• 关键词：蛋白核小球藻  斜生栅藻  pH值  光合作用  无机碳摄取

• 基金项目：国家重点基础研究发展规划(973)项目(No2002CB412301)

• 支彦丽
• 南开大学环境科学与工程学院, 天津 300071

• 金相灿
• 中国环境科学研究院, 北京 100012

• 钟远
• 1. 南开大学环境科学与工程学院, 天津 300071; 2. 天津城市建设学院, 天津 300084

• 李贺
• 南开大学环境科学与工程学院, 天津 300071

• 刘春光
• 南开大学环境科学与工程学院, 天津 300071

• 戴树桂
• 南开大学环境科学与工程学院, 天津 300071

• 庄源益
• 南开大学环境科学与工程学院, 天津 300071

• 摘要：为了探讨藻类对碳酸氢盐的利用,采用pH漂移实验技术,辅以氧测定技术和抑制剂的抑制实验,研究了斜生栅藻(Scenedesmusobliquus)和蛋白核小球藻(Chlorellapyrenoidosa)的光合无机碳摄取速率(PCU)和净光合速率(NPS).结果表明,PCU对pH的曲线上存在明显的转折点(简写为pH_TP),在pH超过pH_TP后存在第2个PCU峰,求此峰的平均值并以PCU_BC表示,可以作为表征藻类碳酸氢盐利用的参数.蛋白核小球藻和斜生栅藻的PCU_BC值分别为269.41和175.98μmol·g^-1·h^-1,它们的平均NPS(pH为4.8～11.0)分别为477.5和495.9μmol·g^-1·h^-1.随着碳酸酐酶抑制剂AZ(acetazolamide)浓度的增加,PCU_BC减小;当AZ达到1.2mmol·L^-1时,蛋白核小球藻的PCU_BC减小到0.随AZ浓度增加,蛋白核小球藻PCU_BC减小的速度比斜生栅藻的快.AZ和阴离子交换抑制剂DIDS(4,4'-diisothiocyanatostilbene-2,2'-disulfonicacid)对蛋白核小球藻的PCU和NPS的抑制作用大于斜生删藻.AZ和DIDS对2株藻的PCU的抑制均大于对它们NPS的抑制.2株藻具有高的PCU_BC值,都是强碳酸氢盐利用者.

• Abstract：In order to understand the bicarbonate utilization by microalgae,photosynthetic carbon uptake rate (PCU) and net photosynthetic rate (NPS) in cultures with different pHvalues were studied separately by running pH-drift experiments and measuring oxygen release with a liquid oxygen electrode. The inhibition of photosynthetic activities by acetazolamide (AZ) and 4,4-diisothiocyanatostilbene-2,2-disulphonic acid (DIDS) were also investigated in the experiments. The results showed a pHturning point (pH_TP) and a second peak of PCUin the curve of PCU～pHafter pH_TP,the average value of which was denoted as PCU_BC and can be used as a characteristic parameter of bicarbonate utilization by alga. PCU_BC were 269.41 and 175.89 μmol·g^-1·h^-1 respectively for Chlorella pyrenoidosa and Scenedesmus obliquus,and the average NPS (pH=4.8～10.0) were 477.5 and 495.9 μmol·g^-1·h^-1 for C. pyrenoidosa and S. obliquus,respectively. The PCU_BC of both algae decreased with the increasing AZconcentration in the culture,and for C. pyrenoidosa became zero when the AZconcentration reached 1.2 mmol·L^-1. The rate of reduction of PCU_BCwith increasing AZwas more rapid in C. pyrenoidosa than that in S. obliquus. Both PCU and NPS of C. pyrenoidosa were more sensitive than S. obliquus to AZand DIDS,whereas the inhibition effects of the algae on PCUare stronger than on NPS. Both algae had high PCU_BC values and a strong ability to utilize HCO₃^-.

• Key words：Chlorella pyrenoidosa  Scenedesmus obliquus  pH value  photosynthesis  inorganic carbon uptake

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