Polyploidy is an important driving force in angiosperm evolution, and much research has focused on genetic, epigenetic and transcriptomic responses to allopolyploidy. Nicotiana is an excellent system in which to study allopolyploidy because half of the species are allotetraploids of different ages, allowing us to examine the trajectory of floral evolution over time. Here, we study the effects of allopolyploidy on floral morphology in Nicotiana, using corolla tube measurements and geometric morphometrics to quantify petal shape. We show that polyploid morphological divergence from the intermediate phenotype expected (based on progenitor morphology) increases with time for floral limb shape and tube length, and that most polyploids are distinct or transgressive in at least one trait. In addition, we show that polyploids tend to evolve shorter and wider corolla tubes, suggesting that allopolyploidy could provide an escape from specialist pollination via reversion to more generalist pollination strategies.

中文翻译：

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烟草多倍体花进化中的海侵表型和通才授粉。


多倍体是被子植物进化的重要驱动力，许多研究集中在异源多倍体的遗传、表观遗传和转录组反应上。烟草是研究异源多倍体的绝佳系统，因为一半的物种是不同年龄的异源四倍体，使我们能够研究花随时间进化的轨迹。在这里，我们研究异源多倍体对烟草花形态的影响，使用花冠管测量和几何形态测量来量化花瓣形状。我们表明，花肢形状和管长度与预期中间表型（基于祖先形态）的多倍体形态差异随着时间的推移而增加，并且大多数多倍体在至少一种性状上是独特的或超越的。此外，我们发现多倍体倾向于进化出更短和更宽的花冠管，这表明异源多倍体可以通过恢复到更通用的授粉策略来逃避专门授粉。