阿特拉津对家蚕生殖发育的影响

为探讨环境激素(EH)对鳞翅目昆虫的性激素作用,用添加阿特拉津(AT)的人工饲料饲养家蚕,调查AT对家蚕生殖发育的影响.结果显示:1)染毒72、96、120h的半数致死浓度LC50分别为0.348、0.326、0.234mmol·kg-1(即75.1、70.3、50.5mg·kg-1),属中等毒性.2)AT染毒可导致雄性家蚕5龄幼虫生殖腺指数显著升高,成虫(蛾)生殖腺指数显著降低.从整个世代看,0.05mmol·kg-1的AT对家蚕精巢的生长即表现出不良影响.AT染毒对雄蚕5龄幼虫、蛹前期精细胞的形成有促进作用,而对蛹后期和成虫(蛾)的精子形成有限制作用,可能AT染毒阻碍了精细胞向精子的发育.3)雌性家蚕幼虫期AT染毒后,5龄幼虫和蛹的卵细胞数量显著少于对照组(p<0.05).从不同发育时期的影响程度看,AT对卵细胞发育的抑制作用具有显著的时间效应(p<0.05).实验浓度下,AT对雌蚕造卵数和产卵数影响不显著,然而随着AT浓度的增加,不受精卵越来越多,AT染毒对雌蚕受精率具有显著抑制作用.AT通过抑制家蚕生殖腺的生长和生殖细胞的发育表现出雌激素效应.

Effects of Atrazine on Genital Development of Silkworm, Bombyx mori L.

In order to research the effects of environmental hormone (EH) on lepidopteron, the author investigated the genital development of silkworm (Bombyx mori L.), by feeding with artificial diet that contains atrazine (AT). The result shows, 1) The LC50 of new hatched larvae after having eaten atrazine 72, 96 and 120 hours is 0.348, 0.326 and 0.234mmol·kg-1, respectively, that is 75.1, 70.3 and 50.5mg·kg-1 respectively. Atrazine has moderate toxicity for silkworm (Bombyx mori L.). 2) Atrazine caused the gonad index of the fifth instar male larvae remarkably elevated, but caused it remarkably reduced in male moths. Seen from the whole generation, the growth of spermary might be affected when the concentration of atrazine is higher than 0.500mmol·kg-1. Atrazine also caused the number of spermoblast increased in the fifth instar larvae and pupae, but caused the number of sperm reduced in moths. The possible reason is that atrazine can hinder the sperm cell from growing to the spermatozoon. 3) The number of ova in the fifth instar larvae and pupae is significantly lower than control groups (p<0.05). The inhibition effects of atrazine on ova development of different developmental stages of silkworm is time-dependent (p<0.05). If the larvae ate atrazine less than 0.40mmol·kg-1, there was no noticeable difference of the number of borne or laid eggs between experimental groups and the controls. However, with the increasing concentration of atrazine, the number of the eggs which cannot be fertilized grows accordingly. It is suggested that the fertility rate of silkworm exposed to atrazine is significantly inhibited. The atrazine functions as estrogen through inhibiting the growth and development of insect gonad and germ cells.