Ultrastructural Differentiation of the Ovarian Transmitting Tissue in Lilium regale

Singh, Sangeeta; Walles, Björn

doi:10.1006/anbo.1995.1045

Cited by 7 publications

(11 citation statements)

References 26 publications

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“…Furthermore, because the structures in onion contain a cytoplasmic core, they are unlike the nuclear reticulum found in Lilium ovary placental cells, in which only the inner membrane of the nuclear envelope invaginates, so that the centers of these invaginations are continuous with the lumen of the ER rather than the cytoplasm (Singh and Walles, 1995;Singh et al, 1998).…”

Section: Nuclear Invaginations In Onion Are Similar To Structures Seementioning

confidence: 99%

“…The Plant Cell placental cells in Lilium ovaries contain a nuclear reticulum in which the inner nuclear membrane forms extensive tubular invaginations that penetrate through the center of the nucleus, the lumen of this reticulum being contiguous with the lumen of the ER (Singh and Walles, 1995;Singh et al, 1998). This type of structure differs from the shallow and narrow invaginations of both membranes of the nuclear envelope found in developing microspores of various species (Aldrich and Vasil, 1970; Bell, 1970, 1972;Li and Dickinson, 1987) and also differs from nuclear vacuoles, membrane-bound inclusions within the nucleus that are also generally found in meiotic cells (Sheffield et al, 1979;Karasawa and Ueda, 1983;Sangwan, 1986;Yi et al, 1994).…”

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Plant Nuclei Can Contain Extensive Grooves and Invaginations [W]

et al. 2000

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Plant cells can exhibit highly complex nuclear organization. Through dye-labeling experiments in untransformed onion epidermal and tobacco culture cells and through the expression of green fluorescent protein targeted to either the nucleus or the lumen of the endoplasmic reticulum/nuclear envelope in these cells, we have visualized deep grooves and invaginations into the large nuclei of these cells. In onion, these structures, which are similar to invaginations seen in some animal cells, form tubular or planelike infoldings of the nuclear envelope. Both grooves and invaginations are stable structures, and both have cytoplasmic cores containing actin bundles that can support cytoplasmic streaming. In dividing tobacco cells, invaginations seem to form during cell division, possibly from strands of the endoplasmic reticulum trapped in the reforming nucleus. The substantial increase in nuclear surface area resulting from these grooves and invaginations, their apparent preference for association with nucleoli, and the presence in them of actin bundles that support vesicle motility suggest that the structures might function both in mRNA export from the nucleus and in protein import from the cytoplasm to the nucleus. INTRODUCTIONAlthough cellular function often requires maximization of surface area relative to volume, notably in organelles such as the endoplasmic reticulum (ER) and Golgi apparatus, traditional representations of the nucleus depict a rounded structure with little internal organization. Recently, however, the nuclei of animal cells have been found to show considerable spatial and structural organization at the chromosomal level. The discrete and comparatively stable territories that chromosomes occupy within the nucleus are separated by interchromosomal domains through which transcribed RNA and other macromolecules can diffuse (reviewed in Lamond and Earnshaw, 1998). Animal nuclei also sometimes deviate from the characteristic rounded shape. Deviations include a folded, grooved, or notched surface (Majno et al., 1969) and tubular invaginations. Electron microscopy has shown that these nuclear invaginations can penetrate deep into the nucleus and confirmed the presence of the double membrane of the nuclear envelope (Ellenberg et al., 1997;Fricker et al., 1997;Clubb and Locke, 1998). However, revelation of the full nature of nuclear invaginations in living animal cells has required confocal microscopy of fluorescent dyes (Fricker et al., 1997;Lui et al., 1998aLui et al., , 1998b or green fluorescent protein (GFP) fusion proteins targeted to the nuclear envelope (Ellenberg et al., 1997;Broers et al., 1999). The number and nature of invaginations vary from cell type to cell type, ranging from simple invaginations to intricate branched structures that can penetrate into and through the nucleus. Invaginations often associate with nucleoli (Fricker et al., 1997) and appear to be stable (Ellenberg et al., 1997;Broers et al., 1999). Nuclear grooves and invaginations substantially increase the surface area of the ...

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Section: Nuclear Invaginations In Onion Are Similar To Structures Seementioning

confidence: 99%

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confidence: 99%

Plant Nuclei Can Contain Extensive Grooves and Invaginations [W]

et al. 2000

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“…These epidermal cells, here referred to as placental cells, are papilla shaped with a domed top on the side facing the lumen (ovarian locus). The cell wall in this dome invaginates into the cell to produce branched convolutions Walles 1992, 1995). These characteristics are typical of a transfer cell (Gunning andPate 1969, Gunning 1977).…”

Section: Introductionmentioning

confidence: 98%

“…In Lilium spp., transfer cells also line the stylar canal (Rosen and Thomas 1970, Vasil'ev 1970, Dashek et al 1971, Yamada 1974, Dickinson et al 1982, Hu et al 1982, Gawlik 1984, Mike-Hirosige et al 1987. The placental cells of L. regale are rich in organelles including mitochondria, chloroplasts, ribosomes, polysomes, lysosomes, multivesicular bodies, an extensive endomembrane system and a deeply lobed nucleus (Singh and Walles 1995). Cross sections through the nuclei often show the presence of numerous vesicular structures, some of which may connect to the inner nuclear envelope.…”

Section: Introductionmentioning

confidence: 99%

The nuclear reticulum in placental cells ofLilium regale is a part of the endomembrane system

1998

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Summary. Placental cells line the ovarian transmitting tract in Lili-um regale and produce exudates for secretion. Sections through the highly lobed nuclei of these cells reveal the presence of membrane profiles which form vesicles with varying dimensions in cross section. Computer reconstruction of the nucleus reveals that the vesicle profiles form a complex reticulum of tubular cisternae, which spans the whole nucleus, enclosing a maze of continuous lumen space. Connections between the vesicles and the inner nuclear envelope are visible at various points along the nuclear envelope. This complex network of tubules which constitutes the reticulum arises from the inner nuclear membrane. The nuclear reticulum dramatically increases the inner-envelope surface area, comprising 82% of the total membrane perimeter of inner nuclear envelope and nuclear reticulum. The inner nuclear envelope invaginates into the nucleus forming the nuclear reticulum and the outer nuclear envelope evaginates into the endoplasmic reticulum (ER), indicating that there is a continuity between the lumens of the nuclear reticulum and the ER. The nuclear reticulum is labelled with zinc iodide-osmium tetroxide, a staining pattern identical to that seen in the ER. Positive reaction to the zinc iodide-osmium tetroxide indicates that the nuclear reticulum is a site for Ca 2+ deposition. The nuclear reticulum forms an extension of the endomembrane system which reaches deep into the nucleoplasm. The lumenal continuity of this system means that there is a channel for communication from the cytoplasm into the nucleoplasm, and that this channel sequesters calcium.Keywords: Endomembrane system; Lilium regale; Nucleus; Placental cell; Transfer cell; Transmitting tissue.Abbreviations: ER endoplasmic reticulum; TEM transmission electron microscope; ZIO zinc iodide-osmium tetroxide.

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“…They re− sembled nuclear vacuoles of mitotic cells (Sheffield et al 1979;Yi et al 1994) and endoplasmic reticulum elements trapped inside nuclei. It is believed that such struc− tures are a part of the membrane system in the cytoplasm (Singh and Walles 1995;Singh et al 1998). Extended endoplasmic reticulum comprising transverse and lon− gitudinal cisternae was observed in the direct proximity of cell nuclei in C. quitensis.…”

Section: Discussionmentioning

confidence: 99%

Cold stress effects on organelle ultrastructure in polar Caryophyllaceae species

Giełwanowska¹,

Pastorczyk²,

Lisowska³

et al. 2014

Polish Polar Research

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This study investigated leaf mesophyll cells of Caryophyllaceae plants growing in polar regions -Cerastium alpinum and Silene involucrata from the Hornsund region of Spitsbergen island (Svalbard Archipelago, Arctic), and Colobanthus quitensis from the Ad− miralty Bay region on King George Island (South Shetland Islands, West Antarctic). Ultra− structural changes were analyzed in mesophyll protoplasts of plants growing in natural Arctic and Antarctic habitats and plants grown in a greenhouse, including plants exposed to short−term cold stress under semi−controlled conditions. Cell organelles of plants growing in natural polar habitats and greenhouse−grown plants were characterized by significant mor− phological plasticity. Chloroplasts of plants studied in this work formed variously shaped pro− trusions and invaginations that visibly increased the contact area between adjacent cell com− partments and reduced the distance between organelles. S. involucrata plants grown under greenhouse conditions, tested by us in this work, were characterized by highly dynamic cell nuclei with single or multiple invaginations of the nuclear membrane and the presence of channels and cisternae filled with cytoplasm and organelles. Crystalline inclusion proteins were observed in the cell nuclei of C. quitensis between nuclear membranes and in the direct proximity of heterochromatin. Our study revealed significant conformational dynamics of organelles, manifested by variations in the optical density of matrices, membranes and enve− lopes, in particular in C. quitensis, which could suggest that the analyzed Caryophyllaceae taxa are well adapted to severe climate and changing conditions in polar regions.

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Ultrastructural Differentiation of the Ovarian Transmitting Tissue in Lilium regale

Cited by 7 publications

References 26 publications

Plant Nuclei Can Contain Extensive Grooves and Invaginations [W]

Plant Nuclei Can Contain Extensive Grooves and Invaginations [W]

The nuclear reticulum in placental cells ofLilium regale is a part of the endomembrane system

Cold stress effects on organelle ultrastructure in polar Caryophyllaceae species

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