【作者】 张立飞；

【导师】 杨万喜；

【作者基本信息】 浙江大学 ， 动物学， 2003， 硕士

【摘要】 本论文采用透射电镜技术比较研究十足目(Decapoda)物种浙江华溪蟹(Sinopotamon chekiangense)、三疣梭子蟹(Portunus，trituberculatus)、脊尾白虾(Exopalarmon carinicanda Holthuis)及罗氏沼虾(Macrobrachium rosenbergii)的精子发生和精子结构。通过对精子发生过程中精原细胞、精母细胞与精细胞的变化及成熟精子形态结构的研究，分析十足目动物精子发生与精子结构中的生殖进化特征，并比较上述物种生殖进化特征的差异，进而探讨其亲缘关系及进化意义。 1．精子发生 罗氏沼虾 精子发生过程中染色质凝集程度逐渐增大，至精细胞中期凝集程度达到最大。核糖体，线粒体和内质网等细胞器数量逐渐增多，到次级精母细胞阶段达到最大，在形成精子的过程中，上述细胞器与高尔基体及膜性泡共同分化或参与形成片层小体，并参与顶体的形成。有别于以往的研究结果，我们发现自初级精母细胞期起，核内不断分泌膜性泡到胞质中，在次级精母细胞阶段存在高尔基体，我们还发现在成熟精子中具有均质核和丝状核两种形态；核仁自生精细胞至精细胞早期持续存在；核膜在精子形成过程中形成片层小体，并参与了顶体的形成。 脊尾白虾 精原细胞有两种类型，即Ⅰ类精原细胞及由它产生的Ⅱ类精原细胞。在生精细胞阶段核内染色质有不同程度的凝集，在成熟精子中核质分化成泡状核和丝状核，整个精子发生过程无核仁发现。在精子发生过程中，线粒体、内质网和核糖体逐渐增多，其中线粒体数目在次级精母细胞阶段达到顶峰，并形成线粒体区，精细胞早期核内出现膜性泡结构，同时次级溶酶体与高尔基体大量存在，这些细胞器共同形成片层复合体，并参与顶体的形成。 三疣梭子蟹 在生精细胞阶段，染色质不同程度的浓缩凝集；在精细胞阶段，核质呈均质状，形成薄壁的圆球形核杯，部分核质延伸入辐射臂内。在整个发生过程中细胞器数量较少，内质网数目在各细胞器中所占比例最大，以滑面内质网为主，线粒体在初级精母细胞中最多，自次级精母细胞开始逐渐减少，高尔基体和溶酶体自次级精母细胞始出现，在发育过程中上述细胞器不断分化，在精细胞阶段形成前顶体腔，最后形成圆球形顶体。与已有的报导不同的是，我们发现精原细胞分为两类，其中I类精原细胞经过分化形成n类精原细胞。 浙江华溪蟹在生精细胞阶段，染色质形态相似，呈不同程度凝集状，核仁在精原细胞期出现;精细胞阶段，染色质分化成纤丝状和致密块状，部分核质延伸入辐射臂内，整个核呈浅杯状。各种细胞器数量在精子发生过程中逐渐增多，其中内质网以粗面内质网为主，线粒体于初级精母细胞阶段始出现，膜轮结构在次级精母细胞中出现，精细胞早期的上述细胞器分化成电子密度高的前顶体腔，并逐渐分化形成方形顶体。核糖体数目少，未见高尔基体。2.精子结构 罗氏沼虾与脊尾白虾的精子结构相近，呈图钉状，由棘突、顶帽和精核组 成。罗氏沼虾的精核边缘呈帽沿状向下翻卷，棘突均质，间有等距横纹，精核 内有囊泡团存在，棘突较短，核分均质核和丝状核。脊尾白虾边缘不翻卷，核 为泡状核和丝状核，棘突由具等距横纹的纤丝组成，较长。三庆梭子蟹和浙江 华溪蟹的精子结构由核杯、辐射臂、顶体囊、顶体管和顶帽及顶体瓣膜共同组 成，前者形态为圆球形、核杯薄、核均质、辐射臂少，顶帽有亚帽带，顶体囊 分内中外三层，穿孔器较多，位于顶体管前端，中心粒位于顶体瓣膜内:后者 形态为椭球形、核杯厚，核分纤丝状和致密块状，辐射臂多，顶体为方形，无 亚帽带，顶体囊分内外两层，穿孔器少，位于顶体管底部，中心粒位于顶体管 底部。3.十足目甲壳动物的生殖进化特征 生精细胞精核的形态变异的特异性可作为一个生殖进化的特征;精子结构 中，精核的形态，顶体的结构，以及两者之间的位置，是生殖进化的重要特征; 在爬行亚目中，辐射臂的多少，穿孔器的位置，多少，顶体囊的分化程度都可以作为生殖进化的特征。4.4个物种的亲缘关系 在对4个物种生精细胞过程中的核与细胞器的变化以及精子结构比较研究的基础上，经过分析4种物种的亲缘关系，推断出各自的进化地位依次为脊尾白虾，罗氏沼虾，浙江华溪蟹及三庆梭子蟹。更多还原

【Abstract】 In this paper, the comparison of spermatogenesis and spermatozoal ultrastructures of four species of decapoda were investigated by electron microscopy (TEM). We had tried to find structural variaton between the four species during their spermatogenesis. From this comparison study, we can pursue the evolution route of the four decapods. 1. spermatogenesisMacrobrachium rosenbergii During spermatogenesis, Chromatins keep on condensing until mid-spermatid stage. The nucleus changes into two forms: fibrous and homogeneous forms . Nucleoli exist from spermatocyte stage to early spermatid stage. In this process, the numbers of ribosomes, mitochondrions and endoplasmic reticulums increase until secondary spermatocyte stage, golgi apparatus emerges at the secondary spermatocyte stage, and then, these organelles change into lamellar complex which finally forms the acrosome.Exopalarmon carinicanda There are two kinds of spermatogenium in this species, the second kind spermatogenium come from the first one. Chromatins condense in each stage at different level. The nucleus changes into two forms: fibrous nuclear and vesicular nuclear. Nucleoli do not emerge in this process. The number of the organelles increase until secondary spermatocyte stage. Mitochondria accumulate together, merging together with lysosomes and golgi bodies at the early spermatid stage, and finally the lamellar structure is formed, which forms the acrosome at last.Portunus, trituberculatus The spermatogonium exist in two different forms, the second form comes from the first one. During spermatogenesis, chromatins condense at different level. The nucleus changes into homogeneous since middle spermatid stage, and the nucleus extends into the radial arm. The number ofmitochondrion is more less than the endoplasmic reticulum, and the smooth endoplasmic reticulum is the main kind of the endoplasmic reticulum; golgi bodies and lysosomes emerge in the secondary spermatocyte stage. Finally, these organelles change into pre-acrosome vesicles which become acrosome at last.Sinopotamon chekiangense During the spermatogenensis, chronmatins condense at different level until middle spermatid stage. The nucleus has two forms at the middle spermatid stage: fibrous one and condensed one. The nucleus extends into the radial arm. The number of organelles keeps increasing until secondary spermatocyte stage. Mitochondria and ribosomes are hard to see, and the ribosome are found to adhere on the surface of endoplasmic reticulum; golgi body and lysosome do not exist, membranous ring emerges at the secondary spermatocyte stage. The organelles change into pre-acrosome vesicles at middle spermatid stage, and finally pre-acrosome forms acrosome. 2. spermal ultrastructureThe sperm ultrastructure of the Macrobrachium rosenbergii and Exopalarmon carinicanda Holthuis analogical, the whole sperm looks like a inversed umbrella, it has a main body, a spike and a little bit cytoplasm. There are some vesicle exist in the M. rosenbergii sperm nucleus. The relatively length of the spike of the E . carinicanda Holthuis is longer than that of M. rosenbergii. There are two forms of nucleus in the E. carinicanda sperm: fibrous and vesicular onesThe sperm ultrastructures of the P. trituberculatus and S. chekiangense consist of nucleus cup ,radial arm, acrosome. The ultrastructure of the acrosome is made up of acrosome cap, acrosome vusicle, acrosome tubule and the acrosome valve .P. trituberculatus has homogeneous sperm nucleus, and S. chekiangense consists of fibrous and condensed sperm nucleus. The number of radial arms in P. trituberculatus is less than the latter’s. the sperm of P. trituberculatus is round in shape, and that of S. chekiangense is square in shape. Tthe centriole locates at the base of the acrosome tubule in S. chekiangenser, but it locates at the acrosome valve . In P. trituberculatus. The location of the center tubule in the two species is different. In P. trituberculatus it locates at the top of the acrosome tubule, and in S.chekiangenser it locates更多还原