INVESTIGADORES
URTUBEY estrella
congresos y reuniones científicas
Título:
Adaptive value of polyploidy: recurrent replacements of diploids by tetraploids in local populations of the Patagonian and Subantarctic plant Hypochaeris incana (Asteraceae).
Autor/es:
K. TREMETSBERGER; E. URTUBEY
Lugar:
Berlin
Reunión:
Congreso; Society of Biological Systematics, German Botanical Society, BioSystematics congress.; 2011
Institución organizadora:
Society of Biological Systematics
Resumen:
Abstract Adaptive value of polyploidy: recurrent replacements of diploids by tetraploids in local populations of the Patagonian and Subantarctic plant Hypochaeris incana (Asteraceae) Tremetsberger, K.1 & Urtubey, E.2 1Institute of Botany, University of Natural Resources and Life Sciences, Gregor Mendel Straße 33, 1180 Vienna, Austria, karin.tremetsberger@boku.ac.at 2Instituto de Botánica Darwinion, Labardén 200, B1642HYD San Isidro, Argentina, eurtubey@darwin.edu.ar Hypochaeris incana grows in the Patagonian and Subantarctic region of southern South America, where it is a characteristic component of the steppe vegetation. It is a self-incompatible and perennial herbaceous plant with leaves in rosettes and the ability to form cushions. A phylogeographic study revealed that the species reacted to Pleistocene climate changes through persistence and dominance shifts or restricted east-west migration rather than through long-distance north-south migration. Today, northern populations are thriving in isolation from each other, whereas southern populations have recently expanded and are connected by extensive gene flow. Moreover, our population genetic data suggest that diploid populations have repeatedly been replaced by tetraploid populations in the northern Patagonian region. Our aim is to evaluate the hypothesis that repeated establishments of tetraploid populations occurred as an adaptive response to post-glacial climate warming and aridification in the northern Patagonian region. We evaluate this hypothesis through fine-scale mapping of fitness traits and plant assemblages accompanying diploid and tetraploid individuals in a mixed ploidy population in northern Patagonia. We expect that, in the absence of habitat segregation, tetraploids are vegetatively and/or reproductively more vigorous than diploids. Indeed, our results indicate lack of substantial spatial and/or micro-niche differentiation between diploid and tetraploid individuals, but significant differences are observed in reproductive fitness traits, with tetraploids having higher reproductive success than diploids. Thus, higher rates of reproduction of tetraploids compared to the diploid progenitors would ultimately lead to the replacement of the diploids in local populations. Our results contribute to the understanding of population processes and ecological factors involved in polyploidization, which is an important means of adaptation in plants.