长吻鮠精巢发育的分期及精子的发生和形成

长吻鮠精巢的发育分为精原细胞增殖期、精母细胞生长期、精母细胞成熟期、精子细胞出现期,精子完全成熟期和精子退化吸收期。精巢的后1/3不产生也不贮存精子,精子的发生和形成经过精原细胞、精母细胞、精子细胞到精子的一系列过程。精原细胞有两种类型。精子无顶体,有中心粒帽,中片长,核凹窝和线粒体发达,鞭毛具侧鳍。

STUDIES ON THE DEVELOPMENTAL STAGES OF TESTIS, SPERMATOGENESIS AND SPERMATOLEOSIS INLeiocassis longirosiris

Optics microscope, scanning and transmission electron microscopy were used to study the spermatogensis and spermatoleosis as well as ultrastructure of spermatozoon in the Chinese freshwater catfish, Leiocassis lonpirostris. The results were summarized as follows. 1. The testis are separated like fingeres in shape. The development of testis may be divided into six stages. 1 ) . multiplication of spermatogonia; 2 ) . growth of spermatocytes; 3 ) . maturation of spermatocytes; 4 ). initial appearance of spermatozoa; 5 ). complete maturation of spermatozoa; 6 ) . degeneration of spermatozoa. The posterior portion of the (estis arc purple and the cells consist of simple columnar epithelium. The purple testis neither produces nor contains the spermatozoa. 2. The spermatogenesis and spermatoleosis are from spermatogonia through the following stages, that is, spermatocytes, spermatids and spermatozoa. The spermatogonia morphologically show deffercnt types, that is, type I and type II . In spermatoleosis, the uncleus became condensed. The spermatozoa have no acrosome, but have centriolar cap, long uncleus, long midpiece, a lot of mitochondria and developed lateral fins. The nuclear fossa is very developed too.