【作者】 徐慧萍；

【导师】 孙世春；

【作者基本信息】 中国海洋大学 ， 水产养殖， 2007， 硕士

【摘要】 用组织切片法对扁额原细首纽虫周年性腺发育及受精过程进行了初步的研究。1.性腺发育:2005年7月15日到2006年10月15日每月15日从青岛太平角采样(在繁殖季节30日加采一次),通过石蜡切片观察并记录性腺。结果表明:扁额原细首纽虫雌雄比例约为1:1;雌雄体长、体重无显著差异;性成熟雌体通常体壁呈玫瑰红色,雄体呈白色,非繁殖季节雌雄体色无明显差异;一年有两次性腺发育,第一次12月开始出现性腺(但不能区分雌雄),1月可辨雌雄,3月15日达到第一次性腺发育高峰,4月15日性腺消失;第二次于4(雌)～5(雄)月开始出现性腺,6月15～30日达到高峰,9～10月性腺消失。该结果显示扁额原细首纽虫可能一年繁殖两次,分别在初春和初夏。2.受精过程:通过人工授精使扁额原细首纽虫的精卵结合,授精后0～60 min每5 min取样一次,60～100 min每隔10 min取样一次进行固定。常规石蜡切片法切片,在显微镜油镜下对扁额原细首纽虫的受精过程与早期卵裂进行观察。扁额原细首纽虫精子入卵时间是在第一次成熟分裂的中期。授精后约30～35 min放出第一极体,第一极体排出后约10 min第二极体排出。授精后约45～50 min雌雄原核形成,并相互融合。授精后约60 min和80 min分别完成第一次和第二次卵裂。更多还原

【Abstract】 The annual cycle of gonad development and the fertilization of the nemertean, Procephalothrix simulus, were studied by histological method.1. Gonad development: During July 15, 2005 to October 15, 2006, P. simulus were sampled monthly or semimonthly (in reproductive seasons) at Taiping Jiao, Qingdao, China. Specimens were examined by histological method to determine the cycle of the gonad development of this nemertean. The results showed that: The sex ratio (female: male) was about 1: 1. The sizes (body width and body weight) of mature males and females were not significantly different; females are rosy in colour and males are white, largely owing to the metamerically arranged gonads. Gonads, which were not detected in samples of autumn months, arose in December, but sexes were indistinguishable until middle January. Both ovaries and testes appeared mature on March 15, and disappeared on April 15. Then P. simulus immediately started another upgrowth stage of gonads. The gonad development of both sexes reached the maximum in June, and disappeared in September to October. These results suggested that P. simulus are likely to spawn twice a year, in the early spring and the early summer, respectively.2. The fertilization of Procephalothrix simulus: Sperm penetration occurred at the metaphase of the first meiosis of oocyte. About 30～35 min after insemination the first polar body was ejected and the second polar body was ejected about 10 min later. The female and male pronucleus formed and fused about 45～50 min after insemination. The first and the second cleavages finished about 60 and 80 min after insemination, respectively.更多还原