Ultrastructural And Histochemical Observation On The Development Of Oocytes Of Haliotis Discus Hannai

Ultrastructural changes of oogenesis in Haliotis discus hannai were observed under TEM and histochemistry. Oogonia lacked organelles in cytoplasm besides of some mitochondria and a lot of ribosomes. At the early stage of vitellogenesis, oocytes contained many mitochondria, reticula and a few of yolk granules. During the vitellogenesis, the size of oocytes rapidly becomed larger, and many mitochondria, reticula and yolk granules were appeared. At the maturation stage, there were more yolk granules, lipid droplets and less organelles in cytoplasm. Also, we analysed the result of histochemistry during the development of oocytes and made a discussion on the formation of yolk granules.