【作者】 郭志刚；

【导师】 赵桂仿；

【作者基本信息】 西北大学 ， 植物学， 2008， 硕士

【摘要】 东亚七筋姑C.udensis Trautv.et Mey.属百合科黄精族七筋姑属(ClintoniaRaf.)多年生草本植物,具有二倍体(2n=14)和四倍体(4n=28)两种细胞型。其中二倍体的分布从中国西南的云南一直延伸到俄罗斯的滨海边区。四倍体除分布在中国云南及其以西的喜马拉雅地区,日本和萨哈林岛以外,在陕西南部化龙山北坡海拔2200米以下的阔叶林或针阔混交林下和湖北木林子较狭的范围内也有分布。在东亚七筋姑种内叶、果实、花序和花粉等形态特征变异复杂多样,但反映不出倍性上的差异,显示出该种目前正处于强烈的分化阶段。本研究采用克隆测序的方法检测了13个东亚七筋姑二倍体居群和5个四倍体居群,共18个居群的rDNA ITS序列。研究表明东亚七筋姑ITS序列长度显示出较高的多态性,ITS1序列的长度在171—270bp之间,ITS2序列的长度在205—238bp之间,5.8s序列的长度在162—164bp之间,序列中GC的含量为45.83%—54.13%。当空位(gap)作缺失处理时,东亚七筋姑ITS区全序列排序后的长度为682个,其中简约性位点289个。用MEGA4.0计算Kimura双参数法遗传距离,得到18个居群之间遗传距离平均值为0.249,结果显示ITS序列在东亚七筋姑种内有着很大的变异和分歧。用SPSS进行双变量相关性分析显示,居群间遗传距离和地理距离有着较强的正相关性(r=0.372,P=0.01)。采取最大简约法(Maximum Parsimony method,MP)、邻接法(Neighbor-joiningmethod,NJ)和最小进化法(Minimum Evolution,ME)对获得的序列进行分析,并构建分子系统树,探讨东亚七筋姑各居群间的关系和多倍体的起源方式。利用PAUP4.0b4a软件,采取最大简约法分析,获得严格一致树,其步长1056,一致性指数(CI)为0.630,保留系数(RI)为0.684。结果表明四倍体居群没有聚为单独的一支,而是和相邻地理单元的二倍体居群聚为一支,支持东亚七筋姑异地多起源的推断。更多还原

【Abstract】 Clniotnia udensis Trautv.et Mey.,a perennial herb,belongs to the genus Clintonia Raf in the tribe Polygonateae(Liliaceae).Two ploid levels exist in this species(2n=14 and 2n=48).The diploid C.udensis is distributed from Northwest China’s Yunnan Province to Russia’s Primorskiy Kray,while the tetraploids are distributed in Yunnan,Himalayas,Japan,Mulinzi in Hubei and a narrow area in the northern hillside of Mt.Hualongshan below 2200 altitude in Shaanxi province.The characters of the shape in leaf,fruit,inflorescence and pollen et.al differentiate greatly in the inner species,but no differences are showed in ploid level,the results infer the species is in the stage of great differentiation.ITS sequences of 13 Clintonia undensis diploid populations and 5 tetraploid populations are reported by cloned sequencing. Sequence analysis shows that the length of ITS1 varies from 171bp to 270 bp;the length of ITS2 is from 205bp to 238 bp and 5.8S is from 162bp to 164bp.Among the 18 ITS sequences 289 sites are informative.The contents of GC of the sequences are between 45.83%～54.13%.Genetic distances are gained by MEGA4.0,the average genetic distance of 18 populations is 0.249,the results indicate that ITS sequences among the 18 populations differentiate significantly.Correlative analysis by SPSS reveals that genetic distances and geographical distances in these populations show positive correlation(r=0.372,P=0.01).Phylogenetic analysis based on the internal transcribed spacers(ITS)of 18-26S rDNA have been conducted,using maximum parsimony method(MP), neighbor-joining method(NJ)and minimum evolution(ME),phylogenetic trees are reconstructed and origin of tetraploids Clintonia undensis and the relationship among the populations are discussed.Phylogenetic analysis of ITS sequences using PAUP4. 0b4a software obtained the MP trees(Length=1056,CI=0.630 and RI=0.684) when the gaps are treated as missing.The results indicate that the diploid populations and tetraploid populations from same region are always clustered.The origin of Clintonia undensis polyploidy is polytopic.更多还原