PREMISE In the complex soil nutrient environments of wild populations of annual plants, in general, low nutrient availability restricts growth and alters root-shoot relationships. However, our knowledge of natural selection on roots in field settings is limited. We sought to determine whether selection acts directly on root traits and to identify which components of the soil environment were potential agents of selection. METHODS We studied wild native populations of Arabidopsis thaliana across 4 years, measuring aboveground and belowground traits and analyzing soil nutrients. Using multivariate methods, we examined patterns of natural selection and identified soil attributes that contributed to whole-plant form. In a common garden experiment at two field sites with contrasting soil texture, we examined patterns of selection on root and shoot traits. RESULTS In wild populations, we uncovered selection for above- and belowground size and architectural traits. We detected variation through time and identified soil components that influenced fruit production. In the garden experiment, we detected a distinct positive selection for total root length at the site with greater water-holding capacity and negative selection for measures of root architecture at the field site with reduced nutrient availability and water holding capacity. CONCLUSIONS Patterns of natural selection on belowground traits varied through time, across field sites and experimental gardens. Simultaneous investigations of above- and belowground traits reveal trait functional relationships on which natural selection can act, highlighting the influence of edaphic features on evolutionary processes in wild annual plant populations.

中文翻译：

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野外整株植物形态的自然变异受多元土壤养分特征的影响：自然选择作用于根系性状

前提 在一年生植物野生种群的复杂土壤养分环境中，一般来说，养分利用率低会限制生长并改变根-芽关系。然而，我们对田间环境中根的自然选择的了解是有限的。我们试图确定选择是否直接作用于根性状，并确定土壤环境的哪些成分是潜在的选择因素。方法我们研究了拟南芥的野生本地种群 4 年，测量地上和地下特征并分析土壤养分。使用多元方法，我们检查了自然选择的模式，并确定了有助于整个植物形态的土壤属性。在两个具有对比土壤质地的田间场地进行的普通花园试验中，我们检查了根和枝条性状的选择模式。结果 在野生种群中，我们发现了对地上和地下大小和建筑特征的选择。我们检测了随时间的变化，并确定了影响水果生产的土壤成分。在花园实验中，我们在持水能力更强的场地检测到总根长的明显正选择，而在养分可用性和持水能力降低的田间场地测量根系结构的措施则为负选择。结论 地下性状的自然选择模式随时间、田间地点和实验花园而变化。对地上和地下特征的同时调查揭示了自然选择可以发挥作用的特征功能关系，