东方扁虾精子发生的超微结构

应用电镜技术研究了东方扁虾（Thenus orientalis)精子发生的全过程，精原细胞呈椭圆形，其染色质分布较均匀，线粒体集中于细胞一端形成“线粒体区”。初级精母细胞较大，染色质凝聚成块，次级精母细胞核质间常出现大的囊泡，胞质内囊泡丰富而线粒体数量却明显减少，早期精细胞核发生极化、解聚，部分胞质被抛弃。中期精细胞外观呈金字塔形，分为三区；正在形成的顶体位于塔顶，核位于塔基部，居间的细胞质基质内富含膜复合物，后期精细胞顶体进一步分化。形成顶体帽和内、外顶体物质等三个结构组份。成熟精子核呈盘状或碗状，具有5-6条内部充满微管的辐射臂。

ULTRASTRUCTURE OF SPERMATOGENESIS IN THE SQUAT LOBSTER( THENUS ORIENTALIS )

The spermatogenesis in the squat lobster (Thenus orientalis) was studied with transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results showed that, the spermatogonium was oval in shape, in which mitochondria concentrate at one end of the cytoplasm to form a mitochondria zone.The chromatin was relatively dispersed, and some heterochromatins distributed along the nuclear envelope in the oval nucleus. The primary spermatocyte was larger than the spermatogonium, its chromatin became denser and lied at one side of the nucleus. The mitochondria zone disappeared and some mitochondria disintegrated to vesicles. The secondary spermatocyte usually contained a large vesicle between the nucleus and the cytoplasmic matrix, in which there were a large number of vesicles with the number of mitochondria decreased distinctly. The early spermatid with nucleus polarized and decondensed was smaller than the secondary spermatocyte. Many vesicles discarded their inclusions outside the early spermatid and then contributed to the development of the membrane complexes containing extensive RER (rough endoplasmic reticulum) in the cytoplasm. The mid-stage spermatid became pyramidal in overall shape, and three distinct regions were apparent:the maturing acrosome formatted by the vesicles originating from the membrane complexes at its apex, the nucleus at its basement and the cytoplasmic matrix containing extensive membrane complexes in the middle. In the late spermatid, the acrosome further developed into inner acrosomal material, outer acrosomal material and acrosomal cap. The thin, polarized and decondensed nucleus contained a large number of microtubules, and some microtubules extended into the radial arms. It was difficult to find the RER in the membrane complexes of the late spermatid with a mature acrosome. In the mature sperm,five to six radial arms packed with microtubules extend out from the plate- or bowl-like nucleus.