Data from: Phenotypic integration in flowers of neotropical lianas: diversification of form with stasis of underlying patterns

Phenotypic integration is essential to the understanding of organismal evolution as a whole. In this study, a phylogenetic framework is used to assess phenotypic integration among the floral parts of a group of Neotropical lianas. Flowers consist of plant reproductive organs (carpels and stamens), usually surrounded by attractive whorls (petals and sepals). Thus, flower parts might be involved in different functions and developmental constraints, leading to conflicting selective forces. We found that Bignonieae flowers have very similar patterns of variance/covariance among traits and that such patterns are uncorrelated with the phylogenetic relationships between species. However, in spite of pattern stasis, our results also indicate that diversification of floral morphology in this group has occurred throughout the evolution of magnitudes of correlation among traits. Thus, we suggest that stabilizing selection has played an important role in phenotypic integration, resulting in the long-term stasis of covariance patterns underlying flower diversification during the ca. 50 Myr of evolution of Bignonieae. This is the first report of long-term stasis in the phenotypic integration of angiosperms, suggesting that patterns of floral morphology can be recognizable as specific attributes of distinct botanical families.

表型整合（phenotypic integration）对于全面理解生物整体演化至关重要。本研究采用系统发育框架（phylogenetic framework），对一类新热带区藤本植物的花部性状间的表型整合模式进行评估。花由植物生殖器官（心皮与雄蕊）组成，通常被具吸引功能的花轮（花瓣与萼片）所环绕。因此，花部结构可能承担不同功能并受发育约束，进而引发冲突性的选择压力。研究结果显示，硬骨凌霄族（Bignonieae）植物的花部性状间的方差/协方差模式高度相似，且此类模式与物种间的系统发育关系不存在相关性。尽管存在模式保守性，本研究结果同时表明，该类群的花部形态多样化始终伴随着性状间相关程度的演化分化。据此我们提出，稳定选择在表型整合过程中发挥了重要作用，使得硬骨凌霄族在约5000万年的演化历程中，支撑花部多样化的协方差模式得以长期保守。这是首个关于被子植物（angiosperms）表型整合模式长期保守的研究报道，表明花部形态模式可作为不同植物科属的专属特征予以识别。