小新月菱形藻碳酸酐酶活性和光合作用对高盐度胁迫的响应  

Response of carbonic anhydrase activity and photosynthesis to high salinity stress in Nitzschia closterium f.minutissima

作　　者：余锦兰[1,2] 夏建荣[1,2] 邹永东[3] 

机构地区：[1]广州大学植物抗逆基因功能广州市重点实验室,广东广州510006 [2]广州大学环境科学与工程学院,广东广州510006 [3]深圳大学生命科学学院,广东深圳518060

出　　处：《水产学报》2011年第4期515-523,共9页Journal of Fisheries of China

基　　金：国家自然科学基金项目(40676079;40976078);广东省自然科学基金(10151009101000001);广州市植物抗逆基因功能研究广州市重点实验室开放基金

摘　　要：以浮游硅藻小新月菱形藻为实验材料,研究其在不同盐度下的生长、胞外碳酸酐酶活性、光合速率和叶绿素a荧光参数的变化。结果显示,与正常海水培养相比,最高盐度(70)培养的细胞比生长速率下降了59.2%;同时,胞外碳酸酐酶活性、叶绿素a、c含量分别降低了66.3%、50.0%和45.7%。高盐度培养下,最大光合速率(Pm)、光合效率(α)、最大光化学效率(Fv/Fm)、实际光化学效率(Yield)和光化学淬灭系数(qP)下降,但非光化学淬灭系数(qN)升高,对无机碳的亲和力明显下降。以上结果表明,盐度升高对小新月菱形藻生长和光合作用具有明显抑制作用,但小新月菱形藻可以通过胞外碳酸酐酶活性变化、对无机碳的亲和力和调整光系统Ⅱ的能量流动与能量利用效率以应对高盐度的胁迫。Salinity is an important ecological factor in the algal growth.Water loss would lead to the increase of salinity in mass culture of fish food diatom,which could affect the algal photosynthesis and inorganic carbon utilization.In this paper,impacts of salinity on the growth,carbonic anhydrase activity,photosynthesis（P-I curve）and chlorophyll a fluorescence parameters in Nitzschia closterium f.minutissima were investigated to explore the photosynthetic mechanism of the diatom under the high salinity.The results showed that the specific growth rate when Nitzschia closterium f.minutissima was grown in high salinity（70）was decreased by 59.2% compared with the normal seawater,but it can maintain the growth to a certain degree in salinity up to 60-70,which suggested that Nitzschia closterium f.minutissima had a stronger tolerance to high salinity.The extracellular carbonic anhydrase activity which was measured by an electrometric method was reduced by 66.3%,and Chl.a and Chl.c contents which was determined spectrophotometrically were also decreased by 50.0% and 45.7% in high salinity（70）.The extracellular CA activity was inhibited in high salinity environment which showed that capacity of HCO-3 catalyzed by extracellular CA into CO2 declined,and high salinity stress can damage the Chl.a/b light harvesting complex（LHCII）and reaction-center complex and affect pigment synthesis.The chlorophyll a fluorescence parameters were measured by saturation pulse,and the maximal efficiency of PSⅡ photochemistry（Fv/Fm）,actual photochemical efficiency of PSⅡ（Yield）,photochemical quenching co-efficient（qP）decreased,whereas non-photochemical quenching co-efficient（qN）increased when the algae were grown in high salinity.These results showed that the high salinity stress would damage the PSⅡ reaction center,inhibit primary reaction of photosynthesis as well as the process of photosynthetic electron transport.The photosynthetic rate in the varied light intensity and inorganic carbon concentration was de

关 键 词：小新月菱形藻 盐度 碳酸酐酶活性 叶绿素A荧光参数 

分 类 号：Q55[生物学—生物化学] S917[农业科学—水产科学]