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Molecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies / Christian Brochmann in American Journal of Botany, 85 (7) (07/1998) 

Public Citation [article]  inAmerican Journal of Botany > 85 (7) (07/1998) . - 135-143 Titre : Molecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies Type de document : Imprimé Auteurs : Christian Brochmann (1953-) ; Xiang ; Brunsfeld ; Douglas E. Soltis (1953-) ; Pamela S. Soltis (1957-) Année de publication : 1998 Article en page(s) : 135-143 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Variabilité, analyse de l'ADN, polymorphisme Mots-clés : Saxifraga  Saxifraga svalbardensis Résumé : The recently described polyploid Saxifraga svalbardensis is endemic to the arctic archipelago of Svalbard. We investigated relationships among four closely related species of Saxifraga in Svalbard and tested three previously proposed hypotheses for the origin of S. svalbardensis: (1) differentiation from the morphologically and chromosomally variable polyploid S. cernua; (2) hybridization between the diploid S. hyperborea and S. cernua; and (3) hybridization between the tetraploid S. rivularis and S. cernua. Fifteen populations were analyzed using random amplified polymorphic DNAs (RAPDs) and nucleotide sequences of the chloroplast gene matK and the internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA). RAPD and matK data suggest that S. svalbardensis has originated from a hybrid with S. rivularis as the maternal parent and S. cernua as the paternal parent, possibly a single time, whereas ITS data could not be used to discriminate among the hypotheses. The data also suggest that the diploid S. hyperborea is a progenitor of the tetraploid S. rivularis. The four populations examined of S. svalbardensis were virtually identical for RAPD and ITS markers, whereas S. cernua showed high levels of variation, suggesting that the latter polyploid either has formed recurrently or has undergone considerable differentiation since its origin. Lien pérenne : DOI : 10.2307/2446562 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=138291 Brochmann, Christian (1953-), Xiang, Brunsfeld, Soltis, Douglas E. (1953-), Soltis, Pamela S. (1957-) 1998 Molecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies. American Journal of Botany, 85(7): 135-143.

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Reproductive strategies in some arctic Saxifraga (Saxifragaceae), with with emphasis on the narrow endemic S. svalbardensis and its parental species / Christian Brochmann in Botanical journal of the Linnean Society, 137 (1) (09/2001) 

Public Citation [article]  inBotanical journal of the Linnean Society > 137 (1) (09/2001) . - 31-49 Titre : Reproductive strategies in some arctic Saxifraga (Saxifragaceae), with with emphasis on the narrow endemic S. svalbardensis and its parental species Type de document : Imprimé Auteurs : Christian Brochmann (1953-) ; Arnood Hapnes Année de publication : 2001 Article en page(s) : 31-49 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Palynologie, conservation des pollens [CBNPMP-Thématique] Reproduction végétative [CBNPMP-Thématique] Semences Mots-clés : Saxifraga sp. Résumé : Arctic saxifrages show conspicuous reproductive and chromosomal variation. We examined sexual and asexual traits in 43 phytotron-cultivated Svalbard populations of nine species, including the endemic, supposedly entirely asexual and aneupolyploid S. svalbardensis and its parental species, S. cernua and S. rivularis. All species were self-compatible hermaphrodites with low pollen/ovule ratios, including the strongly protandrous S. cernua, which previously has been reported as self-incompatible with an androdioecious mating system. Spontaneous selfing resulted in considerable seed set in several species and a few seeds in S. svalbardensis and S. cernua; hand-selfing and cross-pollination often increased seed set in the two latter species. Self-fertilized seeds of S. svalbardensis and S. cernua were viable and developed into normal, vigorous plants. Saxifraga rivularis and its close relative S. hyperborea were strongly autogamous. The bulbil-reproducing S. svalbardensis and S. cernua showed extreme variation in fertility, probably because of frequent aneuploidy. Many plants of S. cernua were fully fertile, suggesting that although natural seed set rarely has been observed, sexual reproduction is frequent enough to maintain its previously reported high levels of clonal diversity. Some plants of S. svalbardensis were also fairly fertile. This species may have considerable evolutionary potential; sexual events can lead to increasingly fertile genets with euploid chromosome numbers. Lien pérenne : DOI : 10.1006/bojl.2001.0450 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=153630 Brochmann, Christian (1953-), Hapnes, Arnood 2001 Reproductive strategies in some arctic Saxifraga (Saxifragaceae), with with emphasis on the narrow endemic S. svalbardensis and its parental species. Botanical journal of the Linnean Society, 137(1): 31-49.

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