Poli Letícia P, Temponi Lívia G, Coan Alessandra I
Departamento de Botânica, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP , Rio Claro , São Paulo , Brazil.
Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná - UNIOESTE , Cascavel , Paraná , Brazil.
PeerJ. 2017 Jan 26;5:e2929. doi: 10.7717/peerj.2929. eCollection 2017.
is the largest genus of Araceae, with 950 species distributed in the neotropics. Despite the great diversity of the genus, the knowledge of its floral vasculature is based on observations in only two species, viz. and , with remarkable variation in vascular carpellary supply: carpels are either vascularized by ventral bundles alone or by reduced dorsal bundles in addition to the ventral ones. Our main objective is to test this peculiar variation through a detailed anatomical study of the floral vasculature in taxa belonging to some sections of designated as monophyletic groups in recent phylogenies.
We compare the floral vasculature of 20 neotropical species belonging to distinct sections of , using both light and confocal laser scanning microscopies.
The number and position of vascular bundles are constant within the tepals and stamens, regardless of the species and sections studied. However, the gynoecium vasculature exhibits variation between species belonging to the same or different sections. Our results reveal two patterns of vasculature: carpels vascularized by synlateral bundles alone (Pattern A) and carpels vascularized by both dorsal and synlateral bundles (Pattern B). Pattern A is shared by the majority of species studied here and corroborates the previous data in the literature. Pattern B occurs in three species: ( sect series ), and ( sect. ), described here for the first time for the genus.
The variation in the supply to the carpels in is corroborated here. However, our results in addition to those from the available literature suggest the existence of three patterns (A, B and C) of carpellary vasculature. Based on the recent phylogeny of it is possible to notice that the three patterns of carpellary vasculature occur in representatives of Clade B and deserve to be investigated in a larger number of species. Pattern A could be a plesiomorphy for the genus and the occurrence of dorsal bundles could be a derived character. Our data contributes to the taxonomy and to the understanding of the floral evolution of the largest neotropical genus of Araceae.
是天南星科最大的属，有950个物种分布于新热带地区。尽管该属具有高度多样性，但其花部维管束的知识仅基于对两个物种的观察，即和，其心皮维管束供应存在显著差异：心皮要么仅由腹侧维管束供应，要么除腹侧维管束外还由退化的背侧维管束供应。我们的主要目标是通过对在近期系统发育中被指定为单系类群的某些组的类群的花部维管束进行详细解剖研究，来检验这种特殊变异。
我们使用光学显微镜和共聚焦激光扫描显微镜，比较了属于不同组的20个新热带物种的花部维管束。
无论所研究的物种和组如何，花被片和雄蕊内维管束的数量和位置都是恒定的。然而，雌蕊群维管束在同一组或不同组的物种之间存在变异。我们的结果揭示了两种维管束模式：仅由侧生维管束供应的心皮（模式A）和由背侧和侧生维管束供应的心皮（模式B）。模式A为这里研究的大多数物种所共有，并证实了文献中的先前数据。模式B出现在三个物种中：（组系列）、和（组），这是该属首次在此描述。
这里证实了心皮供应的变异。然而，我们的结果以及现有文献的结果表明存在三种心皮维管束模式（A、B和C）。基于近期的系统发育，可以注意到三种心皮维管束模式出现在分支B的代表中，值得在更多物种中进行研究。模式A可能是该属的一个祖征，背侧维管束的出现可能是一个衍生特征。我们的数据有助于天南星科最大的新热带属的分类以及对花部进化的理解。
