中文摘要：

研究了无机砷As（V）胁迫对牟氏角毛藻（Chaetoceros mulleri）培育水体中磷酸盐含量、藻细胞密度、叶绿素a含量及其抗氧化活性的影响,As（V）浓度梯度为0、7.3、10.2、23.9、45.2和114.0μg/L（分别记为Ctr和V1—V5）,取样时间为2、3、5、7、14和21 d。结果表明,试验条件下适当浓度As（V）暴露会促进牟氏角毛藻对磷酸盐的吸收速度,而较低浓度暴露时则反之。所有处理组中仅V2组在14d时藻细胞密度增至最大值71×104ind./m L,其它处理组在整个试验期间藻细胞密度变化均不显著（P〉0.01）。2 d时各组藻细胞叶绿素a含量均显著降低,且均显著低于对照;5 d时V5组显著升高（达102.16μg/108cell）,而其它处理组却仍明显低于其初始值;21 d时,除V1组外各处理组均明显高于对照（50.63μg/10~8cell）。在As（V）暴露2 d时,处理组GSH含量均明显低于对照（3.23μg/10~8cell）（P〈0.01）,且随着As（V）暴露浓度的升高呈先升高后逐渐降低的趋势。As（V）暴露对牟氏角毛藻GSH含量具有显著的抑制作用。谷胱甘肽还原酶活性随着As（V）浓度升高基本呈降低趋势。As（V）胁迫可能会抑制牟氏角毛藻的光合作用和抗氧化活性,长期暴露还会对其生长繁殖造成影响。

英文摘要：

We studied the effects of As（V） exposure on growth, chlorophyll-a content, and antioxidant activity of Chaetoceros mulleri. The alga was exposed to inorganic arsenic As（V） for 21 days at 6 levels（0, 7.3, 10.2, 23.9, 45.2, and 114.0μg/L, labeled as Ctr and V1—V5, respectively）, during which phosphate concentration, the alga growth, chlorophyll-a content, and antioxidant parameters of C. mulleri cells were recorded and analyzed on Days 2, 3, 5, 7, 14, and 21. The results show that phosphate assimilation by microalgae cells was promoted in appropriate As（V） exposure dosages but was inhibited in lower dosages. The growth curve shows that only the cell density of group V2 increased to maximum（71×104cells/m L） on Day 14, while that of all other groups rose insignificantly（P〉0.01）. On Day 2, chlorophyll-a content in all groups decreased clearly, and was obviously lower than the control. However, that of group V5 went up greatly to 102.16μg/108 cells on Day 5, and those of all other groups were significantly lower than their initial values（P〈0.01）. Furthermore, on Day 21, chlorophyll-a content in groups V2—V5 was higher than that of the control（50.63μg/108cell）. On Day 2, the GSH content in all the group was remarkably lower than the control（3.23μg/10 8cell）; it increased first and then decreased with the increase of As（V） dosage. Moreover, glutathione reductase activity decreased generally with the increase of the dosage. Therefore, long-term exposure of C. mulleri to As（V） could result in depressing the photosynthesis and antioxidant activity, and might affect the growth and ecological function of marine microalgae.