摘要
应用透射电镜技术详细研究了中华鳖精子头部形成过程的超微结构变化。结果显示,中华鳖精子头部的形成过程可分成5个连续时期:第Ⅰ期前顶体泡形成并移向细胞核一侧,同侧核膜凹陷成浅窝。前顶体泡底部中央出现小的顶体颗粒,纤维物质层位于核前端与前顶体泡底壁之间,其核膜一侧的中央形成更小的顶体下颗粒,将与核内小管的形成有关。细胞核开始端移和变形。第Ⅱ期核浅窝逐渐外推,前顶体泡变成扁囊状覆盖于隆突的核顶端,顶体颗粒弥散成中等电子致密物分布于顶体帽中,纤维物质层发育为顶体下锥。环形核套微管在顶体后端的核周围逐渐形成,核内染色质开始浓缩成圆形颗粒,核膜下出现明显间隙,细胞核体积变小。顶体下颗粒消失,但其下端的核质中可见2—4条核内小管开始发生。第Ⅲ期拉长的细胞核前端突出于精子细胞外,表面有顶体复合体覆盖,核后端最宽并出现植入窝。染色质进一步浓缩,颗粒间隙变小,细胞核更细长。第Ⅳ期染色质浓缩成致密均质物,核肩之前的细胞核变细,成为核前突。环形核套微管先后改建为斜行和纵行核套微管,支持细胞突起形成“袖领”包绕顶体。第Ⅴ期核套微管解聚而消失,顶体周围的“袖领”也消失,顶体下间隙出现。结果显示中华鳖精子头部的形成过程,即核质浓缩的形态变化过程、顶体的形成和核内小管的发育与变化方面,存在许多与其他爬行动物不同之处。
Spermiogenesis of sperm head in soft-shelled turtle, Trionyx sinensis, was examined by transmission electron-microscopy. The program of the formation of the sperm head was divided into five stages. StageⅠ , the preacrosomal vesicle occurred while the nuclear envelope developed a shallow fossa in the same side of the nucleus. A dense acrosomal granule arose on bottom of the preacrosomal vesicle when there was a fibrous layer between the nuclear envelope and the vesicle. A smaller subacrosomal granule was observed in the middle of fibrous layer under the acrosomal granule, which was related to the development of intranuclear tubules. The nucleus began to move eccentrally and be out of shape. Stage Ⅱ , the round preacrosomal vesicle became flat because the nuclear shallow fossa protruded out gradually. The dense acrosomal granule spread in the vesicle when the fibrous layer changed to the subacrosoal cone. Circular manchettes developed around the nucleus while the chromatin concentrated to granules and the nucleus became smaller. There arose a gap between the envelope and chromatin. The intranuclear tubules developed after subacrosomal granule disappeared, Stage Ⅲ, the anterior part of elongating nucleus protruded out of the spermafid and covered by the flat acrosome. The implantation fossa formed at the end of the nucleus. Chromatin further condensed and the nucleus became thinner and longer. Stage Ⅳ , after the chromatin concentrated to dense homogeneous phase, the nuclear protrusion formed on the nuclear shoulder. In this stage, the circular manchette reorganized to the oblique and then, the longitudinal one. The Sertoli process covered the aerosome forming ectoplasmic specialization. Stage Ⅴ, the nuclear manchette dismissed and the ectoplasmic specialization disappeared. The subacrosomal gap occurred. The results showed that there were some differences of the spermiogenesis between Trionyx sinensis and other reptiles in the process of the chromatin condensation, the formation of the acrosome and the development of the intranuclear microtubules.
出处
《水生生物学报》
CAS
CSCD
北大核心
2007年第2期226-232,共7页
Acta Hydrobiologica Sinica
基金
国家自然科学基金资助项目(No.3027096130671513)
关键词
中华鳖
精子头部
形成
超微结构
Soft-shelled turtle
Trionyx Sinensis
sperm head
Development
Uhrastructure
