采用HOECHST 33258染色荧光显微方法,对宽壳全海笋 Barnea dilatata(Souleyet)受精卵早期发育中的生发泡破裂、极体排放、两性原核联合、早期卵裂、多精入卵等细胞学事件进行了研究.结果显示,宽壳全海笋成熟未受精卵呈梨形或卵圆形,处于第一次成熟分裂前期,生发泡尚存;在水温26℃±1℃条件下进行受精.受精后6～9 min,生发泡逐渐萎缩、破裂;受精后18、25 min,受精卵先后排出第一、第二极体,完成第一次和第二次成熟分裂;受精后35 min,雌、雄原核在卵子中央发生染色体联合;随后,联合核的染色体共同排列在纺锤体的赤道板上,形成第一次有丝分裂的中期分裂相;受精后45 min,形成2个大小不等的卵裂球,完成第一次卵裂;第二次卵裂过程与第一次卵裂基本相同,只是卵裂方向与第一次卵裂基本垂直,在受精后60～65 min,第二次卵裂完成,形成1大3小4个卵裂球.另外,实验中发现了明显的第一极体分裂现象争极少量的多精入卵现象.%During fertilization and early embryonic development in Barnea dilatata, a series of characteris-tic cytological events, including germinal vesicle breakdown, polar body emission, association of the male and female pronuclei and polysperm, were studied by the fluorescent microscope with HOECHST 33258 stained. The results indicated that unfertilized mature eggs of B. Dilatata were pear-shaped or egg-shaped and remained at the prophase of the first maturation division with obvious germinal vesicle and nucleolus. At water temperature of 26℃ ± 1℃, sperms quickly attached to the surface of the egg after mixing of sperms and eggs. 6～9 min after insemination, germinal vesicle gradually got smaller and brokedown even-tually. The fertilized eggs released the first and the second polar bodies at about the 18th min and the 25th min respectively. About 35 min, the male and female pronuclei matched into an association nucleus after their chromosomes formed respectively in the center of egg. Subsequently, the chromosomes of association nucleus arranged on the metaphase plate of first cleavage. Until about 45 min, the chromosomes were sepa-rated equally into two daughter cells which are different evidently in size. The process of the second clea-vage was fundamentally similar to the first cleavage, but the cleavage direction was almost vertical to the first cleavage furrow. 60～65 min after insemination, the second cleavage has finished and formed four daughter cells, one big and three small. Additionally, the phenomena of the PB1 division and multisperm were also observed in the experiment.
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