报道了采用细胞松弛素B (CB)处理虾夷扇贝 (Patinopectenyessoensis)受精卵抑制第一极体 (PB1 )释放的处理组与对照组的细胞染色体分离状况。结果表明 ,对照组中的受精卵具有 1 9条四分体染色体 ,经过减数分裂Ⅰ期和减数分裂Ⅱ期 ,放出PB1和PB2 ,受精卵的发育具有不同步性。处理组受精卵在第二次减数分裂中出现了特殊的分离类型 ,即“三级分离”、“联合二级分离”和“独立二级分离”。初步分析了细胞松弛素B抑制第一极体放出的机理 Reported the cytochrome separation of treated and control groups treated with cytochalasin B (CB) to inhibit the release of the first polar body (PB1) from fertilized eggs of Patinopecten yessoensis. The results showed that the fertilized eggs in the control group had 19 tetrad chromosomes. After meiotic stage Ⅰ and meiosis stage Ⅱ, PB1 and PB2 were released, and the development of fertilized eggs was asynchronous. The fertilized eggs of the treatment group showed a special type of separation at the second meiosis, namely “tertiary separation”, “combined secondary separation” and “independent secondary separation”. The mechanism of cytochalasin B inhibiting the release of the first polar body was preliminary analyzed