Syrotchen Jill M, Ferris Kathleen G
Department of Ecology and Evolutionary Biology, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118.
bioRxiv. 2024 Jan 9:2023.08.02.551729. doi: 10.1101/2023.08.02.551729.
Organisms can adapt to environmental heterogeneity through two mechanisms: (1) expression of population genetic variation or (2) phenotypic plasticity. In this study we investigated whether patterns of variation in both trait means and phenotypic plasticity along elevational and latitudinal clines in a North American endemic plant, , were consistent with local adaptation. We grew inbred lines of from across the species' range in two common gardens varying in day length to measure mean and plastic trait expression in several traits previously shown to be involved in adaptation to rocky outcrop microhabitat: flowering time, size-related traits, and leaf shape. We examined correlations between the mean phenotype and phenotypic plasticity, and tested for a relationship between trait variation and population elevation and latitude. We did not find a strong correlation between mean and plastic trait expression at the individual genotype level suggesting that they operate under independent genetic controls. We identified multiple traits that show patterns consistent with local adaptation to elevation: critical photoperiod, flowering time, flower size, mean leaf lobing, and leaf lobing plasticity. These trends occur along multiple geographically independent altitudinal clines indicating that selection is a more likely cause of this pattern than gene flow among nearby populations with similar trait values. We also found that population variation in mean leaf lobing is associated with latitude. Our results indicate that both having more highly lobed leaves and greater leaf shape plasticity may be adaptive at high elevation within Our data strongly suggest that traits known to be under divergent selection between and close relative are also under locally varying selection within .
（1）群体遗传变异的表达或（2）表型可塑性。在本研究中，我们调查了北美特有植物沿着海拔和纬度梯度的性状均值和表型可塑性的变异模式是否与局部适应性一致。我们在两个日长不同的共同花园中种植了来自该物种分布范围内的自交系，以测量先前显示参与适应岩石露头微生境的几个性状的均值和可塑性性状表达：开花时间、与大小相关的性状和叶形。我们检查了平均表型与表型可塑性之间的相关性，并测试了性状变异与种群海拔和纬度之间的关系。我们在个体基因型水平上没有发现平均性状表达与可塑性性状表达之间有很强的相关性，这表明它们在独立的遗传控制下运作。我们确定了多个性状，其表现出与对海拔的局部适应一致的模式：临界光周期、开花时间、花大小、平均叶裂和叶裂可塑性。这些趋势沿着多个地理上独立的海拔梯度出现，这表明选择比具有相似性状值的附近种群之间的基因流动更有可能是这种模式的原因。我们还发现平均叶裂的种群变异与纬度有关。我们的结果表明，在[具体物种名称]内，在高海拔地区具有更多深裂叶和更大的叶形可塑性可能是适应性的。我们的数据强烈表明，已知在[具体物种名称]与其近缘种之间经历趋异选择的性状，在[具体物种名称]内也受到局部变化的选择。
