Selective cell elimination during microsporogenesis in sedges

Ranganath, R. M.; Nagashree, N. Rao

doi:10.1007/pl00009842

Cited by 17 publications

(17 citation statements)

References 55 publications

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“…This species shows the prophasic nuclei in the central region of the cell. According to Ranganath and Nagashree (2000), cell and organelle polarizations are uncommon before meiosis I. However, our results indicate that in R. pubera cellular asymmetry and the polarization of organelles occur in early meiosis.…”

Section: Resultsmentioning

confidence: 51%

Early meiosis in Rhynchospora pubera L. (Cyperaceae) is marked by uncommon ultrastructural features

Martin

Andrade

Vanzela

2009

Cell Biology International

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The family Cyperaceae has an unusual microsporogenesis in which tetrad formation does not occur. In addition, other cytological features are important, such as the occurrence of holokinetic chromosomes and post-reductional meiosis. We have examined the ultrastructural features of the pollen mother cell (PMC) of Rhynchospora pubera. Anthers of several sizes were analyzed using light and transmission electron microscopy. The PMC before meiosis presented a central nucleus and a regular profile of the nuclear envelope. During prophase I, the nucleus was in the abaxial region of the cell. This cellular polarization was accompanied by other marked ultrastructural features in the nuclear envelope. Morphological changes involved dilations of perinuclear cisterns and polarization of the nuclear pore complexes. The results show that polarization occurs in the initial phases of microsporogenesis in R. pubera, unlike other plant species.

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Section: Resultsmentioning

confidence: 51%

Early meiosis in Rhynchospora pubera L. (Cyperaceae) is marked by uncommon ultrastructural features

Martin

Andrade

Vanzela

2009

Cell Biology International

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“…The breakdown of some of these controls may possibly lead to the abortion of three of the four nuclei in most Cyperaceae. Ranganath and Rao Nagashree (2000) pointed out that meiotic cell division in microsporocytes of most Cyperaceae is asymmetric, unlike the condition in most angiosperms. This has important implications for the fate of the daughter cells and parallels the process of megasporogenesis in some angiosperms.…”

Section: Discussionmentioning

confidence: 97%

Phylogenetic relationships in Cyperaceae subfamily Mapanioideae inferred from pollen and plastid DNA sequence data

Simpson

Furness

Hodkinson

et al. 2003

American J of Botany

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Cyperaceae are the third largest monocotyledon family, with considerable economic and conservation importance. In subfamily Mapanioideae there is particular specialization of the inflorescence into units termed spicoids. The structural homology of the spicoid is difficult to interpret, making determination of intrafamilial relationships problematic. To address this, pollen from eight species in Mapanioideae was investigated using light microscopy and scanning and transmission electron microscopy. Pollen development was also examined to identify the type of pollen present in these species. We also analyzed DNA sequence data using the trnL-F and rps16 regions from 25 genera and 35 species of Cyperaceae, Juncaceae, and Thurniaceae. Two types of pollen, Mapania-type and pseudomonad, were identifed. Analysis of combined DNA and pollen data resolved a clade sister to the rest of Cyperaceae, corresponding to Mapanioideae. Within this, two further clades were resolved. One comprised taxa assigned to tribe Hypolytreae, which had Mapania-type pollen. The other comprised taxa mainly assigned to tribe Chrysitricheae, but included two taxa from Hypolytreae, Capitularina and Exocarya. All taxa in this clade had pseudomonad pollen. Thus new groupings within the subfamily have been discovered based on the specialization of some taxa in terms of their pollination biology.

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“…A few plant groups show irregular tetrads, with all four nuclei enclosed in a single cell (Dunbar, 1973;Strandhede, 1973;Ranganath and Nagashree, 2000;Furness and Rudall, 2011). This type is termed a pseudomonad, cryptotetrad or monodynamosporous tetrad (Brown and Lemmon, 2000a).…”

Section: Introductionmentioning

confidence: 99%

“…For example, pseudomonads characterise the tribe Styphelieae of the eudicot family Epacridaceae R. Br. (Ranganath and Nagashree, 2000), and represent a synapomorphy for the family Cyperaceae Juss. Within the monocot order Poales, pseudomonads were reported for a few species of Juncaceae Juss.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric cytokinesis guide the development of pseudomonads inRhynchospora pubera(Cyperaceae)

Martin

Andrade

Mastroberti

et al. 2013

Cell Biology International

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The late stages of microsporogenesis in the family Cyperaceae are marked by the formation of an asymmetrical tetrad, degeneration of three of the four nuclei resulting from meiosis and the formation of pseudomonads. In order to understand the cytological changes involved in the development of pseudomonads, a combination of 11 different techniques (conventional staining, cytochemistry procedures, immunofluorescence, FISH and transmission electron microscopy: TEM) were used to study the later stages of microsporogenesis in Rhynchospora pubera. The results demonstrated the occurrence of two cytoplasmic domains in the pseudomonads, one functional and the other degenerative, which are physically and asymmetrically separated by cell plate with an endomembrane system rich in polysaccharides. Other changes associated with endomembrane behaviour were observed, such as a large number of lipid droplets, vacuoles containing electron-dense material and concentric layers of endoplasmic reticulum. Concomitant with the isolation of degenerative nuclei, the tapetal cells also showed evidence of degeneration, indicating that both tissues under programmed cell death (PCD), as indicated by immunofluorescence and TEM procedures. The results are significant because they associate cellular polarisation and asymmetry with different cytoplasmic domains, and hence open new possibilities for studying cellular compartmentalisation and PCD.

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Selective cell elimination during microsporogenesis in sedges

Cited by 17 publications

References 55 publications

Early meiosis in Rhynchospora pubera L. (Cyperaceae) is marked by uncommon ultrastructural features

Early meiosis in Rhynchospora pubera L. (Cyperaceae) is marked by uncommon ultrastructural features

Phylogenetic relationships in Cyperaceae subfamily Mapanioideae inferred from pollen and plastid DNA sequence data

Asymmetric cytokinesis guide the development of pseudomonads inRhynchospora pubera(Cyperaceae)

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