栉孔扇贝四倍体幼虫的诱导研究

以栉孔扇贝Chlamys farreri为材料，采用浓度为0．5mg／L的细胞松弛素B(CB)处理、抑制受精卵第一极体排放的方法，进行四倍体诱导研究。5次重复实验结果表明，诱导组和对照组的平均受精率分别为45．0％和56．6％，D形幼虫的平均孵化率分别为5．3％和51．1％。经胚胎和幼虫发育观察发现，在诱导组中异常原肠胚的比例高于对照组；受精后48h，诱导组的滞育担轮幼虫的比例显著高于对照组。在受精后48h采用流式细胞术检测孵化的D形幼虫，诱导组中四倍体幼虫的比例为36％-70％，平均为49％，同时发现了平均比例为31％的三倍体幼虫。本研究表明，该项技术能有效地诱发栉孔扇贝四倍体幼虫，但面临四倍体幼虫孵化率低的问题，今后应设法提高四倍体胚胎和幼虫的发育水平。

Production of Tetraploid Larvae of Zhikong Scallop,Chlamys farreri (Jones & Preston)

Tetraploid zhikong scallop Chlamys farreri (Jones & Preston) was produced by inhibiting the first polar body (PB1) in newly fertilized eggs with 0.5 mg/L cytochalasin B (CB). Five replicates were conducted with different batches of brood stocks. The mean fertilization level was 45.0% for CB-treated groups and 56.6% for controls respectively. Survival from fertilized eggs to D-stage larvae averaged 5.3% and 51.1% in CB-treated groups and controls respectively. Observation on embryo and larval development revealed that the proportion of abnormal gastrulae, as well as development-arrested trochophore-stage larvae, was higher in CB-treated group than that in controls. The ploidy of resultant larvae was determined by flow cytometry. The percentage of tetraploids ranged from 36% to 70% averaging of 49% in CB-treated groups at 48 h post-fertilization. In addition, triploids were found in CB-treated groups, accounting for 31% of the total D-stage larvae. In conclusion, tetraploid larvae could be effectively induced in Chlamys farreri with this technique. However, the low yield of tetraploid larvae posed a major problem for development of tetraploids of this species. Further research should be directed at promotion of tetraploid larval development.