半滑舌鳎四倍体鱼苗的诱导与鉴定

采用静水压法处理半滑舌鳎(Cynoglossus semiliaevis)受精卵以抑制其卵裂并进行染色体加倍,筛选出有效的静水压处理起始时间、处理强度及其持续时间。结果表明,孵化水温(23±0.2)℃时,授精后21.5 min,采用40 MPa的静水压压力,休克处理4.5 min,四倍体诱导效果最好,鱼苗四倍体率达到68.3%。采用流式细胞仪分析了四倍体鱼苗细胞DNA含量,表明四倍体鱼苗细胞DNA含量为二倍体对照鱼苗的2倍。通过染色体制作分析表明四倍体鱼苗的染色体数为84条,而二倍体对照鱼苗的染色体数为42条。本研究采用静水压方法,在国内外首次建立了半滑舌鳎四倍体诱导方法。本项技术的建立旨在为大量生产半滑舌鳎三倍体不育群体奠定基础。

Induction and identification of tetraploid fry in Cynoglossus semilaevis

Half-smooth tongue sole(Cynoglossus semilaevis) is an important cultured marine fish species in northern China.Females grow three to four times faster than males.The low growth rate of males leads to an overall reduction in production,thus reducing their value.Given this,the development of all-triploid stocks would be a significant benefit to the commercial aquaculture of half-smooth tongue sole.We developed a method for inducing tetraploidy in this species.The optimal initiation time for pressure shock of fertilized eggs was 21.5 min after fertilization at 23℃.The optimal pressure and treatment duration were 40 MPa and 4.5 min,yielding a tetraploid rate in fry of 68.3%.We analyzed the ploidy of fry using Ploidy analyzer and demonstrated that the tetraploid DNA relative content was two times that of normal diploid fry.We observed 84 chromosomes in triploid fry,whereas normal diploid fry have 42 chromosomes.Our method provides a foundation for production of all-triploid stocks in half-smooth tongue sole.