毕设论文生物科学论文.doc

生物科学论文 I 生物科学论文三种甘蓝雄性不育类型花粉发育的细胞学观察院系生命科学学院专业生物科学生物科学论文 II 中文摘要本实验利用光学显微和电子显微镜在细胞水平和亚细胞水平对三种我国研究和利用较多的甘蓝雄性不育类型进行了较为系统全面的雄性败育特征和时期分析。实验结果表明,隐性核不育类型主要败育时期为减数分裂期,主要败育特征为花粉母细胞期绒毡层细胞和中层细胞异常且异常特征在不同植株上表现不一致,四分孢子正常释放后不能形成正常花粉壁,并迅速败育;萝卜胞质不育类型萝卜胞质不育主要败育时期在四分体前期,败育特征主要表现为从减数分裂后期开始绒毡层细胞活动异常, 绒毡层细胞进行性加厚,其大部分四分孢子能自由释放但受绒毡层细胞挤压败育,其小孢子外壁孢粉素沉积延迟,但最终能发育出较为完全的花粉外壁;显性核不育主要败育时期在四分体后期,主要败育特征是小孢子不能自由释放,但花粉壁能正常沉积孢粉素,包裹在四分体外的胼胝质降解延迟,而花粉母细胞壁直到花粉成熟仍不能降解。关键字: 甘蓝( Brassica oleracea) ,雄性不育, 细胞学观察,小孢子发育生物科学论文 III Abstract The microsporogenesis of three kinds of male sterility in Brassica oleracea Var. capitata were investigated by using light microscope(LM) and transmission electron microscope(TEM). Study here suggested that the first sign of significant phenotype of Ms-cr1 was abnormally developed tapetum and middle layer cells at the stage of meiosis. Free microspores did not form exine and degenerate soon after releasing from tetrads. In the Ogu CMS, the microspore disruption was closely correlated with occurrence of tapetal abnormal. After pletion of meiosis, the tapetum cells showed an abnormal increase in size and the released microspore with normal exine were squashed and degenerated soon. The development of microspores in Ms-cd1 parable to fertile plants up to the time of tetrad formation. After pletion of tetrads stage, the separation of microspores from each tetrad in the mutant was arrested .The microspores with developing bacula and tectum in Ms-cd1 still adhered together. The callosic wall of the mutant around the microspores degenerated much slower than that of wild type. The pollen mother cell wall surrounding the developing microspores in Ms-cd1 remained un-degenerated till very late pollen stage. Key words: cabbage( Brassica oleracea) , male sterility , cytological observation , microsporogenesis 生物科学论文 IV 目录 0引言............................................................................................................................ 1 1 材料与方法...................................