白肛海地瓜精子发生及形态的超微结构

Spermatogenesis and Sperm Morphology of Sea Cucumber Acaudina leucoprocta

通过透射和扫描电镜观察了白肛海地瓜(Acaudina leucoprocta)的精子发生过程及其形态结构,揭示了白肛海地瓜精子发生时期一系列变化,其精子发生分为精原细胞、初级精母细胞、次级精母细胞、精细胞、成熟精子5个时期。精原细胞体积最大。精母细胞染色质开始凝集。精细胞前顶体颗粒形成。白肛海地瓜成熟精子的超微结构为原生型,由头部、中部、尾部组成,头部圆形,最前端为顶体,核染色质凝集成团块状,中部是线粒体和中心粒复合体融合成1个超大结构,尾部长约60μm,尾部鞭毛横切面为典型的"9+2"型结构。

The ultrastructure and development of the sperm of sea cucumber Acaudina leucoprocta were observed by using scanning electronic microscopy （SEM） and transmission electronic microscopy （TEM）. As expected, spermatogenesis was divided into five periods： spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid and mature spermatozoon. Spermatogonia had the biggest volume. Chromatin condensation and a pair of centriole were found in spermatocyte. The mature spermatozoon belonged to primitive type, consisting of head, middle piece and tail. The head was spherical in shape with apical acrosome, and chromatin was condensation in the nucleus. Mitochondria complex and centrioles were observed in the middle piece, and the flagellum showed a simple ＂9 ＋2＂ type.