Localization of actin filaments and cortical microtubules in wood-forming tissues of conifers

ABSTRACT The aim of the present study was to investigate the orientation and localization of actin filaments and cortical microtubules in wood-forming tissues in conifers to understand wood formation. Small blocks were collected from the main stems of Abies firma, Pinus densiflora, and Taxus cuspidata during active seasons of the cambium. Bundles of actin filaments were oriented axially or longitudinally relative to the cell axis in fusiform and ray cambial cells. In differentiating tracheids, actin filaments were oriented longitudinally relative to the cell axis during primary and secondary wall formation. In contrast, the orientation of well-ordered cortical microtubules in tracheids changed from transverse to longitudinal during secondary wall formation. There was no clear relationship between the orientation of actin filaments and cortical microtubules in cambial cells and cambial derivatives. Aggregates of actin filaments and a circular band of cortical microtubules were localized around bordered pits and cross-field pits in differentiating tracheids. In addition, rope-like bands of actin filaments were observed during the formation of helical thickenings at the final stage of formation of secondary walls in tracheids. Actin filaments might not play a major role in changes in the orientation of cortical microtubules in wood-forming tissues. However, since actin filaments were co-localized with cortical microtubules during the formation of bordered pits, cross-field pits and helical thickenings at the final stage of formation of the secondary wall in tracheids, it seems plausible that actin filaments might be closely related to the localization of cortical microtubules during the development of these modifications of wood structure.

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The structure of the cell wall in lignifield collenchyma of Eryngium sp. (Umbelliferae)

Australian Journal of Botany ◽

10.1071/bt9690229 ◽

1969 ◽

Vol 17 (2) ◽

pp. 229 ◽

Cited By ~ 22

Author(s):

AB Wardrop

Keyword(s):

Cell Wall ◽

Cell Division ◽

Cell Differentiation ◽

Secondary Wall ◽

Indoleacetic Acid ◽

Cellulose Microfibrils ◽

Cell Axis ◽

Wall Formation ◽

Microfibril Orientation ◽

Secondary Wall Formation

In Eryngium vesiculosum and E. rostratum, the leaf collenchyma is characterized by the development of a lignified secondary wall in the final stages of cell differentiation. The collenchyma wall is rich in pectic substances which are distributed uniformly. In the outer limiting region of the collenchyma wall the microfibril orientation is random and this structure is considered to be the wall formed at cell division. The collenchyma wall consists of six to eight layers in which the microfibrils are alternately transversely and longitudinally oriented. Each layer consists of a number of lamellae of microfibrils. In the secondary lignified wall the cellulose microfibrils are arranged helically, the direction of their orientation making an angle of 40-45° to the cell axis. Excised leaf segments showed greatest elongation in solutions of glucose and 3-indoleacetic acid, when the collenchyma walls were thin, and no elongation occurred in segments in which secondary wall formation had commenced. In radial sections layers of transversely oriented microfibrils could not be seen distant from the lumen although discontinuities in wall texture were apparent. Layers of transversely oriented microfibrils could be seen adjacent to the lumen. It is suggested that reorientation of layers of initially transversely oriented microfibrils takes place during elongation of the cells.

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Three-Dimensional Imaging and Analysis of Differentiating Secondary Xylem by Confocal Microscopy

IAWA Journal ◽

10.1163/22941932-90001590 ◽

2003 ◽

Vol 24 (3) ◽

pp. 211-222 ◽

Cited By ~ 19

Author(s):

Peter Kitin ◽

Yuzou Sano ◽

Ryo Funada

Keyword(s):

Secondary Wall ◽

Three Dimensional ◽

Wall Formation ◽

Kalopanax Pictus ◽

Bordered Pits ◽

Vessel Elements ◽

Ray Cells ◽

Secondary Wall Formation ◽

Ray Parenchyma Cells ◽

Perforation Plates

We examined the three-dimensional (3-D) structure of differentiating xylem in a hardwood tree, Kalopanax pictus, by confocallaser scanning microscopy (CLSM) using relatively thick, hand-cut histological sections. 3-D studies of plant tissues by mechanical serial sectioning with a microtome are very time-con suming. By contrast, the preparation of samples for CLSM is easier and the 3-D structure of intact tissue is preserved during optical sectioning. We obtained extended-focus images of the surface of specimens and these images resembled the stereographic images obtained by scanning electron microscopy. In addition , we observed radial files of cambial derivative cells at various stages of differenti ation and the internal structure along the 'z' axis of specimens on serial optical sections. We analysed the developmental changes in the morphology of cambial derivat ive cells, for example, the 3-D shape and arrangement of cells, the readjustment of the position of cells, and the development of secondary walls, pits and perforation plates. Our results showed that the arrangement of the differentiating xylem cells mirror s that of the cambial cell s. Deviations from the longitudinal orientation of vessel elements were specified by similar patterns of orientation of fusiform and ray cambial cells. The development of vessel elements progressed more rapidly than that of other xylem elements. When secondary walls with bordered pits and perforation plates with membranes were present in vessel elements and their expansion ceased, no secondary wall formation was detected in adjacent ray cells. The delay in secondary wall formation by the ray parenchyma cells, as compared to that by vessel elements, might facilitate the readju stment of the position of cells in the developing xylem tissue that is a consequence of the considerable expan sion of the vessel elements.

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LIGNIFICATION DURING SECONDARY WALL FORMATION IN COLEUS: AN ELECTRON MICROSCOPIC STUDY

American Journal of Botany ◽

10.1002/j.1537-2197.1970.tb09793.x ◽

1970 ◽

Vol 57 (1) ◽

pp. 85-96 ◽

Cited By ~ 49

Author(s):

Peter K. Hepler ◽

Donald E. Fosket ◽

Eldon H. Newcomb

Keyword(s):

Microscopic Study ◽

Electron Microscopic Study ◽

Secondary Wall ◽

Electron Microscopic ◽

Wall Formation ◽

Secondary Wall Formation

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Mechanical load induces upregulation of transcripts for a set of genes implicated in secondary wall formation in the supporting tissue of Arabidopsis thaliana

Journal of Plant Research ◽

10.1007/s10265-009-0251-7 ◽

2009 ◽

Vol 122 (6) ◽

pp. 651-659 ◽

Cited By ~ 7

Author(s):

Kento Koizumi ◽

Ryusuke Yokoyama ◽

Kazuhiko Nishitani

Keyword(s):

Arabidopsis Thaliana ◽

Secondary Wall ◽

Mechanical Load ◽

Wall Formation ◽

Secondary Wall Formation

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Glucan synthesis by intact cotton fibres fed with different precursors at the stages of primary and secondary wall formation

Planta ◽

10.1007/bf00384571 ◽

1980 ◽

Vol 149 (3) ◽

pp. 306-312 ◽

Cited By ~ 26

Author(s):

Christian Pillonel ◽

Antony J. Buchala ◽

Hans Meier

Keyword(s):

Secondary Wall ◽

Wall Formation ◽

Cotton Fibres ◽

Secondary Wall Formation ◽

Glucan Synthesis

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Chemistry of developing bordered-pit rims in balsam-fir trees

Botany ◽

10.1139/cjb-2016-0002 ◽

2016 ◽

Vol 94 (5) ◽

pp. 347-357

Author(s):

Rodney Arthur Savidge

Keyword(s):

Late Stage ◽

Secondary Wall ◽

Early Stage ◽

Gradient Centrifugation ◽

Abies Balsamea ◽

Strong Acid ◽

Resonance Spectroscopy ◽

Bordered Pits ◽

Secondary Wall Formation ◽

Gas Chromatography Mass Spectroscopy

Rims of bordered pits form on the primary walls of radially enlarged cambial derivatives prior to the onset of general secondary-wall formation. A recent report (Botany, 2014, 92(7): 495–511) raised the possibility that the chemical composition of the rim might be different from that of the secondary wall. To investigate this, early-stage nonfluorescent and late-stage autofluorescent rims were separated from cambial derivatives of Abies balsamea (L.) Mill. and purified to homogeneity by density-gradient centrifugation. Solid state nuclear magnetic resonance spectroscopy, Raman microspectroscopy, combined gas chromatography – mass spectroscopy, enzyme digestion, and chemical resilience data support the interpretation that cellulose alone is the microfibrillar polysaccharide of nonfluorescent early-stage rims. A lignin is additionally present in late-stage rims, and it evidently bonds with cellulose because rims are extraordinarily resistant to hydrolysis by either enzymes or strong acid.

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