合浦珠母贝三倍体的卵诱导四倍体

将合浦珠母贝三倍体的卵与二倍体的精子授精，用０．５μｇ／ｍＬ细胞松弛素Ｂ抑制精卵第一极体的释放诱导四倍体。研究了处理起始时间及持续时间对胚胎孵化率和四倍体诱导率的影响及幼虫的生长及存活。实验结果表明：持续时间与胚胎孵化率呈负相关，而与四倍体诱导率呈正相关，持续时间一般为１５￣１８ｍｉｎ，处理起始时间一般在第一极体出现前３￣５ｍｉｎ。在胚胎期，四倍体诱导率平均为２０％。在幼虫培养阶段，幼虫死亡严重，

Inducement of tetraploid Pinctada martensii in eggs from triploid

Tetraploidy was induced by inhibit ing the f irst polar body in eggs from triploid Pinctada martensii ( Dunker) fertilized with haploid sperms with 0. 5..g/ mL cytochalasin B ( CB) treatment. The effects of treatment duration and timing of treatment after fertilization on embryonic hatching rate and the percentage of tetraploid were examined, the growth and survival of larvae were compared between treated group, untreated group and diploid control. The results indicated that the hatching rate was inversely related to treatment duration time, but the percentage of tetraploid was positively related to treatment duration time. Two optimal moments for treatment application were determined. Optimal treatment duration time was 15..18min, optimal t iming of treatment was 3..5min before the release of polar body 1. The percentage of tetraploidy embryos was 20% averagely, the percent harvest of spat was only 0. 02% due to a heavy mortality of larvae. There was no difference in growth of larvae between treated group and untreated group( p > 0. 05) , but the growth of larvae in both groups was slower than that of diplo id control and the difference was significant ( p< 0. 05) .