除草剂西玛津对非洲爪蟾生存和性腺发育的影响

为了研究三嗪类除草剂西玛津对两栖动物非洲爪蟾(Xenopus laevis)生存和性腺发育的毒性作用,并且与另一种三嗪类除草剂阿特拉津的毒性进行比较,将非洲爪蟾从46/47阶段开始暴露西玛津和阿特拉津到变态1个月后停止,再饲养2个月后将其解剖,取性腺做形态学和组织学观察.暴露期间,每天记录蝌蚪的生长发育情况和存活率.结果显示,在暴露的第1周内(蝌蚪处于46~50阶段),西玛津可导致蝌蚪死亡率明显升高,随后的时间内西玛津对非洲爪蟾的生存不再有明显影响,但却使发育阶段明显的不整齐.阿特拉津对非洲爪蟾的生存和发育则没有明显影响.西玛津和阿特拉津对非洲爪蟾性腺的总体形态和性别比没有明显影响,然而两种除草剂均在一定程度上导致了睾丸组织学的改变.西玛津可能与阿特拉津一样能够通过雌性化/去雄性化作用影响非洲爪蟾睾丸的发育.

Effects of the Herbicide Simazine on the Survival and Gonadal Development of African Clawed Frogs (Xenopus laevis)

The toxicity of the herbicide simazine to the survival and gonadal development of amphibian Xenopus laevis were determined and compared with the effects of atrazine. X. laevis were exposed to simazine or atrazine in water from Nieuwkoop and Faber (NF) stage 46/47 to one month postmetamorphosis. Followed by another two months without exposure, the gonads of frogs were examined in gross morphology and histology. During the exposure period, the growth and survival of frogs were recorded every day. Results showed that, at the first week of exposure, simazine induced higher mortality at stage 46~50, and had no effect on the survival in the following period but caused a lack of synchronicity in development stage. Atrazine had no toxicity to the survival and growth of X. laevis. Simazine as well as atrazine did not affect gross gonadal morphology and the sex ratio. However, simazine as well as atrazine induced histologic degeneration of testis to some degree. The results suggested that simazine as well as atrazine might have the potential to impair testicular development by feminizing/demasculinizing.