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为了解在珍珠贝多倍体诱导中四倍体形成的机制 ,用醋酸地衣红染色技术研究抑制马氏珠母贝(Pinctada martensii)受精卵第一极体排放后的染色体行为。试验用贝为人工养殖贝 ,贝龄为 2～ 3龄。试验用水为沙滤海水 ,海水比重 1.0 18～ 1.0 2 0 ,p H值 8.10～ 8.30。2 6℃～ 2 8℃下人工授精 ,授精前用 6× 10 - 6氨水处理卵子10 m in～ 15 min。处理组用 0 .5 mg/ L 细胞松弛素 B(CB)处理受精卵 15 min;对照组为不做任何处理的受精卵。受精后每隔 3m in取样观察 ,直至受精后 6 0 min。观察结果表明 ,在第 2次减数分裂期间 ,染色体分离有 4种主要类型 ,即“随机三极分离” (2 8.1% )、“不混合三极分离” (7.6 % )、“联合双极分离” (19.3% )和“离散双极分离” (13.6 % ) ,余下的 31.5 %因染色体混乱或难以确定而无法分类 ,但似乎是以上 4种分离的变体。在受精后33m in～ 42 min,在联合双极、三极和离散双极分离的细胞中分别形成 2 ,3和 4个原核。将各种分离类型所出现的频率与产生的三倍体 (33% )和四倍体 (2 2 % )比较 ,表明导致四倍体形成的是“离散双极分离”;“不混合三极分离”也可能导致四倍体的形成 ;导致三倍体形成的是“联合双极分离”;导致非整倍体形成的是“随机三极分离”和其他不规则的分离
In order to understand the mechanism of tetraploid formation in polyploid induction of Pinctada martensii, the chromosomal behavior of Pinctada martensii fertilized eggs inhibiting the discharge of the first polar body was investigated by using lichen red staining technique. Test shellfish for artificial breeding shellfish, shellfish age 2 to 3 years old. The test water was sand filter seawater, the proportion of seawater was 1.0 18 ~ 1.0 2 0, p H value was 8.10 ~ 8.30.2 Artificial insemination at 6 ℃ ~ 2 8 ℃, the egg was treated with 6 × 10 - 6 ammonia water for 10 min ~ 15 min. The treatment group treated with 0 .5 mg / L cytochalasin B (CB) fertilized eggs for 15 min; control group without any treatment of fertilized eggs. After fertilization every 3min sampling observation, until 60min after fertilization. The observations showed that during the second meiosis, there were four main types of chromosomal segregation: “random triplet” (2 8.1%), “unmixed triplet” (7.6%), “united bipolar Separation ”(19.3%) and“ Discrete Bipolar Separation ”(13.6%). The remaining 31.5% could not be classified due to chromosomal disruption or indeterminateness, but it appears to be the above four separate variants. Between 33 and 42 min after fertilization, two, three and four prokaryotes were formed in the unite bipolar, tripolar and discrete bipolar separation cells, respectively. Comparison of the frequency of occurrence of the various types of separation with the generated triploids (33%) and tetraploids (22%) indicates that “discrete bipolar separation” leads to tetraploid formation; “unmixed tripoles Separation ”may also lead to the formation of tetraploids; triploid formation leads to“ joint bipolar separation ”; resulting in aneuploidy is“ random triplet separation ”and other irregular separation