斧文蛤精子超微结构与受精过程的细胞学变化  

Studies on ultrastructure of spermatoazoon and cytological change of nuclear behavior on fertilization in Meretrix lamarkii

作　　者：董迎辉[1] 林志华[1] 姚韩韩[1] 

机构地区：[1]浙江万里学院生物与环境学院,浙江宁波315100

出　　处：《水产学报》2011年第3期356-364,共9页Journal of Fisheries of China

基　　金：国家自然科学基金项目(30972255);国家"八六三"高技术研究发展计划(2006AA10A410);宁波市科技局农业择优委托项目(2010C10011)

摘　　要：采用电镜和荧光显微镜技术,对斧文蛤精子超微结构与受精过程的细胞学变化进行了系统研究。电镜观察表明,斧文蛤精子为鞭毛型,全长45.2～47.7μm,由头部、中段和尾部三部分组成。头部呈稍弯曲的狭茧形,长约2.5μm,由顶体和细胞核组成,顶体呈圆锥形,内部中轴处有亚顶体腔;细胞核为长锥形,有核前窝和核后窝。中段由线粒体围绕中心粒复合体构成,5个近球形的线粒体呈单层梅花状排列;中心粒复合体由近端中心粒和远端中心粒组成,远端中心粒延伸出尾部的轴丝。尾部为细丝状鞭毛,内部的轴丝呈典型的"9+2"结构,外周有波浪状质膜包被。用荧光显微镜观察了斧文蛤受精及早期卵裂过程的细胞学变化,结果发现,斧文蛤成熟未受精卵呈圆球形,核相处于第一次成熟分裂中期;在水温27～28℃条件下受精,受精后6 min,精子入卵并膨胀成球形;受精后12～15 min、20～25 min受精卵排出第一、第二极体;30 min左右,精、卵核膨胀形成雄、雌原核;35 min,两性原核在卵子中央发生染色体联合;40～45 min,受精卵进行第一次卵裂,形成2个大小不等的分裂球;55～60 min,第二次卵裂结束,形成1大3小4个卵裂球,核相变化与第一次卵裂基本相同;75～80 min,第三次卵裂完成,自此次起开始进行螺旋分裂。另外,在斧文蛤受精过程中发现了约1%的多精入卵现象,其对成熟分裂和早期卵裂过程影响很大,常造成成熟分裂紊乱和第一次卵裂染色体分离异常。The ultrastructure of spermatozoon and the cytological change of fertilization process in Meretrix lamarkii were systematically studied by electron microscope and fluorescence microscope.The results indicated that the mature spermatozoon（45.2-47.7 μm in total length）of M.lamarkii,belonging to the primitive type,consists of head,middle piece and tail.The head,like a long cocoon in shape（2.5 μm in length）,is composed of acrosome and nucleus.The acrosome is conical in shape and has a subacrosomal space inside.Nucleuses are cylindrical with fine-grained dense chromatin,having front nuclear pocket and posterior nuclear pocket.The centriolar complex,including proximal and distal centrioles,and surrounding 5 spherical mitochondrias,make up the short middle piece.The tail,a whip-like flagellum,consists of axoneme that is a typical ＂9＋2＂ microtubular structure and wrapped by an wavy plasma membrane.The cytological change of nuclear behavior during fertilization and early cleavage was observed under the fluorescence microscope.Like most of marine mollusks,the unfertilized mature eggs of M.lamarkii were globular and remained at the metaphase of the first maturation division.At water temperature of 27-28 ℃,artificial insemination was conducted.6 min after fertilization,sperm has penetrated into cytoplasm of egg and activated the maturation division.The fertilized eggs released the first polar body about 12-15 min and the second polar body about 20-25 min after fertilization.About 30 min,sperm nucleus and the haploid female nucleus developed into the male and female pronuclei.35 min,the male and female pronuclei matched into an association nucleus after their chromosomes formed respectively in the center of egg.40-45 min,the chromosomes were separated equally into two daughter cells which are different obviously in size.55-60 min,the second cleavage finished and formed four daughter cells,one big and three small.The process of the second cleavage was fundamentally similar to the first cleavage.75-80 min,the

关 键 词：斧文蛤 精子 超微结构 受精 多精入卵 

分 类 号：Q954.4[生物学—动物学] S917[农业科学—水产科学]