Molecular-genetic analysis of trade-offs between vegetative growth and flowering in natural populations of perennial Arabis alpina

点击翻译按钮获取中文摘要

The life cycles of perennial plants are typically divided into phases of vegetative growth and flowering. The duration of each of these phases can be altered by genetic variation. Ecological studies predict that there are trade-offs between the different phases of the life cycle, so that the advantages of flowering and producing progeny are lowered by resulting reductions in biomass and increases in mortality. I propose to study this trade off in natural alpine populations of perennial Arabis alpina, a member of the Brassicaceae. In several populations genetic and phenotypic variation occur for the time of onset and duration of flowering. In the first phase by intensively testing the spatial distribution of phenotypic variation in one natural population at Col du Galibier / Pic Blanc and testing the progeny of wild plants in the glasshouse, we showed that early onset and extended duration of flowering is strongly asymmetric in the population and occurs mainly at lower altitudes. In the second phase I propose to use mapping populations we have already generated to identify allelic variation at genes segregating in this population and conferring differences in timing and duration of flowering. By genotyping plants growing in the natural population and measuring their longevity, we will assess whether there is a correlation between flowering behavior and mortality. To test whether this flowering trait is under local selection we will compare the distribution of flowering alleles with neutral variation across the population, test the outcrossing frequency of plants growing at different positions and perform reciprocal transplant experiments. Furthermore, environmental parameters will be measured across the population to try to correlate selective agents with phenotypic differences. To generalize the observations, similar studies were initiated in two neighbouring alpine populations and one Swedish population of Arabis alpina, and these will be extended in the second phase. This work will test the importance of variation in flowering onset and duration to local adaptation of perennial Arabis alpina.