四种环境激素对萼花臂尾轮虫生活史及生殖影响

【作者】 陆正和；

【导师】 杨家新；

【作者基本信息】 南京师范大学 ， 水生生物学， 2013， 博士

【摘要】 轮虫由于在水生态系统种群动态中起着重要作用,因此为水生态毒理学研究的模式生物,利用轮虫评价环境激素效应为世界关注的热点问题。本文以淡水水体中普遍存在的萼花臂尾轮虫(Brachionus calyciflorus)为受试动物,研究了4种环境激素双酚A(bisphenolA)、阿特拉津(atrazine)、西维因(carbaryl)和久效磷(monocrotophos)对萼花臂尾轮虫急性毒性、生活史、无性生殖与有性生殖影响。主要研究结果如下：1、BPA对萼花臂尾轮虫24h急性毒性LC50值为13.76mg/L；慢性毒性表明,BPA对轮虫主要生活史阶段和生命表参数具有干扰作用,尤以有性生殖影响最为显著。生活史阶段显示,BPA浓度0.25-4.0mg/L对轮虫胚胎发育无显著影响,但BPA浓度2.0-4.0mg/L却显著延迟轮虫幼体发育时间,该浓度显著缩短轮虫生殖期和生殖后期时间；BPA浓度0.5mg/L显著增加轮虫净生殖率(Ro),浓度为2.0、4.0mg/L却显著降低R0,1.0mg/L对R0无显著影响；BPA浓度4.0mg/L显著降低世代时间(T)；BPA浓度为2.0、4.0mg/L时显著降低轮虫生命期望值(e0)；BPA浓度为1.0mg/L及以上浓度时,显著降低轮虫内禀增长率(rm)；BPA浓度为0.5、1.0mg/L时显著增加轮虫所产后代混交率(MR)；研究结果表明R0和MR受BPA影响最为显著。群体研究表明,BPA浓度为0.5、1.0mg/L显著降低轮虫2d的r,而浓度为0.313、0.0625、0.125及0.25mg/L对轮虫2d的r无显著影响；BPA浓度0.25mg/L及以上浓度显著降低轮虫3d的混交/非混交比率、混交率,0.125mg/L及以上浓度显著降低轮虫3d的受精率；休眠卵产量显示,0.125mg/L及以浓度显著降低轮虫7d的休眠卵产量,0.0625mg/L及以上浓度显著降低轮虫3d的休眠卵孵化率。综上所述,轮虫休眠卵孵化率对BPA最敏感,其次为休眠卵产量及受精率,以上指标可作为评价BPA环境激素较敏感指标。2、阿特拉津对轮虫24h的LC50值为39.2mg/L,阿特拉津对轮虫的生活史及生殖具有显著影响。0.64-10.24mg/L的阿特拉津显著延长轮虫生殖前期历时,2.56-10.24mg/L阿特拉津延长胚胎发育历时,但缩短了轮虫生殖期历时和平均寿命;阿特拉津对轮虫生殖后期无显著影响；生命表参数显示,阿特拉津0.64-10.24mg/L显著降低轮虫rm,2.56-10.24mg/L时显著降低e0、R0,阿特拉津0.04-10.24mg/L对T无显著影响。阿特拉津对轮虫后代的影响表明,母体暴露在以上阿特拉津溶液下所产第1胎F1(1st)在正常溶液下培养,2.56-10.24mg/L下产生F1(1st)生殖前期、生殖期、寿命、e0和R0未恢复,0.64-10.24mg/L下所产的F1(1st)的rm未恢复；但在第2胎F1(2nd)中,除2.56-10.24mg/L所产后代rm未恢复,10.24mg/L的生殖前期、R0未恢复,其它指标都得到恢复,显示阿特拉津对轮虫后代具有潜在影响。3、西维因对轮虫24h的LC5o为4.10mg/L,对其生活史研究表明,西维因1.6-2.0mg/L显著延长轮虫生殖前期时间,但缩短生殖期时间和平均寿命；1.2mg/L及以上浓度显著延长胚胎发育期,2.0mg/L缩短轮虫生殖后期时间。生命表参数显示,0.8-2.0mg/L显著降低R0和rm,1.2mg,/L及以上浓度显著降低轮虫世代时间和生命期望值。低剂量阿特拉津(0.02、0.08、0.32、1.28、5.12mg/L)和西维因(0.02、0.06、0.18、0.54、1.62mg/L)对萼花臂尾轮虫2d种群增长、3d有性生殖及7d休眠卵产量、3d休眠卵孵化率有显著影响,实验结果表明,与对照组相比,阿特拉津5.12mg/L、西维因1.62mg/L显著降低轮虫2d的r；阿特拉津1.28、5.12mg/L显著降低混交率,受精率；西维因除0.06mg/L显著增加OF/NOF值外,其它浓度对OF/NOF无显著影响,0.06mg/L的西维因显著增加轮虫混交率,0.54、1.62mg/L西维因显著降低混交率；轮虫7d休眠卵产量及孵化率表明,阿特拉津0.32-5.12mg/L显著降低轮虫休眠卵产量和孵化率,西维因0.18-1.62mg/L降低休眠卵产量,西维因0.06-1.62mg/L显著降低休眠孵化率,显示轮虫休眠卵孵化率对阿特拉津和西维因最敏感。4、久效磷对轮虫24h急性毒性LC5o值为5.65mg/L,久效磷对轮虫生活史及生殖具有显著影响。生活史研究表明,0.5-2.0mg/L显著延长轮虫生殖前期时间、总产卵量,1.0-2.0mg/L显著缩短轮虫生殖期、生殖后期和平均寿命；0.5-2.0mg/L降低R0及rm,。群体培养表明,0.5mg/L降低轮虫3d的种群增长率,0.25mg/L可降低轮虫3d的混交率,0.125-0.5mg/L时显著降低休眠卵产量,0.0625-0.5mg/L久降低休眠卵孵化率,因此轮虫休眠卵孵化率对久效磷敏感性最高。5、阿特拉津(0.02、0.08mg/L)和久效磷(0.0079、0.0157、0.0313mg/L)单独对轮虫2d的r,4d的MR、OF/NOF、FR及7d的休眠卵产量无显著影响,但当阿特拉津和久效磷混合时,轮虫以上生殖指标部分受到交互影响,影响程度主要取决于2种环境激素的浓度；阿特拉津最高浓度与久效磷最高浓度混合作用对轮虫生殖影响最显著,而两者以最低浓度相混合对轮虫生殖指标无显著影响,其它浓度相混合对轮虫生殖影响介于最高与最低之间。阿特拉津与久效磷复合对轮虫生殖影响以休眠卵产量影响最为显著。研究表明,单一环境激素对轮虫生殖影响不能全面地用来评价环境激素效应,因为两种或以上环境激素复合可能对轮虫生殖产生影响,因此在水生态研究中必须关注环境激素对轮虫生殖的复合影响。更多还原

【Abstract】 Rotifers are useful as models in ecotoxicology because they play an important in the freshawater and marine ecosystems. Using the rotifer to evaluate environmental hormone effect is a worldwide concern. The effects of bisphenol A (BPA), atrazine, carbaryl and monocrotophos on the acute test, life history, asexual and sexual reproduction of Brachionus.calyciflorus were studied. The main results were presented as the following:1. The effect of BPA on the acute toxicity (24hLC50) of BPA for B. calyciflorus was13.76mg/L. BPA had a significant interference effect on the life stage and life table parameter, especially on the effect of sexual reproduction. In the life history test, the tested concentration0.25-4.0mg/L had no significant effect on the embryonic development compared to the control, BPA at2.0and4.0mg/L extended significantly the durations of juvenile development than the control, but shortened the reproductive period and post-reproductive period. BPA at0.5mg/L increased significantly net reproduction rate (Ro) compared the control. But BPA at2.0and4.0mg/L decreased significantly the Ro, and BPA at4.0mg/L reduced the generation time (7). BPA from1.0to4.0mg/L decreased significantly the intrinsic rate of increase (rm), the mix rate of total offsprings was increased markedly at0.5and1.0mg/L than the control. The results showed that different endpoints of both development and reproduction had different sensitivity to BPA. Ro and mixis rate endpoint of the rotifers appeared to be more sensitive than other endpoints. The effects of BPA (0.313,0.0625,0.125,0.25,0.5,1.0mg/L) on the population growth rate (r) of rotifer at2d showed that BPA at0.5,1.0mg/L reduced markedly the r, other concentration did not affect the r. The reproduction of3d indicated that BPA from0.25mg/L to1.0mg/L decreased significantly the mictic female/amictic female (MF/AF), mix rate (MR) than the control. At the same time, BPA from0.125mg/L reduced the fertilization rate (FR). The resting egg (RE) production at7d showed that the BPA from0.125mg/L reduced the RE production, and0.0625mg/L and above decreased significantly the resting egg hatching rate at3d. All these results indicated that resting egg hatching rate were most sensitive parameter and resting egg production, fertilization rate were second to assess environmental hormone effect of BPA.2.24h median lethal concentration (24h LC50) value of atrazine for B. calyciflorus were39.2mg/L. life history (rotifer exposed atrazine0.04-10.24mg/L) showed that atrazine from0.64to10.24mg/L significantly pronged pre-reproductive period (JP) compared to the control, atrazine from2.56to10.24mg/L extended significantly the embryonic development time, but reduced significantly the reproduction period and mean life span. Atrazine did not affect the post reproduction period of rotifer. Life table showed that atrazine from0.64mg/L to10.24mg/L decreased significantly the rm,2.56-10.24mg/L reduced markedly the eo and R0, the concentration from0.04mg/L to10.24mg/L had no effect on the Tthan the control. The recovery of rotifer exposed atrazine concentration showed that the first rotifer(1st) produced from mother rotifer(Fo) raised at free atrazine, first brood F1(1st) produced by Fo exposed from2.56and10.24mg/L had no significant effect on pre-reproductive period(PP), reproduction period (RP), mean life (ML), e0and Ro, but from the second brood F1(2nd) from the Fo exposed atrazine all the parameter had been recovered except rm of rotifer produced from the F0exposed2.56-10.24mg/L, PP, Ro of F1(2nd) produced from the mother female (Fo) exposed10.24mg/L had not been recovered, all these results showed that atrazine had potential effect on the offsprings.3. Acute toxicity of carbaryl on the rotifer24h LC50was4.10mg/L. Carbaryl from1.6to2.0mg/L extended the pre-reproductive period (JP), but reduced the PP and ML, concentration from1.2mg/L to2mg/L extended significantly embryonic development time (EP),2.0mg/L decreased markedly PP. Life table showed carbaryl from0.8to2.0mg/L decreased significantly Ro and rm, concentration from1.2mg/L reduced significantly T and e0.Effect of rotifer populations were exposed to atrazine at low concentrations from0to5.12mg/L and carbaryl from0.02mg/L to1.62mg/L, the2-d population growth rate,3-d reproduction parameter,7-d resting egg production (RE), and3-d resting egg hatching rate (HR) were measured. The results showed that atrazine concentration had effect on the mix rate, male number and fertilization rate, and no effect on OF/NOF. The no effect concentration (NOEC) and lowest effect concentration (LOEC) of atrazine were1.28mg/L and5.12mg/L for population growth rate (r), and for carbaryl were0.54mg/L and1.62mg/L. In sexual reproduction, the NOEC and LOEC of atrazine for MR were0.32and1.28mg/L. However, carbaryl did not show similar results because0.06mg/L carbaryl increased the MR compared with the control. The NOEC and LOEC of atrazine for RE and HR were the same (0.08and0.32mg/L) and the NOEC and LOEC of carbaryl for RE were slightly lower. HR was the most sensitive of all indices with NOEC and LOEC of atrazine from0.02to0.32mg/L nominal concentration. The result showed that the resting egg hatching rate was the most sensitive parameter to atrazine and carbaryl.4. Effect of monocrotophos on the life history and reproduction of rotifer were investigated. The24h median lethal concentration value was5.65mg/L. Life history indicated monocrotophos from0.25to2.0mg/L prolonged significantly pre-reproduction period, total eggs, Ro and rm,1.0-2.0mg/L reduced markedly the RP, PP and ML. The results of3d population growth test showed that monocrotophos at0.5mg/L reduced the r,0.25mg/L decreased significantly the mix rate, but had no effect on the fertilization rate, concentration from0.125to0.5mg/L decreased significantly the resting egg production,0.0625-0.5mg/L decreased markedly the resting egg hataching rate. The results showed that resting egg hating rate was the most parameter, and discovered that the fertilization rate sometimes was not the more sensitive parameter than other reproductive parameters.5. Atrazine (0,0.02,0.08mg/L) and monocrotophos(Mop)(0、0.0079、0.0157、0.0313mg/L) had no significant effect on r at2d, MR, OF/NOF, FR at4d, resting egg production at7d of rotifer respectively. But atrazine mixed Mop at different concentrations, the reproductive parameters of rotifer had been affected depended on the concentrations of atrazine and Mop concentration. Atrazine at0.08mg/L mixed Mop at0.0313mg/L had significnt effect on reproduction of rotifer. But atrazine at lowerst concnentration mixed Mop at lowerest concentration had no significant effect on the reproduction of rotifer compared the control. Other concentrations mixed affected the reproduction of rotifer between the lowest and highest concentrations. Compound effect of atrazine and mop on the resting egg production in all reproductive indicides is the most sensitive. The results showed that simple environment hormone could not assess the envirnonmental effect on rotifer fully, but when different environmental hormone mixed, they could affect the reproduction of rotifer. The results showed that the simple environmental hormone might not affect the reproduction of rotifer, but different environmental hormone combined, the reproduction of rotifer might be affected.更多还原