巴布亚硝水母(Mastigias papua)的精巢发育和精子超微结构观察

Development of testis and ultrastructure of spermatozoa in Mastigias papua

以巴布亚硝水母(Mastigias papua)为实验对象,详细研究了其精巢发育过程和精子超微结构。结果显示,伞径为(4.99±0.07)cm的巴布亚硝水母,在实验条件下26~40d后精巢逐渐发育成熟,可持续排放精子束2~3个月。依精小囊结构和精子发生过程,精巢发育可分为3个时期,即Ⅰ期:精巢外部肉眼不可见,精小囊小而透明,排列松散,内部无空腔;Ⅱ期:精巢呈环状乳白色,性腺梯度发育,远离胃丝的精小囊更大排列更紧密,内部有空腔;Ⅲ期:精巢褶皱明显呈囊状,光镜下可见处于不同发育阶段的精小囊,大量精小囊内充满以精子束存在的成熟精子。精子全长(50.64±3.93)μm,包括尖辣椒状的头部(7.61±0.63)μm,略微突出的中段(1.00±0.12)μm和十分细长的尾部(43.03±4.02)μm。头部无顶体,主要由细胞核和薄的质膜组成,质膜散布小的囊泡;中段有两个较大的线粒体,以锚定装置连接尾部;尾部轴丝为典型的9+2双联体微管结构。

In this study,Mastigias Papua was selected as the sample,its testis development and spermatozoa ultrastructure was observed in great detail.The development phases of testis and the ultrastructure of the spermatozoa were also studied.The results showed that the nest of M.papus with a bell diameter of(4.99±0.07)cm gradually became matured after 26d-40d under experimental conditions,and the spermatozoa bundle could be continuously discharged for 2-3 months.According to the structural characteristics of spermatozoa follicles and spermatogenesis,the development of the testis can be divided into three stages,namely stage I:the outer part of the testis is not visible to naked eye,the seminal vesicles are small and transparent,and are arranged loosely,and there is no cavity inside;Phase II:the testis is circular,milky white,with gradient development of the gonads.The seminal vesicles that are far from the gastric filament are larger and more tightly arranged,with an internal cavity;Stage III:The folds of the testis are clearly sac-shaped,and under light microscopy the seminal vesicles at different developmental stages can be seen.A large number of seminal vesicles are filled with mature spermatozoa,present in spermbundles.The spermatozoa of M.papus was(50.64±3.93)μm in length,including a sharp chilli shape head(7.61±0.63)μm,a slightly protruding middle section(1.00±0.12)μm.and a very slender tail(43.03±4.02)μm.There was no acrosome in the spermatozoa head,which was mainly composed of nucleus and thin plasma membrane,small vesicles scattered in the plasma membrane.The middle section is composed of two large mitochondria and is connected to the tail by anchoring apparatus.The internal axial filament of the spermatozoa tail was a typical 9+2 duplex microtubule structure.