长毛对虾精子形成的超微结构

于１９９３－１９９４年在厦门海区采集长毛对虾雄性成虾，取其精巢，输精管和精荚，采用ＪＥＭ－１００ＣＸⅡ透射电镜观察长毛对虾精子形成过程的超微结构，并根据顶体形成过程中超微结构的变化进行分期。结果表明：长毛对虾精子形成过程分为早期精子细胞，中期精子细胞，晚期精子细胞及成熟精子四个时期。在早期精子细胞阶段，细胞质中含有丰富的粗面内质网，其周围分布着许多大小不一的囊泡，囊泡融合前顶体囊，囊内合成前顶体颗

ULTRASTRUCTURE OF SPERMIOGENESIS IN THE SHRIMP PENAEUS PENICILLATES

From 1993 - 1994, mature male shrimp Penaeus penicillate were collected from the coastal areas of Xiamen. Testes, vasa deferentia and sperrnatophores were cut into small fragments and fixed for 2h at 4°C in 2.5% glutaraldehyde, postfixed for 2h at 4°C in 1% osmium tetroxide, and embedded in 618^# resin. Thin sections were cut with glass knives, contrasted with uranyl acetate and lead citrate, and examined on JEM-l00CXII transmission electron microscope.

The study shows that the spermiogenesis of Penaeus penicillates can be divided into four successive stages, namely early spermatid, mid spermatids, late spermatids and mature spermatozoa.

Early spermatid possesses numerous rough endoplasmic reticulum and small vesicles; some of vesicles coalesce with the large proacrosomal vesicle. The nucleus and the voluminous proacrosomal vesicle occupy both cell poles. Within proacrosomal vesicle, the proacrosomal granulated material develops. The nucleus shows extensive areas of condensed chromatin and is entirely separated from the cytoplasm by the nuclear envelope.

In mid spermatids, the nucleus has become uncondensed and the perinuclear cytoplasm is considerably reduced. The chromatin is ?nely granular in appearance. The nuclear envelope has reptured. Proacrosomal granulated material has formed a primordial spike.

In late spermatids, the primordial spike tends to elongate progressively. After reduction in volume, the perinuclear cytoplasm forms a thin band around the nuclear region. The chromatin also undergoes morphologic change to form a flocculent pattern.

In the stage of mature spermatozoa, proacrosomal vesicle further develops into spike, inner acrosomal layer and outer acrosomal layer. The nuclear and cytoplasm have not changed significantly in this stage.

To sum up, during the spermiogenesis in Penaeus penicillates, the chromatin undergoes three morphologic changes. The initially continuous nuclear envelope breaks up, allowing for free nucleocytoplasmic exchange. Proacrosomal vesicles are thought to derive from rough endoplasmic reticulum.