【作者】 王月圆； 许凯； 徐燕； 纪德华； 陈昌生； 谢潮添；

【Author】 WANG Yueyuan;XU kai;XU Yan;JI Dehua;CHEN Changsheng;XIE Chaotian;College of Fisheries, Jimei University;

【机构】 集美大学水产学院；

【摘要】 尽管坛紫菜的生活史早已明确,但到目前为止孢子体世代（丝状体）与配子体世代（叶状体）在光合作用与二氧化碳浓缩机制方面并没有得到很好的研究。本研究发现叶状体的净光合作用率是丝状体的两倍,且PSII的最大量子产量（Fv/Fm）高于丝状体,但其呼吸作用低于丝状体。另外,两个世代间藻红蛋白的含量无显著差异,但叶状体中藻蓝蛋白、别藻蓝蛋白及叶绿素的含量明显高于丝状体。海水中的HCO₃^-是叶状体的主要碳源,HCO₃^-经胞外CA催化形成CO₂,进而被细胞吸收利用。而丝状体有两种碳浓缩途径:一是利用HCO₃^-转运蛋白直接吸收海水中的HCO₃^-,经胞内CA催化形成CO₂进而用于碳固定;二是通过胞外CA催化HCO₃^-形成CO₂,进而被细胞吸收利用。通过解析坛紫菜在CCMs上的世代差异,将加深对坛紫菜生活周期的了解。更多还原

【Abstract】 Despite life-cycle of the red seaweed Pyropia/Porphyra has been extensively studied, the photosynthesis and CO₂ concentrating mechanism（CCM） have not been well comparatively studied between gametophyte phase（leafy thallus） and sporophyte phase（filamentous conchocelis） to date. This study found that the net photosynthetic rates of thalli were about 2 times of that of conchocelis of Py. haitanensis, and the maximal quantum yield of PSII（Fv/Fm） and respiration of thalli were significantly higher and lower than conchocelis, respectively. Additionally, two phases did not shown significant difference on phycoerythrin（PE）, but thalli exhibited significant higher contents on phycocyanin（PC）, allophycocyanin（APC） and chlorophyll α compared with conchocelis. The activity of external carbonic anhydrase（eCA） of thalli were also high than that of conchocelis, but no difference was detected on internal CA（iCA） between two phases. As for the carbon acquisition for photosynthesis, the major carbon source of thalli were seawater HCO₃^- which were absorbed via eCA-catalysed conversion to CO₂; but conchocelis applied HCO₃^- transporter to directly absorb seawater HCO₃^- which contributed equally to photosynthesis compared with the eCA or iCA mediated pathway. The discovery of CCMs differed significantly between thallus and conchocelis phases could help to enhance understanding of the life-cycle regulation in Pyropia更多还原