【作者】 殷继艳；

【导师】 张建国；

【作者基本信息】 中国林业科学研究院 ， 森林培育， 2006， 博士

【摘要】 本研究从新疆额尔齐斯河流域两岸及河谷共收集杨属黑杨派、白杨派和青杨派等3大组6个种共83份样本单株，首次对新疆额尔齐斯河流域两岸及河谷天然林杨属种间亲缘关系、银灰杨杂种形成机制、额河杨和新疆杨的分类地位问题，从分子水平进行了比较系统的研究和分析，取得了一系列有重要价值的结论。 (1)SSR分析结果表明，额尔齐斯河流域天然杨属分为两大类群，即黑杨派和青杨派为一类，白杨派为一类，表明黑杨派和青杨派的亲缘关系比较近，而白杨派则较远。聚类分析显示，来自不同地理生境的苦杨种群其遗传结构差异比较显著，但同一种群内其遗传比较接近。由于额河杨与欧洲黑杨位于同一个大的分支，与苦杨有显著的差异，因此把杂种额河杨放到黑杨派是正确的，同时也表明杂种额河杨具有更多的欧洲黑杨的成分。 (2)银白杨种内相似系数为0.70-0.96，欧洲山杨为0.68-0.96，银灰杨为0.50-1.00，表明白杨派三个树种内部均有不同程度的遗传分化，特别是银灰杨更大，来自不同地点的银灰杨种群遗传差异较大的，但种群内分化相对较小。 (3)研究表明，在欧洲山杨分布区未发现有银灰杨种群的存在，这就暗示了银白杨和欧洲山杨的杂交方式，基因渐渗是通过欧洲山杨花粉的传播优先于从银白杨到欧洲山杨。另一种可能是从银白杨向山杨的花粉传播存在某种障碍，如花期不遇等(因二者分布的海拔不同)。研究发现，欧洲山杨的2个单株样本(大东沟H11、哈巴河H41)在总体聚类中，与来自玛拉斯林场基因库的银白杨E11同源性比较高，而与原山杨种群(H12、H41、H42、H43)的遗传差异比较大，这暗示山杨也可能存在接受银白杨花粉的可能。 (4)关于银灰杨的形成机制，在对第1次采集的样本进行SSR结果分析时，由于来自布尔津的种群G11♀和G12♀与山杨位于同一个聚类分支，因此推测银白杨和欧洲山杨基因渗透的方式与欧洲的方式可能不同，存在银白杨向山杨的基因渗透。由于山杨分布区并没有银灰杨与山杨相伴分布的现象，因此要解释布尔津类群的G11♀和G12♀形成的机制，一种可能是在早期地质时期，现在银灰杨分布的区域，银灰杨与山杨和银白杨共同生长在同一区域，只是随着阿尔泰山脉的隆起，造成了今天白杨组内种的分布格局。进一步推测是来自布尔津类群的G11♀和G12♀形成的年代可能远远早于北屯类群的G2♂和G3♂，它们可能均是早期杂种的克隆繁殖后代。基于这一点，进一步推测来自北屯的哈拉希里克种群(G30♀、G31♀)和西柏渡种群(G32♂、G33♂)均可能都更多还原

【Abstract】 A total of 83 samples belonging to 6 species from 3 sections were collected from natural stands of the genus Populus in Ergis River Watershed in this study, interspecific relationship the forming mechanism of hybrid P.canescens and the classification positions of P. ×jrtyschensis and P.albal were investigated using DNA markers and the main findings were summarized as the following.(1) The SSR analysis showed that the populus natural stands of Ergis River Watershed could be divided into two groups, one is Aigeiros and Tacamahaca, the other is Leuce, so the genetic relationship between Aigeiros and Tacamahaca was closer than that between Leu and Aigeiros or Tacamahaca. It appears that it is more variable in genetic structure of the populations of the P.laurifolia from different entironments than within the populations. In UPGMA tree, P. ×jrtyschensis and P.nigra could be clustered into one group, different from P.laurifolia, supporting the conclusion that P. ×jrtyschensis and P.nigra are the same section, In addition, P. ×jrtyschensis have the more component of P. nigra, and similar to P. nigra in stem form .(2) The similarity coefficient ranging from 0.7-0.96 within the P. alba, 0.68-0.96 within P.tremula , and 0.50-1.00 within P.canescen. The result shows that there are high level of genetic variation of P.canescens, also more among the populations than within populations.(3) Investigation showed that there is no distribution of P.canescens in the distributing range of P.tremula. so it indicated that the pattern of the hybrid between P.tremula and P.alba is that introgression occurs preferentially from P.tremula to P.alba L. via P.tremula pollew. Another reason may be the barrier of P.alba to P.tremula via P.alba pollen, such as different florescence(because elevation of two species is different). In UPGMA tree, 2 samples of P.tremula (H11, H41) are highiy homologous with P.alba E11 (from Manasi gene bank of popular ),and different from populations of P. tremula( H12 H41 H42 . H43), indicating that it is possible for P.tremula obtain P.alba pollen.(4) About the forming mechanism of hybrid P.canescens.we suggest that introgression occurs preferentially from P.alba to P. tremula different from Europe, due to the Bu’erjin populations更多还原