The preprophase band: possible involvement in the formation of the cell wall

1976 ◽  
Vol 22 (2) ◽  
pp. 403-411 ◽  
Author(s):  
M.J. Packard ◽  
S.M. Stack

Numerous vesicles were observed among the microtubules of the “preprophase” band in prophase cells from root tips of Allium cepa. The content of these vesicles looks similar to the matrix of adjacent cell walls, and these vesicles often appear to be involved in exocytosis. In addition, the cell walls perpendicular to the plane of (beneath) the preprophase band are often differentially thickened compared to the walls lying parallel to the plane of the band. Our interpretation of these observations is that the preprophase band may direct or channel vesicles containing precursors of the cell wall to localized regions of wall synthesis. The incorporation of constituents of the cell wall into a narrow region defined by the position of the preprophase band may be a mechanism that ensures unidirecitonal growth of meristematic cells.

2014 ◽  
Vol 71 (3) ◽  
pp. 211-221 ◽  
Author(s):  
Agnieszka Majewska ◽  
Mirosława Furmanowa ◽  
Kazimierz Głowniak ◽  
Joanna Guzewska ◽  
Alicja Zobel ◽  
...  

We investigated the influence of extract from <em>Taxus baccata</em> var. Elegantissima (TbE) shoots in 1:8 dilution, containing paclitaxel in concentration of 81,6 µg/g fresh mass on ultrastructure and tubulin cytoskeleton of meristematic cells of <em>Allium cepa</em> L. root tips. Incubation time 3, 6, 12 and 24 h was followed with postincubation in water for 12 and 24 h. During shorter incubation (till 12 h) the surface of the cell nuclei decreased and chromatin became condensed (in comparison to control) but after 24 h the average surface increased and chromatin condensation decreased. In the course of incubation the average size of plastids and vacuoles increased. Moreover, after treatment mitochondria and plastids showed degradation of ultrastructure, which was reversed after 12 h of postincubation. Immunocytochemical assays demonstrated that in the course of incubation in the ThE extract, the tubulin cytoskeleton became partially disorganised. In most interphase cells, cortical microtubules (MTs) lost their oval transverse orientation. The preprophase band (PPB) position in the cell was often asymmetrical. The MTs array of the karyokinetic spindle and phragmoplast was also disturbed. These alterations were completely reversed during postincubation.


2008 ◽  
Vol 56 (3) ◽  
pp. 341-348
Author(s):  
P. Pepó ◽  
A. Kovács

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.


2015 ◽  
Vol 44 (3) ◽  
pp. 369-376
Author(s):  
Maria Podbielkowska ◽  
Bożena Borys

An influence of hypoxia on the protoplast’s structure in the root tips meristematic cells of onion (<i>Allium cepa</i> L.) and of <i>Tradescantia bracteata</i> Small has been investigated. Hypoxia was caused either by respiratory inhibitors (sodium azide, 2,4-dinitrophenol), phosfon-D or by anaeroibic conditions. In both cases characteristic membranization of cytoplasm was observed. It appeared as spherical and parallel structures of rough endoplasmic reticulum. The observed hypertrophy was not connected with the increase of nucleic acids and proteins synthesis. In the examined cells the membranization was accompanied by an increase of the lipids content.


2018 ◽  
Vol 15 (3) ◽  
pp. 781-795 ◽  
Author(s):  
Merinda C. Nash ◽  
Walter Adey

Abstract. Calcified coralline red algae are ecologically key organisms in photic benthic environments. In recent decades they have become important climate proxies, especially in the Arctic and subarctic. It has been widely accepted that magnesium content in coralline tissues is directly a function of ambient temperature, and this is a primary basis for their value as a climate archive. In this paper we show for two genera of Arctic/subarctic corallines, Leptophytum laeve and Kvaleya epilaeve, that previously unrecognised complex tissue and cell wall anatomy bears a variety of basal signatures for Mg content, with the accepted temperature relationship being secondary. The interfilament carbonate has lower Mg than adjacent cell walls and the hypothallial cell walls have the highest Mg content. The internal structure of the hypothallial cell walls can differ substantially from the perithallial radial cell wall structure. Using high-magnification scanning electron microscopy and etching we expose the nanometre-scale structures within the cell walls and interfilament. Fibrils concentrate at the internal and external edges of the cell walls. Fibrils ∼ 10 nm thick appear to thread through the radial Mg-calcite grains and form concentric bands within the cell wall. This banding may control Mg distribution within the cell. Similar fibril banding is present in the hypothallial cell walls but not the interfilament. Climate archiving with corallines can achieve greater precision with recognition of these parameters.


Caryologia ◽  
2003 ◽  
Vol 56 (3) ◽  
pp. 337-351 ◽  
Author(s):  
Agnieszka Majewska ◽  
Ewa Wolska ◽  
Elwira Śliwińska ◽  
Mirosława Furmanowa ◽  
Natalia Urbańska ◽  
...  

2019 ◽  
Vol Volume-3 (Issue-4) ◽  
pp. 116-118
Author(s):  
Sheetal Kaur ◽  
Priyadarshini Halady ◽  
B. Revathi | Lodhi Bushra | Dr. Swapna ◽  

2019 ◽  
Vol 21 (1) ◽  
pp. 81
Author(s):  
Eleni Giannoutsou ◽  
Basil Galatis ◽  
Panagiotis Apostolakos

The distribution of highly de-esterified homogalacturonans (HGs) in dividing protodermal cells of the monocotyledon Zea mays, the dicotyledon Vigna sinensis, and the fern Asplenium nidus was investigated in order to examine whether the cell wall region adjoining the preprophase band (PPB) is locally diversified. Application of immunofluorescence revealed that de-esterified HGs were accumulated selectively in the cell wall adjacent to the PPB in: (a) symmetrically dividing cells of stomatal rows of Z. mays, (b) the asymmetrically dividing protodermal cells of Z. mays, (c) the symmetrically dividing guard cell mother cells (GMCs) of Z. mays and V. sinensis, and (d) the symmetrically dividing protodermal cells of A. nidus. A common feature of the above cell types is that the cell division plane is defined by extrinsic cues. The presented data suggest that the PPB cortical zone-plasmalemma and the adjacent cell wall region function in a coordinated fashion in the determination/accomplishment of the cell division plane, behaving as a continuum. The de-esterified HGs, among other possible functions, might be involved in the perception and the transduction of the extrinsic cues determining cell division plane in the examined cells.


1987 ◽  
Vol 104 (6) ◽  
pp. 1515-1519 ◽  
Author(s):  
B A Palevitz

F-actin has been identified in the preprophase band of Allium cepa. Cells attached to subbed slides were obtained from formaldehyde-fixed root tips digested in EGTA and Cellulysin. The air-dried cells were extracted in Triton X-100, treated with rhodamine-phalloidin, rinsed briefly in PBS, and viewed in the fluorescence microscope. Interphase cells contain a network of actin fibers that extends into all areas of the cytoplasm. During preprophase, the network is replaced by a band of fibers aligned in the position of the preprophase band. Colocalization of F-actin with rhodamine-phalloidin and microtubules with tubulin immunocytochemistry confirms that the two bands are coincident. The actin appears to comprise a thin layer of fibers next to the plasmalemma. Like the microtubule preprophase band, the actin band narrows as preprophase progresses and disappears by midprophase. Fluorescent actin bands are not seen in fixed cells pretreated with excess unlabeled phalloidin before staining. They are also absent in roots exposed to cytochalasins B and D before fixation, but preprophase band microtubules at all stages of aggregation are still present. Colchicine treatment leads to the loss of both preprophase band microtubules and actin. The possible function of preprophase band actin is discussed.


Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 219-225 ◽  
Author(s):  
L. Donaldson ◽  
A. Frankland

Abstract Iodine staining has been used to study the orientation of cellulose microfibrils in wood using light microscopy. The aim of this work was to understand the exact nature of the staining reaction with iodine and to provide insight into the properties and organisation of the wood cell wall. Based on transmission electron microscopy it is apparent that precipitation of the iodine following treatment with nitric acid results in the formation of crystal cavities within the cell wall, which follow the orientation of the cellulose microfibrils. There is no evidence that iodine precipitates within “drying checks” as previously speculated. High resolution confocal reflectance microscopy of crystal cavity orientation indicates that the microfibril arrangement within pit borders can be both spiral and circular. Crystal cavities are much more abundant within the S1 layer than elsewhere. All of the cells examined had crystal cavities in the S1 region, which may be related to the reduced lignification at the S1/S2 boundary resulting in greater porosity of the cell wall at this location. Within the S2 region, clusters of crystal cavities are randomly distributed and occur in widely varying numbers among adjacent cell walls, suggesting variations in the porosity of the S2 wall within and among adjacent tracheids. Cavities form preferentially within more electron lucent regions of the cell wall. The random nature of crystal cavity formation within S2 clusters probably reflects the underlying random nature of the cell wall nanostructure. We conclude that iodine staining can provide important clues to the nanostructural properties of tracheid cell walls.


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