Cr3+和Cd2+对普通小球藻生长及抗氧化酶活性的影响

目的] 为探究重金属对淡水绿藻生长的影响。方法] 选取对水质检测具有明显指示作用的普通小球藻（Chlorella vulgaris）为实验材料，CdCl₂·2H₂O和CrCl₃·7H₂O提供重金属离子，探究不同浓度Cr³⁺和Cd²⁺在单一和复合胁迫下对藻细胞浓度、叶绿素a及相关抗氧化酶活性的影响。结果] 随着Cr³⁺和Cd²⁺浓度不断增加，藻细胞浓度呈先增长后下降趋势；叶绿素a含量呈现先下降后升高再下降的现象，浓度为1 mg/L的单一和复合胁迫下有最大值，且毒性作用表现为Cr³⁺ < Cd²⁺ < Cr³⁺+Cd²⁺；与藻细胞膜相关的丙二醛（MDA）和过氧化氢（H₂O₂）含量随着重金属离子浓度的增大而增长；重金属离子浓度低于10 mg/L时对藻细胞内抗氧化酶系统中的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）表现为促进作用，而大于10 mg/L时具有抑制作用。结论] 结果表明在单一或复合重金属胁迫下，普通小球藻会充分调动与抗逆性相关的酶来维持自身的正常生长。

Effects of Cr3+ and Cd2+ on the growth and antioxidant enzyme activity of Chlorella vulgaris

Objective] In order to explore the effect of heavy metals on the growth of freshwater green algae. Methods] Chlorella vulgaris, which has been taken as an obvious indicator of water quality detection, was selected as the experimental material. CdCl₂·2H₂O and CrCl₃·7H₂O provided heavy metal ions, and different concentrations of Cr³⁺ and Cd²⁺ were explored effects of single and compound stress on its biomass, chlorophyll a and related antioxidant enzyme activities. Results] With the continuous increase of Cr³⁺ and Cd²⁺ concentrations, the concentration of algae cells increased first and then decreased; the content of chlorophyll a first decreased, then increased, and then decreased, with a maximum of 1 mg/L single and combined stress value, and the toxic effect is Cr³⁺2+3++Cd²⁺; The content of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) related to the cell membrane of algae increases with the increase of the concentration of heavy metal ions; When the concentration of heavy metal ions is lower than 10 mg/L, it will promote superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in the antioxidant enzyme system in algae cells, and it has inhibitory effect when it is greater than 10 mg/L. Conclusion] The results show that under single or compound heavy metal stress, Chlorella vulgaris will fully mobilize enzymes related to stress resistance to maintain its normal growth.