摘要
以 6 0 mg/ L的 6 -甲氨基嘌呤 (简称 6 - DMAP)诱导栉孔扇贝三倍体时 ,在荧光显微镜下观察受精卵的染色体行为以及核相组成 ,对照三倍体率和孵化率 ,探讨了不同减数分裂期 6 - DMAP处理对染色体倍数性的影响。结果表明 ,处理 5～ 15min可见 3种类型图像 ,第 1种图像可见第一极体和一个雌性及雄性原核 ;第 2种图像可见第一极体和两个雌性原核及一个雄性原核 ;第 3种图像可见两个雌性原核和一个雄性原核 ,随着处理时间延长雌雄原核逐渐形成泡状结构。 6 - DMAP抑制第二极体产生的三倍体主要来源于发育至第 2次减数分裂中期的受精卵 ,使一个双倍性的雌性原核与一个雄性原核结合形成三倍体 ;受精卵在第 2次减数分裂的后期时接受处理 ,可使部分受精卵的两个雌性原核和一个雄性原核在融合和分离过程中发生异常。实验证明 ,6 - DMAP有效抑制了栉孔扇贝受精卵的染色体分离和原核移动 ,并可造成染色质分散 。
WT5BX]Chlamys(Azumapecten)farreri eggs were treated 25 min after fertilization with 60 mg/L 6 dimethylaminopurine (6 DMAP). The chromosome behavior and the nuclear stages of the insemination eggs were observed with fluorescence microscope. And the effects of 6 DMAP treatment at various meiotic stages on chromosome ploidy were investigated by assessing the percentage of triploids and embryos. It was concluded that three kinds of nuclear stages were observed after 5 to 15 min treatment:One nuclear stage showed the first polar body, one female pronucleus and one male pronucleus; another showed the first polar body, two female pronuclei and one male pronucleus; and the third stage displayed one male pronucleus and two female pronuclei taking shape of bulliform structure with treatment duration. The triploid induced by 6 DMAP to inhibit the second polar body originated mainly from the fertilized scallop eggs at metaphase of second meiosis, when a diploid female pronucleus combined with a male pronnucleus,The triploid wasformed. Treated at anaphase of second meiosis, two female pronuclei and one male pronucleus of the fertilized eggs became abnormal during their fusion and separation procedure. Our experiment proved that 6 DMAP can induce triploids in fertilized scallop eggs by the ability to block extrusion of polar bodies,when the chromosome separation and pronucleus motion was inhibited effectively.
出处
《海洋水产研究》
CSCD
2000年第1期22-26,共5页
Marine Fisheries Research
基金
国家海洋 863计划项目! ( 863 8190 10 2 )
