【作者】 陈龙；

【导师】 李火根；

【作者基本信息】 南京林业大学 ， 遗传学， 2008， 硕士

【摘要】 鹅掌楸为我国珍惜濒危树种,开展鹅掌楸天然群体遗传结构研究对于该物种的保护及开发利用有重要意义。本研究以鹅掌楸11个天然群体为材料,利用SSR分子标记对其遗传结构、遗传多样性动态变化趋势进行了研究。主要研究结果如下:在物种水平上,14对SSR引物共检测到83个等位基因,平均观察等位基因数(A)为5.93,平均有效等位基因数(Ne)3.3, Shannon多样性指数平均为1.2988,平均期望杂合度(He)为0.5097,Nei遗传多样性指数(h)为0.6493。表明鹅掌楸天然群体中存在较高的遗传多样性。在群体水平上,各群体内的有效等位基因数介于2.04-2.77之间,各居群内观察杂合度(Ho)值变动范围为0.398-0.615,期望杂合度(He)值变动范围为0.425-0.630,说明各居群间的多态性水平差异较大。基因分化系数(Fst)0.1931,即有19.31%的遗传变异存在11个群体之间,绝大部分变异(80.69%)存在于群体内。基因流(Nm)为1.0444,表明群体间存在一定水平的基因流,且西部群体基因流明显大于东部。通过Nei’s遗传距离的UPGMA聚类分析,11个群体大体可分为4个大类:四川叙永,贵州习水,云南文山,云南金平4个群体为一类;贵州黎平,贵州松桃,浙江安吉,安徽绩溪4个群体为一类;湖北咸宁群体为一类;浙江遂昌与福建武夷山2个群体为一类。以黎平天然林群体及其子代群体为材料,研究了鹅掌楸群体遗传多样性的变化趋势。鹅掌楸子代群体遗传多样性略大于亲本天然群体,表明自然状况下,鹅掌楸具有遗传多样性自我保持的机制。最后,根据本实验结果结合鹅掌楸濒危现状,本文还对鹅掌楸种质资源保存利用策略进行了探讨。更多还原

【Abstract】 In this paper population genetic structure and genetic diversity of 11 natural populations of Liriodendron chinense were studied by means of Simple Sequence Repeat(SSR) markers. The main results are highlighted in the following:On the species level, the total polymorphic alleles in 14 loci were 83. The average number of alleles (A) and effective number of alleles (Ne) of Liriodendron chinense were 5.93 and 3.3, respectively. Shannon diversity index was 1.2988 on average. The mean expected heterozygosity (He) was 0.5097. The mean Nei’s diversity index was 0.6493.By the population level, the effective number of alleles of 11 populations ranged from 2.04 to 2.77. The range of expected heterozygosity (He) among populations was from 0.425 to 0.630, which indicated a relatively high level of genetic diversity in Liriodendron chinense natural populations.The coefficient of genetic differentiation was 0.1931 on average, which indicated that 19.31% of the genetic variation occurred among populations and 80.69% occurred within populations. That means a relatively high level of genetic differentiation among populations despite the existence of most genetic variation within populations. The gene flow (Nm) revealed was 1.044, which showed a low gene flow among the 11 populations of natural Liriodendron chinense and the gene flow among western populations was higher than eastern populations obviously.The cluster analysis results showed that the 11 populations could be divided into four groups: populations from Xuyong county in Sichuan province, Xishui county in Guizhou province, Wenshan county and Jinping county in Yunnan province were included in group 1; populations from Liping county and Songtao county in Guizhou province,Anji county in Zhejiang province,Jixi county in Anhui province were included in group 2; the population from Xianning county in Hubei province was included in group 3,and the other two populations were in group In addition, the genetic diversity was compared between natural population in Liping and its offspring population. A little higher genetic diversity was found in offspring population, indicating that Liriodendron chinense natural populations could conserve its genetic diversity if no human disturbution.Based on the research of population genetic structure strategies,the conservation of these germplasm resources of Liriodendron chinense was also discussed.更多还原