Paule Juraj, Wagner Natascha D, Weising Kurt, Zizka Georg
Department of Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.
Plant Molecular Systematics, Department of Sciences, University of Kassel, D-34132 Kassel, Germany.
Ann Bot. 2017 Aug 1;120(2):233-243. doi: 10.1093/aob/mcw245.
The distribution of polyploidy along a relatively steep Andean elevation and climatic gradient is studied using the genus Fosterella L.B. Sm. (Bromeliaceae) as a model system. Ecological differentiation of cytotypes and the link of polyploidy with historical biogeographic processes such as dispersal events and range shift are assessed.
4',6-Diamidino-2-phenylindole (DAPI) staining of nuclei and flow cytometry were used to estimate the ploidy levels of 159 plants from 22 species sampled throughout the distribution range of the genus. Ecological differentiation among ploidy levels was tested by comparing the sets of climatic variables. Ancestral chromosome number reconstruction was carried out on the basis of a previously generated phylogeographic framework.
This study represents the first assessment of intrageneric, intraspecific and partially intrapopulational cytotype diversity in a genus of the Bromeliaceae family. In Fosterella , the occurrence of polyploidy was limited to the phylogenetically isolated penduliflora and rusbyi groups. Cytotypes were found to be ecologically differentiated, showing that polyploids preferentially occupy colder habitats with high annual temperature variability (seasonality). The combined effects of biogeographic history and adaptive processes are presumed to have shaped the current cytotype distribution in the genus.
The results provide indirect evidence for both adaptive ecological and non-adaptive historical processes that jointly influenced the cytotype distribution in the predominantly Andean genus Fosterella (Bromeliaceae). The results also exemplify the role of polyploidy as an important driver of speciation in a topographically highly structured and thus climatically diverse landscape.
以福斯特凤梨属（Fosterella L.B. Sm.，凤梨科）为模型系统，研究多倍体在相对陡峭的安第斯山脉海拔和气候梯度上的分布情况。评估细胞型的生态分化以及多倍体与历史生物地理过程（如扩散事件和分布范围变化）之间的联系。
使用4',6-二脒基-2-苯基吲哚（DAPI）细胞核染色和流式细胞术来估计该属分布范围内22个物种的159株植物的倍性水平。通过比较气候变量集来测试倍性水平之间的生态分化。基于先前生成的系统发育地理框架进行祖先染色体数目的重建。
本研究是对凤梨科一个属内的属内、种内和部分居群内细胞型多样性的首次评估。在福斯特凤梨属中，多倍体的出现仅限于系统发育上孤立的垂花凤梨组和鲁斯比凤梨组。发现细胞型在生态上存在分化，表明多倍体优先占据年温度变异性（季节性）高的较寒冷栖息地。推测生物地理历史和适应性过程的综合作用塑造了该属当前的细胞型分布。
研究结果为适应性生态过程和非适应性历史过程提供了间接证据，这些过程共同影响了主要分布在安第斯山脉的福斯特凤梨属（凤梨科）的细胞型分布。研究结果还例证了多倍体在地形高度结构化且气候多样的景观中作为物种形成重要驱动力的作用。
