scholarly journals Winter Nights during Summer Time: Stress Physiological Response to Ice and the Facilitation of Freezing Cytorrhysis by Elastic Cell Wall Components in the Leaves of a Nival Species

2020 ◽  
Vol 21 (19) ◽  
pp. 7042 ◽  
Author(s):  
Matthias Stegner ◽  
Barbara Lackner ◽  
Tanja Schäfernolte ◽  
Othmar Buchner ◽  
Nannan Xiao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Atmospheric Temperature ◽  
Cellular Level ◽  
Spongy Parenchyma ◽  
Mesophyll Cells ◽  
After Effects ◽  
Cell Wall Chemistry ◽  
Specific Tissue ◽  
Summer Time

Ranunculus glacialis grows and reproduces successfully, although the snow-free time period is short (2–3 months) and night frosts are frequent. At a nival site (3185 m a.s.l.), we disentangled the interplay between the atmospheric temperature, leaf temperatures, and leaf freezing frequency to assess the actual strain. For a comprehensive understanding, the freezing behavior from the whole plant to the leaf and cellular level and its physiological after-effects as well as cell wall chemistry were studied. The atmospheric temperatures did not mirror the leaf temperatures, which could be 9.3 °C lower. Leaf freezing occurred even when the air temperature was above 0 °C. Ice nucleation at on average −2.6 °C started usually independently in each leaf, as the shoot is deep-seated in unfrozen soil. All the mesophyll cells were subjected to freezing cytorrhysis. Huge ice masses formed in the intercellular spaces of the spongy parenchyma. After thawing, photosynthesis was unaffected regardless of whether ice had formed. The cell walls were pectin-rich and triglycerides occurred, particularly in the spongy parenchyma. At high elevations, atmospheric temperatures fail to predict plant freezing. Shoot burial prevents ice spreading, specific tissue architecture enables ice management, and the flexibility of cell walls allows recurrent freezing cytorrhysis. The peculiar patterning of triglycerides close to ice rewards further investigation.

Histological aspects of the cryopreservation of potato

2008 ◽  
Vol 56 (3) ◽  
pp. 341-348
Author(s):  
P. Pepó ◽  
A. Kovács
Keyword(s):  
Cell Wall ◽  
Low Temperatures ◽  
Cell Walls ◽  
Cellular Level ◽  
Adaptive Mechanism ◽  
Epidermal Layer ◽  
Freezing And Thawing ◽  
Meristematic Cells ◽  
Suitable Solution ◽  
Vacuolated Cells

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

Biodegradability of mature grass cell walls in relation to chemical composition and rumen microbial activity

1987 ◽  
Vol 108 (1) ◽  
pp. 201-209 ◽  
Author(s):  
C. W. Ford ◽  
R. Elliott
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Latin Square ◽  
Structural Features ◽  
Barley Straw ◽  
Grass Species ◽  
Tropical Species ◽  
Variable Degree ◽  
Cell Wall Constituent ◽  
Cell Wall Chemistry

SummaryCell walls from mature stems of three tropical grass species (Digitaria decumbens(pangola),Setaria anceps(cv. Kazangula) and sugar cane), and temperate barley straw, were analysed for lignin, carbohydrate, and the maj or acyl groups ferulate, ρ-coumarate and acetate. Samples were incubated in nylon bags in the rumen of sheep in a 4 x 4 latin-square design, and rates of disappearance of cellulose, hemicellulose, xylose, arabinose, ferulate, ρ-coumarate and acetate were determined during 60 h incubation. Interspecies differences in cell-wall chemistry appeared largely in the variable degree of acylation with p-coumaric acid (1·0–3·3%) and acetate (0·5–3·6%), and the high glucose concentration in the hemicellulose from pangola (17%) andSetaria(9%). Barley had much lower concentrations of these components than the tropical species. After 24 h incubation, losses of cellulose and acyl groups were greatest from pangola, whereas hemicellulose and its major components xylose and arabinose were degraded to the greatest degree from barley straw.Setariacell-wall components were generally more resistant to degradation than the other species. No relationship was found between the concentration of any cell-wall constituent and degradability measurements. Nor were changes in microbial population, indicated by measuring the accumulation of cystine on the fibres, related to the rate or degree of degradation of any of the measured cell-wall constituents. Lignin was fractionated with alkali into insoluble and soluble fractions. The latter (25–50% of original lignin) gave high interspecies correlations with the degradability of total hemicellulose and its component monosaccharides. It was concluded that variability in the biodegradability of the cell walls was more likely due toin situstructural features, such as cross-linking between polymers, than to the concentration of any particular cell-wall constituent.

scholarly journals Unique lignin modifications pattern the nucleation of silica in sorghum endodermis

2020 ◽  
Vol 71 (21) ◽  
pp. 6818-6829 ◽  
Author(s):  
Nerya Zexer ◽  
Rivka Elbaum
Keyword(s):  
Cell Wall ◽  
Silicic Acid ◽  
Cell Walls ◽  
Dry Weight ◽  
Cell Wall Chemistry ◽  
Modified Lignin ◽  
Trace Concentrations ◽  
High Degree ◽  
Micrometer Scale ◽  
The Impact

Abstract Silicon dioxide in the form of hydrated silica is a component of plant tissues that can constitute several percent by dry weight in certain taxa. Nonetheless, the mechanism of plant silica formation is mostly unknown. Silicon (Si) is taken up from the soil by roots in the form of monosilicic acid molecules. The silicic acid is carried in the xylem and subsequently polymerizes in target sites to silica. In roots of sorghum (Sorghum bicolor), silica aggregates form in an orderly pattern along the inner tangential cell walls of endodermis cells. Using Raman microspectroscopy, autofluorescence, and scanning electron microscopy, we investigated the structure and composition of developing aggregates in roots of sorghum seedlings. Putative silica aggregation loci were identified in roots grown under Si starvation. These micrometer-scale spots were constructed of tightly packed modified lignin, and nucleated trace concentrations of silicic acid. Substantial variation in cell wall autofluorescence between Si+ and Si– roots demonstrated the impact of Si on cell wall chemistry. We propose that in Si– roots, the modified lignin cross-linked into the cell wall and lost its ability to nucleate silica. In Si+ roots, silica polymerized on the modified lignin and altered its structure. Our work demonstrates a high degree of control over lignin and silica deposition in cell walls.

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 Glutamine synthetase encoded by glnA-1 is necessary for cell wall resistance and pathogenicity of Mycobacterium bovis

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3669-3677 ◽  
Author(s):  
Harish Chandra ◽  
Seemi Farhat Basir ◽  
Manish Gupta ◽  
Nirupama Banerjee
Keyword(s):  
Cell Wall ◽  
Glutamine Synthetase ◽  
Mycobacterium Bovis ◽  
Mycobacterium Smegmatis ◽  
Cell Walls ◽  
Culture Medium ◽  
Wild Type Strain ◽  
Glutamine Supplementation ◽  
Antitubercular Drugs ◽  
Cell Wall Chemistry

Pathogenic strains of mycobacteria produce copious amounts of glutamine synthetase (GS) in the culture medium. The enzyme activity is linked to synthesis of poly-α-l-glutamine (PLG) in the cell walls. This study describes a glnA-1 mutant of Mycobacterium bovis that produces reduced levels of GS. The mutant was able to grow in enriched 7H9 medium without glutamine supplementation. The glnA-1 strain contained no detectable PLG in the cell walls and showed marked sensitivity to different chemical and physical stresses such as lysozyme, SDS and sonication. The sensitivity of the mutant to two antitubercular drugs, rifampicin and d-cycloserine, was also increased. The glnA-1 strain infected THP-1 cells with reduced efficiency and was also attenuated for growth in macrophages. A Mycobacterium smegmatis strain containing the M. bovis glnA-1 gene survived longer in THP-1 cells than the wild-type strain and also produced cell wall-associated PLG. The M. bovis mutant was not able to replicate in the organs of BALB/c mice and was cleared within 4–6 weeks of infection. Disruption of the glnA-1 gene adversely affected biofilm formation on polystyrene surfaces. The results of this study demonstrate that the absence of glnA-1 not only attenuates the pathogen but also affects cell surface properties by altering the cell wall chemistry of the organism via the synthesis of PLG; this may be a target for drug development.

Factors that Influence the Yield, Stability in Culture and Cell Wall Regeneration of Spinach Mesophyll Protoplasts

1980 ◽  
Vol 7 (6) ◽  
pp. 713 ◽  
Author(s):  
R.J Rose
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Yield Stability ◽  
Developmental Studies ◽  
Cell Wall Regeneration ◽  
Mesophyll Cells ◽  
Isolation Medium ◽  
Mesophyll Protoplasts ◽  
Wall Regeneration ◽  
Ability To Regenerate

A study has been made of factors that influence the yield, stability in culture, and ability to regenerate cell walls of isolated spinach (Spinacia olevacea L.) mesophyll protoplasts. The presence of 7 mM CaZ + or 7 mM Mg2+ in the isolation medium, which also included 1.5 % (w/v) Driselase, 0.25 % (w/v) pectinase and 0.8 M sorbitol, increased the yield and stability in culture of the protoplasts in a liquid nutrient medium. This latter medium has been used previously in the culture of spinach leaf discs, and does not support the division of spinach mesophyll cells. Protoplasts isolated in the presence of CaZ+ showed a greater capacity for cell wall regeneration compared with protoplasts isolated in the absence of ions or in the presence of Mg2+. Though darkness during culture improved the initial protoplast stability, it inhibited wall regeneration. The initial stability of protoplasts appeared to be dependent on plasma membrane stability, but after a few days in culture the most effective treatments were those which stimulated cell wall regeneration. In many cases, associated with cell wall regeneration, there was a budding off of small vesicles which sometimes contained chloroplasts. Protoplasts isolated in the presence of Ca2+ and incubated in low light had a 50% survival rate after 8 days culture and most had regenerated cell walls. Such culture of spinach protoplasts has not been shown previously and should be useful in developmental studies of spinach chloroplasts.

scholarly journals ATR-FTIR Microspectroscopy Brings a Novel Insight Into the Study of Cell Wall Chemistry at the Cellular Level

2020 ◽  
Vol 11 ◽  
Author(s):  
Clément Cuello ◽  
Paul Marchand ◽  
Françoise Laurans ◽  
Camille Grand-Perret ◽  
Véronique Lainé-Prade ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cellular Level ◽  
Ftir Microspectroscopy ◽  
Cell Wall Chemistry ◽  
Insight Into

Development of epidermal crystals in leaflets of Stylosanthes guianensis (Leguminosae; Papilionoideae)

1989 ◽  
Vol 67 (6) ◽  
pp. 1664-1670 ◽  
Author(s):  
Curt L. Brubaker ◽  
Harry T. Horner
Keyword(s):  
Cell Wall ◽  
Epidermal Cells ◽  
Spongy Parenchyma ◽  
Calcium Oxalate Crystals ◽  
Palisade Parenchyma ◽  
Abaxial Epidermis ◽  
Mesophyll Cells ◽  
Stylosanthes Guianensis ◽  
Wall Materials ◽  
Cell Wall Materials

In developing leaflets of Stylosanthes guianensis (Aubl.) Sw., twin prismatic calcium oxalate crystals form in adaxial and abaxial epidermal crystal idioblasts. These cells eventually die and collapse, leaving the crystals embedded in a matrix of cutin and cell-wall materials. Adaxial crystal idioblasts develop above large conical cells that, in turn, are interspersed among smaller, multiple-layered palisade parenchyma. Abaxial crystal idioblasts develop beneath a uniseriate layer of large horizontally branched cells abutting the abaxial epidermis. Spongy parenchyma occupies the middle mesophyll above the layer of branched cells. The abaxial crystals and the branched cells of the lowermost mesophyll develop simultaneously. Adaxial crystals and the conical cells develop later and in conjunction with each other. In mature leaflets, the adaxial and abaxial crystals and their associated collapsed crystal idioblasts form networks, the interstices of which are occupied by either single stomates and accompanying epidermal cells (adaxial) or clusters of stomates and accompanying epidermal cells (abaxial). Epidermal crystals are known from other Leguminosae; however, to our knowledge this is the first report where epidermal crystal development involving cell death and collapse is correlated with two types of specialized mesophyll cells.

Silica formation in sorghum (Sorghum bicolor) roots

2021 ◽  
Author(s):  
Nerya Zexer ◽  
Rivka Elbaum
Keyword(s):  
Cell Wall ◽  
Sorghum Bicolor ◽  
Silicic Acid ◽  
Cell Walls ◽  
Dry Weight ◽  
Soluble Form ◽  
Cell Wall Chemistry ◽  
Modified Lignin ◽  
Auto Fluorescence ◽  
The Impact

<p>Silicon oxides are the most abundant mineral group in soils. Therefore, plant roots are always exposed to some silicic acid (Si(OH)<sub>4</sub>), which is the soluble form of silicates. Monosilicic acid molecules are taken up by roots, carried in the xylem, and subsequently polymerize to silica in varied silicifying target sites. This biogenic silica (SiO<sub>2</sub>·<em>n</em>H<sub>2</sub>O) can constitute several percent by dry weight in certain plant taxa. However, the mechanisms of its formation remain mostly unknown. In the roots of sorghum (<em>Sorghum bicolor</em>), silica aggregates form in an orderly pattern along the cell walls of endodermis cells. To investigate the structure and composition of root silica aggregates, we studied their development along roots of hydroponically grown sorghum seedlings. By using Raman micro-spectroscopy, auto-fluorescence, and scanning electron microscopy, we found that putative silica aggregation loci could be identified in roots grown under Si starvation. These micrometer-scale spots were constructed of tightly packed modified lignin and were capable of nucleating trace concentrations of silicic acid. Substantial variation in cell wall auto-fluorescence between roots grown with and without silicic acid demonstrated the impact of silicon on cell wall chemistry. Taken together, this work demonstrates a high degree of control over lignin and silica deposition in cell walls. Such regulation implies an important, yet unknown, function for silicon in plant biology.</p>

Intercellular pectic strands in parenchyma: studies of plant cell walls by scanning electron microscopy.

1975 ◽  
Vol 23 (1) ◽  
pp. 95 ◽  
Author(s):  
SGM Carr ◽  
DJ Carr
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Chemical Composition ◽  
Light Microscope ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Scanning Electron

Rows of pectic strands, each 0.3-0.4�m in diameter, are shown to connect palisade mesophyll cells in regular ladder-like configurations ('pectic scala'). These structures are illustrated in some species of eucalypts, but probably occur in other kinds of plants. Less regular wall filaments can be observed in the intercellular spaces between other types of cells. They are particularly numerous in the parenchyma of species of ferns. These filaments and the pectic scala are readily observable by scanning electron microscopy, but can also be seen in conventional preparations for the light microscope. The structure, formation, chemical composition and possible function of these and other kinds of cell wall protuberances, described in the literature, are discussed.

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