Phylogenetic, Biogeographic, and Monographic Studies of Asian Core Araliaceae

以往对北半球的生物地理研究强调东亚与其他主要地区的关系，如北美东部、北美西部、欧洲和西亚。然而，东亚的生物地理格局很少利用现代系统发育证据进行调查。大多数洲际研究将东亚的广大地区（通常包括喜马拉雅山脉）视为一个单一的生物地理单元或一个特有的地区，但这当然是一种过度简化。许多植物区系观察和研究清楚地表明，东亚在生物地理上非常多样化。反过来，对亚洲生物地理模式缺乏可检验的假设阻碍了对北半球洲际生物地理演变的更普遍的理解。这项拟议的研究打算采用一个大的亚洲五加科植物群（人参科）作为模型来检查亚洲内部的生物地理关系，强调东亚和南亚以及喜马拉雅山。为便于讨论，本地区简称为“亚洲”。这个“亚洲五香科”群包括大约18个属，广泛分布在整个“亚洲”，亚洲五香科的几个亚群在这个感兴趣的地区表现出平行的分布模式。因此，亚洲五五科代表了一个理想的系统来研究“亚洲”内的个体和一般生物地理格局。文君博士和她在美国和中国的同事提出的这项研究的目标是：(1)基于形态学、核糖体DNA和叶绿体DNA的证据，构建一个强大的亚洲五加科属水平的系统发育（进化或谱系关系）；(2)利用4个分子数据集（核糖体ITS序列、叶绿体ndhF序列、atpB-rbcL间隔区序列和trnC-trnD区序列），构建了亚洲五加科两个主要谱系——拟南芥（Eleutherococcus - Macropanax - Metapanax）类群和芸苔（Brassaiopsis - Trevesia - Hedera）类群的种级系统发育；(3)基于该地区至少三个五加科谱系的系统发育（上面提到的两个类群，以及温博士目前正在研究的五加- Panax复合体），研究东亚、南亚和喜马拉雅地区的生物地理关系；(4)重新评价亚洲五重科植物的传统分类和属界划分，包括形态特征演化的评价；(5)提供五加科五加科专著，包括建立亚洲五加科系统网页。拟议研究的结果将有几个重要的含义。这将是第一批使用特定植物群的系统发育框架来研究东亚和南亚广大地区以及喜马拉雅山脉的生物地理学的研究之一。亚洲五加科的系统发育分析将有助于进一步对亚洲以及世界范围内人参科进行系统、进化和生物地理研究。

Previous biogeographic studies of the Northern Hemisphere have emphasized the relationships of eastern Asia to other major areas, such as eastern North America, western North America, Europe, and western Asia. Biogeographic patterns within eastern Asia, however, have rarely been investigated using modern phylogenetic evidence. Most intercontinental studies treat the vast area of eastern Asia (often including the Himalayas) as a single biogeographic unit or an area of endemism, but this is certainly a gross oversimplification. Many floristic observations and studies clearly demonstrate that eastern Asia is biogeographically very diverse. In turn, the lack of testable hypotheses for biogeographic patterns within Asia has hindered more general understanding of the evolution of intercontinental biogeography of the Northern Hemisphere. The proposed study intends to employ a large Asian group of the plant family Araliaceae (the ginseng family) as a model to examine biogeographic relationships within Asia, emphasizing eastern and South Asia and the Himalayas. This region is herein referred to as "Asia" for the convenience of discussion. This "Asian Araliaceae group" comprises about 18 genera with a wide distribution throughout "Asia," and several of the subgroups within the Asian Araliaceae exhibit parallel distributional patterns across this region of interest. Thus, the Asian Araliaceae represent an ideal system to examine both individual and general biogeographic patterns within "Asia". The goals of the proposed study by Dr. Jun Wen and her colleagues in the U.S. and China are to (1) construct a robust genus-level phylogeny (evolutionary or genealogical relationships) of the Asian Araliaceae based on evidence from morphology, nuclear ribosomal DNA, and chloroplast DNA; (2) construct species-level phylogenies for two major lineages of the Asian Araliaceae: the Eleutherococcus - Macropanax - Metapanax group and the Brassaiopsis - Trevesia - Hedera group using four molecular data sets (sequences of nuclear ribosomal ITS, and chloroplast ndhF, atpB-rbcL spacer and trnC-trnD regions); (3) examine the biogeographic relationships of eastern and South Asia and the Himalayas based on phylogenies of at least three lineages of Araliaceae in this region (two groups mentioned above, and the Aralia - Panax complex currently being investigated by Dr. Wen); (4) re-evaluate the traditional taxonomic classification and generic delimitations of taxa within the Asian Araliaceae, including an assessment of morphological character evolution; and (5) provide a monograph of Aralia sect. Pentapanax, including the establishment of an internet page on the systematics of the Asian Araliaceae. Results from the proposed study will have several important implications. This will be one of the first studies to examine the biogeography of the vast region of eastern and South Asia and the Himalayas using a phylogenetic framework for a particular plant group. The phylogenetic analyses of the Asian Araliaceae will facilitate further systematic, evolutionary, and biogeographic studies in Asia as well as in the ginseng family worldwide.