中文摘要：

以铜绿微囊藻（Microcystis aeruginosa）为试验材料,研究了四环素暴露对铜绿微囊藻光合作用和抗氧化酶活性的影响。结果显示,0.80-35.00 mg·L^-1四环素暴露胁迫4 d时,铜绿微囊藻的叶绿素荧光和潜在最大电子传递速率（Re,t,max）受到抑制,抑制作用随ρ（四环素）的增加而增强,最大抑制率分别为39.95%和44.08%;暴露7 d时,2者最大抑制率分别升高至59.48%和91.90%。抗氧化酶系统也受到四环素的影响,暴露4和7 d时,超氧化物歧化酶（SOD）活性分别下降30.36%-35.92%和25.03%-35.51%,不同四环素浓度组间差异不显著;过氧化物酶（POD）活性升高,在7 d内呈现诱导现象。可见,四环素暴露能够阻碍铜绿微囊藻光合作用,破坏抗氧化酶系统平衡,抑制藻类生物量的增长。

英文摘要：

Tetracycline is one of the widely used antibiotics for animals as prescription drugs and as growth promoters in livestock.As a matter of fact,much of the tetracycline is excreted with urine or feces and released into the aquatic environment through many pathways,thus posing a potential threat to aquatic organisms.Microcystis aeruginosa is an important algae in the aquatic ecosystem.In order to determine toxic effects of tetracycline on non-target aquatic organisms,M.aeruginosa was used as a subject in this study,and effects of tetracycline on photosynthesis and antioxidant enzymes of M.aeruginosa were investigated.Results show that exposed to tetracycline（0.80-35.00 mg·L^-1）,the algae declined significantly in chlorophyll fluorescence and potential maximal relatively electron transport rate（Re,t,max）.The inhibiting effects intensified with the increase in concentration of tetracycline,with the maximal inhibitation rates being 39.95% and 44.08%,respectively,after 4 days,and rising up to 59.48% and 91.90% after 7 days.The activity of superoxide dismutase（SOD） in the algae dulled by 30.36%-35.92% and 25.03%-35.51% after 4 and 7 days of exposure,respectively,and no significant difference was found among treatments different in tetracycline concentration.The activity of peroxydase（POD） was intensified after 7 days of exposure.The findings indicate that tetracycline hinders photosynthesis of M.aeruginosa,disturbs balance of the antioxidant enzymes system,and then inhibits growth of the algae.