斜生四链藻对水中四环素的胁迫响应及去除作用

四环素由于其低生物降解性和水溶性而在水环境中持续存在，对生态环境安全造成较高的潜在风险。为探讨水环境中残留的四环素与藻类的相互作用，以斜生四链藻为研究对象，考察了斜生四链藻对水中不同浓度四环素（0.5、1.0、1.5、2.5、4.0和6.0 mg·L^-1）的胁迫响应及去除作用。结果表明，各浓度四环素处理组均对斜生四链藻的生长产生抑制作用，最高抑制率达到了72.99%，四环素对斜生四链藻的半数效应质量浓度（96 h - EC₅₀）和抑制效应为80%质量浓度（96 h - EC₈₀）分别为2.46和6.9 mg·L^-1。在相同浓度四环素胁迫下，斜生四链藻的光合色素含量和F_v/F_m值呈现出和斜生四链藻细胞密度变化相同的趋势，与对照组相比，6.0 mg·L^-1浓度处理组中斜生四链藻的叶绿素a、叶绿素b和类胡萝卜素含量在96 h的抑制率分别是87.32%、66.91%和87.58%，F_v/F_m值降幅达到了77.4%。在低、中、高浓度四环素（0.5、1.5和6.0 mg·L^-1）胁迫下暴露96 h，斜生四链藻的丙二醛（MDA）含量整体呈现出先上升再下降的趋势；超氧化物歧化酶（SOD）活性和谷胱甘肽（GSH）含量均受到不同程度的诱导作用，6.0 mg·L^-1浓度处理组暴露96 h时，SOD活性为对照组的1.25倍，GSH含量为对照组的1.53倍。在斜生四链藻初始OD₆₉₀值为0.15，四环素浓度为4.0 mg·L^-1的条件下，48 h内斜生四链藻对四环素的去除率为90%，对照组的去除率为19%。研究结果为四环素对水体初级生产者的生态毒性提供了新资料，同时也为水体中残留四环素的生态修复提供了新的方向。

Response and remove of Tetradesmus obliquus to tetracycline in water

Tetracycline persists in the water environment due to its low biodegradability and water solubility, posing a high potential risk to ecological environment. In order to explore the toxic effect of tetracycline residual in water environment on algae, the stress response and removal effect of Tetradesmus obliquus to different concentrations of tetracycline (0.5, 1.0, 1.5, 2.5, 4.0 and 6.0 mg·L^-1) in water were investigated. The results showed that the growth of T. obliquus was inhibited at each concentration of tetracycline treatment group, with the highest inhibition rate reaching 72.99%, and the half effect mass concentration (96 h-EC₅₀) and inhibitory effect 80% mass concentration (96 h-EC₈₀) of tetracycline on T. obliquus were 2.46 and 6.9 mg·L^-1, respectively. Under the stress of the same concentration of tetracycline, the photosynthetic pigment content and F_v/F_m value of T. obliquus showed the same trend as the cell density of T. obliquus. Compared with the control group, the inhibition rates of chlorophyll a, chlorophyll b and carotenoid content in 6.0 mg·L^-1 concentration group at 96 h were 87.32%, 66.91% and 87.58% respectively , and the F_v/F_m value decreased by 77.4%. Under the stress of low, medium and high concentrations of tetracycline (0.5, 1.5, 6.0 mg·L^-1) for 96 h, the malondialdehyde (MDA) content of T. obliquus showed a trend of increasing first and then decreasing; the activity of superoxide dismutase (SOD) and the content of glutathione (GSH) were induced in different degrees. After exposure for 96 h, the activity of SOD and the content of GSH in the 6.0 mg·L^-1 group were 1.25 and 1.53 times higher than those in the control group. When the initial OD₆₉₀ value of T. obliquus was 0.15 and the concentration of tetracycline was 4.0 mg·L^-1, the removal