Torus-Bearing Pit Membranes in Cercocarpus

IAWA Journal ◽  
2010 ◽  
Vol 31 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Roland Dute ◽  
Jaynesh Patel ◽  
Steven Jansen
Keyword(s):  
Secondary Wall ◽  
Membrane Surface ◽  
Parenchyma Cell ◽  
Protective Layer ◽  
Wall Material ◽  
Tracheary Elements ◽  
Bordered Pit ◽  
Parenchyma Cells ◽  
Conducting Cell ◽  
Cell Ontogeny

Intervascular pit membranes of Cercocarpus possess torus thickenings. The thickenings, or pads, consist of lignified, secondary wall material. Torus pad deposition occurs late in cell ontogeny and is not associated with a microtubule plexus. Half-bordered pit pairs between tracheary elements and parenchyma cells often have a torus pad on the membrane surface facing the conducting cell. In contrast, a thick protective layer fills the pit cavity on the side of the parenchyma cell. Ontogeny of the torus thickenings in Cercocarpus represents a third mode of torus development in eudicots when compared to that occurring in Osmanthus/Daphne and Ulmus/Celtis.

Wound Effects on Xylem Cell Differentiation in a Conifer

IAWA Journal ◽  
1984 ◽  
Vol 5 (4) ◽  
pp. 295-305 ◽  
Author(s):  
Keiko Kuroda ◽  
Ken Shimaji
Keyword(s):  
Cell Differentiation ◽  
Loblolly Pine ◽  
Parenchyma Cell ◽  
Cell Maturation ◽  
Bordered Pit ◽  
Xylem Cell ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Cambial Zone ◽  
Ray Parenchyma Cells

Modified xylem cells formed around a minute injury due to pin insertion in the cambium of loblolly pine stern were observed periodically in order to study the mechanism of xylem cell differentiation in conifers. Ray parenchyma cells in the mature xylem as well as in the cambial zone were strongly activated. They not only proliferated randomly in the wound gap, but also invaded into some mature tracheids through the pinoid pits to form tylosis-like structures. Then they reticulately thickened and lignified their wall much earlier and more excessively than the normal ray parenchyma cells. Immature ray tracheids, which also divided several times abnormally in the cambial zone, differentiated into ray tracheids without differentiating into any other elements, although some of them had modified pits. Immature axial tracheids near the injury differentiated normally even though some sporadic transverse or radial division occurred before maturation. Only exceptionally, some peculiar groups of small bordered pit pairs were formed between them. It was clear that a shift from differentiating direction on the way of cell maturation, for instance from immature tracheid to parenchyma cell, was never induced by injury. Cambial initials, both ray and fusiform, were very stable.

Ultrastructural observations on pit membrane alterations and associated effects in elm xylem tissues infected by Ceratocystis ulmi

1978 ◽  
Vol 56 (20) ◽  
pp. 2567-2588 ◽  
Author(s):  
G. B. Ouellette
Keyword(s):  
Protective Layer ◽  
Cavity Formation ◽  
Bordered Pit ◽  
Fibrillar Material ◽  
Host Cytoplasm ◽  
Pit Membrane ◽  
Bordered Pits ◽  
Parenchyma Cells

Gradations in the degree of pit membrane alteration in tissues infected by Ceratocystis ulmi (Buism.) C. Moreau and collected at various intervals after inoculation are described. Membranes of bordered pit pairs are coated and apparently impregnated with bands or masses of osmiophilic material; this coating may be thick and stratified and the pit cavities completely occluded. Similar osmiophilic material also occurs in decreasing amounts over and within membranes of simple or half-bordered pits and within the adjacent protective layer. Various degrees of distention and cavity formation in these pit membranes are associated with the osmiophilic material. Products released into vessels from disintegrating pit membranes seem to be sparse. Host cytoplasm in contiguous parenchyma cells can have diverse reactions.Examination of specimens at various angles established the interrelationship between osmiophilic material and remnants of pit membranes. Variously oriented lamellar-like structures and a fibrillar material intermixed with a more amorphous one characterize the osmiophilic material. The significance of these observations is discussed.

Pit Pairs With Tori in the Wood of Osmanthus Americanus (Oleaceae)

IAWA Journal ◽  
1987 ◽  
Vol 8 (3) ◽  
pp. 237-244 ◽  
Author(s):  
Roland R. Dute ◽  
Ann E. Rushing
Keyword(s):  
Middle Lamella ◽  
Radial Component ◽  
Wall Material ◽  
Sodium Chlorite ◽  
Variable Amount ◽  
Tracheary Elements ◽  
Bordered Pit ◽  
Compound Middle Lamella ◽  
Pit Membrane

Bordered pit pairs connecting tracheary elements in the wood of Osmanthus americanus (L.) Benth. ' Hook. ex Gray contained a torus in the pit membrane. This structure is approximately 2.5 μm in diameter, and is located at or near the centre of the pit membrane. The encrusting material of the torus could be removed by treatment with sodium chlorite. Thin seetions through theJorus showed it to consist of a pad of wall material appressed to either side of the compound middle lamella. The membrane surrounding the torus (the margo) consisted of fibrils and a variable amount of enc10sing matrix. The fibrils were generally c1oseIy packed and randomly oriented, although occasionally a radial component was also present. Aspiration of the pit membrane in air-dried material caused the torus to seal off one of the pit apertures. During this process the torus probably prevented rupture of the pit membrane at that site.

Development and Structure of Pit Membranes in the Rhizome of the Woody Fern Botrychium Dissectum

IAWA Journal ◽  
1998 ◽  
Vol 19 (4) ◽  
pp. 429-441 ◽  
Author(s):  
Angela C. Morrow ◽  
Roland R. Dute
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
Matrix Material ◽  
Parenchyma Cell ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Combined Features ◽  
Early Fall ◽  
Secondary Wall Formation ◽  
Parenchyma Cell Wall

Botrychium dissectum Sprengel rhizomes were examined at monthly intervals from February 1993 through December 1994. Sampies taken ranged from those with an inactive cambium and only mature tracheids to those having an active cambium and immature tracheids. The vascular cambium became activated in the early fall prior to maturation of the leaf and fertile spike complex. Intertracheid pit membranes with tori were present in all sampies, although the morphology of the torus varied. The presence of tori was first observed in a tracheid that had just initiated its secondary wall formation. As the pit membrane matured, matrix material was hydrolyzed first from the margo area, then from the torus, and eventually the pit membrane was represented only by a very thin network of microfibrils. In addition, studies confirmed that tracheids bordering parenchyma cells developed a torus thickening, aIthough no thickening of the parenchyma cell wall occurred. Torus ontogeny in B. dissectum combined features previously described for angiosperms and gymnosperms.

Torus Structure and Development in Species of Daphne

IAWA Journal ◽  
1990 ◽  
Vol 11 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Roland R. Dute ◽  
Ann E. Rushing ◽  
James W. Perry
Keyword(s):  
Tracheary Element ◽  
Tracheary Elements ◽  
Bordered Pit ◽  
Fibrillar Material ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Daphne Odora

A torus is present in intervascular pit membranes in the wood of Daphne odora and D. cneorum, but not in D. mezereum. In the two former species, each torus is surrounded by a margo consisting of fibrillar material in a tightly woven pattern. Tori are of greater diameter than pit apertures and completely occlude the apertures during aspiration. Evidence from D. odora indicates that torus deposition is spatially associated with vesicles and a plexus of microtubules, and does not begin until pit border formation is complete. The material deposited during torus synthesis also impregnates the wall of the pre-existing pit membrane. The plasmalemma often is closely appressed to the pit membrane at the site of the developing torus. In half-bordered pit pairs between tracheary elements and parenchyma cells, a torus thickening is deposited only on the side of the tracheary element. As in Osmanthus americanus, it is hypothesised that the presence of tori in species of Daphne prevents rupture of the pit membrane during aspiration.

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.

Cytochemistry of the wall of infected cells in Casuarina actinorhizae

1988 ◽  
Vol 66 (10) ◽  
pp. 2038-2047 ◽  
Author(s):  
R. Howard Berg ◽  
Lorraine McDowell
Keyword(s):  
Infected Cell ◽  
Secondary Wall ◽  
Chromic Acid ◽  
Cortical Cell ◽  
Wall Material ◽  
Primary Cell Wall ◽  
Acid Digestion ◽  
En Bloc ◽  
Lignin Modification ◽  
Infected Cells

Development of the wall of infected cells in Casuarina actinorhizae differs from that of many actinorhizae. After the endophyte penetrates the wall of a cortical cell, that (primary) cell wall becomes lignified, based on histochemical (autofluorescence, phloroglucinol staining) and cytochemical (permanganate staining, enzyme etching) evidence. Subsequently, the remaining walls of the infected cell become lignified. Adjacent noninfected cells somehow are stimulated to deposit a lignified secondary wall only on those walls bordering the infected cell. This remarkable participation of all adjacent noninfected cells in the development of a given infected cell results in an increased thickness and strength of the wall material surrounding infected cells. When they mature, there is a further modification of some of the wall layers surrounding infected cells, manifested in a relative impermeability to en bloc staining with permanganate. Unlike lignified walls, the permanganate-impermeable region is selectively stained by osmium or ferricyanide-reduced osmium and is relatively resistant to concentrated chromic acid digestion. A region that remains permeable to (and stained by) permanganate (part of the secondary wall of bordering noninfected cells) may be developmentally related to phi thickenings. An earlier contention that the permanganate-impermeable region contains suberin is unconfirmed. This region is most likely an unusual lignin modification or results from unidentified material impregnated in its ligninlike matrix.

An ultrastructural study of acid phosphatase localization in Phaseolus vulgaris xylem by the use of an azo-dye method

1975 ◽  
Vol 19 (3) ◽  
pp. 543-561
Author(s):  
I. Charvat ◽  
K. Esau
Keyword(s):  
Acid Phosphatase ◽  
Phaseolus Vulgaris ◽  
Azo Dye ◽  
Secondary Wall ◽  
Parenchyma Cell ◽  
Middle Lamella ◽  
Primary Cell Wall ◽  
Vessel Element ◽  
Primary Wall ◽  
Final Reaction

The localization of acid phosphatase during xylem development has been examined in the bean, Phaseolus vulgaris. The azo dye, the final reaction product, is initially prominent in the dictyosomes, vesicles apparently participating in secondary wall formation, and in the middle lamella of the young vessel element. Final reaction particles are also present in mitochondria, chloroplasts, and certain vacuoles and are sparsely scattered in the cytoplasm. At a later stage of vessel differentiation, the azo dye is concentrated in the disintegrating cytoplasm and along the fibrils of the partially hydrolysed primary wall and middle lamella. In the mature vessel element, the azo dye is still present along the disintegrated primary wall at the side of the vessel and covers the secondary wall. In the parenchyma cell adjacent to the vessel element, acid phosphatase localization is found in the dictyosomes, endoplasmic reticulum, mitochondria, small vacuoles, and the middle lamella. The controls from all stages of vessel element development were free of azo dye particles. The concentration of acid phosphatase along the secondary walls of the mature vessels and in the middle lamella between other cells indicates that this enzyme has other functions besides autolysis of the cytoplasm and primary cell wall. Acid phosphatase may participate in the formation of the secondary wall and may also have a role in the secretion and transport of sugars.

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.

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.

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