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

多年生植物的生命周期通常分为营养生长和开花两个阶段。每个阶段的持续时间都可以通过遗传变异而改变。生态学研究预测，在生命周期的不同阶段之间存在权衡，因此开花和产生后代的优势被生物量的减少和死亡率的增加所降低。我建议在芸苔科植物Arabis alpina的多年生高山自然种群中研究这种权衡。在一些种群中，遗传和表型变异发生于开花的开始时间和持续时间。在第一阶段，通过对coldu Galibier / Pic Blanc自然种群表型变异空间分布和野生植物后代在温室内的测试，我们发现早开和花时延长在种群中具有强烈的不对称性，并且主要发生在低海拔地区。在第二阶段，我建议使用我们已经生成的种群图谱来确定该种群中分离基因的等位基因变异，并赋予开花时间和持续时间的差异。通过对自然种群中生长的植物进行基因分型并测量它们的寿命，我们将评估开花行为与死亡率之间是否存在相关性。为了验证这一开花性状是否存在局部选择，我们将比较具有中性变异的开花等位基因在群体中的分布，测试不同位置植株的异交频率，并进行互移栽实验。此外，将测量整个种群的环境参数，以试图将选择因子与表型差异联系起来。为了概括观察结果，在两个邻近的高山种群和一个瑞典的阿拉伯高山种群中开始了类似的研究，这些研究将在第二阶段扩大。本研究将检验多年生阿拉伯高山植物开花开始和持续时间的变化对当地适应的重要性。

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.