铜、镉对绿鳍马面鲀胚胎和初孵仔鱼的毒性效应

Toxic Effects of Copper and Cadmium on Embryos and Larvae of Thamnaconus septentrionalis

以绿鳍马面鲀(Thamnaconus septentrionalis)胚胎及初孵仔鱼为实验对象,采用静水试验方法,研究Cu^(2+)、Cd^(2+)对绿鳍马面鲀胚胎及初孵仔鱼的毒性效应。结果表明,随着重金属溶液浓度升高,绿鳍马面鲀胚胎畸形率呈上升趋势,孵化率呈下降趋势,初孵仔鱼呈现V、S、L、U等各种畸形状态;囊胚期至神经胚、器官分化至出膜2个阶段发育时长均随Cu2+浓度的增加呈先缩短后延长趋势,2个阶段发育时长均随Cd2+浓度的增加呈延长趋势;不同Cu2+、Cd2+浓度组在2个发育阶段死亡率均随浓度增加而升高,同一浓度下,器官分化至出膜阶段胚胎死亡率低于囊胚期至神经胚阶段;初孵仔鱼存活率与重金属溶液浓度和培育时间呈反比,畸形率与溶液浓度呈正比。Cu^(2+)、Cd^(2+)对初孵仔鱼72 h-LC50值分别为0.063 mg·L^(-1)和3.589 mg·L^(-1),其对应的95%置信区间分别为0.052~0.072 mg·L^(-1)和3.184~3.944 mg·L^(-1)。安全浓度分别为0.006 mg·L^(-1)和0.359 mg·L^(-1)。本实验表明,Cu^(2+)对绿鳍马面鲀胚胎发育及初孵仔鱼的毒性大于Cd^(2+)。

The toxic effects of Cu^(2+)and Cd^(2+)on embryos and hatchling larvae of Thamnaconus septentrionalis were studied by static water test.The results showed that with the increase of the concentration of heavy metal so-lution,the embryo deformity rate of the T.septentrionalisincreased and the hatching rate decreased.Compared with the control group,the embryo deformity rate in 3 mg·L^(-1) Cd^(2+)and 7 mg·L^(-1) Cd^(2+)groups increased about 5 and 15 times,respectively.At 48 h,the survival rates of 0.17 mg·L^(-1) Cu^(2+)group,5 mg·L^(-1),7 mg·L^(-1) Cd^(2+)group were 0,and there were significant differences between the other concentration groups and the control group.In the heavy metal solution,the embryos showed embryonic body atrophy,arrested development,turbidity of cytoplasm in em-bryo disc,embryonic body hyperplasia and head hypoplasia.The newly hatched larvae showed various deformities such as V,S,L and U shape.With the increase of Cu^(2+)concentration,the developmental time of the two stages from blastocyst stage to neurula stage and organ differentiation to membrane development stage first shortened and then extended,and the developmental time of the two stages extended with the increase of Cd^(2+)concentration.The mortalities of Cu^(2+)and Cd^(2+)increased with the increase of Cu^(2+)and Cd^(2+)concentrations in the two developmental stages.Under the same concentration,the embryonic mortality from organ differentiation to membrane development stage was lower than that from blastocyst to neurula stage.In the high concentration of heavy metal solution,the newly hatched larvae swam excessively actively for a short time,and their sense of direction was weakened,and then they lost their swimming ability with the increase of time until they died.The survival rate of newly hatched larvae was inversely proportional to the concentration of heavy metal solution,and the incubation time,and the malformation rate was directly proportional to the concentration of heavy metal solution.With the increase of Cu^(2+)and Cd^(2+)concentration,the incubation time and survival rate of newly hatched larvae decreased.At 72 h,the sur-vival rates of 0.18 mg·L^(-1) Cu^(2+)group and 8 mg·L^(-1) Cd^(2+)group were 0,and the survival rates of other groups were significantly different from the control group.With the increase of Cu2+and Cd^(2+)concentration,the malforma-tion rate of hatchling larvae increased,and they were significant higher than the control group(P≤0.05).The mal-formation rates of 0.18 mg·L^(-1) Cu^(2+)group and 8 mg·L^(-1) Cd^(2+)group were the highest,which were(47.78±4.01)%and(56.67±1.93)%,respectively,which are bout 14,17 times of the control group.LC50 values of Cu^(2+)and Cd^(2+)for hatchlings at 72 h were 0.063 mg·L^(-1) and 3.589 mg·L^(-1),respectively,and the corresponding 95% confidence intervals were 0.052~0.072 mg·L^(-1) and 3.184~3.944 mg·L^(-1).The safe concentrations were 0.006 mg·L^(-1) and 0.359 mg·L^(-1),respectively.Considering the survival rate and malformation rate,Cu^(2+)was more toxic than Cd^(2+)to T.septentrionalislarvae.