Evolution, biodiversity and biogeography of parasitic plants using the genus cuscuta (CONVOLVULaceae) as a model of study

在开花植物的系统发育中，寄生作用已经独立进化了几次。共有寄生植物约4000种，隶属于22科277属。虽然对它们的研究已经很久了，但对它们的进化、生物多样性和生物地理学，特别是在物种水平上的了解仍然很少。葫芦属(葫芦科)将被用作研究的模式，因为它的经济意义、保护问题以及它在全球范围内提出的复杂的理论问题。短期目标是了解北美洲和南美洲的蜈蚣物种的进化和生物地理，以及为这些物种建立一个生物多样性数据库。我们将检验以下进化假说：(1)杂交和多倍体在荞麦的进化中发挥了作用。(2)属下分类不能反映该属的系统发育。(3)仍有未记述的种，但已记述的一些种在分类学上不健全。生物多样性数据库将可在互联网上搜索，并应包括以下条目：保护/入侵状况、分类信息、地理分布、寄主范围、生物学和生态数据以及用于识别的图像。数据库中包含的地理信息将被用来绘制每个物种和变种的分布范围，并与进化结论一起，结果应该有助于了解该属的历史生物地理。此外，还将检验与生物地理学有关的两个假说：(1)萌发要求至少部分影响物种的地理分布；(2)DOUDER的自养幼苗可能形成菌根联合，这反过来又可能影响物种的分布。长期目标是建立一个关于寄生植物的综合研究计划。首先，遵循与这里描述的方法类似的方法，我将把葫芦科的研究扩大到世界范围，其次，我也将考虑寄生植物的新属/科。

Parasitism has evolved independently several times in the phylogeny of flowering plants. There are roughly 4000 species of parasitic plants classified in 277 genera from 22 families. Although they have been studied for a long time, their evolution, biodiversity and biogeography, especially at species level are still poorly understood. The genus Cuscuta (dodders, Convolvulaceae) will be used as a model of study because of its economic significance, conservation problems, and the complexity of theoretical problems it brings up at a global scale. THE SHORT-TERM GOALS are to understand the evolution and biogeography of the North and South American species of dodder, as well as to create a biodiversity database for these species. The following evolutionary hypotheses will be tested: (1) Hybridization and polyploidy have played a role in the evolution of dodders. (2) The infrageneric classification of the genus does not reflect its phylogeny. (3) There are still undescribed species, whereas some of the species described are not sound taxonomically. The biodiversity database will be searchable over the internet and should include entries such as: the conservation/invasive status, taxonomic information, geographic distribution, the host range, biology and ecology data, and images for identification. The geographical information contained in the database will be used to map the distribution ranges for each species and variety and, together with the evolutionary conclusions, the results should give an understanding of the historical biogeography of this genus. In addition, two hypotheses in relation to biogeography will be tested: (1) Germination requirements influence, at least in part, the geographical distribution of species; (2) Autotrophic seedlings of dodders may form mycorrhizal associations, which in turn may influence the distribution of species. THE LONG-TERM OBJECTIVES are to build up an integrative research program on parasitic plants. Firstly, following similar approaches to those described here, I will expand the study of Cuscuta to a worldwide scale, and secondly, I will consider new genera/families of parasitic plants as well.