合浦珠母贝精子发生过程的超微结构观察

OBSERVATION ON THE ULTRASTRUCTURE OF SPERMATOGENESIS AND SPERMATOZOON OF PEARL OYSTER,PINCTADA MARTENSII DUNKER

报道了透射电镜下合浦珠母贝精子发生过程超微结构的观察结果。描述了精子发生过程中线粒体，中心体（鞭毛），顶体泡和细胞核的演变过程。精子细胞核内染色质以颗粒状形式凝集，精子核呈圆桶状，圆形的顶体泡迁移到顶体部位后变形成为圆锥形顶体。合浦珠母贝精子经过精度原细胞，精母细胞和精子细胞，最终发育成为成为成熟的精子，成熟的精子由头部（长约２μｍ），中段（长约０．６８μｍ，宽约１．

The ultrastructure of spermatogenesis and spermatozoon of pearl oyster,Pinctada martensii Dunker was observed with EM.We find that the flagellum structure first appear in spermatocyte .Mitrochondrias get fused to form big globular mitochondrias in spermatid.Chromatin condense in granular pattern.Preaerosome vesicle form in spermatid and during spermiogenesis ,it migrate to the apex of the sperm,change shape and become a conical acrosome.Mature sperm are of primitive type,cosisting of three regions:head (2 μm in lengeh),middle piece (0.68×1.6μm) and tail (50～60×0.2 μm),a crosone vesicle contain two distinguish materals.1,a electron- dense body at the anterior and 2.a less dense,homogenerous material at the posterior.The nuclear is barrel —shaped and the chromatid is highly condensed ,but nuclear vacuoles also remain.Four (occasionally Five) large globular mitoehondrias with well developed eristaes and two centrioles with normally 9+0 structures are found at middle piece of mature sperm.The distal centriole become the basal body of fragellum.Associated with distal centriole are radiating arms which directly attach to the cell membrane where electron- dense material is found.The flagellún is a standard 9+2 microtubular structure limited by the cell membrane.Ocasionally,two or three set of 9+2 structure are found in the same cell membrane.Intercellular bridge are found at every stage of spermatogenesis and remain till mature sperm.