<b>Flowering responses of the woodland strawberry to local climate and reduced precipitation along a European latitudinal gradient</b>

Climate change creates novel environmental conditions that plant species must adapt to. Since plants are finely tuned to the seasonality of their environments, shifts in their phenology serve as some of the most compelling evidence of climate change’s impact. Understanding how key fitness-related phenological traits, such as flowering onset, respond to novel environments is crucial for assessing species’ plasticity and/or adaptive potential under climate change. Here, we investigated the onset of flowering in <i>Fragaria vesca</i> (woodland strawberry; Rosaceae) by translocating genotypes between four sites along a south-north gradient in Europe, encompassing its entire latitudinal distribution range with varying temperatures, precipitation patterns, and photoperiods. At each site, we included a reduced precipitation treatment using rain-out shelters to simulate drought conditions and assess their impact on flowering onset. Our findings revealed that southern and central European genotypes exhibited a delayed onset of flowering when translocated to the northernmost site. In contrast, no difference among genotypes was found in the onset of flowering when grown in more southerly sites. Reduced precipitation accelerated flowering across several sites and all genotypes, irrespective of their latitudinal origin. Overall, northern European genotypes showed a greater capacity to adjust their onset of flowering in response to the different photoperiods and temperatures across the latitudinal gradient compared to southern European genotypes, suggesting that they may be more resilient to shifting environmental conditions. Differences in phenotypic plasticity among genotypes translocated to higher versus lower latitudes highlight the role of photoperiod in evaluating a species’ capacity to cope with climate change.气候变化造就了植物物种必须适应的全新环境条件。由于植物高度适应其所处环境的季节节律，其物候（phenology）变化是气候变化影响的最有力证据之一。明晰与适合度相关的关键物候性状（如开花始期（flowering onset））对全新环境的响应机制，对于评估气候变化下物种的表型可塑性（phenotypic plasticity）及/或适应潜力至关重要。 本研究以森林草莓（*Fragaria vesca*，蔷薇科（Rosaceae））为研究材料，通过将不同来源的基因型移植至欧洲沿南北纬度梯度布设的4个样地——该梯度覆盖了该物种的完整纬度分布范围，各点位的温度、降水格局与光周期均存在差异——探究其开花始期的响应规律。在每个样地中，我们均设置了减雨处理组：利用防雨棚（rain-out shelters）模拟干旱环境，以此评估干旱对开花始期的影响。 研究结果显示：欧洲南部与中部的基因型被移植至最北部样地时，其开花始期显著延迟。与之相反，当基因型种植于更南部的样地时，不同基因型间的开花始期未表现出显著差异。无论基因型的纬度起源如何，减雨处理均能在多个样地中促进所有基因型提前开花。 总体而言，相较于欧洲南部基因型，欧洲北部基因型在沿纬度梯度的不同光周期与温度条件下，对开花始期的调控能力更强，这意味着北部基因型对环境条件变化的适应弹性更高。移植至高纬度与低纬度样地的基因型间表型可塑性差异，凸显了光周期在评估物种应对气候变化能力中的关键作用。