【作者】 侯亚妮；

【导师】 张迎梅；

【作者基本信息】 兰州大学 ， 动物学， 2007， 硕士

【摘要】 近年来，随着环境污染的日益加重，两栖类动物物种在全球范围内正急剧衰减或消失，已有研究证明消失的情况与除草剂和杀虫剂等农药有关。本文就目前广泛使用的杀虫剂敌百虫(trichlorphon)对花背蟾蜍(Bufo raddei Strauch)蝌蚪早期生长发育、重要酶活性以及遗传物质的影响进行了研究。实验分两部分进行。前期为B．raddei蝌蚪早期生长发育试验，敌百虫处理浓度设为(0.5、0.1、5.0 mg／L)；后期为B．raddei蝌蚪酶活实验和遗传毒性实验，敌百虫处理浓度设为(0.05、0.5、1.0、2.5 mg／L)。得出结果如下：经过敌百虫(0.5、0.1、5.0 mg／L)浸染的B．raddei蝌蚪，前30d时低浓度组0.5 mg／L和1.0 mg／L蝌蚪的生长发育在对照组与处理组之间差异不显著(P＞0.05)，30d之后，较对照组发育快且1.0 mg／L组＞0.5 mg／L组＞对照组，而5.0 mg／L浓度组与对照组相比抑制了蝌蚪的生长发育。不同浓度处理组蝌蚪均出现畸形，蝌蚪畸形多为尾部断裂或尾部向胸腹部弯曲，尾部畸形的个体往往旋转式运动，最后完全丧失运动能力，继而死亡。B．raddei蝌蚪经敌百虫(0.05、0.5、1.0、2.5 mg／L)浸染后，低浓度的敌百虫(0.05 mg／L)可诱导肝脏和肌肉中SOD和CAT活性的升高，而较高浓度的敌百虫(0.5、1.0和2.5 mg／L)在整个处理过程中都对肝脏和肌肉中SOD和CAT表现出了极大的抑制作用，且和对照组差异显著或极显著(P＜0.05或P＜0.01)。敌百虫B．raddei蝌蚪尾部肌肉AChE活性有抑作用，且处理浓度越高，抑制越明显。敌百虫可引起B．rode蝌蚪血红细胞微核率和核异常率的变化。除0.05 mg／L组与对照组微核率和核异常率差异不显著(P＞0.05)外其它各组与对照组相比较均差异极显著(P＜0.01)；14d，21d和28d时各处理组与对照组均差异极显著(P＜0.01)。B．raddei蝌蚪肝细胞DNA损伤水平各敌百虫处理组均高于相应的对照组相比较且差异显著(P＜0.05)。在相同时间里，随处理浓度的增大而增大，表现出一定的剂量—效应关系；各处理组随时间的延长DNA损伤率也随之增大，但在处理后期有所下降。总之，有机磷农药敌百虫除具有抑制AChE活性使机体产生神经毒性外，还能通过影响抗氧化物酶活性、诱导遗传物质变异等途径对机体产生毒性作用。实验所选择的指标适于以蝌蚪为材料的水体污染检测可灵敏的反映水体变异。利用蝌蚪红细胞微核实验和肝细胞单细胞凝胶电泳实验检测水体污染易操作，灵敏度高，是水体环境生物检测的可行性指标。更多还原

【Abstract】 Amphibian populations have globally declined over the past decades, including a number of species extinction. Now, some reports have proved the pesticide (herbicide, insecticide et al) was one resulting in amphibian population declination. In order to evaluate the toxicity and discuss the toxic mechanism of the organophosphorus pesticide (OP) trichlorphon to Bufo raddei Strauch, tadpole early development, activities of Acetylcholinesterase (AChE), Superoxide dismutase(SOD) and Catalase(CAT), erythrocyte micronucleus ratio and DNA-single strand break in tadpoles.The experiment included tow parts: one was on tadpole early development experiment in which the tadpoles of B. raddei were exposed to trichlorfon at concentration o f 0.5 mg/L, 1.0mg/L, 5.0mg/L for 40d respectively. Another experiment was on the activities of antioxidant enzymes and genotoxicity of trichlorfon in B. raddei tadpoles exposed to trichlorfon at concentration of 0.05 mg/L, 0.05 mg/L, 1.0 mg/L, 2.5 mg/L for 7d, 14d, 21d or 28d respectively. The results showed that:When the tadpoles of B. raddei were exposed to trichlorfon at concentration o f 0.5 mg/L,1.0mg/L,5.0mg/L for 30d respectively, the development of tadpoles had no significant difference with those of the relative control groups(P>0.05). After 30d, the 0.5 mg/L and 1.0mg/L groups grew up quicker than the relative control groups but the 5.0 mg/L groups inhibited the development of tadpoles. Tadpoles with tail flexure and swirling in each treating group were found.The results indicated that the lower concentration (0.05 mg/L) had no significant effect on the activities of SOD and CAT in the short term (7d). But, after 21d, the activity of SOD at the concentration of 0.05mg/L marked lower than control group and the activity of CAT at the concentration of 0.05mg/L significantly (P>0.05) higher than control group that indicated the lower concentration (0.05mg/L) could inhibit the activity of SOD and induced the activity of CAT in the long term exposure (>21d). But the activities of SOD and CAT were both inhibited at each higher concentration (>0.05mg/L) exposure. The activity of AChE was inhibited both at the lower and higher level of trichlofon.The results also showed that frequency of micronuclei and nuclear anomalies of each concentration group for the tadpoles exposed to trichlorfon were higher than those of the control group (P <0. 01) except the tadpoles exposed to trichlorfon for 7d at the concentration of 0.05 mg/L which had no significant difference respect to those from control group. The level of DNA damage in each concentration group for the tadpoles exposed to trichlorfon was significantly higher than that of control group (P < 0. 05, P< 0. 01) and increased gradually with the dose increasing of trichlorfon in the same exposure period. There existed dose-effect but no time-effect relationship among the tested concentrations.In one word, the organophosphorus pesticide (OP) trichlorphon did harms to B. raddei tadpoles by inhibiting the activity of AChE, and by affecting antioxidant defense system and genetic materials.For more credibility of the result, the biomarkers are signed out in our experiment. Through detecting the activity of AChE, SOD and CAT, the number of erythrocytes nucleus anomalies and tadpole live cell DNA damage, the toxicity of trichlorphon is evaluated, which indicates that trichlorphon has toxicity on aquatic animals.更多还原