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杨属(Populus)5个派中,青杨派(sect.Tacamahaca)种类最多,且绝大部分都分布于我国西北、西南、华北及东北地区.青杨派中的青杨(Populus cathayana Rehd.)为我国特有,分布范围仅次于小叶杨,位居青杨派中的第二位.青杨整个分布区内种内遗传变异性很大,但对此开展的研究并不多,除王建园、杨自湘对苗期种源差异,以及杨自湘对不同产地的叶片进行较详细的研究以外,青杨的其他表型性状及同工酶、DNA水平的研究都未见报道.物种或群体的遗传多样性大小是长期进化的产物,是其生存(适应)和发展(进化)的前提.一个群体或种内的遗传多样性越高或遗传变异越丰富,对环境变化的适应能力就越强,越容易扩散其分布范围和开拓新的环境,无性繁殖为主的种也不例外.理论推导和大量实验证据表明,群体的遗传变异的大小与其进化速率成正比,因此对遗传多样性的研究,可以揭示物种和群体的进化历史(起源的时间、地点和方式),也能为进一步分析其进化潜力和未来的命运提供重要的资料.本文用RAPD技术对广泛分布区内的青杨进行分析,揭示青杨种内具有丰富的遗传变异性,并探讨群体发生遗传分化的机制.
Populus genus Populus cathayana Rehd., The most species of sect.Tacamahaca, and most of them are distributed in Northwest, Southwest, North China and Northeast China Populus cathayana Rehd. ) Is endemic to our country, the distribution area is second only to Populus euphratica, which is the second highest among Populus alba L. Populus euphratica has a great intraspecific genetic variability within the entire distribution area, but there is not much research on this field except Wang Jian Yuan, Yang Zixiang on seedling differences in provenance, as well as Yang Zixiang leaves from different areas more detailed study, other phenotypic traits and isozymes, DNA level of the study have not been reported. Species or population genetic Diversity is the product of long-term evolution, which is the prerequisite for its survival (adaptation) and development (evolution). The higher the genetic diversity or genetic variation within a population or species, the more adaptable to environmental changes, The more it is easy to spread its distribution range and open up a new environment, the asexual reproduction of the species is no exception.Theoretical derivation and a large number of experimental evidence shows that the size of the population genetic variation and its evolution rate is proportional to the genetic diversity of research, Can reveal species And the evolutionary history of the group (time, place and manner of origin) can also provide important information for further analysis of their evolutionary potential and future destiny.This paper analyzes the Populus euphratica in widely distributed areas by using RAPD technique, Within the species is rich in genetic variability, and to explore the mechanism of genetic differentiation occurred in groups.