Localisation structurale et ultrastructurale d'activités peroxydasiques dans les parois du mésophylle et des fibres en cours de lignification chez l'alfa (Stipa tenacissima)

1984 ◽  
Vol 62 (12) ◽  
pp. 2644-2649 ◽  
Author(s):  
M. Harche
Keyword(s):  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Cell Walls ◽  
Secondary Wall ◽  
Outer Part ◽  
Potassium Cyanide ◽  
Primary Wall ◽  
Stipa Tenacissima ◽  
Parenchyma Cells

Using diaminobenzidine as substrate, peroxidase activity was localized in the walls of parenchyma cells and differentiating fibres. In mature fibres and parenchyma a slight activity could be recognized in primary walls only. In parenchyma cells, peroxidase activity was fairly inhibited with heat, potassium cyanide, and aminotriazole, which could indicate the presence of catalase within the cell walls. However, in plasmodesmatal regions peroxidases were- resistant to the above inhibitors. Syringaldazine oxidase activity was present only in the primary wall and the outer part of the secondary wall of differentiating fibres. The parallelism between lignification and peroxidase activity in the secondary walls supports the hypothesis of the involvement of these enzymes in the lignification process.

scholarly journals Arrangement of Cellulose Microfibrils in Walls of Elongating Parenchyma Cells

1958 ◽  
Vol 4 (4) ◽  
pp. 377-382 ◽  
Author(s):  
G. Setterfield ◽  
S. T. Bayley
Keyword(s):  
Cell Walls ◽  
Secondary Wall ◽  
Cellular Differentiation ◽  
Cellulose Microfibrils ◽  
Field Region ◽  
Primary Wall ◽  
Parenchyma Cells ◽  
Pit Field ◽  
Wall Growth ◽  
Electron Microscopes

The arrangement of cellulose microfibrils in walls of elongating parenchyma cells of Avena coleoptiles, onion roots, and celery petioles was studied in polarizing and electron microscopes by examining whole cell walls and sections. Walls of these cells consist firstly of regions containing the primary pit fields and composed of microfibrils oriented predominantly transversely. The transverse microfibrils show a progressive disorientation from the inside to the outside of the wall which is consistent with the multinet model of wall growth. Between the pit-field regions and running the length of the cells are ribs composed of longitudinally oriented microfibrils. Two types of rib have been found at all stages of cell elongation. In some regions, the wall appears to consist entirely of longitudinal microfibrils so that the rib forms an integral part of the wall. At the edges of such ribs the microfibrils can be seen to change direction from longitudinal in the rib to transverse in the pit-field region. Often, however, the rib appears to consist of an extra separate layer of longitudinal microfibrils outside a continuous wall of transverse microfibrils. These ribs are quite distinct from secondary wall, which consists of longitudinal microfibrils deposited within the primary wall after elongation has ceased. It is evident that the arrangement of cellulose microfibrils in a primary wall can be complex and is probably an expression of specific cellular differentiation.

Cytochemical localization of peroxidase activity in wound vessel members of Coleus

1972 ◽  
Vol 50 (5) ◽  
pp. 977-983 ◽  
Author(s):  
Peter K. Hepler ◽  
Rita M. Rice ◽  
William A. Terranova
Keyword(s):  
Peroxidase Activity ◽  
Cell Walls ◽  
Secondary Wall ◽  
Primary Wall ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Secondary Thickening ◽  
Vessel Elements ◽  
Microscopic Investigations

Peroxidase activity has been localized in the cell walls and cytoplasm of wound vessel elements of Coleus which had been fixed in glutaraldehyde, incubated in diaminobenzidine (DAB) and H2O2, and postfixed in OSO4. Electron microscopic investigations revealed prominent staining in the reticulate secondary wall and in the primary wall where the secondary thickenings attach. The stain in the secondary wall is finely textured and heavier towards its periphery than towards its core. The staining of the primary wall, however, is coarsely granular. In the cytoplasm of differentiating vessel elements electron-opaque deposits are observed in the plasmalemma, especially where it overlies the secondary thickening, and in the dictyosomes and their associated vesicles. Staining also occurs on the internal membranes of developing chloroplasts where it is most likely the result of photooxidation of DAB.Staining, except in chloroplasts, appears to be due specifically to peroxidase, since either removal of H2O2 or preincubation with KCN markedly reduces staining, whereas preincubation with aminotriazole, an inhibitor of catalase, does not. The similarity of localization of peroxidase and lignin in the walls of Coleus wound vessel elements supports the postulate that the enzyme participates in lignification.

The fine structure of the pits of Eucalyptus regnans (F. Muell.) and their relation to the movement of liquids into the wood

1960 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
J Cronshaw
Keyword(s):  
Secondary Wall ◽  
Structural Features ◽  
Cellulose Microfibrils ◽  
Primary Wall ◽  
Detailed Structure ◽  
Eucalyptus Regnans ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Observstion in the electron microscope of carbon replicas of the pits of vessels, ray parenchyma cells, fibres, and tracheids of Eucalyptus regnans has shown the detailed structure of the pit borders and the pit closing membranes. In all cases in the mature wood the primary wall is left apparently without modification as the pit membrane. Unlike the borders of the pits of fibre tracheids and tracheids, the pit borders of the vessels are not separate; the cellulose microfibrils of a border may be common to several pits. The pit borders of fibre traoheids and tracheids are developed as separate entities and have a structure similar to the pit borders of softwood tracheids. The structure of the secondary wall layers associated with the pits is described and related to the structure of the pits. The fine structural features of the pits, especially of the pit closing membranes, are discussed in relation to the movement of liquids into wood.

A HISTOLOGICAL STUDY OF SUGAR MAPLE DECAYED BY POLYPORUS GLOMERATUS PECK

1951 ◽  
Vol 29 (3) ◽  
pp. 215-223 ◽  
Author(s):  
H. M. Good ◽  
C. D. Nelson
Keyword(s):  
Cell Walls ◽  
Sugar Maple ◽  
Histological Study ◽  
Outer Part ◽  
Rapid Variation ◽  
Parenchyma Cells ◽  
Dark Color

Parenchyma cells of maple wood were found to remain alive, for many years after incorporation into the heartwood In wood invaded by Polyporus glomeratus Peck these cells had been killed in advance of the spreading mycelium, and their contents transformed into masses of dark brown wound gum. These, and similar masses which occasionally formed in the vessels and fibers, gave the outer part of the infected heartwood a characteristic dark color. The presence of wound gum appeared to inhibit development of decay, possibly by reason of the increase in pH with which it has been associated consistently. In tissues containing wound gum, decay was limited to slight delignification of certain cells in the intervessel areas, but following its disappearance disintegration of the tissues was rapid. Variation in resistance to decay was found to be related to variations in the reactions of cell walls to several staining procedures.

scholarly journals In Planta Analysis of the Radial Movement of Minerals from Inside to Outside in the Trunks of Standing Japanese Cedar (Cryptomeria japonica D. Don) Trees at the Cellular Level

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 251
Author(s):  
Katsushi Kuroda ◽  
Kenichi Yamane ◽  
Yuko Itoh
Keyword(s):  
Cell Walls ◽  
Cryptomeria Japonica ◽  
Outer Part ◽  
Japanese Cedar ◽  
Cellular Level ◽  
Radial Movement ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Standing Trees ◽  
Ray Parenchyma Cells

Although the radial movement of minerals in tree trunks is a widely accepted phenomenon, experimental evidence of their movement in standing trees and underlying mechanisms is very limited. Previously, we clarified that cesium (Cs) artificially injected into the outer part of the sapwood of standing Japanese cedar (Cryptomeria japonica D. Don) trunks moved to the inner part of the sapwood, including the intermediate wood, via active transport by xylem parenchyma cells and diffusion through cell walls and then moved into the heartwood by diffusion. To understand the mechanism underlying the radial movement of minerals in the standing tree trunk, it is necessary to clarify their movement in the opposite direction. Therefore, the present study aimed to determine the radial movement of minerals from inside to outside in the trunks of standing trees at the cellular level. For this, a long hole across the center part of the trunk, which reached the heartwood, intermediate wood, and sapwood, was made in standing Japanese cedar trunks, and a solution of stable isotope Cs was continuously injected into the hole for several days as a tracer. The injected part of the trunk was collected after being freeze-fixed with liquid nitrogen, and the frozen sample was subjected to analysis of Cs distribution at the cellular level using cryo-scanning electron microscopy/energy-dispersive X-ray spectroscopy. The Cs injected into the inner sapwood or intermediate wood rapidly moved toward the outer sapwood via xylem ray parenchyma cells together with diffusion through the cell walls. In contrast, the Cs injected into the heartwood barely moved to the sapwood, although it reached a part of the inner intermediate wood. These results suggest that minerals in xylem ray parenchyma cells in the sapwood are bidirectionally supplied to each other; however, the minerals accumulated in the heartwood may not be supplied to living cells.

Peroxidase in healthy and diseased elm trees investigated by the benzidine histochemical technique

1968 ◽  
Vol 46 (12) ◽  
pp. 1491-1494 ◽  
Author(s):  
Camilien Gagnon
Keyword(s):  
Peroxidase Activity ◽  
Cell Walls ◽  
Histochemical Technique ◽  
Axial Parenchyma ◽  
American Elm ◽  
Pathological Alteration ◽  
Incubation Solution ◽  
Parenchyma Cells ◽  
Blue Reaction

Peroxidase activity was localized in the xylem of healthy and diseased American elm trees by the benzidine test. The activity in the cell walls resulted in a violet-brown color, while the activity in the protoplasm produced a blue reaction. The localization of the enzyme in healthy trees was much improved by impregnation of tissues with celloidin before sectioning; this procedure reduced the diffusion of peroxidase from the tissues into the incubation solution. The cambium region of both healthy and diseased trees showed a very strong peroxidase activity; such activity was also detected in ray and axial parenchyma cells. Only in infected trees was the activity found in fibers and vessels. The role of peroxidase in the pathological alteration of xylem tissues is discussed.

Cell-Wall-Associated Oxidases from the Lignifying Xylem of Angiosperms and Gymnosperms: Monolignol Oxidation

Holzforschung ◽  
1999 ◽  
Vol 53 (5) ◽  
pp. 503-510 ◽  
Author(s):  
Nigel Deighton ◽  
Andrew Richardson ◽  
Derek Stewart ◽  
Gordon J. McDougall
Keyword(s):  
Cell Wall ◽  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Cell Walls ◽  
Specific Activity ◽  
Coniferyl Alcohol ◽  
Liquid Chromatography Mass Spectrometry ◽  
Sinapyl Alcohol ◽  
Marked Preference ◽  
Dehydrogenation Polymers

Summary Cell-wall-associated oxidases extracted from the lignifying xylem of Sitka spruce and ash oxidise sinapyl alcohol at a greater rate than coniferyl alcohol and p-coumaryl alcohol (SA > CA > pCA). The enzyme from ash shows a marked preference, on a specific activity basis, for the oxidation of SA over CA and pCA (SA ≫ CA ≥ pCA) and has a particularly low affinity for the oxidation of coniferyl alcohol compared to the enzyme from spruce (SA > CA > pCA). This difference in monolignol preference between the spruce and ash enzymes may relate to their required functions during lignification, in that the hardwood enzyme would be supplied mainly SA and the softwood enzyme would be supplied mainly CA. The spruce enzyme also displayed a marked preference for the oxidation of sinapyl alcohol over sinapyl aldehyde even when the two compounds were presented in a mixture. Purified cell walls from the lignifying xylem of spruce could oxidise CA by the action of bound oxidase activity and dissolved oxygen (~ 240 μM) but CA oxidation was increased many fold by the action of the bound peroxidase activity and 240 μM H2O2. However, the initial dimeric and trimeric products of the peroxidase- and oxidase-catalysed reactions detected by liquid chromatography-mass spectrometry were the same and present in similar proportions. This indicates that the oxidation of CA by oxidase or by peroxidase proceeds via the same intermediates and occurs by a similar mechanism. Insoluble dehydrogenation polymers (DHPs) of CA were formed in similar yields by spruce extracts in the absence (oxidase activity) or presence (peroxidase activity) of H2O2. The peroxidase-catalysed DHPs and the oxidase-catalysed DHPs gave Fourier transform infra-red spectra with maxima that were characteristic of DHPs of CA. However, differences in the comparative intensities of some maxima suggest that the oxidase-catalysed DHPs were less condensed than the peroxidase-catalysed polymers. These findings are discussed with respect to the possible contribution of oxidases to lignin structure in developing wood.

scholarly journals Involvement of CesA4, CesA7-A/B and CesA8-A/B in secondary wall formation in Populus trichocarpa wood

2019 ◽  
Vol 40 (1) ◽  
pp. 73-89 ◽  
Author(s):  
Manzar Abbas ◽  
Ilona Peszlen ◽  
Rui Shi ◽  
Hoon Kim ◽  
Rui Katahira ◽  
...  
Keyword(s):  
Solid State ◽  
Mechanical Strength ◽  
Cell Walls ◽  
Secondary Wall ◽  
Populus Trichocarpa ◽  
Wood Formation ◽  
Fiber Cell ◽  
Modulus Of Rupture ◽  
Cellulose Content ◽  
Wall Formation

Abstract Cellulose synthase A genes (CesAs) are responsible for cellulose biosynthesis in plant cell walls. In this study, functions of secondary wall cellulose synthases PtrCesA4, PtrCesA7-A/B and PtrCesA8-A/B were characterized during wood formation in Populus trichocarpa (Torr. & Gray). CesA RNAi knockdown transgenic plants exhibited stunted growth, narrow leaves, early necrosis, reduced stature, collapsed vessels, thinner fiber cell walls and extended fiber lumen diameters. In the RNAi knockdown transgenics, stems exhibited reduced mechanical strength, with reduced modulus of rupture (MOR) and modulus of elasticity (MOE). The reduced mechanical strength may be due to thinner fiber cell walls. Vessels in the xylem of the transgenics were collapsed, indicating that water transport in xylem may be affected and thus causing early necrosis in leaves. A dramatic decrease in cellulose content was observed in the RNAi knockdown transgenics. Compared with wildtype, the cellulose content was significantly decreased in the PtrCesA4, PtrCesA7 and PtrCesA8 RNAi knockdown transgenics. As a result, lignin and xylem contents were proportionally increased. The wood composition changes were confirmed by solid-state NMR, two-dimensional solution-state NMR and sum-frequency-generation vibration (SFG) analyses. Both solid-state nuclear magnetic resonance (NMR) and SFG analyses demonstrated that knockdown of PtrCesAs did not affect cellulose crystallinity index. Our results provided the evidence for the involvement of PtrCesA4, PtrCesA7-A/B and PtrCesA8-A/B in secondary cell wall formation in wood and demonstrated the pleiotropic effects of their perturbations on wood formation.

Cell grouping and primary wall generations in the cambial zone, xylem, and phloem in Pinus

1968 ◽  
Vol 16 (2) ◽  
pp. 177 ◽  
Author(s):  
A Mahmood
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Secondary Wall ◽  
Radial Direction ◽  
Cell Plate ◽  
Tangential Direction ◽  
Primary Wall ◽  
Photographic Evidence ◽  
Secondary Wall Deposition ◽  
Cambial Zone

The use of the term cambium, or equivalent terms, in modern literature is discussed. The term cambial zone adopted in this paper includes the cambial initial and the dividing and enlarging cells. The tissue mother cell produced at each division of the initial produces a group of four cells in xylem or two cells in phloem. Theoretical constructs have been made for xylem and phloem production by associating the concepts that xylem and phloem are produced in alternate series of initial divisions and that a new primary wall is deposited around each daughter protoplast at each cell division. Correlations are derived from the theoretical constructs for the thickness of primary wall layers lying in the tangential direction and of those lying in the radial direction at progressive histological levels. Deductions from theoretical constructs are made when the initial is producing xylem, when it changes its polarity from xylem to phloem production, and when the reverse change occurs. Most of the theoretical deductions are supported by photographic evidence. The chief point of this study is the demonstration of generations (multiplicity) of primary parental walls. The term intercellular material proposed in this paper includes the cell plate plus any remnants of ancestral primary walls between the current primary walls surrounding the adjacent protoplasts. This term is still applicable to cells where secondary wall deposition is taking place or has been completed.

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

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