Cd、Pb胁迫下湿地匍灯藓(Plagiomnium acutum)叶绿素荧光特性研究  

Fluorescent Characteristics of Chlorophylls in Plagiomnium acutum Under Cd and Pb Stresses

作　　者：李朝阳[1,2] 吴昊[1] 田向荣[1,2] 李菁 周羲[1] 杜晓濛 

机构地区：[1]吉首大学生物资源与环境科学学院,湖南吉首416000 [2]植物资源保护与利用湖南省高校重点实验室,湖南吉首416000

出　　处：《农业环境科学学报》2014年第1期49-56,共8页Journal of Agro-Environment Science

基　　金：湖南省研究生科技创新基地项目(201203A);湖南省重点学科建设项目(JSU071312Z01)

摘　　要：采用浸没培养实验研究了不同浓度Cd(0、1、5、10 mg·L-1)、Pb(0、10、25、50 mg·L-1)单一以及二者低、中、高浓度组合复合处理对湿地匍灯藓(Plagiomnium acutum)叶绿素荧光以及细胞膜透性的影响。结果表明:(1)湿地匍灯藓Fv/Fm、Fv/Fo、Fv′/Fm′、ETR、Y(II)的下降程度与Cd、Pb胁迫浓度及胁迫时间存在明显的剂量、时间-效应关系;随胁迫时间延长,Y(NO)总体呈现持续上升的趋势,qN表现为先升后降,而qP则呈现出先降后升趋势。(2)湿地匍灯藓的叶绿素荧光参数对Pb、Cd胁迫的响应存在差异,单一Pb胁迫初期各荧光参数即出现不同程度的下降,单一Cd胁迫下上述参数均在处理第4 d才出现明显下降;在胁迫第1 d,中、低浓度Cd、Pb单一及复合胁迫均引起湿地匍灯藓的Fv/Fm、Fv/Fo、Fv′/Fm′增加。(3)Cd、Pb胁迫均使处理液电导率升高,升幅大小顺序为Cd/Pb复合胁迫>Cd胁迫>Pb胁迫。表明湿地匍灯藓在Cd、Pb胁迫初期可通过应激性增加PSII活性中心数来抵御重金属的毒害,但由于电子传递和热耗散能力较弱,使PSII活性中心受损,最终导致光合系统损伤;Cd、Pb复合胁迫对湿地匍灯藓细胞膜的损伤和毒害作用显著强于单一胁迫,Cd对细胞膜的毒害作用又强于Pb;Fv/Fo可作为Cd、Pb胁迫的敏感指标。Plant chlorophyll fluorescence is sensitive to the environmental stresses. In this study, we studied the effects of Cd and Pb alone or in combination on chlorophyll fluorescence and cell membrane permeability of Plagiomnium acutum(Lindb.)T. Kop exposed to varied Cd(0, 1, 5, 10 mg·L-1)and Pb(0, 10, 25, 50 mg·L-1)concentrations for 1, 2, 4, 7 and 10 days in hydropnic conditions. High dose and long-time stresses of Cd and Pb caused obvious decreases in maximal photochemical efficiency of PSII(Fv/Fm), ratios of variable fluorescence to initial fluorescence(Fv/Fo), effective photochemical efficiency of PSII(Fv′ /Fm′), acyclic electron transfer rate(ETR) and photochemical quantum efficiency[Y(Ⅱ)]. In all treatments under 10 days exposure, quantum yield of non-regulated energy dissipation Y(NO)was continuously increased. Coefficients of nonphotochemical quenching(qN)reached a peak at day 2, whereas those of photochemical quenching(qP)showed a slight decrease from day 1 to day 4 and then a slight increase from day 4 to day 10. At low concentrations, values of Fv/Fm, Fv/Fo and Fv′/Fm′ had a transient increase at day 1. Additionally, different responses of P. acutum to Pb and Cd were observed during the early period of the treatments. All parameters of chlorophyll fluorescence showed an obvious decrease for Pb at day 1, while for Cd at day 4. The solution conductivity started to increase from day 6 and then reached a peak at day 9. In conclusion, Pb and Cd treatments can dramatically alter chlorophyll fluorescence and the values of Fv/Fo can be used to predict Pb and Cd toxicity to P. acutum.

关 键 词：湿地匍灯藓(Plagiomnium acutum(Lindb.)T.Kop) CD PB 叶绿素荧光特性 

分 类 号：X172[环境科学与工程—环境科学]