[目的]研究野外黑眶蟾蜍(Bufo melanostictus)蝌蚪的生存状况。[方法]研究分别在碱性水(p H 7.5~8.0)以及酸性水(p H 5.5~6.0)2种模拟环境条件下,通过急性毒性试验方法以不同的浓度梯度Mg~(2+)对黑眶蟾蜍蝌蚪进行24和48 h的胁迫试验。[结果]在相同浓度梯度和相同观察时间下,黑眶蟾蜍蝌蚪在碱性水中的存活率低于酸性水;不同p H的水环境与Mg~(2+)的协同作用显著影响黑眶蟾蜍蝌蚪的48 h存活率(F7,32=3.373,P<0.05);黑眶蟾蜍蝌蚪在酸性水环境下适宜生存的Mg~(2+)浓度范围为1 418.41~1 590.54 mg/L,半致死浓度(LC_(50))为2 357.32 mg/L,安全浓度为521.51 mg/L;在碱性水环境下适宜生存的Mg~(2+)浓度范围为1 264.91~1 418.41 mg/L,LC_(50)为1 879.81 mg/L,安全浓度为533.99 mg/L。[结论]该研究可为今后黑眶蟾蜍的保护提供理论依据。[Objective]The aim was to study the survival status of Bufo melanostictus tadpoles in the field.[Method]The regular acute toxicity test was carried out that Bufo melanostictus tadpoles were breed in the alkaline water( p H 7.5-8.0) and acidity water( p H 5.5-6.0)with different Mg~(2+) concentration gradient for 24 and 48 h.[Result]The results showed that the survival rate of Bufo melanostictus tadpoles in the alkaline water was lower than the acidity water in the same condition.Synergistic effects of different p H and Mg~(2+) concentration had a significant effect on the survival rate of Bufo melanostictus tadpoles in the 48 h toxicity experiment( F7,32= 3.373,P < 0.05).In the acidity water environment,48 h toxicity experiment results showed that the optimal Mg~(2+) concentration was 1 418.41-1 590.54 mg / L,the median lethal concentration( LC_(50)) was 2 357.32 mg/L and the safe concentration was 521.51 mg/L.By contract,these three indexes in the alkaline water environment were 1 264.91-1 418.41,1 879.81 and 533.99 mg / L,respectively.[Conclusion] The study can provide theoretical basis for protection of Bufo melanostictus.国家自然科学基金项目(31271124);; 广东省自然科学基金项目(s2013010016062
