HCO-3碱度对铜绿微囊藻生长与光合活性的影响

研究了23 mM (ALK23)和124 mM (ALK124) HCO-3对铜绿微囊藻(〖WTBX〗Microcystis aeruginosa〖WTBZ〗 FACHB 927)生长与光合特性的影响。实验结果表明，ALK23显著抑制铜绿微囊藻的生长，至培养结束，与对照相比对生物量的抑制率为38%，ALK124条件下虽然至培养结束生物量没有显著变化，但碱度增加铜绿微囊藻生物量有一个快速的增殖期，之后其生长速率持续下降。碱度增加强烈抑制光合色素Chla的合成，ALK23和ALK124条件下对Chla含量抑制率分别为74％和56％。藻胆蛋白与叶绿素a的比值（PBP/Chla）在碱度增加的条件下有显著升高。HCO-3碱度增加，铜绿微囊藻的光合活性先降低之后逐渐恢复，至处理结束表现出低碱度（ALK23）促进光合活性，高碱度（ALK124）对光合活性影响不显著。说明HCO-3碱度增加对铜绿微囊藻有一定伤害作用，与高碱度（ALK124）相比，低碱度（ALK23）对细胞的伤害程度更大，随着细胞的增殖，碱度对细胞的伤害作用逐渐恢复，且低碱度下细胞恢复更快。暗示碱度可以作为水华控制的手段之一.

EFFECTS OF HCO-3 ALKALINITY ON GROWTH AND PHOTOSYNTHETIC ACTIVITY OF MICROCYSTIS AERUGINOSA FACHB 927

The effect of alkalinity on higher plants has been studied extensively，but little is known for aquatic plants，especially bloom forming cyanobacteria．In order to study the impacts of alkalinity on bloom forming cyanobacterium，〖WTBX〗Microcystis aeruginosa〖WTBZ〗 FACHB 927 was cultured under two different bicarbonate (HCO-3) alkalinity including 23 mM (ALK23) and 124 mM (ALK124) and its growth，photosynthetic performance and pigments were investigated in present study.ALK23 reduced the biomass by 38% at the end of culture in comparison with the control.ALK124 showed no significant effect on the biomass，but there was a rapid multiplication at the prophase.The results showed that the contents of chlorophyll a decreased by 74% and 56% under ALK23 and ALK124 respectively.Elevated alkalinity increased PBP/Chla ratio.Photosynthetic activity was restrained at the prophase of culture and then resumed at the anaphase under elevated alkalinity.It is shown that low alkalinity (ALK23) could promote photosynthetic activity，whereas high alkalinity (ALK124) made no remarkable difference.Thus it can be concluded that alkalinity may be a scientific tool for preventing and managing 〖WTBX〗Microcystis〖WTBZ〗 bloom in freshwater.