shown both in vitro and in field experiments to be the result of action of Al ions. The mechanism of this action was found to be the inhibition of uptake of Ca ions into the matrix of the cell walls, which changes the macromolecular and physical properties of the pectin molecules which form the primary cell wall of meristemic and parenchymatic tissues in the root tip region.

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