甜菜单胚雄性不育系与保持系花药及小孢子发生的超微结构观察

为阐明甜菜单胚雄性不育系和保持系花药及小孢子发育的超微结构差异．以自育的甜菜单胚细胞质雄性不育系（CMS系）TB9-CMS和保持系（O型系）TB9-O为试验材料，在甜菜花芽分化、现蕾初期、开花初期分别进行4次花蕾取样．电子显微镜观察花药及小孢子发育过程的超微结构差异。结果表明．甜菜单胚CMS系与。型系花药和小孢子发育过程的超微结构存在明显差异。甜菜单胚CMS系花药壁产生初始期与。型系相似．但小孢子母细胞的数量较少，液泡化明显；绒毡层发育初期也形成乌氏体原始颗粒，但仅维持初始状态而停止发育：绒毡层在四分体期收缩离位，瓦解内移；小孢子母细胞形成四分体后，胼胝质壁较厚，小孢子逐渐变异开始退化。观察还发现，甜菜绒毡层细胞间以及形成四分体的胼胝质壁间有胞间连丝结构．

Ultrastructural Observations on the Anther and Microsporogenesis in Monogerm CMS Lines and Its O-type Lines of Sugarbeet

Uhrastructural differences were observed on the anther and microspore genesis in monogerm cytoplamsic male sterile （CMS） lines and its O-type lines of sugarbeet. Ultrastructural characteristics of anther and microsporogenesis at flower bud differentiation, early budding stage and early flower stage of CMS lines and O-type lines in sugarbeet were described in detail under electron microscope. Though monogerm CMS lines and its O-type lines of sugarbeet had a similar structure in initial period of anther wall, microspore mother cells were clearly vacuolized and fewer in numbers. The early development of tapetum, original particles of ubisch bodies were formed, which maintain their initial state. Morever, tapetum was contracted into dislocation and collapsed at tetrad stage. Callose wall was thick after microspore mother cells formed into tetrad. Meanwhile, microspores were varied gradually and degraded. Plasmodesmi were detected among the tapetum cells and callose wall of the tetrad.