KIB OpenIR  > 昆明植物所硕博研究生毕业学位论文
云贵高原多星韭(Allium wallichii Kuth.)多倍体地理分布格局与起源研究
Thesis Advisor周浙昆
Degree Grantor中国科学院研究生院
Degree Discipline植物学
Abstract多倍体指含有3个或更多个染色体组或基因组的个体、居群和种。多星韭(Allium wallichii Kunth.)为葱科(Alliacae)葱属(Allium)草本植物,云贵高原是其主要分布区。本文对该种在云贵高原的分布及起源问题进行了研究。采用根尖常规染色体制片法对云贵高原的多星韭17个居群进行核型分析;测定ITS和2个叶绿体片段,对多星韭四倍体起源次数问题进行分析。主要结论如下:(1)多星韭的细胞地理分布格局。二倍体居群、二倍体与四倍体混生居群分布于云南中部至西北部,四倍体居群分布于云贵高原。四倍体海拔分布较二倍体宽。 (2)四倍体的种内起源。二倍体与四倍体核型类型相似度较高;云南西北部二倍体和四倍体多星韭形态上不可区分;ITS系统发育关系表明多星韭为单系。以上表明多星韭四倍体应为同源四倍体。(3)四倍体的多次起源。基于petL-psbE与trnQ-rps16联合分析,推测多星韭四倍体在云贵高原至少起源3次。(4)二倍体与四倍体的生殖隔离。二倍体与四倍体多星韭ITS系统发育分析显示,两者均为单系类群,表明两者已建立生殖隔离。基于cpDNA单倍型和ITS变异式样的分析,发现四倍体间已发生广泛杂交和基因渐渗。
Funding ProjectPolyploidy, the presence of three or more genomes in an organism, has occurred extensively in plants, and plays a major role in the evolution and speciation of angiosperm. Despite extensive study of the cytotypes distribution and origin of polyploidy, few studies have been reported in China, especially in southwest region. Allium wallichii Kunth (Alliaceae) is a perennial herb, distributed in southwest China, northen India, Nepal, Sikkim and Bhutan. The multiple ploidy levels and rapid differentiation has made A. wallichii a good candidate for studying polyploidy. The cytotypes distribution and origin of A. wallichii polyploidy has been studied in Yunnan-Guizhou Plateu, a main distribution area of this plant. Root-tip squashes were used to identify the ploidy level and karyotypes of 412 plants from 17 populations sampled from Yunnan-Guizhou Plateau. Based on nuclear ITS DNA sequences in 83 individuals from 17 populations, phylogentic analysis were performed to investigate types of A. wallichii polyloids, and determine if the reproductive isolation has been established between diploids and tetraploids. Based on two chloroplast DNA (cpDNA) fragments (petL-psbE, trnQ-rps16), haplotypes were identified , and the origination of tetraploids were analyzed. The main results and conclusions are as follows: 1. Distribution of cytotypes, Cytotype distribution was analyzed based on 412 newly studied plants from seventeen populations and published literatures. Nine diploid populations, six diploid-tetraploid mixed populations occur in central to northwest Yunnan, while twelve tetraploid populations occur in the Yunnan-Guizhou Plateau. Furthermore, tetraploids has a wider altitude range (1400-3726 m) than diploids (2100-3638 m), which suggests the adaptative ability of tetraploid is much stronger than its diploid pregnancies. Tetraploid populations distributed in northwest Yunnan have much lower karyotype asymmetry with the asymmetry indexes (AI) ranges from 1.83 to 2.87 compared to other populations of other areas (AI, 2.03-3.02). This suggests tetraploid in northwest Yunnan is likely to have an earlier derivation. 2. Autoploidization origin of the tetraploids, Diploids are all 2A type except that Zhongdian D and Baoshan populations are 3A type, and tetraploids are all 2A type but Huize and Hezhang populations are 2B type. It shows high similarity of karyotypes of diploid and tetraploids. In addition, the undistinguishable morphology of A. wallichii with different ploidy levels in northwest Yunnan and the monophyly of A. wallichii in ITS strict consensus tree all suggest autopolyploid origins of tetraploids A. wallichii. 3. Multiple origins of tetraploids, Based on two cpDNA fragments (petL-psbE, trnQ-rps16) in 85 individuals from 17 populations across the Yunnan-Guizhou Plateau, a total of 17 haplotypes were identified, among them, 3 in diploids only, 11 in tetraploids only, and 3 found in both cytotypes. This, plus network analyses, indicated that tetraploids have arisen independently from diploids at least three times. 4. Productive isolation between diploids and teraploids, ITS phylogenetic analyses between diploid and tetraploid A. wallichii shows that diploids and tetraploids are both monophyly, with bootstrap value 100% and 88% respectively, indicating that the reproductive isolation has been established between them. Based on cpDNA haplotypes and ITS variation types analyses, extensive hybridization and gene introgression may have occurred among tetraploids.
Document Type学位论文
Recommended Citation
GB/T 7714
翟艳红. 云贵高原多星韭(Allium wallichii Kuth.)多倍体地理分布格局与起源研究[D]. 中国科学院研究生院,2010.
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