6-甲氨基嘌呤诱导栉孔扇贝三倍体的细胞学机理

以６０ｍｇ／Ｌ的６－甲氨基嘌呤（简称６－ＤＭＡＰ）诱发栉孔扇贝三倍体时，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原核及雄性原核；第２种图像可见第一极体和两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枋，随着处理时间

PRELIMINARY STUDIES ON THE CYTOLOGICAL MECHANISM OF TRIPLOID INDUCTION IN SCALLOP CHLAMYS(AZUMAPECTEN)FARRERI BY APPLICATION OF 6-DIMETHYLAMINOPURINE (6-DMAP)

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.