中国淡水蛏卵子发生的超微结构

运用透射电镜研究中国淡水蛏Novaculina chinensis卵子发生过程中细胞和细胞器的超微结构变化，结果表明，卵原细胞的胞质含有丰富的核糖体及少量线粒体和内质网，其它细胞器不发达，卵黄合成前期，卵母细胞胞体增大，线粒体较多，量小泡装和条索状的内质网；同时随着发育的进行，出现卵黄膜、合成少量卵黄粒及产生大量脂滴，卵黄全成期卵母细胞胞体迅速增大，细胞核伸出伪足状突起；胞 内出现丰富的线粒体、溶酶体及结构独特的内质网、卵黄粒越来越多，而脂滴越来越少，成熟期卵母细胞胞体达到最大，细胞器不发达，胞质中充满大量卵黄粒，仅少量脂滴。首次观察到卵母细胞表面伸出伪足状突起，这也是外源卵黄发生的证据。讨论了中国淡水蛏卵子发生的特点.

ULTRASTRUCTURES OF NOVACULINA CHINENSIS DURING OOGENESIS

Ultrastructural changes of oogenesis in Novaculina chinensis were observed under TEM. Oogonia lack organelles in cytoplasm besides of some mitochondria and a lot of ribosomes. At previtellogenic stage,oocytes contain many mitochondria and rough endoplasmic reticula.Yolk membrane, a few of yolk granules and many lipid droplets are found in this later stage. During the vitellogenesis, the size of oocytes rapidly becomes larger. The nuclei of oocytes expand amoeboid processes.There are also many various and developing organelles (mitochondria, lysosomes, rough endoplasmic reticula). At the same time,the yolk granules become more and more, and the lipid droplets become less and less.At maturation stage, there are more yolk granules and less lipid droplets in cytoplasm. Several organelles are presumed to involve in formation of yolk granules. We observed amoeboid processes on surface of oocytes for the frist time. This article also dicusses features of oogenesis in Novaculina chinensis . Fig 2, Ref 13