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Auteur Katherine Mavraganis |
Documents disponibles écrits par cet auteur (2)
Affiner la rechercheEffect of population size on the mating system in a self-compatible, autogamous plant, Aquilegia canadensis (Ranunculaceae) / Matthew B. Routley in Heredity, 82 (5) (05/1999)
Titre : Effect of population size on the mating system in a self-compatible, autogamous plant, Aquilegia canadensis (Ranunculaceae) Type de document : Imprimé Auteurs : Matthew B. Routley ; Katherine Mavraganis ; Christopher George Eckert (1960-) Année de publication : 1999 Article en page(s) : 518-528 Langues : Français (fre) Mots-clés : Aquilegia sp. Résumé : In self-compatible plants, small populations may experience reduced outcrossing owing to decreased pollinator visitation and mate availability. We examined the relation between outcrossing and population size in eastern Ontario populations of Aquilegia canadensis. Experimental pollinations showed that the species is highly self-compatible, and can achieve full seed-set in the absence of pollinators via automatic self-pollination. We estimated levels of outcrossing (t) and parental inbreeding coefficients (F) from allozyme variation in naturally pollinated seed families for 10 populations ranging in size from 32 to 750 reproductive individuals. The proportion of seeds produced through outcrossing was generally low (mean = 0.29 ± 0.02 SE) and varied widely among populations (range = 0.00–0.83). Accordingly, estimates of F were large (mean = 0.26 ± 0.05) and significantly greater than zero in seven populations. As expected, four small populations (N < 40) outcrossed less (0.17 ± 0.03) than six large populations (N > 90; 0.38 ± 0.03). However, parental plants were not significantly more inbred in small than large populations (P= 0.18). There was no difference in the germination of seeds from hand self- and cross-pollinations. However, population genetic estimates of inbreeding depression for survival expressed from seed to reproductive maturity were very high (mean δ = 1 − relative fitness of selfed seed = 0.88 ± 0.14). The combination of self-compatibility and automatic self-pollination makes the mating system of A. canadensis sensitive to variation in ecological factors that affect the likelihood of cross-pollination. Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137834
in Heredity > 82 (5) (05/1999) . - 518-528Routley, Matthew B., Mavraganis, Katherine, Eckert, Christopher George (1960-) 1999 Effect of population size on the mating system in a self-compatible, autogamous plant, Aquilegia canadensis (Ranunculaceae). Heredity, 82(5): 518-528.Documents numériques
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Titre : Experimental analysis of protogyny in Aquilegia canadensis (Ranunculaceae) Type de document : Imprimé Auteurs : Steven R. Griffin ; Katherine Mavraganis ; Christopher George Eckert (1960-) Année de publication : 2000 Article en page(s) : 1246-1256 Langues : Anglais (eng) Mots-clés : Aquilegia sp. Aquilegia canadensis Résumé : Dichogamy is very common in flowering plants and is widely thought to reduce pollen-pistil interference, especially self-pollination. Yet, the functional significance of dichogamy has rarely been studied. We investigated the nature and functioning of dichogamy in eastern Ontario populations of Aquilegia canadensis, a highly selfing columbine previously described as protogynous. We then manipulated flowers to determine whether increased protogyny would reduce self-fertilization. Contrary to previous reports, A. canadensis is not dichogamous. Controlled pollinations in a greenhouse showed that pollen tubes generally begin to develop after anther dehiscence. Although stigmas can collect pollen early in floral development, naturally pollinated flowers collected from four populations had few pollen grains on stigmas and almost no pollen tubes in styles until after anther dehiscence. Limited pollen deposition before anther dehiscence was also associated with low nectar availability and limited sepal expansion. Because inbreeding depression is strong in this species, selection may favor increased protogyny if it reduces selfing. We tested this hypothesis by comparing the level of selfing in flowers rendered protogynous by the removal of the first 19 (of 39) anthers to develop, with nonprotogynous control flowers. Contrary to expectations, protogyny did not reduce selfing. Our results emphasize the importance of detailed field observations and manipulative experiments in understanding the nature and functional significance of dichogamy. Lien pérenne : DOI : 10.2307/2656717 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137835
in American Journal of Botany > 87 (9) (07/2000) . - 1246-1256Griffin, Steven R., Mavraganis, Katherine, Eckert, Christopher George (1960-) 2000 Experimental analysis of protogyny in Aquilegia canadensis (Ranunculaceae). American Journal of Botany, 87(9): 1246-1256.Documents numériques
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