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Titre :	Population size, plant performance, and genetic variation in the rare plant Arnica montana L. in the Rhön, Germany
Type de document :	Tiré à part de revue
Auteurs :	Stefanie Kahmen ; Peter Poschlod
Année de publication :	2000
Importance :	43-51
Langues :	Anglais (eng)
Catégories :	[CBNPMP-Thématique] Génétique et écologie (dynamique, démographique, sélection) [CBNPMP-Thématique] Variabilité en protéines, polymorphisme enzymatique [CBNPMP-Thématique] Variabilité morphologique
Mots-clés :	Arnica montana L.
Résumé :	Phenotypic and genetic variation of the rare plant species Arnica montana L. were investigated in populations which had been fragmented by afforestation since 1930 in the Rhön, a mountain region in Central Germany. The aim of the study was to analyse whether small populations show less genetic variation and a lower fitness than large populations. Morphological and reproductive traits from eleven Arnica-populations of different size were examined in the field. Principal component analysis (PCA) reduced the nine traits measured to two main components, one of which correlated with phenotypic traits of the maternal plants in the field while the other corresponded to traits associated with offspring production, weight and germinability. The latter component, which we considered to be fitness-related, was significantly positively correlated with population size. We screened four isozymes to study the genetic variation of the populations. The mean number of alleles per locus (A), the mean observed heterozygosity (Ho), and the mean expected heterozygosity (He) were used to measure genetic variation. Population size and genetic variation were not significantly correlated. In addition, there were no significant correlations between the two main components of the PCA and genetic variation when controlling for population size. The results of the study suggest that small populations of plants exhibit a reduced reproductive success which could not be attributed to genetic erosion. It might be attributed to the longevity of the clonal A. montana that the genetic structure of the populations examined has remained unaffected by the habitat fragmentation so far. In addition, gene flow has probably still been taking place between the fragmented populations. Possibly, the reduced reproductive success of plants in the small populations was caused by missing availability of cross-compatible pollen because of a reduced set of S-alleles due to genetic drift. Furthermore, environmental maternal effects may have played an important role in reproduction and germinability.
Lien pérenne :	DOI : 10.1078/1439-1791-00007
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=130696

Population size, plant performance, and genetic variation in the rare plant Arnica montana L. in the Rhön, Germany [Tiré à part de revue] / Stefanie Kahmen ; Peter Poschlod . - 2000 . - 43-51.
Langues : Anglais (eng)

Catégories :	[CBNPMP-Thématique] Génétique et écologie (dynamique, démographique, sélection) [CBNPMP-Thématique] Variabilité en protéines, polymorphisme enzymatique [CBNPMP-Thématique] Variabilité morphologique
Mots-clés :	Arnica montana L.
Résumé :	Phenotypic and genetic variation of the rare plant species Arnica montana L. were investigated in populations which had been fragmented by afforestation since 1930 in the Rhön, a mountain region in Central Germany. The aim of the study was to analyse whether small populations show less genetic variation and a lower fitness than large populations. Morphological and reproductive traits from eleven Arnica-populations of different size were examined in the field. Principal component analysis (PCA) reduced the nine traits measured to two main components, one of which correlated with phenotypic traits of the maternal plants in the field while the other corresponded to traits associated with offspring production, weight and germinability. The latter component, which we considered to be fitness-related, was significantly positively correlated with population size. We screened four isozymes to study the genetic variation of the populations. The mean number of alleles per locus (A), the mean observed heterozygosity (Ho), and the mean expected heterozygosity (He) were used to measure genetic variation. Population size and genetic variation were not significantly correlated. In addition, there were no significant correlations between the two main components of the PCA and genetic variation when controlling for population size. The results of the study suggest that small populations of plants exhibit a reduced reproductive success which could not be attributed to genetic erosion. It might be attributed to the longevity of the clonal A. montana that the genetic structure of the populations examined has remained unaffected by the habitat fragmentation so far. In addition, gene flow has probably still been taking place between the fragmented populations. Possibly, the reduced reproductive success of plants in the small populations was caused by missing availability of cross-compatible pollen because of a reduced set of S-alleles due to genetic drift. Furthermore, environmental maternal effects may have played an important role in reproduction and germinability.
Lien pérenne :	DOI : 10.1078/1439-1791-00007
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=130696