雄性四倍体与雌性二倍体杂交培育全三倍体长牡蛎(Crassostrea gigas)的研究

将美国雄性四倍体长牡蛎与中国北方海区雌性二倍体长牡蛎杂交 ,进行全三倍体长牡蛎培育研究。结果表明 ,四倍体与二倍体杂交的受精率为 47.4%─ 88.9% ,平均为 69.5 % ;来自同样雌贝的二倍体对照组的受精率平均为 91 .4%。杂交组和对照组面盘幼虫的平均孵化率分别为 5 3.9%和 61 .6% ;受精卵发育至稚贝的存活率 ,杂交组和对照组分别为 1 .3%和1 .9%。杂交组累计培育出眼点幼虫 8.32 4亿 ,稚贝 1 .843亿。杂交组幼虫的生长略快于对照组 ,但无显著差异。经流式细胞仪分析 ,杂交组的幼虫、稚贝、幼贝等均为 1 0 0 %三倍体。中国北方海区的长牡蛎可以与美国的雄性四倍体长牡蛎实现良好的杂交 ,产生 1 0 0 %三倍体。利用长牡蛎四倍体培育三倍体 ,方法简便高效 ,显示出四倍体在贝类三倍体商业生产中的巨大应用价值。

细胞松弛素B诱导虾夷扇贝多倍体初探

Triploid shellfish are useful for aquaculture because of their sterility,superior growth and improved meat quality.Tetraploid are also valuable for 100% producing triploids through mating with diploid.We tested polyploid induction in Japanese scallop,Patinopecten yessoensis,by inhibiting polar body Ⅰ (PB group) and both polar bodyⅠandⅡ (PPB group) in newly fertilized eggs.Cytochalasin B (0.6 mg/L) was applied at 11～22 min post fertilization (PF),and terminated in PB group when polar body Ⅰ was released about 70% in untreated eggs,in PPB group when polar lobe was observed in control group.The treatment and its control were repeated 5～7 times using different pairs of parents.The ploidy was determined by counting chromosome number at embryo stage,and then was detected by flow cytometry (FCM) at larvae stage and juvenile stage.\;In PB group,aneuploid (31.13%),triploid (3.96%),tetraploid (17.46%) and pentaploid (46.65%) embryos were produced,and in PPB groups,pentaploid embryos became higher (56.2%),triploid and tetraploid were 2.42% and 9.11%.At day 3 PF,the larvae showed tetraploid,pentaploid and aneuploid peaks through checking with FCM in PB group,and showed mainly higher pentaploidy peak in PPB groups.However,at day 14 PF diploids were mainly left,sometimes with small triploid peak.It suggested that most tetraploid,aneuploid and pentaploid larvae were died within the first two weeks PF.At three months PF,a few diploid juveniles were harvested in three control groups.Only 12 juvenile scallops were harvested in one of treated group (PB-7),and 11 of them died accidentally,the alive one in treated group was triploid through checking with FCM.

利用细胞松弛素B抑制第一极体排放诱导近江牡蛎(Crassostrea rivularis)四倍体

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。