Cypridopsis vidua is one of the few ostracods which can surrive from heavy pollution water.The toxic effects of Cd2+ on C.vidua and its intestinal ultrastructure were examined using a static renewal system.The LC50 values for cadmium in C.vidua were 5.00,2.01,0.46 and 0.14 mg/L at 24,48,72 and 96 h exposure respectively,and the safe concentration of Cd2+ for long-term C.vidua survival was less than 0.014 mg/L.To observe the structure changes of its intestinal,four Cd2+ concentrations were set up,and two of them were below the safe concentration of Cd2+ (0.001 and 0.004 mg/L) and the other concentrations were above its safe concentration (0.016 and 0.064 mg/L).The experiment lasted for 7 days.When microstructure of C.vidua was observed,the gastrointestinal organization was not damaged below the safe concentration;while the degree of injury showed a certain amount of time and dose effects in 24-72 hours above the safe concentration,and some structures among those surviving animals were slightly recovered in 7 days under same concentration.Sub-microscopic analysis of intestinal cells of C.vidua in two concentrations (0.004 and 0.064 mg/L) groups showed,different degrees of structure damage were found in the cell membrane,cytoplasm and organelles,which worsened with increasing Cd2+ concentrations.Among these cellular structures,the damage to the membrane system of the cell was especially serious.%Cypridopsis vidua是少数能在重污染水体中生存的介形类之一.本文采用急性毒性实验方法,研究了Cd2+对介形类C.vidua及其肠壁结构的影响,结果表明,24、48、72和96 h时Cd2+对C.vidua的半致死浓度(LC50)分别为5.00、2.01、0.46和0.14 mg/L,安全浓度为0.014mg/L.在急性毒性试验的基础上,于安全浓度上下分别设置了两个Cd2+实验浓度对介形类进行攻毒研究,目的是进一步探讨在安全浓度附近,Cd2+对C.vidua肠壁细胞的损伤情况,实验持续7d.显微结果显示,在安全浓度以下时,Dvidua的胃肠道结构基本没有受到损伤,但超过安全浓度后,C.vidua的胃肠道结构损伤程度于96 h以内表现出了一定的时间和剂量效应,但至第7天时部分幸存下来的C.vidua其受损胃肠道结构出现一定程度的恢复,但已无法恢复到最初的状态了;亚显微切片显示,肠壁细胞的膜结构、胞质、胞器等均有不同程度的损伤,且随镉离子浓度的升高损伤明显加剧,其中细胞的膜结构损伤尤为严重.
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