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2 résultat(s) recherche sur le mot-clé 'bulbille' 
trié(s) par (Pertinence décroissant(e), Titre croissant(e)) Affiner la recherche Générer le flux rss de la rechercheMinor differences with big consequences : Reproductive patterns in the genus Gagea (Liliaceae) / Martin Schnittler in Flora, vol. 208 (Année 2013)
Titre : Minor differences with big consequences : Reproductive patterns in the genus Gagea (Liliaceae) Type de document : Livre Auteurs : Martin Schnittler, Auteur ; Angela Peterson, Auteur ; Jens Peterson, Auteur ; Saltanat Beisenova, Auteur ; Rakhmetkazhi I. Bersimbaev, Auteur ; Tanja Pfeiffer, Auteur Année de publication : 2013 Article en page(s) : pp. 591-598 Langues : Anglais Catégories : [Espèces (in biblio)] Gagea
[Thèmes] Bulbe, rhizomes, tubercules
[Thèmes] ReproductionMots-clés : bulbille morphologie graine Résumé : "Reproductive patterns in ten species of Gagea Salisb. were compared by counts and measurements of bulbs, bulbils and flowers in large cohorts including all life stages. Two types of bulbils were found: taxa with “type I bulbils” start to develop a single to several bulbils as soon as the replacement bulb has reached a certain diameter and then continue to form them indefinitely throughout the life of the plant. “Type II bulbils” are only temporarily produced in immature, non-flowering plants of some species, but not in fully grown, flowering individuals, a phenomenon termed “reproductive switch”. Patterns of bulbil formation are species-specific: G. davlianidzeae, G. nigra, G. peduncularis, G. pratensis, and G. spathacea produce only type I bulbils; G. angelae, G. fedschenkoana and G. lutea develop only type II bulbils. Both bulbil types occur simultaneously in G. fragifera and G. villosa. The quantitative investigations demonstrate the existence of species-specific thresholds for the development of bulbils as well as flowers. Compared to the adult volume of the replacement bulb (where 90% of all plants flower), both types of bulbils have usually low thresholds: 0–5% (type I, all but one species) and 3–13% (type II). Inflorescences develop if plants attain between 38 and 60% of the adult bulb volume. Minor changes in patterns of bulbil formation and thresholds for their development may ensure survival of highly sterile taxa (e.g. G. spathacea, G. fragifera). This, in turn, can facilitate speciation in the genus driven by both hybridization and polyploidization." (source : auteurs) Type de publication : périodique Référence biblio : Schnittler M., Peterson A., Peterson J., Beisenova S., Bersimbaev R., Pfeiffer T., 2013 - Minor differences with big consequences : Reproductive patterns in the genus Gagea (Liliaceae). Flora, 208 : 591-598. ID PMB : 69048 DOI : 10.1016/j.flora.2013.09.002 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=69048
in Flora > vol. 208 (Année 2013) . - pp. 591-598[article]Exemplaires
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Titre : Natural hybridization between diploid Ficaria calthifolia and tetraploid Ficaria verna subsp. verna in central Europe : evidence from morphology, ecology and life-history traits Type de document : Livre Auteurs : Ondrej Popelka, Auteur ; Bohumil Travnicek (Trávníček, Bohumil), Auteur ; Pavla Siková (%u0160iková, Pavla), Auteur ; Michaela Jandová, Auteur ; Martin Duchoslav, Auteur Année de publication : 2019 Article en page(s) : pp. 179-212 Langues : Anglais Catégories : [Espèces (in biblio)] Ficaria calthifolia
[Espèces (in biblio)] Ficaria verna
[Thèmes] TaxonomieMots-clés : Ficaria × sellii bulbille cytométrie hybridation morphométrie phénologie viabilité du pollen polyploïdie Résumé : "The genusFicariais a taxonomically intricate group in which polyploidization and hybridizationcontribute to taxa diversification. Incentral Europe, populations of diploidF. calthifoliaandtetraploidF. vernasubsp.vernaoccasionally come into contact, which results in an interspecifictriploid hybrid, as recently demonstrated using molecular markers, genome size estimation andexperimental crossing. In this study, we aimedto estimate the frequency and distribution of thetriploid hybrid in central Europe, to identify those phenotypic traits that can be used to discrimi-nate between hybrid and parental taxa and compare the phenology, pollen viability, sexual andasexual reproduction and niche differentiation of the triploid hybrid and parental taxa. Flow-cytometry analyses of 1171 individuals sampledfrom 67 localities revealed that triploid hybridswere regularly found at 89% of the sites sampled where there were sympatric populations of bothparental taxa, with a mean percentage of 19.4% occurring at sites where there was a mixture ofcytotypes. No pure hybrid population was found. The hybrids were intermediate between theparental taxa in most morphological characters and did not show any novel morphological charac-ters. The characters that best differentiate the taxonomic groups were the production of axillarybulbils, aborted and well-developed achenes, leaf shape and plant habit. Almost all hybrids weresexually sterile: the pollen viability was considerably reduced (mean 8.4%) and on average 98%of the achenes were aborted. Local dispersal of the hybrids is possible through the production ofbulbils in the leaf axils, although the number of bulbils per node and the mean weight of one bulbilwere two and three times lower in the hybrid than inF. vernasubsp.verna.The hybrid niche wasintermediate between those of the parental taxa but shifted slightly towards that ofF. vernasubsp.verna. In addition, the taxonomic and nomenclatural treatment of the hybrid, which is describedasFicaria×selliiDuchoslav, Popelka et Trávn., as well as a key for identifying the central Euro-pean taxa ofFicaria, are presented." (source : auteurs) Type de publication : périodique Référence biblio : Popelka O., Travnicek B., Siková P., Jandová M., Duchoslav M., 2019 - Natural hybridization between diploid Ficaria calthifolia and tetraploid Ficaria verna subsp. verna in central Europe : evidence from morphology, ecology and life-history traits. Preslia, 91 : 179-212. ID PMB : 69008 DOI : 10.23855/preslia.2019.179 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=69008
in Preslia > vol. 91 (Année 2019) . - pp. 179-212[article]Exemplaires
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