毛茛科银莲花族属间关系界定和系统学研究

Anemoneae is a tribe of the buttercup family (Ranunculaceae). Flower forms and fruit traits of Ranunculaceae exhibit strikingly diverse among the angiosperms. To date, numerous studies for the family and generic levels have been investigated in diverse fields. Nevertheless, molecular systematics of tribe Anemoneae, and phylogenetic relationship of genera within the tribe are not resolved well, specifically for the Chinese taxa are unsolved. In this project, we will sample all genera and at least 60% taxa of this tribe, and sequence two nuclear (ITS and 26S) and four chloroplastic genes (matK, trnL-F, atpB-rbcL, rpoB-trnC or rpl16). Seuqnce matrixes perfom phylogenetic analysese using Maximum Parsimony (MP), Maximum Liklihood (ML) and Bayesian Inference (BI) approaches. Morphological traits including floral organogeny and development, pllen mopholoy, fruit and seed traits and leaf epidermis are mapped to phylogenetic trees, or are analyzed using cluster analysis and principal component analysis (PCA). The main goals of this project are: i) to recontruct phylogenetic relationship of tribe Anemoneae on the basis of both sequences and morphological traits, especially to re-delimit generic boundary of Anemone and Clematis; ii) to clarify the traditionally systematic status among Anemone, Hepatica and Pulsatilla for Chinese species; iii) to identify taxonomic treatments of two monotypic genera, Anemoclema and Metanemone, and their systematic relationships to Anemone, Hepatica and Pulsatilla; and iv) to compare development of petal and staminode between Naravelia and Clematis. Our results can provide such basic information for investigations of systematics and evolultion and taxonomic revision of Anemoneae, and boost reseach paces of Ranunculaceae for Chinese researchers; their information will be useful for proposing conservational policies of Anemoclema and Metanemone.

银莲花族隶属于毛茛科。长久以来，有关毛茛科及其属级水平的相关研究非常之多，但是银莲花族的分子系统学，及其族下属间关系却暂不清楚，特别是对于国产类群。本项目将采用传统的形态与解剖，结合分子证据，重建国产银莲花族的系统关系，阐明该族属间关系。拟解决四个问题：1）重建银莲花族亚族和属间的系统学发育，重新界定银莲花属和铁线莲属；2）阐明传统上所界定的银莲花属、獐耳细辛属和白头翁属三属之间的关系；3）确认中国特有单型属罂粟银莲花属和毛茛莲花属与另三属：银莲花属、獐耳细辛属和白头翁属之间的关系；4）比较铁线莲属和锡兰莲属的花器官早期发生与分化，结合形态比较学研究，重新界定两属属间关系，并进一步结合分子系统树，进行性状演化重建。本研究揭示银莲花族物种多样化的可能成因。研究结果为开展该族的系统与进化，及分类修订提供基础资料，可推进国内学者研究毛茛科的步伐；为罂粟银莲花和毛茛莲花的保护必要性提供理论基础。

在以往的分类系统中，银莲花亚族包括了8个属，即银莲花属、白头翁属、獐耳细辛属、罂粟莲花属、毛茛莲花属、Barneoudia、Oreithales和Knowltonia，其中罂粟莲花属、毛茛莲花属和Oreithales是单型属，前5个属中国有产。根据对欧美地区一些物种研究结果显示，银莲花属的范围应该包括白头翁属、獐耳细辛属和Knowltonia属，以及Barneoudia和Oreithales。在东亚地区，特别是中国，对于银莲花亚族的研究较少。本项目主要利用分子系统研究方法，结合形态学比较和分化时间估算，澄清银莲花族内部类群的相互关系。.我们通过对该族119种系统发育分析，阐明银莲花族内系统关系。我们认为罂粟莲花属应转移到铁线莲亚族中；广义银莲花属可被采纳，其包括银莲花属、白头翁属、獐耳细辛属、Barneoudiay、Oreithales和Knowltonia；罂粟莲花属应为独立的属，与铁线莲属姐妹；锡兰莲属应该归入广义铁线莲属。.15种银莲花属的花粉形态学观察确认有四种萌发孔类型，即三沟、多沟、散沟和散孔。研究确认花粉在属下等级划分具有参考价值，支持席以珍和张金谈提出的花粉演化式样：三沟型花粉→多沟型花粉→散沟型花粉→散孔型花粉。.15个形态性状进行主成分分析明确将广义铁线莲属和广义银莲花属分开，且罂粟莲花属和广义银莲花属关系较近。形态性状演化分析表明木质化的茎和花萼4是铁线莲属区别与银莲花族其他类群的关键特征。肉质化叶片是獐耳细辛属和Barneoudia区别于其他类群的重要性状。长宿存花柱是罂粟莲花属、广义铁线莲属、白头翁属、Barneoudia和Oreithales的重要鉴别特征。Knowltonia区别于其他类群的主要是瘦果光滑，且宿存柱头不明显。.分化时间估算出银莲花族起源时间约70.78 Mya，随后在56.38 Mya分化为银莲花亚族和铁线莲亚族。罂粟莲花属和铁线莲属分异时间在41.0 Mya，铁线莲属发生快速分化大约是在28.31 Mya。广义银莲花属被分裂为两大类的时间约是53.02 Mya。非洲产的Knowltonia与南美洲Barneoudia和Oreithales的分化时间是35.4 Mya，而南美洲类群较早就发生了分化。獐耳细辛属和白头翁属的快速分化都是在中新世期间。分化时间证实银莲花组各个类群早期就形成分化，并沿各自方向独立演化。