Department of Biology, Pennsylvania State University, State College, PA 16803, USA.
Smithsonian National Museum of Natural History, 10th and Constitution Avenue, NW, Washington, DC 20560, USA.
Mol Phylogenet Evol. 2019 Nov;140:106577. doi: 10.1016/j.ympev.2019.106577. Epub 2019 Aug 12.
Paullinia L. is a genus of c. 220 mostly Neotropical forest-dwelling lianas that display a wide diversity of fruit morphologies. Paullinia resembles other members of the Paullinieae tribe in being a climber with stipulate compound leaves and paired inflorescence tendrils. However, it is distinct in having capsular fruits with woody, coriaceous, or crustaceous pericarps. While consistent in this basic plan, the pericarps of Paullinia fruits are otherwise highly variable-in some species they are winged, whereas in others they are without wings or covered with spines. With the exception of the water-dispersed indehiscent spiny fruits of some members of Paullinia sect. Castanella, all species are dehiscent, opening their capsules while they are still attached to the branch, to reveal arillate animal-dispersed seeds. Here we present a molecular phylogeny of Paullinia derived from 11 molecular markers, including nine newly-developed single-copy nuclear markers amplified by microfluidics PCR. This is the first broadly sampled molecular phylogeny for the genus. Paullinia is supported as monophyletic and is sister to Cardiospermum L., which together are sister to Serjania Mill + Urvillea Kunth. We apply this novel phylogenetic hypothesis to test previous infrageneric classifications and to infer that unwinged fruits represent the ancestral condition, from which there were repeated evolutionary transitions and reversals. However, because the seeds of both winged and unwinged fruits are dispersed by animals, we conclude that the repeated transitions in fruit morphology may relate to visual display strategies to attract animal dispersers, and do not represent transitions to wind dispersal.
宝儿藤属（Paullinia L.）是约 220 种主要分布于新热带森林中的藤本植物，其果实形态多样。宝儿藤属植物与宝儿藤族（Paullinieae）的其他成员相似，都是攀援植物，具有具托叶的复叶和对生的花序卷须。然而，它的果实为蒴果，具有木质、革质或角质的果皮，与其他成员明显不同。宝儿藤属植物的果实虽然在基本形态上保持一致，但果皮形态却存在高度的可变性——在一些物种中，果皮具有翅，而在另一些物种中则没有翅或被刺覆盖。除了某些宝儿藤属节（sect. Castanella）的水散型不裂具刺果实外，所有物种的果实都是开裂的，在仍附着于枝上时开裂，露出具假种皮的动物传播种子。在这里，我们基于 11 个分子标记，包括通过微流控 PCR 扩增的 9 个新开发的单拷贝核标记，提供了宝儿藤属的分子系统发育。这是该属首次广泛采样的分子系统发育研究。宝儿藤属被支持为单系群，与 Cardiospermum L. 为姐妹群，而 Cardiospermum L. 与 Serjania Mill + Urvillea Kunth 为姐妹群。我们应用这一新的系统发育假说来检验先前的种下分类，并推断无翅果实代表祖先状态，从该状态发生了多次进化转变和逆转。然而，由于有翅和无翅果实的种子都是由动物传播的，我们得出结论，果实形态的反复转变可能与吸引动物传播者的视觉展示策略有关，而不是向风传播的转变。
