泥蚶受精和早期卵裂过程核行为的细胞学观察

利用石蜡切片技术,对泥蚶受精和早期卵裂过程核行为进行了系统地细胞学观察。泥蚶成熟未受精卵核相处于第一次成熟分裂中期;精卵混合后,精子迅速附着于卵子周围,受精后3 min左右精子入卵,启动成熟分裂,9~12 min排出第一极体、18~20 min排出第二极体,完成第一次和第二次成熟分裂;受精后25 min左右雌、雄性原核形成;受精后30 min左右雌、雄原核以原核联合的方式结合;受精后35 min左右第一次卵裂结束,形成2个大小不等的卵裂球;受精后45 min左右第二次卵裂结束,形成1大3小4个卵裂球。本研究发现了多精入卵现象,多个精子入卵可启动成熟分裂,排出第一、第二极体,形成多个雄性原核并与雌性原核联合,染色体分离紊乱形成多极纺锤体;对多精入卵的成因、发育结局进行了初步探讨。

Cytological observation on nuclear behavior in fertilization and early cleavage in Tegillarca granosa

The cytology of the fertilization and early embryonic development of Tegillarca granosa were consecutively observed by optical microscope and paraffin section method.The unfertilized mature eggs were at metaprophase of first meiosis;After mixing of sperms and eggs,sperms quickly attached to the surface of the egg,and the maturation division began;At about 9-12 min and 18-20 min,the fertilized eggs released the first and the second polar bodies respectively in the progress of maturation division;After completion of second maturation division,at about the 20 min,sperm nucleus and the haploid female nucleus expanded immediately and developed into the male and female pronuclei,and the male pronucleus formed earlier than the female pronucleus;At about 25 min,the two pronuclei combined and their chromosomes formed respectively;At about 35 min,the chromosomes were separated equally into two daughter cells which are different evidently in size;At about 45 min,the second cleavage was completed with the result of forming four daughter cells,one big and three small.Additionally,polyspermy were observed in the experiment,and several male pronuclei can combine with the female pronucleus and form polyspindles.The reasons of polyspermy and results of embryonic development of Tegillarca granosa were also discussed deeply.