Data from: The edaphic environment mediates flowering-time differentiation between adjacent populations of Leptosiphon parviflorus

Flowering time is an important life history trait in plants that often affects fitness. The optimal time to flower may be influenced by trade-offs between flowering time and growth-related traits and is thus likely to differ among habitats. Because flowering-time differences between populations can also reduce gene flow, understanding the factors that contribute to variation in flowering time among closely adjacent populations that experience gene flow is of particular interest. Plant adaptation to different edaphic environments provides some of the best examples of adaptive divergence at small spatial scales, and often coincides with flowering-time shifts. The current study addresses the causes of flowering-time differences in two populations of Leptosiphon parviflorus that are locally adapted to adjacent serpentine and sandstone soils despite moderate levels of gene flow and close geographic proximity. Field reciprocal-transplant studies and watering manipulations in the greenhouse demonstrate the contribution of both the genotype and the environment to observed flowering-time differences. The plasticity of flowering time in response to soil type appears to be driven by differences in soil moisture. In addition, selection on flowering time was measured in both soil types across 4 years of study using a set of F5 advanced-generation hybrids and found to differ between the habitats. Therefore, both selection and plasticity contribute to flowering-time differences between these populations and thus have likely played an important role in the initiation and/or maintenance of adaptive divergence in this system.开花时间是影响植物适合度（fitness）的重要生活史性状（life history trait）。植物的最优开花时间可能受开花时间与生长相关性状间的权衡（trade-offs）作用影响，因此不同生境下的最优开花时间往往存在差异。由于种群间的开花时间差异还会降低基因流（gene flow），因此探究地理邻近且存在基因流的近缘种群间，导致开花时间变异的影响因素，具有特殊的研究价值。植物对不同土壤生境（edaphic environments）的适应，是小尺度空间下适应性分化（adaptive divergence）的经典范例之一，且通常伴随开花时间的改变。本研究针对两种小花细管花（Leptosiphon parviflorus）种群展开探究：这两个种群虽地理距离相近且存在中等水平的基因流，但已分别本地适应于相邻的蛇纹岩土与砂岩土壤生境。野外互惠移植实验（reciprocal-transplant studies）与温室控水调控实验证实，基因型与环境共同作用于观测到的开花时间差异。植物开花时间对土壤类型的表型可塑性响应，似乎由土壤水分差异所驱动。此外，本研究历时4年，利用一套F5代高级杂交群体（F5 advanced-generation hybrids），对两种土壤生境下的开花时间选择压进行了测定，结果发现不同生境的选择压力存在差异。综上，选择作用与表型可塑性共同促成了这两个种群间的开花时间差异，因此二者可能在该系统的适应性分化起始与/或维持过程中发挥了重要作用。