PDF(Pubmed)
Abstract：
Few studies of angiosperms have focused on androecial evolution in conjunction with evolutionary shifts in corolla morphology and pollinator relationships. The Western Hemisphere clade of Justiciinae (Acanthaceae) presents the rare opportunity to examine remarkable diversity in staminal morphology. We took a phylogenetically informed approach to examine staminal diversity in this hypervariable group and asked whether differences in anther thecae separation is associated with phylogenetically informed patterns of variation in corolla morphology. We further discuss evidence for associations between anther diversity and pollinators in this lineage.
For the Dianthera/Sarotheca/Plagiacanthus (DSP) clade of Western Hemisphere Justiciinae, we characterized floral diversity based on a series of corolla measurements and using a model-based clustering approach. We then tested for correlations between anther thecae separation and corolla traits, and for shifts in trait evolution, including evidence for convergence.
There is evolutionary vagility in corolla and anther traits across the DSP clade with little signal of phylogenetic constraint. Floral morphology clusters into four distinct groups that are, in turn, strongly associated with anther thecae separation, a novel result in Acanthaceae and, to our knowledge, across flowering plants. These cluster groups are marked by floral traits that strongly point to associations with pollinating animals. Specifically, species that are known or likely to be hummingbird pollinated have stamens with parallel thecae, whereas those that are likely bee or fly pollinated have stamens with offset, divergent thecae.
Our results suggest that anther thecae separation is likely under selection in concert with other corolla characters. Significant morphological shifts detected by our analyses corresponded to putative shifts from insect to hummingbird pollination. Results from this study support the hypothesis that floral structures function in an integrated manner and are likely subject to selection as a suite. Further, these changes can be hypothesized to represent adaptive evolution.
For the Dianthera/Sarotheca/Plagiacanthus (DSP) clade of Western Hemisphere Justiciinae, we characterized floral diversity based on a series of corolla measurements and using a model-based clustering approach. We then tested for correlations between anther thecae separation and corolla traits, and for shifts in trait evolution, including evidence for convergence.
There is evolutionary vagility in corolla and anther traits across the DSP clade with little signal of phylogenetic constraint. Floral morphology clusters into four distinct groups that are, in turn, strongly associated with anther thecae separation, a novel result in Acanthaceae and, to our knowledge, across flowering plants. These cluster groups are marked by floral traits that strongly point to associations with pollinating animals. Specifically, species that are known or likely to be hummingbird pollinated have stamens with parallel thecae, whereas those that are likely bee or fly pollinated have stamens with offset, divergent thecae.
Our results suggest that anther thecae separation is likely under selection in concert with other corolla characters. Significant morphological shifts detected by our analyses corresponded to putative shifts from insect to hummingbird pollination. Results from this study support the hypothesis that floral structures function in an integrated manner and are likely subject to selection as a suite. Further, these changes can be hypothesized to represent adaptive evolution.
摘要：
目的：很少有被子植物的研究集中在雄激素的进化以及花冠形态和传粉者关系的进化变化上。西半球Justiniinae（Acanthaceae）进化枝提供了难得的机会来检查雄蕊形态的显着多样性。我们采取了系统发育知情的方法来检查这个高变组的雄蕊多样性，并询问花药分离的差异是否与花冠形态变异的系统发育知情模式有关。我们进一步讨论了该谱系中花药多样性与传粉者之间关联的证据。
方法：对于西半球Justiiniinae的Dianthera/Sarotheca/Plagiacanthus（DSP）进化枝，我们基于一系列花冠测量并使用基于模型的聚类方法来表征花卉多样性。然后我们测试了花药分离和花冠性状之间的相关性，以及性状进化的变化，包括趋同的证据。
结果：在整个DSP进化枝的花冠和花药性状中存在进化的模糊性，几乎没有系统发育约束的信号。花卉形态分为四个不同的组，反过来,与花药分离密切相关，在棘科和一个新的结果，根据我们的知识，跨越开花植物。这些簇群以花卉特征为标志，这些特征强烈指向与授粉动物的联系。具体来说,已知或可能是蜂鸟授粉的物种的雄蕊具有平行的雄蕊，而那些可能是蜜蜂或苍蝇授粉的雄蕊偏移，分歧的thecae。
结论：我们的结果表明，花药分离可能与其他花冠特征一致。通过我们的分析检测到的显着形态变化对应于从昆虫到蜂鸟授粉的推定变化。这项研究的结果支持以下假设：花卉结构以综合方式发挥作用，并且可能会被选择为套件。Further,可以假设这些变化代表适应性进化。
方法：对于西半球Justiiniinae的Dianthera/Sarotheca/Plagiacanthus（DSP）进化枝，我们基于一系列花冠测量并使用基于模型的聚类方法来表征花卉多样性。然后我们测试了花药分离和花冠性状之间的相关性，以及性状进化的变化，包括趋同的证据。
结果：在整个DSP进化枝的花冠和花药性状中存在进化的模糊性，几乎没有系统发育约束的信号。花卉形态分为四个不同的组，反过来,与花药分离密切相关，在棘科和一个新的结果，根据我们的知识，跨越开花植物。这些簇群以花卉特征为标志，这些特征强烈指向与授粉动物的联系。具体来说,已知或可能是蜂鸟授粉的物种的雄蕊具有平行的雄蕊，而那些可能是蜜蜂或苍蝇授粉的雄蕊偏移，分歧的thecae。
结论：我们的结果表明，花药分离可能与其他花冠特征一致。通过我们的分析检测到的显着形态变化对应于从昆虫到蜂鸟授粉的推定变化。这项研究的结果支持以下假设：花卉结构以综合方式发挥作用，并且可能会被选择为套件。Further,可以假设这些变化代表适应性进化。
