水环境Mg^(2+)对长白山林蛙蝌蚪生存的影响

Effects of Mg^(2+) on Survival of Tadpoles of Frog(Rana chensinensis changbaishanensis)

采用养殖池水添加化学试剂的方法配制实验水,通过室内急性中毒实验,研究水环境Mg2+质量浓度对21d龄、体长为(18.7±2.4)mm的长白山林蛙(Rana chensinensis changbaishanensis)蝌蚪生存的影响。结果表明,水环境Mg2+对蝌蚪的急性毒性呈单向剂量效应;在Mg2+质量浓度为0.2￣501.6 mg.L-1的水环境中,蝌蚪48h存活率在85%￣100%。蝌蚪生存适应的Mg2+质量浓度为0￣580.8 mg.L-1;最高耐受限1 699.4 mg.L-1,长期生存的安全浓度为261.2 mg.L-1。蝌蚪对水环境Mg2+的适应能力与其他水生动物之间存在一定的差别,养殖水环境应注意Mg2+浓度的调节,其质量浓度宜控制在200￣500 mg.L-1。

Rana chensinensis changbaishanensis is one of the principal wild economic animal of the Changbai Mountain Area in China. MgC12 is widely adopted in improving culture effect and female proportion for tadpole. Acute toxicity was determined at 17.2℃＋0.8 ℃ and at pH 7.3-8.2 in indoor by one-way toxicity test in the present study. The tadpoles used in the present test were cultured by our institute at 21 days of age with body length （18.7±2.4） mm. The water in tadpole pond was used for basic water in test. The concentration of Mg^2＋ were designed at 0.2-1 839.2 mg·L^-1, controlled by MgCl2·6H2O, and designed as 10 groups of the concentrations in equidistance logarithm, each gradient with two replicates and 15 individuals each. The results showed that the concentration of Mg^2＋ was in a range of 0.2-501.6 mg·L^-1, survival rate of tadpole for 48 hours was in a range of 85%-100%. The median lethal concentration of Mg^2＋ for 24 and 48 hours was 1 148.2 and 1 047.1 mg· L^-1 at 501.6-1 839.2 g· L^-1, respectively. The concentration of Mg^2＋ with a range of 0 - 580.8 mg· L^-1 was optimal for tadpoles living, while the maximum limit of tolerance was 1 699.4mg· L^-1, the safe concentration of Mg^2＋ was 261.2 mg· L^-1. Suitable concentration of Mg^2＋ was found to be in a range of 200-500mg· L^-1 in culturing waters.