Department of Biology, University of Florida, Gainesville, FL 32611, United States; Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, United States; Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, United States.
Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, United States.
Mol Phylogenet Evol. 2018 Oct;127:878-890. doi: 10.1016/j.ympev.2018.06.035. Epub 2018 Jun 27.
Pollinator-mediated selection is a major driver of evolution in flowering plants, contributing to the vast diversity of floral features. Despite long-standing interest in floral variation and the evolution of pollination syndromes in Polemoniaceae, the evolution of floral traits and known pollinators has not been investigated in an explicit phylogenetic context. Here we explore macroevolutionary patterns of both pollinator specificity and three floral traits long considered important determinants of pollinator attraction across the most comprehensive species-level phylogenetic tree yet produced for the family. The presence of floral chlorophyll is reconstructed as the ancestral character state of the family, even though the presence of floral anthocyanins is the most prevalent floral pigment in extant taxa. Mean corolla length and width of the opening of the floral tube are correlated, and both appear to vary with pollinator type. The evolution of pollination systems appears labile, with multiple gains and losses of selfing and conflicting implications for patterns of diversification. Explicit testing of diversification models rejects the hypothesis that selfing is an evolutionary dead-end. This study begins to disentangle the individual components that comprise pollination syndromes and lays the foundation for future work on the genetic mechanisms that control each trait.
传粉媒介选择是开花植物进化的主要驱动因素，促成了花卉特征的广泛多样性。尽管人们对 Polemoniaceae 科的花卉变异和传粉综合征的进化长期以来一直很感兴趣，但在明确的系统发育背景下，尚未对花卉特征和已知传粉媒介的进化进行研究。在这里，我们探索了传粉媒介特异性和三个长期以来被认为是吸引传粉者的重要决定因素的花卉特征的宏观进化模式，这是迄今为止为该科制作的最全面的种系发生树上的特征。尽管花色素在现存类群中最为普遍，但花中叶绿素的存在被重建为该科的祖先特征状态。花管开口的平均花冠长度和宽度相关，并且似乎都随传粉媒介类型而变化。传粉系统的进化似乎不稳定，具有多次自交的获得和丧失，以及对多样化模式的冲突影响。对多样化模型的明确测试拒绝了自交是进化死胡同的假设。这项研究开始分解构成传粉综合征的各个组成部分，并为未来研究控制每个特征的遗传机制奠定了基础。
