单 位：
中国海洋大学海水养殖教育部重点实验室;国家海洋局第一海洋研究所海洋生物活性物质重点实验室
关键词：
小球藻;微绿球藻;杜氏盐藻;Cd2+;温度;叶绿素荧光
摘 要：
本文研究了不同Cd2+浓度与不同温度交互作用对中国海洋大学微藻种质库(MACC)保存的小球藻(Chlorellasp.)、微绿球藻(Nannochloris oculata)和杜氏盐藻(Dunaliella salina)的叶绿素荧光参数(PSII的最大光化学量子产量Fv/Fm、PSII的实际光能转化效率Yield、光化学淬灭qP和非光化学淬灭NPQ)、叶绿素相对含量以及细胞密度的影响。结果表明,随着Cd2+浓度的升高,3株微藻的主要荧光参数、叶绿素相对含量和细胞密度均呈明显下降趋势。但微绿球藻的荧光参数Fv/Fm在对照组与10μmol/LCd2+浓度时基本一致,这可能与低浓度Cd2+在一定程度上刺激了微藻生长有关。相关性分析结果表明,3株微藻荧光参数Fv/Fm和Yield均与Cd2+浓度呈极显著的负相关,小球藻和微绿球藻的叶绿素相对含量和细胞密度与Cd2+浓度呈显著的负相关,杜氏盐藻的叶绿素相对含量和细胞密度在48h后与Cd2+浓度呈显著的负相关,随着Cd2+浓度的增加而降低。多重比较结果表明,小球藻在25℃时对Cd2+的耐受性最强,该温度下荧光参数(Fv/Fm和Yield)、细胞密度和叶绿素相对含量显著高于20℃与30℃处理组。与20℃和25℃相比,在30℃时微绿球藻对Cd2+更加敏感,各荧光参数值均较低,细胞密度和叶绿素相对含量明显下降。杜氏盐藻在25℃时对Cd2+的耐受性最强,15℃与35℃温度条件下,各参数均明显下降,表明不适合的温度会增加重金属Cd2+的胁迫作用。本文还初步探讨了叶绿素荧光技术在重金属与环境因子联合胁迫研究中的应用。
译 名：
THE INTERACTION EFFECTS OF DIFFERENT CD~(2+) CONCENTRATIONS AND TEMPERATURE ON THE GROWTH AND CHLOROPHYLL FLUORESCENCE OF 3 MICROALGAL STRAINS
作 者：
WANG Shuai1,2,LIANG Ying1(1.Key Laboratory of Mariculture of Ministry of Education,Ocean University of China,Qingdao 266003,China;2 Key Laboratory of Marine Biological Active Substances,First Institute of Oceanography,SOA,Qingdao 266061,China)
关键词：
Chlorella sp.;Nannochloris oculata;Dunaliella salina;Cd2+;temperature;chlorophyll fluorescence
摘 要：
Chlorophyll fluorescence measurement has several good characteristics,such as very quick,extremely sensitive,non-invasive and non-destructive,thus becomes a widely used technique for the investigation of mechanisms of photosynthesis and to study the effects of various environmental conditions(temperature,salinity,heavy metal stress,nutrient deficiency) on the microalgal photosynthetic reactions,particularly for stress physiology of microalgae.In this study,the interaction effects of different Cd2+ concentrations(Chlorella sp.: 0,20,40μmol/L;Nannochloris oculata: 0,10,30μmol/L;Dunaliella salina: 0,70,140μmol/L) and different temperature(Chlorella sp.and N.oculata: 20,25,30℃;D.salina: 15,25,35℃) on the chlorophyll fluorescence parameters(Fv/Fm,Yield,qP and NPQ),relative chlorophyll content and cell density of 3 microalgal strains were reported.The above fluorescence parameters including the ratio of variable to maximal chlorophyll fluorescence(Fv/Fm),which has been shown to be a sensitive indicator of photosynthetic performance and photoinhibition,the actual photochemical efficiency of PSII in the light(ΦPSII),the photochemical quenching(qP) and the non-photochemical quenching(NPQ).The 3 microalgal strains used in the experiment were obtained from the Microalgae Culture Center(MACC),Ocean University of China.Cultures were grown in sterilized seawater enriched with f/2 medium.The salinity was adjusted to 28 by using distilled water,and the light intensity was 100μmol·m-2·s-1.The results showed that the chlorophyll fluorescence parameters,relative chlorophyll contents and cell densities all decreased obviously in the 3 microalgal strains with the increasing heavy metal(Cd2+) concentrations,with the exception of Fv/Fm in N.oculata,where there was no significant difference between the control and the l0μmol/L Cd2+ concentration treatment.This was primarily due to the stimulation algal growth by low Cd2+ concentrations.The correlation analysis results indicated that there were significant negative correlations between the fluorescence parameters(Fv/Fm and Yield) and the Cd2+ concentrations in 3 microalgal strains.The relative chlorophyll contents and cell densities were also exhibited significant negative correlations with Cd2+ concentrations in Chlorella sp.and N.oculata,excepted that in D.salina,where the same correlations with Cd2+ concentrations were found after 48h,the above parameters all decreased with the increasing Cd2+ concentrations.Multiple comparison tests showed that Chlorella sp.had more tolerance to Cd2+ in 25℃.The fluorescence parameters(Fv/Fm and Yield),the relative chlorophyll content and cell density were also reached their highest values in this temperature when compared with those in 20℃ and 30℃.For N.oculata,the most sensitive to Cd2+,as well as the minimal chlorophyll fluorescence parameters,relative chlorophyll contents and cell densities were all recorded in 30℃ treatment in comparison with 20℃ and 25℃ treatments.As to D.salina,the values of fluorescence parameters,relative chlorophyll contents and cell densities in 25℃ treatment were higher than those in 15℃ and 35℃ treatments,indicating that D.salina had more tolerance to Cd2+ in 25℃,and low or high temperature could enhance heavy metal(Cd2+) stress.In addition,the possibility of using chlorophyll fluorescence techniques in studying the interaction effects between heavy metal and environmental conditions was also discussed in this paper.
