Zn^(2+)对黑斑蛙早期发育的影响

Studing on Toxicity of Zn^(2+) to Early Development of Rana nigromaculata

以黑斑蛙受精卵为实验材料,采用人工配制的不同质量浓度的锌离子(分别为0,1,5,10,20,30,45,60,80mg/L)作为培养液,研究锌离子对黑斑蛙胚胎出膜及蝌蚪生长发育的影响.其结果表明,不同质量浓度的锌离子会显著缩短黑斑蛙胚胎50%出膜时间(P<0.05,n=8),但对黑斑蛙蝌蚪的最终出膜率没有显著影响(P>0.05,n=8);与对照组相比,染毒组蝌蚪的畸变率大大增加,且畸变类型具有多样性,表现为:尾部呈泡状膨大、尾部呈‘S’型、头部呈泡状膨大、个体形态较小(是正常个体的50%~65%),总体表现是锌离子浓度越大,毒性效应越强,致畸率越高,与对照组相比,染毒组蝌蚪的畸形比率受锌离子浓度影响差异极其显著(P<0.01,n=8),且蝌蚪尾部的弯曲程度也随锌离子浓度的增加更趋严重,这与锌对尾部神经系统的毒害有关;锌离子对黑斑蛙蝌蚪的死亡率也有很大的影响,实验初期各质量浓度组蝌蚪死亡现象不明显,个体的死亡多发生在出膜后第5天到第10天,在肌肉感应期出现死亡高峰,与对照组相比锌处理组的蝌蚪死亡率明显增加,而且浓度越高死亡率越高.

The zygote of Rana nigormaculata was cultivated in Zn^2＋of different density to study the effects of Zn^2＋ on the hatching rate and development of tadpoles. The results showed that different density of Zn^2＋can significantly shorten the time when 50% of Rana nigormaculata hatched （P〈0.05,n =8）, but have no significant effect on tadpoles final rate （P 〈0. 05, n = 8）;Compared with the comparison group, the control group greatly increased the deformation rate ,and the types of deformation diversified, such as ：expansed tails with the shape of bubble,tail with ‘s＇ type,expansed heads with the shape of bubble,and smaller individual figures （which is 50% - 65 % of the normal individual）. Overall, this manifests that the greater the density of Zn^2＋is,the stronger toxic effects and the higher deformation rate it is. Compared with the comparison group,the deformation ratio of the control group is affected significantly the different density of Zn^2＋ （P〈0.01. n=8）,and the bending extent of the rear parts of tadpoles become more serious with the increase in density of Zn^2＋. The density of Zn^2＋ also had a great impact on mortality rate,it is not remarkable during the time of embryo,but it occurs from 5 days to 10 days after hatching, and reaches the peak during the time of muscle reaction.. Contrast with the comparison group,the processing group of Zn^2＋ have a remarkable increase in mortality,and the higher the density is ,the higher the mortality is.