滇蛙多盘吸虫精子发生的超微结构

ULTRASTRUCTURE OF SPERMATOGENESIS IN POLYSTOMA SP.(MONOGENEA:POLYOPIS THOCOTYLEA:POLYSTOMATIDAE)

利用透射电镜研究滇蛙多盘吸虫的精子发生。它属于典型的寄生扁形动物Ｃｅｒｃｏｍｅｒｉｄｅａ类型。本吸虫的特点是精子形成的早期，两根鞭毛轴丝相互垂直成９０°，中央间体由三根条带组成，不等长，中央带长于侧带；线粒体在融合前未观察到围核现象。文中分析比较了多盘科内不同亚科精子发生的特点。

The present paper deals with the ultrastructure of spermatogenesis in Polystoma sp. collected from the urinary bladder of Rana pleuruden in Yunnan province, 1996 . The spermatogenesis of this species is described for the first time. In general, it is similar to that of Cercomeridea pattern found in most parasitic Platyhelminthes including Aspidobothrea, Digenea, Monogenea and Cestodaria ( Justine,1991). But spermatogenesis in Polystoma sp. differs from the standard type in two aspects : 1. the two axonemes are perpendicular to each other forming a right angle at the early stage of spermiogenesis; 2. the mitochondria are not surrounding the nucleus during the spermiogenesis as observed in most of other Platyhelminthes . A brief comparison of characters of spermiogenesis among Polystoma sp. from subfamily Polystomatinae ( present paper ), Neopolystoma spratti from subfamily Polystomoidinae (Watson and Rohde,1995 ), and Concinnocotyla australensis from subfamily Concinnocotylinae ( Watson et al .,1995) has been given in Table 1. All of these three subfamilies belong to the same Family Polystomatidae. It has been shown that among them there are a series of differences in morphology and structure of the intercentriolar body, mitochondria and rootlets and the relative position of two axonemes at the early stage of spermiogenesis. It clearly reveals that the differences in spermatogenesis among different groups of monogeneans could be a useful tool for understanding their phylogeny and the relative relationships among them.