The Golgi apparatus and an early stage in cell plate formation

Whaley, W. Gordon; Dauwalder, Marianne; Kephart, Joyce E.

doi:10.1016/s0022-5320(66)80102-8

Cited by 97 publications

(18 citation statements)

References 10 publications

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“…Nine out of 1123 microtubules (~0.8%) were found to cross the cell-plate mid-line but none were organized into close pairs or bundles. These results are consistent with findings of many earlier electron-microscope studies of somatic-type cell-plate formation (Pickett-Heaps and Northcote, 1966;Whaley et al, 1966;Hepler and Newcomb, 1967;Samuels et al, 1995).…”

Section: Discussionsupporting

confidence: 93%

“…Phragmoplast microtubules do not interdigitate at the cell-plate mid-line during somatic-type cytokinesis During the past 40 years, studies have come to different conclusions concerning the extent of microtubule interdigitation at the cell-plate mid-line during somatic-type cytokinesis (Pickett-Heaps and Northcote, 1966;Whaley et al, 1966;Hepler and Newcomb, 1967;Hepler and Jackson, 1968;Asada et al, 1991;Samuels et al, 1995;Müller et al, 2004;Van Damme et al, 2004). Nevertheless, it is generally assumed that phragmoplast microtubules do interdigitate, as in the depiction of somatic-type phragmoplasts with interdigitating microtubules in textbooks (Raven et al, 1999;Alberts et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

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Quantitative analysis of changes in spatial distribution and plus-end geometry of microtubules involved in plant-cell cytokinesis

Austin

Seguí-Simarro

Staehelin

2005

Journal of Cell Science

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The cell plate of higher plants is formed within a ribosome-excluding cell plate assembly matrix. Phragmoplast microtubules facilitate cell-plate formation by forming a scaffold that directs Golgi-derived vesicles to the forming cell plate. Here, we analyse the effects of the cell-plate assembly matrix on phragmoplast microtubule plus-end geometry by electron tomography of cryogenically fixed Arabidopsis meristem cells. Five distinct microtubules plus-end geometries are seen - blunt, extended, horned, flared and hybrid extended/horned. We have quantified and mapped these types of plus-end morphology during the different stages of cell-plate formation and analysed the effects of cell-plate assembly matrix association on microtubule plus-end morphologies. Our results show that somatic-type phragmoplast microtubules do not interdigitate at the cell plate mid-line. The cell-plate assembly matrix is shown to stabilize microtubule plus ends, as evidenced by the fact that of these microtubules that do not terminate in such a matrix, 40-80% are horn-shaped (shrinking), whereas of those that end in such a matrix, 50-70% are blunt (metastable). Also, a third of the blunt-ended microtubules within the cell-plate assembly matrix end at a distance of ∼30 nm from the cell plate.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Quantitative analysis of changes in spatial distribution and plus-end geometry of microtubules involved in plant-cell cytokinesis

Austin

Seguí-Simarro

Staehelin

2005

Journal of Cell Science

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“…In root tip cells, slime and cell wall substances are brought to the cell surface by these vesicles (9,11,26), as is also true in Micrasterias, both of which may be transported by the several kinds of vesicles derived from dictyosomes (12,22,23). Among these vesicles, LVs may contribute greatly to the formation of primary walls or slime in growing cells of Micrasterias.…”

Section: Discussionmentioning

confidence: 89%

Membrane Structure of Dictyosomes, Large Vesicles and Plasma Membranes in a Green Alga, <I>Micrasterias crux-melitensis</I>

Noguchi

Tanaka

Ueda

1981

Cell Struct. Funct.

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ABSTRACT. Freeze-fracture replicas of the cisternal membranes of dictyosomes, large vesicle (LV) membranes and plasma membranes in the green alga, Micrasterias crux-melitensis, were examined by electron microscopy. Intramembrane particles were evenly distributed in the cisternal membranes in resting cells. In growing cells, the particle density decreased from the centre to the periphery of the cisternal membranes and was greatly diminished at the vesiculated parts. The particle density in LV membranes was about twenty percent that in cisternal membranes, but equivalent generally in the plasma membranes of growing daughter semicells. The possibility of the direct supply of LV membranes to the plasma membrane is discussed. In the plasma membranes of fully grown cells, rosette complexes with a hexagonal array were observed. Each rosette consisted of six particles. These complexes were assumed to correlate with microfibril formation in the cell wall.Dictyosomes show the conspicuous structural changes during cell growth in Micrasterias crux-melitensis (23). This structural change largely consists of the formation of large vesicles (LVs) at the margins of the dictyosomal cisternae. The LVs, in turn, may contribute to the formation of primary walls, adding their contents exocytotically to growing cell walls (22,24). Thus, the series of movements and transformations of dictyosomes and their derivative vesicles are closely related to cell wall synthesis. The behavior of dictyosomes and LVs during cell growth has been extensively studied by electron microscopy of thin sections (23). However, these sections provide little information about the particles embedded in membranes. Recently, the structural relationship between cell wall microfibrils and plasma membrane particles has been pointed out using the freeze-fracture technique (10,14,16,18,19). In our study, intramembrane particles of dictyosomes, LVs and plasma membranes were examined by the freeze-fracture technique in order to gain further insight into cell wall synthesis and related questions.

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“…The closest parallel to the latter is the formation of septa in higher plant cells. Whaley, Dauwalder & Kephart (1966) illustrated the formation of a septum across the spindle plate of a dividing root cell of maize (Zea mays L.). Here the septum, in contrast to that of Rhizopus, begins at the centre of the cell and develops outwards, but it extends by the incorporation of coalesced vesicles in a manner essentially similar to that described above (p. 373).…”

Section: E H a W K E R A N D M A G O O D A Y Discussionmentioning

confidence: 99%

Delimitation of the Gametangia of Rhizopus sexualis (Smith) Callen: an Electron Microscope Study of Septum Formation

Hawker

Gooday

1967

Journal of General Microbiology

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The development of the septa which cut off the gametangia of Rhizopus sexualis from the suspensor cells was studied by electron microscopy. The edge of the ingrowing septum extends by the incorporation of coalesced vesicles which were previously aligned in the plane of the developing septum. The membranes surrounding these vesicles fuse to form the plasmalemmas of the gametangium and suspensor cell and are eventually continuous with the plasmalemma of the original progametangium. New wall material is laid down between these plasmalemmas. Associated with this process is a considerable increase in complexity of the endoplasmic reticulum which forms broad, irregular bands on either side of the septum. Fine tubules, resembling plasmodesmata, pass through the wall at intervals. Thickening of the septum proceeds more rapidly on the gametangial side. I N T R O D U C T I O NSoon after a pair of progametangia of Rhizopus sexualis make contact at their apices, the terminal parts (gametangia) become cut off from the suspensor cells by the formation of transverse septa. This paper describes the process of formation of these septa as revealed by the electron microscope. METHODSThe fungus was grown on cellophane laid on the surface of malt-agar plates. Young colonies with all stages of zygospore development present were fixed in 2 yo (w/v unbuffered KMn04 for 30 min. at room temperature, and washed several times in distilled water. The hyphae became brittle during fixation and the zygospores were readily detached from the mycelium during washing. Zygospores were then collected in centrifuge tubes, dehydrated, and embedded in Epon or Vestopal. Sections were cut at approximately 450-550A thickness. RESULTSThe first sign of septum development detectable by light microscopy is a slight decrease in density of the cell contents on the inner side of the enveloping walls of the progametangium at the site from which the septum would be expected to develop. The electron microscope revealed, however, that in such a specimen a thin wall (about 135oA thick at the junction with the progametangial wall and tapering to about 385A thickness at the advancing inner edge) was already parti ally developed, extending inwards from the peripheral wall and leaving a central gap of about one third of the

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The Golgi apparatus and an early stage in cell plate formation

Cited by 97 publications

References 10 publications

Quantitative analysis of changes in spatial distribution and plus-end geometry of microtubules involved in plant-cell cytokinesis

Quantitative analysis of changes in spatial distribution and plus-end geometry of microtubules involved in plant-cell cytokinesis

Membrane Structure of Dictyosomes, Large Vesicles and Plasma Membranes in a Green Alga, <I>Micrasterias crux-melitensis</I>

Delimitation of the Gametangia of Rhizopus sexualis (Smith) Callen: an Electron Microscope Study of Septum Formation

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