不同衣藻光合作用响应汞胁迫的比较研究  

COMPARATIVE OF PHOTOSYNTHESIS OF DIFFERENT CHLAMYDOMONAS REINHARDTII IN RESPONSE TO MERCURY STRESS

作　　者：夏亦雪 艾晓寒 朱飞霞 毕永红[1] XIA Yi-Xue;AI Xiao-Han;ZHU Fei-Xia;BI Yong-Hong(State Key Laboratory of Freshwater Ecology and Biotechnology,Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan 430072,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Fisheries&Life Science,Dalian Ocean University,Dalian 116023,China)

机构地区：[1]中国科学院水生生物研究所淡水生态与生物技术国家重点试验室,武汉430072 [2]中国科学院大学,北京100049 [3]大连海洋大学水产与生命学院,大连116023

出　　处：《水生生物学报》2024年第6期1040-1050,共11页Acta Hydrobiologica Sinica

基　　金：国家重点研发计划(2020YFA0907402)资助。

摘　　要：为筛选耐受汞胁迫的衣藻(Chlamydomonas reinhardtii)藻株,研究不同衣藻光合作用过程响应汞胁迫的差异,比较了不同汞浓度下11株衣藻的生长、叶绿素a含量及叶绿素荧光活性。结果表明,随着汞离子浓度升高,叶绿素a含量显著下降且生长受抑制,叶绿素荧光活性参数W_(k)、V_(j)和M_(o)快速增加,ψ_(o)和φEo快速下降,表明光合系统Ⅱ(PSⅡ)反应中心的供体侧和受体侧的电子传递受阻,光合活性被抑制。在11株衣藻中,衣藻FACHB-889(EC_(50)为0.762 mg/L)对汞耐受能力最弱,衣藻FACHB-2217对汞耐受能力最强(EC_(50)为2.848 mg/L)。与对照相比,在低浓度汞(<0.5 mg/L)胁迫下,衣藻FACHB-889 PSⅡ活性显著降低(P<0.05),衣藻FACHB-2217光合系统Ⅱ(PSⅡ)活性无显著差异。在高浓度汞(>1.0 mg/L)胁迫下,衣藻FACHB-889光合活性受抑制,单位面积活性反应中心数量(RC/CS_(o))显著下降(P<0.05),单位活性反应中心吸收的能量(ABS/RC)持续增加,单位反应中心耗散的能量(DIo/RC)和单位反应中心捕获的用于电子传递的能量(ET_(o)/RC)呈下降趋势,表明吸收的能量不能被光合作用有效利用,且无法通过热耗散释放,导致能量的非正常积累,使细胞失活甚至死亡;衣藻FACHB-2217单位活性反应中心吸收的能量(ABS/RC)、用于还原Q_(A)的能量(TR_(o)/RC)及用于电子传递的能量(ET_(o)/RC)均显著升高,细胞通过有活性的单位反应中心光合能力的增强,有效转化吸收的能量,消除部分反应中心失活的负面影响。研究表明,光合活性及其能量分配的差异是衣藻对汞敏感/耐受的重要原因。Algal growth and photosynthesis are susceptible to Hg stress.To screen for Hg-tolerant Chlamydomonas reinhardtii strains,the growth,chlorophyll a content,and chlorophyll fluorescence activity of 11 Chlamydomonas reinhardtii strains were compared at different Hg concentrations.The results showed a significant decrease in chlorophyll a content d and inhibited growth as mercury ion concentration increased.Parameters such as Vj and Mo increased rapidly,while ψo and φEo decreased rapidly.It indicated a disruption in the electron transfer between the donor and acceptor side of the photosynthesis system Ⅱ(PSⅡ) reaction center,leading to inhibition of photosynthetic activity.Among the11 Chlamydomonas reinhardtii strains,Chlamydomonas reinhardtii FACHB-889 displayed the lowest tolerance to Hg(EC50 of 0.762 mg/L),whereas Chlamydomonas reinhardtii FACHB-2217 demonstrated the highest tolerant(EC50 of2.848 mg/L).Under low mercury concentration stress(<0.5 mg/L),PSⅡ activity of Chlamydomonas reinhardtii FACHB-889 was significantly reduced compared to the control( P <0.05),and there was no significant difference in the activity of photosynthetic system Ⅱ(PSⅡ) of Chlamydomonas reinhardtii FACHB-2217.Under high mercury concentration stress(>1.0 mg/L),Chlamydomonas reinhardtii FACHB-889 inhibited photosynthetic activity,with a notable decrease in the number of active reaction centers per unit area(P<0.05).This resulted in the inefficient utilization of absorbed energy by photosynthesis,leading to abnormal energy accumulation and cell inactivation or death.In contrast,Chlamydomonas reinhardtii FACHB-2217 showed a significant increase in energy absorbed(ABS/RC),energy used for QA reduction(TRo/RC),and energy used for electron transfer(ETo/RC) in the active unit reaction centers(URCs),and the cells were able to efficiently convert the absorbed energy through the increased photosynthetic capacity of active URCs.energy and eliminating the negative effects of partial reaction center inactivation.The study suggests that diffe

关 键 词：汞 光系统Ⅱ 毒性效应 衣藻 

分 类 号：X171.5[环境科学与工程—环境科学]