虎耳草属山羊臭组分子系统学研究

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	虎耳草属山羊臭组分子系统学研究
其他题名	Molecular Systematics of Saxifraga sect. Ciliatae (Saxifragaceae)
	张得钧
学位类型	博士
导师	陈世龙
	2008-06-07
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	西北高原生物研究所
关键词	虎耳草属山羊臭组虎耳草属核糖体dna Its 叶绿体基因系统发育生物地理学
摘要	虎耳草属Saxifraga L山羊臭组sect. Ciliatae Haw.是该属中最大的一个组，共有175种，主要分布在喜马拉雅地区，我国分布有166种，占总种数的95%；其中，112种为中国特有。约80%的种类分布在我国青藏高原和西南地区，是中国喜马拉雅植物成分的代表类群。山羊臭组内物种分化十分显著，分类系统复杂，该组内类群间的系统发育关系不明确。本文利用3个DNA片段，即1个核糖体DNA ITS和2个叶绿体基因片段（trnL-F、psbA-trnH）分析了71种虎耳草属植物，重建了虎耳草属山羊臭组内的演化关系及与虎耳草属其他组的系统发育关系。在此基础上，进一步探讨了虎耳草属山羊臭组物种间的分化时间及其起源扩散。主要结果如下： 1、山羊臭组所有类群聚为单独一支，且与垫状组sect. Porphyrion、虎耳草组sect. Saxifraga、球茎组sect. Mesogyne和仅在欧洲分布的sect. Cymbalaria和sect. Cotylea等8个组聚成的另一分支构成姊妹群； 2、根据形态特征建立的山羊臭组的3个亚组即唐古拉亚组subsect. Hirculoideae、莲座状亚组subsect. Rosulares和具芽亚组subsect. Gemmiparae各自聚为一支。唐古拉亚组和莲座状亚组又聚为一亚分支与具芽亚组构成姊妹群，而且具芽亚组最早从山羊臭组这一支中分化出来。同时，山羊臭组的鞭匐枝亚组subsect. Flagellares和subsect. Hemisphaericae的代表类群位于具芽亚组类群分支内部而不能成立； 3、对虎耳草属山羊臭组及其他组的分歧时间进行了估算，推测小花组与虎耳草属分化的时间大约是64.3-64.7百万年前左右。山羊臭组分歧的时间为30.4-35.9百万年前。在山羊臭组内，具芽亚组分化最早，分歧时间大约是16.7-27.5百万年前；莲座亚组次之，分歧时间大约是13.9-20.3百万年前；唐古拉亚组分化最晚，分歧时间大约是8.53-14.01百万年前，该亚组是山羊臭组中最年轻的一个类群。DIVA分析结果表明，虎耳草属可能在白垩纪晚期起源于亚洲东北部地区，而山羊臭组可能在渐新世起源于东亚地区，研究结果与来自古地质和古地理的证据较为一致。
其他摘要	The largest section of the genus Saxifraga (Saxifragaceae), sect. Ciliatae Haw. consists of 175 morphologically diverse species. This Section is mainly distributed in the Qinghai-Tibetan Plateau and adjacent regions of southwestern China, and more than 80% of the total number of species are endemic to this region. Not only are whether this section is monophyletic uncertain, but also phylogenetic relationships within sect. Ciliatae and among sections of Saxifraga are yet unclear. In this study, the phylogeny and evolutionary history of Saxifraga sect. Ciliatae including 71 species were explored using sequences of three DNA fragments from ITS and cpDNA (trnL-F and psbA-trnH). In addition, we estimated the divergence time of the main lineages of Saxifraga sect. Ciliatae and inferred its biogeographic history. The results are as follows: 1. Saxifraga sect. Ciliatae, as traditionally defined, was recovered as a monophyletic clade and its sister group is a well supported clade that includes species from 8 sections, such as sect. Porphyrion, sect. Saxifraga and sect. Mesogyne etc. 2. In sect. Ciliatae clade, subsect. Gemmiparae, subsect. Hirculoideae and subsect. Rosulares were also recovered as three monophyletic subclades. Subsect. Hirculoideae and subsect. Rosulares clustered together as sister subclade while subsect. Gemmiparae subclade diverged early. Subsect. Flagellares and subsect. Hemisphaericae can not be treated as distinct entities because of their representatives nested within the subsect. Gemmiparae subclade. 3. The divergence times of Saxifraga sect. Ciliatae and other sections of Saxifraga were estimated. The results suggested that sect. Micranthes diverged from the genus Saxifraga about 64.3-64.7 Ma (Million years ago), and the divergence times of sect. Ciliatae, subsect. Gemmiparae, subsect. Rosulares and subsect. Hirculoideae were approximately 30.4-35.9 Ma, 16.7-27.5 Ma, 13.9-20.3 Ma and 8.53-14.01 Ma, respectively. We suggested that the genus Saxifraga most likely arose in northeastern Asia during the Cretaceous, and the sect. Ciliatae evolved from the genus Saxifraga in eastern Asia during the Oligocene based on the DIVA analysis.
页数	82
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3228
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	张得钧. 虎耳草属山羊臭组分子系统学研究[D]. 西北高原生物研究所. 中国科学院西北高原生物研究所,2008.

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