【作者】 夏涵涵；

【导师】 梁国鲁； 张大明；

【作者基本信息】 西南大学 ， 细胞生物学， 2011， 硕士

【摘要】 麦冬(Ophiopogon japonicus (L.f.) Ker-Gawl)属于百合科沿阶草属,是多年生草本植物,作为沿阶草属的模式种,也是该属内分布最为广泛的种。前人研究表明重庆金佛山地区麦冬存在丰富的染色体数目变异。本研究对该处投影面积约为0.5平方公里,海拔高度在750-900米的区域内分布的麦冬进行穷尽式的采样。通过对金佛山生境的调查,麦冬染色体水平的探究、基因组水平的审视分析麦冬野生居群内变异和同域物种形成的可能性。实验结果以及论证如下：(1)细胞学研究表明麦冬的体细胞染色体数目存在丰富变异,出现X=17和X=18两类基数变异,以及二倍体、四倍体、五倍体、六倍体的倍性变异。(2)原位杂交结果显示,四倍体麦冬(2n=68)具有两对杂交信号。(3)通过近缘属铃兰的引物及自行设计的EST-SSR引物扩增表明居群内不同基数的个体间存在变异。染色体基数的变异可以使得生殖隔离得到快速建立,从而使X=17和X=18分别形成新的物种。在金佛山地区发生的这一染色体重组带来的瞬间成种模式,还为同域物种形成提供了新例证。最后,我们对麦冬野生群体遗传多样性的研究,为我们保护麦冬的遗传资源,制定相应的保护策略提供了重要的指导。更多还原

【Abstract】 As a perennial herb, Ophiopogon japonicus belongs to Ophiopogon in liliaceae family. It is a model and most widely distributed species of Ophiopogon. Previous researches indicated that O. japonicus from Mt. Jinfoshan in Chongqin had profuse variation in chromosome number. Hence, we exhaustively sampled in Mt. Jinfoshan, the projection area of which is 0.5 square meter and altitude is 700-900 meter. Through investigating the habitat niche in Mt. Jinfoshan, studying O.japonicus both in the choromosome level and genomic level, this research showed that:1, Abundant variation of somatic chromosome number existed in O. japonicus. Chromosome counting exposes two basic chromosome numbers(x=17&18 respectively) and ploidy variation like diploid, tetraploid, pentaploid, hexaploid frequently happended in this population2, The result of FISH(Fluorescent in situ hybridization) showed that tetraploid has 2 pairs of signals.3, The genomic data from amplification by primers based on convallariae that is a closely related genera of O. japonicus and self-designed primers according to EST-SSR revealed the distinct divergence between these individuals with different chromosome basic number.Variation in chromosome basic number resulted in the reproductive isolation and contributes the species of x=17 and x=18 divergent into two species. Here we provide a new support of sympatric speciation in a case study of instantaneous speciation model in sibling species of O. japonicus. At last, protections for plant germplasm resources and genetic diversities are proposed basing on our research.更多还原