广西北部湾海域施氏獭蛤精巢发育、精子发生及超微结构观察

Testis development,spermatogenesis and sperm ultrastructure of Lutraria sieboldii in the Beibu Gulf,Guangxi

为探究广西北部湾海域施氏獭蛤精巢周年发育、精子发生的组织学和超微结构变化,文章采用组织切片、扫描及透射电镜技术对广西北部湾海域施氏獭蛤精巢周年发育、精子发生和超微结构进行了研究。结果表明,广西北部湾海域施氏獭蛤精巢发育周期为1年,可划分为增殖期、生长期、成熟期、排放期和休止期,繁殖盛期为12月至翌年4月,每期5%~10%个体精巢发育略滞后。精子发生可划分为增殖期、生长期、成熟期和变态期。雄性生殖细胞的发育可划分为精原细胞期、初级精母细胞期、次级精母细胞期、精细胞期、成熟精子期。施氏獭蛤精子属于鞭毛型,全长(39.76±0.50)μm。精子头部由近椭圆形的顶体和精核组成,顶体底部与精核相连处凹陷形成亚顶体腔,精核顶部形成核前窝,精核底部形成核后窝,细胞核内电子密度均匀,核中部存在间隙。中心粒复合体周围有4个线粒体围绕组成精子中部,线粒体近圆形,内嵴明显。质膜包裹轴丝形成精子尾部,尾部横切面可明显观察到“9+2”双联体微管结构。此外,施氏獭蛤存在A、B两种不同类型的精原细胞,A型精原细胞核内核仁不明显, B型精原细胞核内核仁明显, B型精原细胞存在于增殖期和生长期。

To explore the histological and ultrastructural changes of the annual development of the testis and spermatogenesis of Lutraria sieboldii in Beibu Gulf of Guangxi,the annual development of testis and ultrastructure of spermatozoa of L.sieboldii were studied through tissue section,scanning and transmission electron microscopy.Results showed that the testis completes a cycle in one year,which can be divided into proliferating stage,growing stage,maturing stage,spawning stage and resting stage.The spawning was from December to April of the following year,and the testis development of 5%~10%individuals in each stage was slightly delayed.Spermatogenesis can be divided into proliferation period,growth period,mature period and metamorphosis period.The male reproductive cell can be divided into Spermatogonia stage,primary spermatocyte stage,secondary spermatocyte stage,spermatocyte stage and mature sperm stage.The sperm of L.sieboldii belongs to the flagella type,whose total length is(39.76±0.50)μm.The sperm head was composed of a nearly subelliptic spermatic acrosome and nucleus,the bottom of the acrosome and the spermatozoa connected with the spermatozoa were depressed to form a subacrosomal cavity.The electron density in the nucleus was uniform,and there was a gap in the middle of the nucleus.There are four mitochondria around the centriole complex to form the middle part of sperm,and the mitochondria are nearly round with apparent internal ridge.The plasma membrane wraps around the axial filaments to form sperm tail,and the“9+2”doublet microtubule structure can be clearly observed in the transverse section of the tail.In addition,there are two different types of spermatogonia:type A spermatogonia has no nucleolus in the nucleus while type B spermatogonia has nucleolus in the nucleus,and type B spermatogonia is distributed in the testis at different stages.