Water availability as an agent of selection in introduced populations of Arabidopsis thaliana: impacts on flowering time evolution

Flowering is one of the most influential events in the life history of a plant and one of the main determinants of reproductive investment and lifetime fitness. It is also a highly complex trait controlled by dozens of genes. Understanding the selective pressures influencing time to flowering, and being able to reliably predict how it will evolve in novel environments, are unsolved challenges for plant evolutionary geneticists. Using the model plant species, Arabidopsis thaliana, we examined the impact of simulated high and low winter precipitation levels on the flowering time of naturalized lines from across the eastern portion of the introduced North American range, and the fitness consequences of early versus late flowering. Flowering time order was significantly correlated across two environments—in a previous common garden experiment and in environmental chambers set to mimic mid-range photoperiod and temperature conditions. Plants in low water flowered earlier, had fewer basal bra...开花是植物生活史中最具影响力的事件之一，同时也是决定繁殖投入与终身适合度的核心因素之一。它同时也是一类受数十个基因调控的高度复杂性状。解析影响开花时间的选择压力，并可靠预测其在新环境中的演化规律，是植物进化遗传学家尚未攻克的研究难题。本研究以模式植物拟南芥（Arabidopsis thaliana）为实验材料，探究了模拟冬季高、低降水水平对北美引入分布区东部各地归化株系开花时间的影响，以及早开花与晚开花对应的适合度差异。在两项实验环境中——此前的同质园实验，以及设置为模拟中等光周期与温度条件的环境培养箱实验——植株的开花时间排序均呈现显著相关性。低水分处理组的植株开花更早，且基生结构（原文截断为basal bra）数量更少。