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Ajouter le résultat dans votre panierDoes self-pollination provide reproductive assurance in Aquilegia canadensis (Ranunculaceae)? / Christopher George Eckert in American Journal of Botany, 85 (7) (07/1998)
Titre : Does self-pollination provide reproductive assurance in Aquilegia canadensis (Ranunculaceae)? Type de document : Imprimé Auteurs : Christopher George Eckert (1960-) ; A. Schaefer Année de publication : 1998 Article en page(s) : 919-924 Langues : Anglais (eng) Mots-clés : Aquilegia sp. Aquilegia canadensis Résumé : The ability to produce seeds when pollinators or potential mates are scarce is thought to be one of the main advantagesof self-fertilization in flowering plants. However, whether autonomous selfing increases seed set in natural populations hasseldom been tested, and even fewer studies have evaluated the advantage of selfing across a gradient of pollen availability.This study examines the fertility consequences of autonomous selfing inAquilegia canadensis(Ranunculaceae), a short-lived, spring-flowering perennial typically found in small, patchy populations on rock outcrops. We used a pollinator exclu-sion experiment to confirm reports thatA. canadensishas a well-developed capacity for autonomous selfing resulting fromincomplete protogyny and close proximity of stigmas and anthers during dehiscence. Flowers excluded from pollinators set87% as many seeds per carpel (X ̄61SE57.161.4 seeds) as hand-pollinated flowers (8.161.3 seeds), and seedproduction in unpollinated flowers correlated negatively with the distance between stigmas and anthers (r520.46). Au-tonomous selfing could be potentially valuable in providing reproductive assurance because only 2.760.5 pollen grainswere deposited on each stigma before anther dehiscence, compared to 134.1617.9 pollen grains by the end of antherdehiscence. However, prevention of autonomous selfing by anther removal before dehiscence did not decrease seed set, evenfor plants at low plant densities where outcross pollen may have been in short supply. Emasculated flowers set as manyseeds per carpel (9.360.9) as intact flowers (8.461.1), indicating that sufficient cross pollen is deposited for full seedset. These results do not support the hypothesis that autonomous selfing byA. canadensishas been selected because itprovides reproductive assurance. Lien pérenne : DOI : 10.2307/2446357 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137833
in American Journal of Botany > 85 (7) (07/1998) . - 919-924Eckert, Christopher George (1960-), Schaefer, A. 1998 Does self-pollination provide reproductive assurance in Aquilegia canadensis (Ranunculaceae)? American Journal of Botany, 85(7): 919-924.Documents numériques
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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
in American Journal of Botany > 85 (7) (07/1998) . - 135-143Brochmann, 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.Documents numériques
Article (1998)URL
