Jingyi Sun, Chunyan Zhao, Shuang Zhao, Wei Dai, Jinlin Liu, Jianheng Zhang, Juntian Xu, Peimin He
College of Marine Ecology and Environment, Shanghai Ocean University, Hucheng Ring Road 999, Shanghai, China
Many algae respond to the limitation of CO2 in seawater by inducing CO2 concentrating mechanism (CCM) and obtain enough inorganic carbon to meet their photosynthetic needs. Ulva sp. as the dominant species of the large-scale algal bloom disaster of green tide, its thick floating pad is bound to be strongly restricted by inorganic carbon, and it must have evolved a variety of carbon acquisition strategies, such as CCM, to cope with this limitation. In this paper, the existence of CCM in Ulva prolifera was confirmed by experiments, and based on this, the position and function of the important components of CCM (carbonic anhydrase, Rubisco and pyrenoid) in CCM were briefly summarized. Several indexes to measure and quantify the relative function of CCM in macroalgae and their applications were introduced in terms of CO2 affinity of photosynthesis and Rubisco, carbonic anhydrase inhibitor, the use of bicarbonate as photosynthetic substrate and the change of affinity for external inorganic carbon based on the change of inorganic carbon supply. The paper also summarizes the different response mechanisms of Ulva sp. CCM under different carbon sources and the related genes that may be involved in the operation of CCM mechanism. These results show that the study on the CO2 concentration mechanism of Ulva has certain theoretical and practical significance, and can provide a theoretical basis for the subsequent explanation of the dominant position of U. prolifera in the green tide.