作 者：
陈琼琳;李加琦;姜娓娓;薛素燕;李阳;沈淑芳;卞大鹏;方建光;毛玉泽
单 位：
上海海洋大学水产与生命学院;海洋国家实验室海洋生态与环境科学功能实验室;农业部海洋渔业可持续发展重点实验室山东省渔业资源与生态环境重点实验室中国水产科学研究院黄海水产研究所;国家海产贝类工程技术研究中心
摘 要：
采用实验生态学方法研究了不同质量浓度Hg~(2+)和Pb~(2+)胁迫对脆江蓠(Gracilaria chouae)生长及光合生理的影响。实验设置Hg~(2+)质量浓度为0.01 mg/L、0.025 mg/L、0.05 mg/L、0.1 mg/L、0.25 mg/L和0.5 mg/L,Pb~(2+)质量浓度为0.05 mg/L、0.1 mg/L、0.5 mg/L、1 mg/L、2 mg/L和4 mg/L,以未添加重金属的实验组为对照,持续培养7 d,分别测定不同处理藻体的生长速率、光合放氧速率、光合色素含量、叶绿素荧光和光合碳代谢途径中关键酶活等生理生化指标。结果表明,在Hg~(2+)胁迫下,藻体特定生长率(SGR)显著下降(P<0.05),质量浓度达到0.5 mg/L时藻体出现负增长;光合放氧速率降低35.48%~77.59%;叶绿素a、类胡萝卜素含量显著下降(P<0.05),Hg~(2+)质量浓度高于0.1 mg/L时藻体藻蓝蛋白和藻红蛋白含量显著降低(P<0.05);最大光合效率(F_v/F_m)和实际光合效率(Y(Ⅱ))随着Hg~(2+)浓度增加先降低后升高,0.05 mg/L时出现第二个峰值,丙酮酸磷酸双激酶(PPDK)也出现相似趋势。藻体对Pb~(2+)的敏感程度低于Hg~(2+),Pb~(2+)质量浓度为0.5 mg/L时,光合产氧速率显著下降(P<0.05),质量浓度到达1 mg/L时,藻体SGR和叶绿素a、类胡萝卜素出现显著下降(P<0.05),而叶绿素荧光参数和藻蓝蛋白含量则无显著性差异;Pb~(2+)质量浓度达到4 mg/L时1,5-二磷酸核酮糖羧化酶(RuBiSCO)出现显著下降(P<0.05),PPDK酶活性则显著上升(P<0.05)。实验结果证实:重金属Hg~(2+)和Pb~(2+)胁迫对脆江蓠的生长和光合作用都有不利影响,藻体对Hg~(2+)胁迫的敏感度要高于Pb~(2+),Hg~(2+)质量浓度为0.01 mg/L时,藻体出现胁迫,并随着浓度的增加而加剧,Pb~(2+)质量浓度超过1 mg/L时,藻体胁迫明显。
译 名：
Effects of Hg~(2+) and Pb~(2+) on the growth and photosynthetic physiological characteristics of Gracilaria chouae
作 者：
CHEN Qionglin;LI Jiaqi;JIANG Weiwei;XUE Suyan;LI Yang;SHEN Shufang;BIAN Dapeng;FANG Jianguang;MAO Yuze;College of Fisheries and Life Science, Shanghai Ocean University;Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences;Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology;National Engineering and Research Center of Marine Shellfish;
关键词：
Gracilaria chouae;;Hg2+;;Pb2+;;photosynthetic physiological characteristics
摘 要：
In this study, we investigated the impact of Hg~(2+) and Pb~(2+) on the growth and photosynthetic physiological characteristics of Gracilaria chouae by exposing algal thalli to five concentrations of HgCl_2(0.01 mg/L, 0.025 mg/L, 0.05 mg/L, 0.1 mg/L, 0.25 mg/L, and 0.5 mg/L) and PbCl_2(0.05 mg/L, 0.1 mg/L, 0.5 mg/L, 1.0 mg/L, 2.0 mg/L, and 4.0 mg/L); the reference group exposed to seawater without Hg~(2+) and Pb~(2+). The growth rate, photosynthetic rate, pigment content, chlorophyll II fluorescence characteristics, and the activity of Ru Bis CO and PPDK in the thalli were measured after 7 days of incubation. The special growth rate(SGR) reduced significantly as the Hg~(2+)level increased(P<0.05), mortality was observed following incubation with the highest concentration of Hg~(2+), and the photosynthetic rate reduced by 35.48%–77.50%. Similar trends were also observed for chlorophyll a(Chla) and carotenoid(Car) levels(P<0.05). Phycoerythrin(PE) and phycocyanin(PC) content was significantly lower at Hg~(2+) levels above 0.1 mg/L(P<0.05). The trend of the variation of F_v/F_m and Y(Ⅱ) with Hg~(2+) concentration was close to a bimodal curve, and the second peak appeared at 0.05 mg/L;PPDK activity showed a similar trend. The specific growth rate and Chla and Car content was significantly lower at Pb~(2+) levels above 1 mg/L(P<0.05). However, no significant change in either chlorophyll II fluorescence characteristics or the level in PC content was found among different Pb~(2+) levels. Significantly lower RuBisCO activity was found at the highest Pb~(2+)concentration than at lower concentrations, while PPDK activity was significantly higher(P<0.05). In conclusion, Hg~(2+) and Pb~(2+) both showed detrimental effects on the growth and photosynthesis of G. chouae; however, this alga is more susceptible to Hg~(2+). A stress response was observed after the Hg~(2+)concentration reached 0.01 mg/L, and this response increased as Hg~(2+)concentration increased, while no stress response was observed at Pb~(2+)concentrations below 1 mg/L.
