长竹蛏精子发生和精子的超微结构观察

Observation on ultrastructure of the spermatogenesis and mature sperm of Solen strictus

利用透射电镜观察长竹蛏Solen strictus精子发生和精子的超微结构,揭示了从精原细胞发育为精子过程中超微结构的变化。其过程主要包括:生精细胞体积逐级减小,细胞核由椭圆形转变为圆形,染色质以颗粒状形式浓缩,内质网和高尔基体分泌的前顶体颗粒融合形成前顶体囊、前顶体囊最终形成顶体,线粒体逐渐融合与发达,以及中心体移动及鞭毛形成。精细胞的分化可分为4个时期。成熟精子属原生型,全长约38—43μm,由头部、中段和尾部3部分组成。头部顶体较短,约为核径的五分之一,呈倒置的碗状,轴向纵切面为马鞍形,顶体物质为分布均匀的高电子密度物质;亚顶体腔几乎伸达顶体的顶端,内含均匀的较低电子密度物质。细胞核呈圆球形,无核前窝,但有一浅的核后窝。中段由4—5个椭圆形线粒体和2个相互垂直的中心粒组成。尾部为典型的“9+2”型结构。

The ultrastructure of spermatogenesis and spermatozoon of Solen strictus was observed by using transmission electronic microscope, and the ultrastructural changes from spermatogonia to spermatozoa were showed, incl from ellipsoidal to uding the processes of spermatogenic cells minishing gradually and nucleus changing spherical, the granular condensation of chromatin, the formation of proacrosomal vesicles by fusion of rough endoplasmic reticula and proacrosomal granules from Golgi bodies and final formation of acrosome, the fusion and development of mitochondria, the transfer of centrioles and the formation of flagella. The differentiation of the spermatid could be divided into four stages. The mature sperm was a typical primitive type （38-43μm long）, consisting of three segments （head, middle piece and tail）. The acrosome with materials of high density was upside-down bowl-shaped, and was saddle-shaped in longitudinal section. The subacrosome space with materials of low density was almost up to the apex of the acrosome. The nuclear was spherical, with a posterior nuclear fossa but no anterior nuclear fossa. The middle piece was composed of four or five ellipsoidal mitochondria and two centrioles. The tail was a typical ＂9＋2＂ microtubular structure.