温度、盐度对似刺鳊鮈胚胎发育过程的影响

设置10℃、15℃、20℃、24℃、27℃、30℃6个温度组和0‰、2.5‰、5‰、10‰、15‰、太湖湖水组6个盐度组,探讨了温度和盐度对似刺鳊鮈(Paracanthobrama guichenoti)胚胎发育的影响。温度实验结果表明:似刺鳊鮈胚胎发育的起始温度(生物学零度)为9.5℃,适宜的发育水温为20～24℃。水温10℃时胚胎卵裂异常,未能进入原肠期;水温升至30℃时胚胎在发育至原肠期前后死亡。水温度为24℃时孵化时间仅为73.5 h,孵化率高达80%,畸形率为0,为最适孵化水温;水温对胚胎发育速率的影响后期较前期大。盐度实验表明:似刺鳊鮈胚胎对盐度有一定的耐受力,各盐度梯度下的胚胎发育速率差异不大,但孵化率的差异极显著。在水温18℃、盐度为2.5‰的水体中胚胎的孵化率为81.67%,高于太湖湖水组的孵化率,此盐度应为似刺鳊鮈胚胎发育较适盐度。

Effects of temperature and salinity on the embryonic development of Paracanthobrama guichenoti

Fertilized eggs of Paracanthobrama guichenoti were treated with a serial temperatures(10 ℃,15 ℃,20 ℃,24 ℃,27 ℃,30 ℃) and salinities(0‰,2.5‰,5‰,10‰,15‰) to identify the effects on embryonic development.The results from temperature experiments showed that the threshold and suitable water temperature for embryonic development were 9.5 ℃ and 20~24 ℃,respectively.The cleavage was abnormal and no gastrulation was in progress when the temperature was 10 ℃.When the temperature reached 30 ℃,no embryos were survival before gastrul stage.However,at water temperature of 24 ℃,the incubation period was 73.5 h,the hatching and abnormality rate were 80% and 0%,respectively,these indicated that 24 ℃was the optimal temperature.The water temperature had greater influence in the later period of embryonic development.The results from salinity experiments showed that embryo P.guichenoti had a certain degree of tolerance of salinity.No significant difference in embryonic development speed was observed in fertilized eggs treated with various salinities.However,a significant difference was found in hatching rate.The appropriate salinity was 2.5‰,at which the hatching rate(81.67%) was higher than that of Taihu group(control group) at water temperature of 18 ℃.