Influence of the Multilayered Structure on the Morphogenesis of Marchantia Spermatids

Kreitner, Gerald L.

doi:10.1002/j.1537-2197.1977.tb07605.x

Cited by 18 publications

(12 citation statements)

References 10 publications

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“…The variation in the number of spline microtubules also may be related to the stage of development. In view of the developmental changes which occur during maturation of the sperm of some mosses (see Kreitner, 1977;Robbins and Carothers, 1978), it is possible that the MLS's in free-living zoospores would be different (presumably simpler) from those shown in the present report. Both additional maturity and active function could alter the morphology of the MLS's and their angles of approach to and contact with the basal bodies.…”

Section: Discussion-contrasting

confidence: 53%

Ultrastructure of Cephaleuros virescens (Chroolepidaceae; Chlorophyta). III. Zoospores

Chapman

1981

American Journal of Botany

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Transmission electron microscopic examination of Cephaleuros virescens Kunze growing on leaves of Camellia spp. and Magnolia grandiflora L. indicates that unreleased zoospores in mature zoosporangia are similar to those produced by the related genus Phvcopeltis epiphyton Millardet and unlike the quadriflagellate motile cells produced by taxa in other families of Chlorophyta. The zoospores bear four smooth isokont bilaterally "keeled" flagella containing typical "9 + 2" axonemes and lacking scales. Flagellar insertion is apical and the parallel basal bodies overlap laterally at two levels. A cross section through the four basal bodies shows a trapezoidal arrangement wherein the two upper (anterior) basal bodies are closer together than are the lower (posterior) two. Serial sections indicate that diagonally opposing upper and lower basal bodies anchor flagella which emerge from the same side of the apical papilla. Each of the four basal bodies is associated with a microtubular spline which extends beneath the plasmalemma to the posterior end of the zoospore. A distinct multilayered structure is associated with each of the lower basal bodies. A nucleus, mitochondria (two of which are closely associated with the nucleus and spline microtubules), a chloroplast, and cytoplasmic haematochrome droplets are present in each zoospore. Pyrenoids and eyespots are absent. Flagellar insertion is characterized by "reversed bilateral symmetry": and zoospores with both right-handed and left-handed arrangements are produced. The ultrastructure of the zoospores clearly indicates that: I) the mode of flagellar insertion: 2) morphology, number, and arrangement of multilayered structures, and 3) bilaterally keeled flagella are characteristic of the Chroolepidaceae.CEPHALEUROS VIRESCENS Kunze, a subaerial, subcuticular parasite of higher plants, has been more fully described in a previous report (Chapman, 1976b). Similarly, a report on the ultrastructure of biflagellate gametes (Chapman, 1980) presents additional introductory material and provides a basis for comparison between biflagellate and quadriflagellate cells.The description of Cephaleuros zoospores has been complicated by several factors. First, the quadriflagellate cells are more complex than the biflagellate gametes. Second, the condition of "reversed bilateral symmetry" documented and discussed in the gamete paper (Chapman, 1980) makes the interpretation of two-dimensional electron micrographs especially difficult because the micrographs, a priori, do not conform to a single cell model.

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Section: Discussion-contrasting

confidence: 53%

Ultrastructure of Cephaleuros virescens (Chroolepidaceae; Chlorophyta). III. Zoospores

Chapman

1981

American Journal of Botany

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“…The Dishevelled-PCP pathway that mediates basal body docking in animals is absent in plants. Instead, docking is associated with a multilayered structure (MLS) that comprises a 'spline' subtended by a lamellar strip (Paolillo, 1974;Kreitner, 1977;Miller et al, 1983). The lamellar strip is a highly specialized microtubule-organizing centre from which the spline is formed.…”

Section: Basal Body Positioningmentioning

confidence: 99%

The evolution of land plant cilia

et al. 2012

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SummaryEukaryotic cilia ⁄ flagella are ancient organelles with motility and sensory functions. Cilia display significant ultrastructural conservation where present across the eukaryotic phylogeny; however, diversity in ciliary biology exists and the ability to produce cilia has been lost independently on a number of occasions. Land plants provide an excellent system for the investigation of cilia evolution and loss across a broad phylogeny, because early divergent land plant lineages produce cilia, whereas most seed plants do not. This review highlights the differences in cilia form and function across land plants and discusses how recent advances in genomics are providing novel insights into the evolutionary trajectory of ciliary proteins. We propose a renewed effort to adopt ciliated land plants as models to investigate the mechanisms underpinning complex ciliary processes, such as number control, the coordination of basal body placement and the regulation of beat patterns.

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“…Plusieurs auteurs ont supposé que la couche S 1 pouvait intervenir dans la circulation antéro-postérieure d'éléments synthétisés à un des pôles du gamète, métabolites ou molécules informatives (Kreitner, 1977;Courtens, 1982); pour certains (Moestrup, 1982) les microtubules correspondraient à la voie par laquelle est transmise au corps cellulaire l'information perçue au niveau des flagelles lorsque les gamètes arrivent au contact (Goodenough et Weiss, 1978 ;Lovlie et Bryhni, 1976).…”

Section: °) Intervention Dans Les éChanges Intracellulairesunclassified

“…Pour certains, ils exerceraient une pression sur les organites, entraînant leur déformation (Mac lntosch et Porter, 1967). Cependant en présence d'inhibiteurs de polymérisation des tubulines le noyau s'allonge, seule la mise en forme est perturbée ce qui conduit à admettre que S 1 joue un rôle passif ; elle constituerait un moule contre lequel le noyau viendrait prendre forme ; elle ne serait pas à l'origine de la force entraînant l'élongation ; celle-ci pourrait être cherchée soit dans la condensation chromatinienne (Fawcett et coll., 1971 ;Kreitner, 1977) soit dans l'intervention de fibres contractiles situées à proximité de l'enveloppe nucléaire (Myles et Hepler, 1977 ;Courtens et Loir, 1981).…”

Section: °) Intervention Dans Les éChanges Intracellulairesunclassified

Le cytosquelette des gamètes mobiles des végétaux

Rejon

1989

Bulletin de la Société Botanique de France. Actualités Botaniqu

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Laboratoire de Biolosïe de la reproduction de• tJésitoru. Uniwr.ité Pierre et Marie Curie. 4. Plooe Juaaieu.. F-75252 Paria Cedex OS Raauné.-Lu donn6ea rbntea aur la morphologie et la morphogenàe du cytoaquelette dana ln gamtt .. mobilel dn rig6taux aont présent6es.Su.mmory.· The present state of knowledge about morphology and morphogeneala of cytoskeleton ln plant motDe gametel la drawn up.La reproduction sexuée implique le rapprochement puis l'union de deux cellules haploïdes, les gamètes. Chez de très nombreux végétaux (Algues, Champignons inférieurs, Bryophytes, Ptéridophytes et certaines Gymnospermes) ce rapprochement de cellules, produites par des organismes différents, est actif, c'est-à-dire que l'une des cellules appelées à fusionner {parfois les deux) est libérée dana le milieu extérieur où eUe se déplace par elle~même.Ce mode de fécondation, la zoïdogamie, est considéré comme primitif car, pendant la période du transfert, le matériel génétique transporté par la (ou les) cellule est exposé aux agressions du milieu extérieur. Les gamètes mobiles, qui le plus souvent sont les gamètes mâles ou spermatozoïdes, sont des cellules extrêmement spécialisées ct cette spécialisation s'accompagne le plus souvent d'une différenciation morphologique, parfois très importante, dans laquelle les éléments constituant le cytosquelette sont très largement impliqués.

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Influence of the Multilayered Structure on the Morphogenesis of Marchantia Spermatids

Cited by 18 publications

References 10 publications

Ultrastructure of Cephaleuros virescens (Chroolepidaceae; Chlorophyta). III. Zoospores

Ultrastructure of Cephaleuros virescens (Chroolepidaceae; Chlorophyta). III. Zoospores

The evolution of land plant cilia

Le cytosquelette des gamètes mobiles des végétaux

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