scholarly journals Fractionation of cell-wall preparations from grass leaves by centrifuging in non-aqueous density gradients

1981 ◽  
Vol 193 (3) ◽  
pp. 765-771 ◽  
Author(s):  
A H Gordon ◽  
J S Bacon
Keyword(s):  
Cell Wall ◽  
Density Gradient ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Italian Ryegrass ◽  
Vascular Bundles ◽  
Density Gradients ◽  
Roll Mill ◽  
Close Relationship ◽  
Polysaccharide Composition

1. Dried preparations of cell walls from perennial-ryegrass (Lolium perenne) and Italian-ryegrass (L. multiflorum) leaves were suspended in mixtures of carbon tetrachloride with light-petroleum (b.p. 45–50 degrees C) or alcohols and layered on density gradients formed from the same solvents. 2. On centrifugation, the cell walls become distributed throughout a suitably chosen gradient. Fractions corresponding to various regions of the gradient were separated, examined under the microscope and analysed. 3. Cell-wall preparations made from leaf material ground in liquid N2, or in a triple roll mill, showed considerable heterogeneity in particle size, and their behaviour in the density gradient was variable, although there was a general indication that walls derived from vascular bundles were less dense than those from sclerenchyma. 4 Treatment in a vibratory ball mill decreased the size of the particles and produced a more uniform material, but made it impossible to distinguish the origins of the particles. This material behaved more reproducibly in the density gradient. 5. Some fractionations were also made by successive centrifugation in media of increasing relative density. 6. Analyses of the fractions obtained by each method indicated that the less dense had a greater proportion of xylose in the polysaccharide components, and higher contents of acetyl groups and lignin, confirming the close relationship between these components in plant cell walls. 7. The results show that there are differences in polysaccharide composition between the cell-wall types in the grass leaf, the vascular tissue being richer in hemicellulose relative to cellulose than the sclerenchyma.

Electron microscopic observations of infection threads in driselase treated nodules of Astragalus sinicus

1986 ◽  
Vol 32 (12) ◽  
pp. 947-952 ◽  
Author(s):  
Shiro Higashi ◽  
Kazuya Kushiyama ◽  
Mikiko Abe
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
Enzyme Treatment ◽  
Vascular Bundles ◽  
Electron Microscopic ◽  
Astragalus Sinicus ◽  
Infection Threads

The morphological characteristics of infection threads in the root nodules of Astragalus sinicus were examined by scanning and transmission electron microscopy. The infection threads, epidermal cell walls, and vascular bundles of the nodule were not altered when a nodule was treated with driselase (a plant cell wall degrading enzyme), although the cell walls of meristematic and bacteroid-including zones were completely decomposed by the enzyme treatment. Some infection threads were funnel shaped at the site of attachment of the infection thread to the host cell wall.

Cell wall reinforcement in watermelon shoot base related to its resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. niveum

2014 ◽  
Vol 153 (2) ◽  
pp. 296-305 ◽  
Author(s):  
T.-H. CHANG ◽  
Y.-H. LIN ◽  
K.-S. CHEN ◽  
J.-W. HUANG ◽  
S.-C. HSIAO ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Cell Walls ◽  
Phenylalanine Ammonia Lyase ◽  
Signal Molecules ◽  
Vascular Bundles ◽  
Structural Barriers ◽  
Shoot Base ◽  
Bound Phenolics

SUMMARYFusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum, is one of the limiting factors for watermelon production in Taiwan. In recent research, the phenylalanine ammonia lyase (PAL) gene expressed in the shoot base of the Fusarium wilt resistant line JSB was related to Fusarium wilt resistance. Phenylalanine ammonia lyase is the key regulatory enzyme in the phenylpropanoid metabolic pathway. The downstream products of phenolic compounds are considered to be involved in the complicated plant defence mechanisms. They could act as signal molecules, antimicrobial substances and/or structural barriers. To study the resistant mechanisms of Fusarium wilt, the resistant JSB line was examined for comparison of F. oxysporum-watermelon interactions with the susceptible Grand Baby (GB) cultivar. Unlike infected GB, which was seriously colonized by F. oxysporum in the whole plant, the pathogen was limited below the shoot base of inoculated JSB, suggesting that the shoot base of JSB may contribute to Fusarium resistance. The data indicated that a significant increase in PAL activity was found in shoot bases of the resistant JSB line at 3, 9, 12 and 15 days after inoculation (DAI). Shoot bases of resistant watermelons accumulated higher amounts of soluble and cell wall-bound phenolics at 3–9 DAI; the susceptible GB cultivar, however, only increased the cell wall-bound phenolics in shoot bases at 3 DAI. High lignin deposition in the cell walls of vascular bundles was observed in the shoot bases of JSB but not of GB seedlings at 6 and 9 DAI. In the roots and shoot bases of JSB seedlings at 6 DAI, peroxidase enzyme activity increased significantly. In summary, the results suggest that accumulation of cell wall-bound phenolics and increase of peroxidase activity in shoot bases of JSB seedlings during F. oxysporum inoculation, together with the rapid deposition of lignin in the cell walls of vascular bundles, may have provided structural barriers in resistant JSB line to defend against F. oxysporum invasion.

scholarly journals Functional Analysis of the Phosphate Transporter Gene MtPT6 From Medicago truncatula

2021 ◽  
Vol 11 ◽  
Author(s):  
Yuman Cao ◽  
Jinlong Liu ◽  
Yuanying Li ◽  
Jing Zhang ◽  
Shuxia Li ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Vascular Tissue ◽  
Phosphate Transporter ◽  
Vascular Bundles ◽  
Transporter Gene ◽  
Cortical Cells ◽  
Close Relationship ◽  
Localization Analysis ◽  
Global Agriculture ◽  
Almost All

Phosphorus is one of the essential macronutrients required by plant growth and development, but phosphate resources are finite and diminishing rapidly because of the huge need in global agriculture. In this study, 11 genes were found in the Phosphate Transporter 1 (PHT1) family of Medicago truncatula. Seven genes of the PHT1 family were available by qRT-PCR. Most of them were expressed in roots, and almost all genes were induced by low-phosphate stress in the nodule. The expression of MtPT6 was relatively high in nodules and induced by low-phosphate stress. The fusion expression of MtPT6 promoter-GUS gene in M. truncatula suggested that the expression of MtPT6 was induced in roots and nodules by phosphate starvation. In roots, MtPT6 was mainly expressed in vascular tissue and tips, and it was also expressed in cortex under low-phosphate stress; in nodules, it was mainly expressed in vascular bundles, cortical cells, and fixation zone cells. MtPT6 had a close relationship with other PHT1 family members according to amino acid alignment and phylogenetic analysis. Subcellular localization analysis in tobacco revealed that MtPT6 protein was localized to the plasma membrane. The heterologous expression of MtPT6 in Arabidopsis knockout mutants of pht1.1 and pht1.4 made seedlings more susceptible to arsenate treatment, and the phosphate concentrations in pht1.1 were higher in high phosphate condition by expressing MtPT6. We conclude that MtPT6 is a typical phosphate transporter gene and can promote phosphate acquisition efficiency of plants.

Physical structure of white clover, rape, spurrey and perennial ryegrass in relation to rate of intake by sheep, chewing activity and particle breakdown

1995 ◽  
Vol 125 (1) ◽  
pp. 43-50 ◽  
Author(s):  
E. J. Mtengeti ◽  
D. Wilman ◽  
G. Moseley
Keyword(s):  
Cell Wall ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Vascular Tissue ◽  
Physical Structure ◽  
Vascular Bundles ◽  
Size And Shape ◽  
Similar Weight ◽  
Chewing Activity

SUMMARYFour plant species were compared in each of three harvest periods (in August/September) in 1991 and 1992 at Aberystwyth: white clover (Trifolium repens L.), rape (Brassica napus L.), spurrey (Spergula arvensis L.) and perennial ryegrass (Lolium perenne L.). Plant physical structure was considered in relation to rate of intake by sheep, chewing activity and the effectiveness of chewing in breaking the diet into particles.White clover had a much lower proportion of cell wall than perennial ryegrass, but the rate of intake and the number of chews per min were similar for the two species. White clover petioles broke down into long, thin particles, similar in size and shape to those derived from perennial ryegrass leaf sheaths; many of the clover petioles were not split longitudinally by chewing, in contrast to the ryegrass sheaths. A white clover leaflet was typically broken into about 20 blocky particles, whereas a petiole of similar weight was broken into only about three particles. Veins were close together in ryegrass leaf sheaths and blades, particularly the latter; approximately one in seven strips of weaker tissue between veins was ruptured by chewing leaf sheaths and one in 16 in the case of leaf blades, in each case resulting in particles of c. 2 mm width. Rape had a low proportion of cell wall and a low proportion of vascular tissue in its leaf blades, petioles and stems. Rape leaf blades were eaten quickly, but the stems were eaten slowly. The length and width of particles derived from rape leaf blades were very similar to those of particles derived from white clover leaflets. Spurrey had a high proportion of cell wall and was low in in vitro digestibility, but the rates of intake and chewing were high and relatively few chews were required per g of dry matter ingested. The vascular bundles in the spurrey stems were only half the thickness of the bundles in white clover petioles; pieces of spurrey stem were typically broken at about two places along their length and were not split during eating.The study illustrates the wide variation in plant anatomy among species which can be available to herbivores and some effects of the abundance, thickness and orientation of vascular bundles on rate of intake, chewing activity and the size and shape of particles produced by chewing.

scholarly journals Synchrotron FTIR and Raman spectroscopy 1 ectroscopy provide unique spectral fingerprints for Arabidopsis floral stem vascular tissues

2018 ◽  
Author(s):  
S Dinant ◽  
N Wolff ◽  
F De Marco ◽  
F Vilaine ◽  
L Gissot ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Double Mutant ◽  
Vascular Tissue ◽  
Cell Wall Composition ◽  
Specific Cell ◽  
Xylem Cell ◽  
Phloem Cell ◽  
Ftir And Raman Spectroscopy

AbstractCell walls are highly complex structures that are modified during plant growth and development. For example, the development of phloem and xylem vascular cells, which participate in the transport of sugars and water as well as support, can be influenced by cell-specific cell wall composition. Here, we used synchrotron radiation-based infrared (SR-FTIR) and Raman spectroscopy to analyze the cell wall composition of wild-type and double mutant sweet11-1sweet12-1, which impairs sugar transport, Arabidopsis floral stem vascular tissue. The SR-FTIR spectra showed that in addition to modified xylem cell wall composition, phloem cell walls in the double mutant line were characterized by modified hemicellulose composition. Moreover, combining Raman spectroscopy with a Classification and Regression Tree (CART) method identified combinations of Raman shifts that could distinguish xylem vessels and fibers. Additionally, the disruption of SWEET11 and SWEET12 genes impacts xylem cell wall composition in a cell-specific manner, with changes in hemicelluloses and cellulose observed at the xylem vessel interface. These results suggest that the facilitated transport of sugars by transporters that exist between vascular parenchyma cells and conducting cells is important to ensuring correct phloem and xylem cell wall composition.HighlightCombining vibrational spectroscopy techniques and multivariate analysis shows that the disruption of SWEET genes impacts phloem cell wall composition and that the effect on xylem cell wall composition is cell-specific.

Cell Wall Composition and Ultrastructural Immunolocalization of Pectin and Arabinogalactan Protein during Olea europaea L. Fruit Abscission

2020 ◽  
Vol 61 (4) ◽  
pp. 814-825 ◽  
Author(s):  
Ruben Parra ◽  
Miguel A Paredes ◽  
Juana Labrador ◽  
Cláudia Nunes ◽  
Manuel A Coimbra ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Separation ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Arabinogalactan Protein ◽  
Cell Wall Polysaccharide ◽  
Ripe Fruit ◽  
Olive Fruit ◽  
Fruit Abscission ◽  
Polysaccharide Composition

Abstract Cell wall modification is integral to many plant developmental processes where cells need to separate, such as abscission. However, changes in cell wall composition during natural fruit abscission are poorly understood. In olive (Olea europaea L.), some cultivars such as ‘Picual’ undergo massive natural fruit abscission after fruit ripening. This study investigates the differences in cell wall polysaccharide composition and the localization of pectins and arabinogalactan protein (AGP) in the abscission zone (AZ) during cell separation to understand fruit abscission control in ‘Picual’ olive. To this end, immunogold labeling employing a suite of monoclonal antibodies to cell wall components (JIM13, LM5, LM6, LM19 and LM20) was investigated in olive fruit AZ. Cell wall polysaccharide extraction revealed that the AZ cell separation is related to the de-esterification and degradation of pectic polysaccharides. Moreover, ultrastructural localization showed that both esterified and unesterified homogalacturonans (HGs) localize mainly in the AZ cell walls, including the middle lamella and tricellular junction zones. Our results indicate that unesterified HGs are likely to contribute to cell separation in the olive fruit AZ. Similarly, immunogold labeling demonstrated a decrease in both galactose-rich and arabinose-rich pectins in AZ cell walls during ripe fruit abscission. In addition, AGPs were localized in the cell wall, plasma membrane and cytoplasm of AZ cells with lower levels of AGPs during ripe fruit abscission. This detailed temporal profile of the cell wall polysaccharide composition, and the pectins and AGP immunolocalization in the olive fruit AZ, offers new insights into cell wall remodeling during ripe fruit abscission.

scholarly journals Immunohistochemical analyses on two distinct internodes of stinging nettle show different distribution of polysaccharides and proteins in the cell walls of bast fibers

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Claudia Faleri ◽  
Xuan Xu ◽  
Lavinia Mareri ◽  
Jean-Francois Hausman ◽  
Giampiero Cai ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Developmental Stages ◽  
Cell Wall Polysaccharides ◽  
Stinging Nettle ◽  
Bast Fiber ◽  
Bast Fibers ◽  
Biochemical Approach ◽  
Immunohistochemical Analyses

AbstractStinging nettle is a perennial herbaceous species holding value as a multi-purpose plant. Indeed, its leaves and roots are phytofactories providing functional ingredients of medicinal interest and its stems produce silky and resistant extraxylary fibers (a.k.a. bast fibers) valued in the biocomposite sector. Similarly to what is reported in other fiber crops, the stem of nettle contains both lignified and hypolignified fibers in the core and cortex, respectively, and it is therefore a useful model for cell wall research. Indeed, data on nettle stem tissues can be compared to those obtained in other models, such as hemp and flax, to support hypotheses on the differentiation and development of bast fibers. The suitability of the nettle stem as model for cell wall-related research was already validated using a transcriptomics and biochemical approach focused on internodes at different developmental stages sampled at the top, middle, and bottom of the stem. We here sought to complement and enrich these data by providing immunohistochemical and ultrastructural details on young and older stem internodes. Antibodies recognizing non-cellulosic polysaccharides (galactans, arabinans, rhamnogalacturonans) and arabinogalactan proteins were here investigated with the goal of understanding whether their distribution changes in the stem tissues in relation to the bast fiber and vascular tissue development. The results obtained indicate that the occurrence and distribution of cell wall polysaccharides and proteins differ between young and older internodes and that these changes are particularly evident in the bast fibers.

scholarly journals Anatomy of the Windmill Palm (Trachycarpus fortunei) and Its Application Potential

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1130 ◽  
Author(s):  
Jiawei Zhu ◽  
Jing Li ◽  
Chuangui Wang ◽  
Hankun Wang
Keyword(s):  
Cell Wall ◽  
Vascular Bundle ◽  
Vascular Tissue ◽  
Leaf Sheath ◽  
Indentation Modulus ◽  
Vascular Bundles ◽  
Fibrous Sheath ◽  
Force Microscopy ◽  
Significant Difference ◽  
Tissue Proportion

The windmill palm (Trachycarpus fortunei (Hook.) H. Wendl.) is widely distributed and is an important potential source of lignocellulosic materials. The lack of knowledge on the anatomy of the windmill palm has led to its inefficient use. In this paper, the diversity in vascular bundle types, shape, surface, and tissue proportions in the leaf sheaths and stems were studied with digital microscopy and scanning electron microscope (SEM). Simultaneously, fiber dimensions, fiber surfaces, cell wall ultrastructure, and micromechanics were studied with atomic force microscopy (AFM) and a nanoindenter. There is diversity among vascular bundles in stems and leaf sheaths. All vascular bundles in the stems are type B (circular vascular tissue (VT) at the edge of the fibrous sheath (FS)) while the leaf sheath vascular bundles mostly belong to type C (aliform (VT) at the center of the (FS), with the wings of the (VT) extending to the edge of the vascular bundles). In addition, variation among the vascular bundle area and tissue proportion in the radial direction of the stems and different layers of the leaf sheaths is also significant. Microscopically, the fibers in the stem are much wider and longer than that in the leaf sheath. The secondary walls of stem fibers are triple layered while those in the leaf sheath are double layered. The indentation modulus and hardness of the cell wall of leaf sheath fibers are higher than that of the stem. An independent sample t-test also showed a significant difference between stems and leaf sheaths. All this indicates that windmill palm stems and leaf sheaths are two different materials and have different application prospects.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

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