水生生物学报2024，Vol.48Issue(5)：753-761,9.DOI:10.7541/2024.2023.0290
雪衣藻叶绿素荧光特性及抗氧化系统对汞胁迫的响应
RESPONSE OF CHLOROPHYLL FLUORESCENCE CHARACTERISTICS AND ANTIOXIDANT SYSTEMS OF CHLAMYDOMONAS NIVALIS UNDER MERCURY STRESS
摘要
Abstract
Mercury(Hg)pollution is a global environmental problem and a major hazard to human health.Investigat-ing the interactions between algae and Hg can provide a scientific basis for the assessment of Hg toxicity and ecologi-cal risk in aquatic ecosystems,as well as the bioremediation of Hg pollution.In this study,we selected Chlamy-domonas nivalis as the object due to its strong adaptive ability to Hg,aiming to understand how algal cells respond to mercury stress and its tolerance mechanism.The results showed a time-dependent quantitative relationship between Hg2+stress and algal cells,with a 48h half-effect concentration of 1.44 mg/L.Compared with the control group,algal cells subjected to low concentrations of Hg2+(≤1.5 mg/L)maintained growth and photosynthetic activity.The biomass and pigment content of the 2.0 mg/L Hg2+treated group did not change significantly(P＞0.05)at 6h of stress,but both decreased significantly(P＜0.05)at 48h.As Hg2+concentration and exposure time increased,the maximal photochemi-cal efficiency,the maximum electron transfer reaction,half-saturation light intensity,and light use efficiency were reduced.Algal cells experienced inhibited photosynthetic electron transfer,as evidenced by notable alterations in rapid fluorescence-induced kinetic curve and Q(-A)reoxidation.Hg2+stress disrupted energy flow,inactivated reaction centers in algal cells,led to a significant increase in energy dissipation,and elevated the photosynthetic efficiency of active reaction centers,maintaining energy balance and metabolic activity.The damage to the photosynthetic system led to an increase in the cellular reactive oxygen species content,a decrease in the total soluble protein content,a significant increase in superoxide dismutase activity and a decrease in the reduced glutathione content.In this study,we confirmed that Hg2+tolerance was strong in Chlamydomonas nivalis,and photosystem Ⅱ was the target of Hg2+;the photosyn-thetic energy allocation strategy and antioxidant system were the important detoxification mechanisms of cells against Hg2+stress.关键词
汞/叶绿素荧光/氧化应激/雪衣藻Key words
Mercury/Chlorophyll fluorescence/Oxidative stress/Chlamydomonas nivalis分类
资源环境引用本文复制引用
艾晓寒,夏亦雪,许萍萍,涂晓杰,毕永红..雪衣藻叶绿素荧光特性及抗氧化系统对汞胁迫的响应[J].水生生物学报,2024,48(5):753-761,9.基金项目
国家重点研发计划(2020YFA0907402)资助[Supported by the National Key Research and Development Project(2020YFA0907402)] （2020YFA0907402）
