Autofluorescent and ultraviolet-absorbing components in cell walls and papillae of barley coleoptiles and their relationship to disease resistance

1986 ◽  
Vol 64 (2) ◽  
pp. 266-272 ◽  
Author(s):  
James R. Aist ◽  
Herbert W. Israel
Keyword(s):  
Disease Resistance ◽  
Cell Walls ◽  
Secondary Wall ◽  
Epidermal Cells ◽  
Ultraviolet Absorption ◽  
Absorption Properties ◽  
Vessel Elements ◽  
Histochemical Tests ◽  
Phenolic Derivatives ◽  
Periclinal Walls

Earlier studies showed that normal-size papillae induced in barley coleoptile epidermal cells by Erysiphe graminis f. sp. hordei were less effective in resisting fungal penetration attempts than were oversize papillae. To determine if a differential content of phenolic derivatives could account for this difference in resistance, we analyzed normal papillae and oversize papillae by histochemical, epifluorimetric, and ultraviolet-microspectrophotometric methods. Whereas the histochemical tests revealed phenolic derivatives only in oversize papillae, the autofluorescence and ultraviolet-absorption properties indicated that both types of papillae contain phenolics. Ultraviolet-absorption spectra indicated that the phenolics were primarily phenylpropanoid groups. Phenolics in papillae were distinct from both those in the secondary wall thickenings of coleoptile xylem vessel elements and those in the periclinal walls of coleoptile epidermal cells. The deposition of phenolics in oversize papillae long before they were challenged by the fungus, the presence of certain phenolics that, tentatively, were detected histochemically only in the oversize papillae, or both could have rendered them resistant to penetration by the fungus.

Relationship of autofluorescent and ultraviolet-absorbing components in cell walls and wall appositions to disease resistance in kohlrabi roots

1986 ◽  
Vol 64 (2) ◽  
pp. 273-275 ◽  
Author(s):  
James R. Aist ◽  
Herbert W. Israel
Keyword(s):  
Cell Walls ◽  
Secondary Wall ◽  
Root Hairs ◽  
Root Hair Cell ◽  
Vessel Elements ◽  
Wall Appositions ◽  
Olpidium Brassicae ◽  
Phenolic Derivatives ◽  
Relationship Of ◽  
Resistance To Penetration

It has been shown that wound plugs induced mechanically by bending of kohlrabi root hairs are more resistant to subsequent penetration attempts by Olpidium brassicae than are papillae induced by the fungus. A histochemical, autofluorescence, and ultraviolet-microspectrophotometric study was undertaken to determine if a differential composition of phenolic derivatives could explain this difference in resistance. Phenolics in the secondary wall thickenings of xylem vessel elements of roots were distinct from those in wound plugs, papillae, and root hair cell walls. But phenolics in wound plugs and papillae could not be distinguished from each other by the methods employed. Thus, the results do not support the hypothesis that wound plugs are more resistant to penetration than are papillae because they contain phenolic derivatives not found in the latter. However, the possibility that an earlier deposition of phenolics in wound plugs accounts for their greater resistance to penetration has not been ruled out.

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.

Morphological peculiarities of seeds of some species of the genus Epipactis Zinn. (Orchidaceae Juss.) of Ukrainian flora

2019 ◽  
Vol 11 (1) ◽  
pp. 93-100
Author(s):  
T Ljubka ◽  
O Tsarenko ◽  
I Tymchenko
Keyword(s):  
Seed Coat ◽  
Cell Walls ◽  
Morphological Study ◽  
Population Level ◽  
Intercellular Spaces ◽  
Different Populations ◽  
Periclinal Walls ◽  
High Degree ◽  
Shape And Size ◽  
Generative Organs

The investigation of macro- and micromorphological peculiarities of seeds of four species of genus Epipactis (Orchidaceae) of Ukrainian flora were carried out. The genus Epipactis is difficult in the in in taxonomic terms and for its representatives are characterized by polymorphism of morphological features of vegetative and generative organs of plants and ability of species to hybridize. The aim of the research was to perform a comparative morphological study of seeds of E. helleborine, E. albensis, E. palustris, E. purpurata and to determine carpological features that could more accurately identify species at the stage of fruiting. A high degree of variation in the shape of the seeds in different populations within the species and overlap of most quantitative carpological characteristics of studied species are noted. There were no significant differences in micromorphological features of the structure of the testa at species or population level. The reticulate surface of the testa is characteristic of all species, the cells of testa are mostly elongated, penta-hexagonal, individual cells almost isodiametric-pentagonal. From the micropillary to the chalasal end, a noticeable change in the shape and size of the seed coat cells is not observed. There are no intercellular spaces, the anticlinal walls of adjacent cells are intergrown and the boundaries between them become invisible. The outer periclinal walls have a single, mainly longitudinal thin ribbed thickenings. Anticlinal cell walls are thick, dense, smooth. The longitudinal Anticlinal walls are almost straight, transverse - straight or sometimes curved in some cells. Epicuticular deposits on the periclinal walls are absent. It is concluded that the use of macro and micromorphological characteristics of seeds of these species for clearer diagnosis at the stage of fruiting is low informative.

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.

Phenological Comparison of the Onset of Vessel Formation Between Ring-Porous and Diffuse-Porous Deciduous Trees in a Japanese Temperate Forest

IAWA Journal ◽  
1996 ◽  
Vol 17 (4) ◽  
pp. 431-444 ◽  
Author(s):  
Mitsuo Suzuki ◽  
Kiyotsugu Yoda ◽  
Hitoshi Suzuki
Keyword(s):  
Secondary Wall ◽  
Leaf Expansion ◽  
Vessel Element ◽  
Early Maturation ◽  
Vessel Formation ◽  
Wall Deposition ◽  
Water Conduction ◽  
Vessel Elements ◽  
Secondary Wall Deposition ◽  
Diffuse Porous

Initiation of vessel formation and vessel maturation indicated by secondary wall deposition have been compared in eleven deciduous broadleaved tree species. In ring-porous species the first vessel element formation in the current growth ring was initiated two to six weeks prior to the onset of leaf expansion, and secondary wall deposition on the vessel elements was completed from one week before to three weeks after leaf expansion. In diffuse-porous species, the first vessel element formation was initiated two to seven weeks after the onset of leaf expansion, and secondary wall deposition was completed four to nine weeks after leaf expansion. These results suggest that early maturation of the first vessel elements in the ring-porous species will serve for water conduction in early spring. On the contrary, the late maturation of the first vessel elements in the diffuse-porous species indicates that no new functional vessels exist at the time of the leaf expansion.

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.

Resistance of hardwood vessels to degradation by white rot Basidiomycetes

1988 ◽  
Vol 66 (9) ◽  
pp. 1841-1847 ◽  
Author(s):  
Robert A. Blanchette ◽  
John R. Obst ◽  
John I. Hedges ◽  
Karen Weliky
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
White Rot ◽  
Fungal Decay ◽  
Acacia Koa ◽  
Monomer Composition ◽  
Lignin Removal ◽  
Vessel Elements ◽  
Parenchyma Cells ◽  
Unusual Type

White stringy rot, an unusual type of selective fungal decay, can be found in wood of some dicotyledonous angiosperms. Stages of advanced decay consist of a mass of vessel elements with only remnants of other cells adhering to the vessel walls. Degradation by various white rot Basidiomycetes causes loss of fibers, fiber tracheids, and parenchyma cells but not vessels. In wood of Acacia koa var. koa with a white pocket rot caused by Phellinus kawakamii, fibers and parenchyma cells were preferentially delignified. After extensive lignin removal the cellulose remaining in the secondary wall was degraded. Large vessel elements remained relatively intact after other cells were completely degraded. The resistance of vessels to degradation appears to be due to their high ligninxarbohydrate ratio, lignin monomer composition, and cell wall morphology.

The epidermis in Passerina/ (Thymelaeaceae): structure, function and taxonomic significance

Bothalia ◽  
2000 ◽  
Vol 30 (1) ◽  
pp. 69-86 ◽  
Author(s):  
C. L. Bredenkamp ◽  
A. E. Van Wyk
Keyword(s):  
Cell Walls ◽  
Mediterranean Climate ◽  
High Light Intensity ◽  
Epidermal Cells ◽  
Cell Orientation ◽  
Abaxial Surface ◽  
Epidermal Structure ◽  
Interspecific Differences ◽  
Epidermal Features ◽  
Structural Adaptations

Epidermal features were studied in all 17 species of Passerina, a genus endemic to southern Africa. Leaves in Passerina are inversely ericoid, the adaxial surface concave and the abaxial surface convex. Leaves are inversely dorsiventral and epistomatic. The adaxial epidermis is villous, with unicellular, uniseriate trichomes and relatively small thin-walled cells, promoting flexibility of leaf margins owing to turgor changes. In common with many other Thymelaeaceae, abaxial epidermal cells are large and tanniniferous with mucilaginous cell walls. The cuticle is adaxially thin, but abaxially well devel­oped, probably enabling the leaf to restrict water loss and to tolerate high light intensity and UV-B radiation. Epicuticular waxes, present in all species, comprise both soft and plate waxes. Epidermal structure proves to be taxonomically impor­tant at family, genus and species levels. Interspecific differences include arrangement of stomata and presence or absence of abaxial epidermal hair. Other diagnostic characters of the abaxial epidermal cells are arrangement,size and shape, cutic- ular ornamentation and presence or absence of wax platelets. Two groups of species on the basis of abaxial epidermal cell orientation are recognised. Many leaf epidermal features in Passerina are interpreted as structural adaptations to the Mediterranean climate of the Cape.

Lignin Distribution in Coppice Poplar, Linseed and Wheat Straw

Holzforschung ◽  
2001 ◽  
Vol 55 (4) ◽  
pp. 379-385 ◽  
Author(s):  
Lloyd Donaldson ◽  
Jamie Hague ◽  
Rebecca Snell
Keyword(s):  
Wheat Straw ◽  
Secondary Wall ◽  
Middle Lamella ◽  
Laser Scanning Microscopy ◽  
Interference Microscopy ◽  
Confocal Laser ◽  
Lignin Concentration ◽  
Lignin Distribution ◽  
Vessel Elements ◽  
Parenchyma Cells

Summary Lignin distribution was determined by interference microscopy, and by confocal laser scanning microscopy (CLSM) for a range of agricultural residues including coppice poplar, linseed, and wheat straw. Interference microscopy was used to determine the lignin concentration in the middle lamella at the cell corner, and for the secondary wall of libriform fibres in the secondary xylem of poplar and linseed. Wheat was examined in the same way for cortical fibres. In addition the secondary wall of vessel elements was examined for poplar. Confocal microscopy was used to confirm the results from interference microscopy by providing semiquantitative information based on lignin autofluorescence, and by staining with acriflavine. Wheat had the lowest level of lignification, with 31 % lignin in the middle lamella of cortical fibres and 9% lignin in the secondary wall. Poplar had a lignin concentration of 63% in the middle lamella and 6% in the secondary wall of libriform fibres, while linseed had corresponding values of 69 % and 13 %. The secondary wall of poplar vessel elements had a lignin concentration of 25 %. In all three species most of the stem tissue was lignified except for phloem and bark, where present. In linseed the pith was unlignified. In wheat, most of the parenchyma cells were lignified except for a few cells lining the stem cavity. Libriform fibres in poplar and linseed sometimes had an unlignified gelatinous layer in samples containing tension wood. In linseed, lignification was greater in xylem fibres compared to bast fibres. Ray parenchyma cells of poplar and linseed appeared to be lignified to the same extent as xylem fibres.

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