云南中甸黄花杓兰(Cypripedium flavum)的遗传结构及克隆多样性分析
其他题名Genetic Structure and Clonal Diversity of Cypripedium flavum (Orchidaceae) Populations from South-west China
蔡凝枫
学位类型硕士
导师胡虹
2007-05-23
学位授予单位中国科学院昆明植物研究所
学位授予地点昆明植物研究所
学位专业植物学
关键词黄花杓兰 遗传结构 克隆多样性 Aflp
摘要黄花杓兰(Cypripedium flavum),兰科(Orchidacaea)杓兰属(Cypripedium)植物,为我国特有植物,分布于云南西北部、西藏东南部、四川、甘肃南部和湖北西部的高海拔地区,是一种典型的多年生高山草本植物。近年来,由于人为破坏及自身繁殖困难等原因导致居群数量急剧下降,急需探明黄花杓兰的濒危机制并发展有效的保护策略。论文的主要研究目的在于采用AFLP分子标记方法对云南省中甸分布的黄花杓兰居群进行研究,通过研究居群的遗传多样性水平、遗传结构及克隆多样性、克隆空间结构,探讨有性和无性两种繁殖方式的相对比例,揭示黄花杓兰的繁殖策略和遗传变异程度,进而为杓兰的物种保护提供理论依据。 本研究利用AFLP分子标记对黄花杓兰在云南中甸的6个自然居群共121个个体进行分析得到以下结果:两组引物共产生104个位点,其中86个为多态位点,多态位点百分率为82.69%。黄花杓兰具有丰富的遗传变异(物种水平上,He = 0.2884,Ho = 0.4312;居群水平上,P = 64.59%, He = 0.2449, Ho = 0.3606)。其中,小中甸(He =0.2618)和天生桥(He =0.2610)居群的Nei的基因多样性系数较高,仙人洞(He = 0.2237)最低。黄花杓兰居群的遗传分化不大(Gst = 0.154),居群间基因交流较为频繁(Nm = 2.7460)。 选择天生桥和五凤山居群作克隆多样性及克隆空间结构的分析。采用样方法(10×16 m2)取样,在每格1m2的正方形的四个顶点取样,分别采集样品94个和44个,共138个个体。AFLP分析结果为:居群的克隆多样性水平高(D = 0.9638-0.9960,G/N = 0.83-0.96),仙人洞和尼西两个居群检测到的克隆分株较多;两个居群中都有一定的克隆生长,同一个克隆的分株距离邻近,两个居群共检测出九个克隆系,其余都为基因型不同的个体。 黄花杓兰的种子极小,种子繁殖投入的资源成本相当巨大,通过幼苗补充来重建居群很困难。本研究结果表明,黄花杓兰的遗传多样性水平较高,居群间遗传分化不大,克隆繁殖能力有限。因此推测黄花杓兰资源遭受严重破坏的主要原因是人类干扰,如公路修建,旅游开发,放牧压力,过度采挖等,对黄花杓兰的生态环境造成很大的破坏,居群数量急剧下降。因此,原生地生态保护及进行人工繁育是较为合适的保护策略。
其他摘要Cypripedium flavum is a terrestrial, herbaceous, perennial orchid with a yellow flower and one of the endemic species in China. C. flavum has two ways of reproduction, sexual and clonal reproduction. We study the genetic diversity, genetic structure, clonal diversity and spatial structure of C. flavum to reveal the relationship of sexual and clonal reproduction and to develop effective strategy for conservation and recruitment. Six populations of the rare plant species Cypripedium flavum were included in a study of genetic diversity, genetic structure, and clonal diversity in Shangri-La (Zhongdian) County, Yunnan Province (South-west China). We selected two AFLP primer combinations which generated 86 polymorphic loci, and the proportion of polymorphic loci was 82.69%. Using POPGENE software, a relatively high level of genetic diversity was revealed: He = 0.2884,Ho = 0.4312 (at species level); P = 64.59%, He = 0.2449, Ho = 0.3606 (at population level). Nei’s gene diversity in XZD population was the highest (He =0.2618), while in XRD population was the lowest (He = 0.2237). Genetic differentiation among populations was not high (Gst = 0.154). A relatively high level of gene flow was obtained among populations. Two rectangular sampling plots of 10×16 m2 were selected in two populations (TSQ and WFS). Within the plots, 94 and 44 leaves of C. flavum were collected at each point of intersection of a 1×1 m grid, respectively and immediately preserved in silica gel to prevent DNA degradation. Clonal diversity of populations was high (D = 0.9638-0.9960,G/N = 0.83-0.96). All of the genotypes were population specific. The clusters of Cypripedium flavum, discriminated in space, consisted of different number of genets. Ramets of same genotype were adjacent, and population expansion through clonal growth was limited. C. flavum has dust-like seeds, and most seeds have no embryo, or no active embryo. Population restoration through seedling recruitment is difficult. The result of our study suggested high level of genetic diversity and low genetic divergence of C. flavum populations in Shangri-La County. Clonal reproduction in C. flavum populations is limited. Therefore, the main reason for the considerable decline of C. flavum in Shangri-La County may be human activities, such as highway construction, tourism, grazing pressure and over collection. In situ conservation and constructing rapid propagation will be two efficient measures for restoration of wild populations of C. flavum in local environments.
页数42
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/202
专题昆明植物所硕博研究生毕业学位论文
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蔡凝枫. 云南中甸黄花杓兰(Cypripedium flavum)的遗传结构及克隆多样性分析[D]. 昆明植物研究所. 中国科学院昆明植物研究所,2007.
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