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Floral development and the formation of unisexual spikelets in the Andropogoneae (Poaceae) / L.G. Le Roux in American Journal of Botany, 86 (3) (1999)
[article]
Titre : Floral development and the formation of unisexual spikelets in the Andropogoneae (Poaceae) Type de document : Imprimé Auteurs : L.G. Le Roux ; E.A. Kellogg Année de publication : 1999 Article en page(s) : 354-366 Langues : Anglais (eng) Catégories : [CBNPMP-Thèmes] Biologie florale, floraison Mots-clés : Heteropogon contortus (L.) P. Beauv. ex Roemer & Schul Résumé : We investigated spikelet development in four distantly related species of the grass tribe Andropogoneae to determine whether spikelet development and the formation of unisexual florets are uniform throughout the tribe. We studied development in Bothriochloa bladhii, Coelorachis aurita, Heteropogon contortus, and Hyparrhenia hirta, and compared these with Panicum, a member of the sister tribe Paniceae. Many aspects of spikelet development in the species we have studied correlate with what is already known for Tripsacum and maize (both Andropogoneae), despite variation in how unisexual florets are distributed on the plant. The formation of unisexual spikelets is also uniform. All florets initiate both pistil and stamen primordia. In florets destined to be male, cell death occurs in the subepidermal layers of the gynoecium after the formation of a gynoecial ridge. In florets destined to be female, there is no apparent cell death in the stamens, but growth ceases after anther formation. The similarity in spikelet development and the formation of unisexual florets point to a common genetic mechanism for sex determination throughout the Andropogoneae and possibly the entire Panicoideae. Use of a cell death pathway to cause gynoecial abortion may be the basis of one morphological character that defines the subfamily. Lien pérenne : DOI : 10.2307/2656757 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137396
in American Journal of Botany > 86 (3) (1999) . - 354-366Le Roux, LG., Kellogg, EA. 1999. Floral development and the formation of unisexual spikelets in the Andropogoneae (Poaceae). American Journal of Botany, 86(3): 354-366.Documents numériques
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article (1999)URL Mixed first and second division restitution in male meiosis of Hierochloe odorata (L.) Beauv (Holy Grass) / Colin Ferris in Heredity, 69 (1) (1992)
[article]
Titre : Mixed first and second division restitution in male meiosis of Hierochloe odorata (L.) Beauv (Holy Grass) Type de document : Imprimé Auteurs : Colin Ferris ; Robert S. Callow ; Alan J. Gray Année de publication : 1992 Article en page(s) : 21-31 Langues : Anglais (eng) Catégories : [CBNPMP-Thèmes] Morphologie, anatomie, histologie, cytologie, reproduction de la cellule, embryologie, embryogenèse Mots-clés : Heteropogon contortus (L.) P. Beauv. ex Roemer & Schul Résumé : Hierochloë odorata is a rhizomatous perennial grass of northern latitudes with a highly restricted distribution in Britain and Ireland. Six clones sampled from Scotland are tetraploid (2n = 4x = 28) and most show irregular male meiosis, characterized by the exclusion of laggards as micronuclei, and are probably pseudogamous. In both these respects they resemble H. odorata from Swedish Lapland which is octaploid (2n = 8x = 56). Material from one Scottish locality shows meiotic restitution in the majority of its pollen mother cells (77 per cent). One in two first divisions leads to restitution (52 per cent) and one in seven of these (14 per cent) remains undivided even at telophase-II. Of those dyads formed from normal first division, almost half (46 per cent) show failure of one of the second divisions but only one in 20 shows double second division failure. This remarkable mixture of first and second division restitution is reflected in an extensive range of ploidy (n = 2x, 4x, 8x) and pollen grain size (35–113 µm3). Seed-set in this material is low (2 per cent). Genetic variation in British material is revealed by isozyme electrophoresis while studies of total seed proteins in Swedish material indicate genetic uniformity. Implications for parthenogenesis are discussed. Lien pérenne : DOI : 10.1038/hdy.1992.90 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137398
in Heredity > 69 (1) (1992) . - 21-31Ferris, C., Callow, RS., Gray, AJ. 1992. Mixed first and second division restitution in male meiosis of Hierochloe odorata (L.) Beauv (Holy Grass). Heredity, 69(1): 21-31.Documents numériques
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Article (1992)URL