Context‐dependent concordance between physiological divergence and phenotypic selection in sister taxa with contrasting phenology and mating systems
Context‐dependent concordance between physiological divergence and phenotypic selection in sister taxa with contrasting phenology and mating systems
复制标题
具有对比物候和交配系统的姊妹类群的生理分歧和表型选择之间的上下文依赖性一致性
DOI：
10.1002/ajb2.16016
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发表时间：
2022
影响因子：
3
通讯作者：
Dudley, Leah S.
中科院分区：
文献类型：
--
作者：
Mazer, Susan J.;Hunter, David J.;Hove, Alisa A.;Dudley, Leah S.
前提对密切相关的类群中功能性状的表型分化和选择的研究提供了检测自然选择在驱动多样化中的作用的机会。如果野外种群中选择的强度或方向在类群之间存在差异，其模式与它们之间的表型差异一致，那么自然选择就会强化这种差异。很少有研究寻求这种生理特征一致性的证据。方法使用植物标本记录来检测姐妹类群之间的物候差异，而与收集地点气候长期变化对开花时间的影响无关。在田间，记录了克拉克氏菌两个分类单元对的 13 个田间种群在营养生长和开花期间光合速率、蒸腾速率和瞬时水分利用效率的生理差异，每个种群均包含一个自花授粉和一个异交分类单元。结果从历史上看，每个自交分类单元的开花早于其异交姐妹分类单元，与当地长期气候条件的影响无关。姐妹类群在所有焦点特征上都存在差异，但分歧的程度和（在一种情况下）方向取决于生命阶段。一般来说，自花授粉类群具有较高的气体交换率，这与其较早的成熟一致。在 18 个比较中的 6 个中，选择模式与姐妹类群之间的表型差异（或缺乏表型差异）一致。结论在异质条件下测量的生理性状的选择模式并不能可靠地反映姐妹类群之间的差异，强调需要对类群内部和类群之间的选择方向进行重复研究。
PremiseThe study of phenotypic divergence of, and selection on, functional traits in closely related taxa provides the opportunity to detect the role of natural selection in driving diversification. If the strength or direction of selection in field populations differs between taxa in a pattern that is consistent with the phenotypic difference between them, then natural selection reinforces the divergence. Few studies have sought evidence for such concordance for physiological traits.MethodsHerbarium specimen records were used to detect phenological differences between sister taxa independent of the effects on flowering time of long‐term variation in the climate across collection sites. In the field, physiological divergence in photosynthetic rate, transpiration rate, and instantaneous water‐use efficiency were recorded during vegetative growth and flowering in 13 field populations of two taxon pairs ofClarkia, each comprising a self‐pollinating and a outcrossing taxon.ResultsHistorically, each selfing taxon flowered earlier than its outcrossing sister taxon, independent of the effects of local long‐term climatic conditions. Sister taxa differed in all focal traits, but the degree and (in one case) the direction of divergence depended on life stage. In general, self‐pollinating taxa had higher gas exchange rates, consistent with their earlier maturation. In 6 of 18 comparisons, patterns of selection were concordant with the phenotypic divergence (or lack thereof) between sister taxa.ConclusionsPatterns of selection on physiological traits measured in heterogeneous conditions do not reliably reflect divergence between sister taxa, underscoring the need for replicated studies of the direction of selection within and among taxa.