水华鱼腥藻生长与光合作用对大气CO_2浓度升高的响应

RESPONSES OF GROWTH AND PHOTOSYNTHESIS OF ANABENA FLOS-AQUAE TO ELEVATED ATMOSPHERIC CO_2 CONCENTRATION

为了探讨大气CO2 浓度升高对水华藻类的影响 ,利用水华鱼腥藻 (Anabenaflos_aquae)作为实验材料 ,研究了大气CO2 浓度加倍对其生长和光合作用的影响 ,结果显示大气CO2 浓度升高导致水华鱼腥藻的生物量、光饱和光合速率、光合效率和光系统II的光化学效率 (Fv/Fm)明显提高 ,但对暗呼吸速率和光饱和点没有明显影响。CO2加倍条件下藻细胞光合作用对无机碳的亲和力降低 ,表明其利用HCO-3 的能力受到抑制。

The atmospheric CO_2 concentration is predicted to double to 700 μl·L -1 during this century. The effect of doubled atmospheric CO_2 on higher plants has been studied extensively, but little is known for aquatic plants, especially freshwater bloom-algae. In order to study the impacts of elevated atmospheric CO_2 concentration on freshwater bloom-algae, Anabena flos-aquae was cultured with doubled CO_2 concentration (700 μl·L -1) and its growth, photosynthesis and chlorophyll and fluorescence were investigated. Atmospheric CO_2 enrichment increased the biomass by 50% at the end of culture in comparison with the ambient CO_2 concentration (350 μl·L -1). Light-saturated photosynthetic rate, photosynthetic efficiency and photochemical efficiency of PSⅡ (Fv/Fm) of Anabena flos-aquae also increased by CO_2 enrichment. However, elevated atmospheric CO_2 concentration had no significant effect on the dark respiration and light-saturated points. The photosynthetic affinity for Dissolved Inorganic Carbon (DIC) reduced when the cells were grown in CO_2 enriched conditions, which implies that HCO-_3 utilization was depressed. It was concluded that elevated atmospheric CO_2 concentration resulted in the increasing biomass, which is due to the elevated photosynthetic rate.