Abstract This study explores the activity of total superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR), biomass accumulation and chlorophyll a content in Scenedesmus ellipsoideus Chodat grown under conditions of varying zinc (Zn) concentrations. In addition, the activity of different SOD isozymes (MnSOD, FeSOD and CuZnSOD) was measured separately to determine the intracellular extent of oxidative stress resulting from Zn toxicity. We found that the activity of FeSOD and MnSOD was induced by lower Zn concentration (2 μg ml−1 and 4 μg ml−1, respectively), whereas CuZnSOD activity was not affected, which indicates that chloroplasts are the first location in S. ellipsoideus cells where superoxide accumulation is accelerated by Zn toxicity. The activity of total SOD and APX was significantly increased by moderate Zn concentrations, probably due to some oxidative stress caused by Zn toxicity. The higher level of Zn application, however, led not only to the inhibition of total SOD and APX activity, but also to the reduction of biomass accumulation and chlorophyll a content. As a result, it can be concluded that the accumulation of superoxide radicals and H2O2 in S. ellipsoideus cells induced by Zn toxicity may be responsible for the reduced growth rate and the impairment of photosynthetic pigments.

中文翻译：

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锌对椭圆栅藻生长和抗氧化酶影响的评估

摘要 本研究探讨了在不同锌 (Zn) 浓度条件下生长的 Scenedesmus ellipsoideus Chodat 中总超氧化物歧化酶 (SOD)、抗坏血酸过氧化物酶 (APX) 和谷胱甘肽还原酶 (GR) 的活性、生物量积累和叶绿素 a 含量。此外，还分别测量了不同 SOD 同工酶（MnSOD、FeSOD 和 CuZnSOD）的活性，以确定锌毒性导致的细胞内氧化应激程度。我们发现 FeSOD 和 MnSOD 的活性受到较低 Zn 浓度（分别为 2 μg ml-1 和 4 μg ml-1）的诱导，而 CuZnSOD 活性不受影响，这表明叶绿体是 S. ellipsoideus 的第一个位置Zn 毒性加速了超氧化物积累的细胞。中等浓度的锌显着增加总 SOD 和 APX 的活性，这可能是由于锌毒性引起的一些氧化应激。然而，较高水平的锌施用不仅导致总 SOD 和 APX 活性的抑制，而且导致生物量积累和叶绿素 a 含量的减少。因此，可以得出结论，Zn 毒性诱导的椭圆 S. ellipsoideus 细胞中超氧自由基和 H2O2 的积累可能是生长速度降低和光合色素受损的原因。