摘要
采用细胞松弛素B(CB)处理受精卵,抑制第一极体的排放,对近江牡蛎四倍体的诱导和培育进行了研究。结果表明,近江牡蛎在25—28℃时受精卵发育同步性较高。在28℃条件下,CB适宜处理剂量为0.6mg/L。在个别受精卵出现第一极体时实施处理,至对照组的第一极体出现率达到50%终止处理,四倍体的诱导效果较好。5个处理组D形幼虫的平均孵化率为11.0%,显著低于对照组72.4%的平均孵化率。在受精后4—12d期间处理组幼虫的存活率显著低于对照组。处理组胚胎和D形幼虫阶段四倍体的平均比例分别为41.8%和37.9%。四倍体的比例随着幼虫的生长发育呈下降趋势,至受精后12d在各处理组已检测不到四倍体。2组幼虫完成附着变态,从受精卵至稚贝的累计存活率平均为0.3%。本研究结果表明,使用CB处理抑制受精卵第一极体的释放可以有效诱导近江牡蛎四倍体,但所获得的四倍体幼虫存活力差,需要在未来的研究中解决。
Tetraploids in Jinjiang oyster, Crassostrea rivularis, were induced by inhibiting the first polar body （PB1） with cytochalasin B （CB）. Increasing temperature from 25℃ to 28℃ led to an increase in the synchrony of zygote development. The optimal dosage of CB for tetraploid induction was 0.6mg/L at 28℃. The following timing of CB treatment was effective for tetraploid production： starting when the first signs of PB1 extrusion were observed and ending as 50% of fertilized eggs in control group expulsed PB1. On average, the yield of D-stage larvae in treatment groups was 11.0%, which was significantly lower than that of controls （72.4%） （ P 〈 0.01 ）. Most mortality occurred to the induced larvae during the first 8-10 days post fertilization （PF）. Compared to controls, aver- age larval survival of treatment groups was significantly lowered during the period of 4-12 days PF in all five replicates （P 〈 0.05）. Tetraploids were obtained in both embryos and D-stage larvae from five replicates. The proportion of tetraploids varied from 37 % to 48 %, averaging 41.8 % in embryos, as confirmed by chromosome counting. Diploids, triploids and aneuploids were observed in CB-treatment groups. Flow cytometric analysis of D-stage larvae of treatment groups revealed ploidy compositions similar to that of embryos. The average percentage of diploids, triploids, tetraploids and aneuploids was 21.3%, 18.2%, 37.9% and 22.5%, respectively, in D-stage larvae. The percentage of tetraploids decreased over the time of larval development. Tetraploids were undetectable at Day 12 PF. Two of five replicates of CB-treatment groups survived beyond settlement and metamorphosis. The average cumulative survival from fertilized eggs to spat was 0.3 % for CB-treated groups. Tetraploids were not found in spat, indicating the weak survival of tetraploid larvae. Overall, tetraploids can be effectively induced by blocking PB1 with CB treatment. However, how to enhance the survival of tetraploid larvae remains a challenge for future research.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
2005年第5期437-444,共8页
Oceanologia Et Limnologia Sinica
基金
国家杰出青年科学基金资助项目
39825121号
国家自然科学基金项目
30100141号
30471326号
国家863项目
2001AA628060号。
关键词
近江牡蛎
细胞松弛素B
第一极体
四倍体
三倍体
非整倍体
Crassostrea rivularis, Cytochalasin B, Polar body I, Tetraploids, Triploids, Aneuploids
