南方鲇卵子发生的超微结构研究

1996年 4月至 1998年 4月 ,以嘉陵江北碚段收集和人工繁殖饲养的处于不同发育阶段的南方鲇雌鱼性腺为材料 ,利用透射电镜研究了其卵子的发生过程 ,共分为卵原细胞期、卵黄发生前期、卵黄发生期、卵黄发生后期和成熟卵子 5个阶段 .卵原细胞的核质比例大 ,有中央大核仁 ,胞质中细胞器少 .处于卵黄发生前期过程中的卵母细胞 ,核膜波曲 ,核仁物质外排明显 ,有线粒体云的存在 .线粒体云主要由线粒体组成 ,同时还有内质网、高尔基体及泡状结构等组分 .卵黄发生期的主要标志是皮层泡的出现 ,皮层泡由高尔基体产生 ,到卵黄发生旺盛阶段 ,核仁物质大量外排 ,排出的核仁物质在胞器、膜性小泡或直接在胞质中沉积形成卵黄小板 .线粒体、内质网、高尔基体、核糖体等胞器丰富、功能活跃 ,其中 ,线粒体尤为突出 .卵母细胞的胞饮作用也特别明显 .卵黄发生后期 ,卵黄物质占据卵母细胞的大部分 ,各种细胞器减少 ,功能减退 ,卵黄合成能力大大减弱 .到成熟卵子 ,卵黄物质几乎充满整个细胞 ,除少部分细胞器维持卵子的功能外 ,其余的均沉积卵黄物质形成卵黄小板

Ultrastructural Studies on Oogenesis of Silurus meridionalis Chen

From April, 1996 to April, 1998, oogenesis of Silurus meridionalis was studied by transmission electron microscope (TEM). Fishes with different stages of ovary, were reproduced artificially in hatching pools of School of Life Science, Southwest China Normal University, or collected from Beibei section of the Jialing River. The oogenesis in S.meridionalis could be divided into five stages: oogonia, provitellogenic, vitellogenic, postvitellogenic and ovum. The characteristics of oogania were as follows: high nuclear cytoplasmic ratio, big nucleolus in the centre of nucleus and a few organells in the ooplasm. During provitellogenic stage, the characteristics were observed: waving nuclear membrane, apparent release of nucleolus component from the nucleus, mitochondrial cloud which mainly consisting of mitochondria (M) and a little endoplasmic reticulum (ER), golgi complex (G) and vesicles (V). Cortical alveola which came from G, marked the begining of vitellogenic stage. When vitellogenesis was vigorous, most nucleolus component was released into ooplasm. In ooplasm, the nucleolus component was deposited in organells and vesicles or directly deposited in ooplasm to form the yolk plate. M, ER, G and ribosome (R) were abundant and functional vigorous. Especially, M was most outstanding. During postvitellogenic stage, most of oocyte was occupied by yolk plate, the type and function of orgenells declined. So speed of producing yolk plate reduced. When oocyte became mature, ooplasm was nearly filled with yolk plate, most organelles became into yolk plate except a littl functional organells.