植物碳酸酐酶对岩溶作用的影响及其生态效应

The plant carbonic anhydrase at karst area and its ecological effects

广泛存在各种类型生物细胞中的碳酸酐酶(CA),通过催化CO2和HCO3-之间的相互转化,驱动岩溶过程。文章通过分析我国西南典型岩溶区植物叶片和根系CA活性,探讨其与岩溶作用的相互关系,结果表明:岩溶生态系统中植物的碳酸酐酶活性差异较大,并在植物的生长期发生变动,植株根系CA活性>成熟叶片CA活性,因而在土壤水分充足的条件下,根系分泌的CA催化CO2+H2O HCO3-+H+过程,促进石灰岩溶解,加快成土速率,并通过固定根呼吸和土壤微生物分解所释放的CO2产生岩溶碳汇效应;非岩溶生态系统由于土壤碳酸钙含量低,造成植物根系CA表达活性较低。

CO2 as the important driving force in karstification process, Carbonic anhydrase （CA） can quickly catalyses the reversible interconversion of carbon dioxide and bicarbonate. Typical karst region in Southwest China was selected to investigate the relationship between Carbonic anhydrase of plant and karstification. The results shows that plant CA activity changes with living period and seasons and have the sequence just as root 〉mature leaves. The high CA activity in root at karst ecosystem indicates that CA in plant can quickly catalyses the reversible interconversion of carbon dioxide and bicarbonate when the soil has sufficient water. It will accelerate the dissolution of limestone and improve the rate of soil rock weathering. In turn, the nutrients released from limestone will improve plant growth and metabolism. It also can produce the CO2 sink from soil. Moreover, at non-karst area, the plants don＇t need to express high CA activity due to this kind of soil lake of limestone.