光合作用的关键酶Rubisco只能与CO2结合进行固碳，然而水体尤其是海水中的CO2浓度极低，为此藻类进化获得了CO2浓缩机制（CCM）。潮间带一些大型海藻不同发育阶段所处的生存环境截然不同，其CCM是否发生变化？这一直是大型海藻研究的热点之一。本项目拟以条斑紫菜为研究对象，系统研究二倍孢子体和单倍配子体CCM机制，主要聚焦于C4路径的存在与否以及生活史不同阶段无机碳固定途径的异同，阐明参与C3和C4路径的酶在孢子体和配子体细胞中的定位信息，明确二者固碳途径及其调控机制。研究结果不仅对我们深入认识大型海藻光合固碳具有重要意义，而且将为大型海藻尤其是条斑紫菜的苗种培育提供理论指导。

Rubisco, a key enzyme of photosynthesis, only can bind with CO2 for carbon fixation. However, CO2 concentration is very low in water body, especially in seawater. Therefore, the algae have evolved and obtained CO2 concentration mechanism (CCM). In different developmental stages of some macroalgae in the intertidal zone, the growth environment is very different, does the CCM change between the stages? This has been one of the hot spots in the research of macroalgae. This project intends to choose Porphyra yezoensis as the research object, to study the CCM of sporophyte and gametophyte, mainly focuses on the existence or non-existence of C4 pathway and the differences and similarities of inorganic carbon fixation in different generations. It will clarify the localization of the enzymes involved in the C3 and C4 pathways in the sporophyte and gametophyte cells, and identify the carbon fixation pathway and regulatory mechanism. The results will not only have important significance to understand the photosynthesis and carbon fixation of macroalgae, but also provide theoretical guidance for the cultivation of macroalgae, especially for P. yezoensis.