CO2浓度梯度对两种岩溶微藻碳酸酐酶活性的影响

Effects of CO_2 concentration gradient on carbonic anhydrase of two karst microalgae

以经岩溶水驯化的小球藻(Chlorella vulgaris)和喜钙念珠藻(Nostoc calcicola Breb.)为实验对象,在封闭体系中用Willbur和Anderson方法比较研究两种不同微藻在不同CO_2浓度下碳酸酐酶活性变化情况。结果表明:在低于3%CO_2浓度的环境中岩溶微藻可通过快速调节自身碳酸酐酶活性来应对CO_2升高带来的生境影响,在影响最大的2.5%的环境下小球藻与喜钙念珠藻碳酸酐酶活性分别提高了1.46倍和2.12倍;岩溶微藻应对CO_2浓度增大带来的pH下降有着重要的恢复作用,随培养时间增长培养环境中的pH得到恢复;随着CO_2浓度的增大,岩溶因子对碳酸酐酶有着重要的影响;培养48h时Ca^(2+)与喜钙念珠藻碳酸酐酶的相关性最高,而电导率(EC)与小球藻碳酸酐酶相关程度最高。

In response to the challenge of global warming,it is important to study karst microalgae and its carbonic anhydrase for greenhouse effect owing to carbon sequestration.Yaji experimental site is an independent karst hydrological-geological system located in the peak-cluster depression and the peak-forest plain border zone.The experiment was conducted on the Chlorella vulgaris and Nostoc calcicola Breb.cultured on the spring water which sources from the limestone of Rongxian formation,the upper Devonian at the site.We compared the carbonic anhydrase activities of two different microalgae under different carbon dioxide concentrations by using the methods of Willbur and Anderson in a closed system and analyzed the changes of karst factor by using the WTW350i multifunctional water quality analyzer and the hardness and alkalinity kits.The results showed that the karst micro-algae could deal with the habitat impact of elevated carbon dioxide by rapidly regulating its carbonic anhydrase activity in the environment of less than 3%carbon dioxide concentration.The activities of carbonic anhydrase in Chlorella vulgaris was increased by 1.46 times and Nostoc calcicola Breb.was increased by 2.12 times respectively in the environment of 2.5%.The increase of carbon dioxide concentration leads to the change of karst factor,resulting in the decrease of pH,HCO-3 and dissolved oxygen（DO）and the increase of electrical conductivity（EC）.Karst microalgae play an important role in coping with the decrease of pH and HCO^（-3） induced by the increase of carbon dioxide concentration.With the increase of incubation time,the pH and the HCO-3 in the culture environment is recovered,indicating that the karst area is an important participant in response to global warming.With the increase of carbon dioxide concentration,karst factors have an important influence on carbonic anhydrase.The correlation between calcium ion of Nostoc calcicola Breb.and carbonic anhydrase was the highest at 48 h,but the correlation between EC and carbonic anhydrase of（Chlorella vulgaris）reached it highest at 48 h.Due to the correlation between carbonic anhydrase and calcium ion,the influence of calcium ion can not be neglected when we study the relationship between carbonic anhydrase and karst dynamics in karst area.