【作者】 王静澄；

【导师】 安新民；

【作者基本信息】 北京林业大学 ， 林木遗传育种， 2010， 硕士

【摘要】 毛白杨(Populus tomentosa Carr.)是优良的绿化和用材树种,但是毛白杨花期飞絮现象严重,不仅影响环境质量,而且存在安全隐患,给正常的生活生产秩序带来诸多不便。本文针对飞絮污染之一问题,通过石蜡切片技术研究了毛白杨雌花发育一般过程,首次揭示了毛白杨种毛纤维的形态发生规律,发现种毛纤维是由子房底部胎座及珠柄表面的一层细胞发育而来。进一步通过对种毛纤维发生过程中可溶性糖的积累与蔗糖代谢相关酶活性的分析发现：(1)子房中葡萄糖含量变化、SS活性变化存在密切的相关性；(2)SS活性和葡萄糖含量变化趋势与种毛纤维的形态发生在时间上相耦合。这些结果为种毛的形态发生提供了生理生化依据,说明SS是毛白杨种毛纤维发生过程中的一个关键酶。为进一步了解毛白杨SS酶相关基因在种毛形成的可能作用,采用semi-quantitative RT-PCR技术对编码SS的PtSS基因家族成员的表达规律进行了分析,发现PtSS1和PtSS2在毛白杨各个部位中均有表达,PtSS1在根及花芽中表达量较高,在茎、叶和叶芽中较低,PtSS2在各部位中近似恒定表达且表达量均较高,PtSS3、PtSS4和PtSS6除去茎和叶外各个部位均有表达,表达模式相似,而PtSS7则只在茎中有表达,且表达量较低。本文从形态解剖、生理生化、分子表达三个层次,由表及里研究了毛白杨种毛形成的形态学规律、生理生化基础和分子基础,首次揭示种毛始发于子房底部胎座及珠柄表层细胞和蔗糖合酶基因家族成员的组织表达模式,研究结果不仅对于阐明杨树种毛形成的分子生理机制具有重要的理论意义,而且为通过基因工程手段控制杨树飞絮污染,进而选育无种毛杨树新品种奠定了理论基础。更多还原

【Abstract】 Populus tomentosa Carr. (Chinese white poplar) is a native species of great greening and timber value, yet serious catkin-caused pollution of which at flowering phase inconveniences people’s normal work and life. Herein, our research on general process of floral development with female Populus tomentosa using paraffin section initially uncovers a complete morphogenesis of seed hair, and that seed hair developing from the superficial cells of ovary placentas and funicles was confirmed. Study on accumulation of soluble sugar and activity of sucrose-metabolizing enzyme in fibrogenesis reveals that, the change of glucose content and that of SS activity are temporally accordant with the morphology of seed hair fiber, thus providing convincing physiological supports for morphogenesis of seed hair, and identifying SS as a key enzyme during the whole fibrogenesis. Furthermore, analysis of PtSS family members encoding SS through semiquantitative PCR technique shows a far-ranging expression of PtSS1 and PtSS2 in all tissues, while essentially equal amounts of PtSS3 and PtSS4 and PtSS6 transcript in all tissues but stem and leaf, and a low transcript of PtSS7 in stem only. More specifically, PtSS1 expresses most highly in both root and floral bud, which is not the case for that in other tissues. PtSS2 expresses in all tissues in a critical high and constant fashion.A complete seed hair genesis process is firstly represented in this paper, and its physiological support has been obtained. Ultimately, expression patterns of each member in PtSS family for this process identify PtSS7 as a member expressing specifically to stem. The above-mentioned results do not only make a profound theoretical sense for illuminating molecular mechanism of such gene family in the genesis of seed hair, but also lay a theoretical foundation for addressing the flying catkin-caused pollution through gene engineering and further breeding a new poplar cultivar without seed hair.更多还原