CO₂ concentration and temperature for growth of photosynthetic organisms are two important factors to ensure better photosynthetic performance. In this study, we investigated the effects of CO₂ concentration and temperature on the photosynthetic performance in a marine centric diatom Chaetoceros gracilis. Cells were grown under four different conditions, namely, at 25 °C with air bubbling, at 25 °C with a supplementation of 3% CO₂, at 30 °C with air bubbling, and at 30 °C with the CO₂ supplementation. It was found that the growth rate of cells at 30 °C with the CO₂ supplementation is faster than those at other three conditions. The pigment compositions of cells grown under the different conditions are altered, and fluorescence spectra measured at 77 K also showed different peak positions. A novel fucoxanthin chlorophyll a/c-binding protein complex is observed in the cells grown at 30 °C with the CO₂ supplementation but not in the other three types of cells. Since oxygen-evolving activities of the four types of cells are almost unchanged, it is suggested that the CO₂ supplementation and growth temperature are involved in the regulation of photosynthetic light-harvesting apparatus in C. gracilis at different degrees. Based on these observations, we discuss the favorable growth conditions for C. gracilis.

CO ₂浓度和光合生物生长温度是保证更好光合性能的两个重要因素。在这项研究中，我们研究了 CO ₂浓度和温度对海洋中心硅藻Chaetoceros gracilis光合性能的影响。细胞在四种不同的条件下生长，即在 25°C 下进行空气鼓泡、在 25°C 下添加 3% CO ₂、在 30 °C 下进行空气鼓泡以及在 30 °C 下添加 CO ₂。发现 30 °C 下细胞的生长速率与 CO ₂补充比其他三个条件更快。在不同条件下生长的细胞的色素成分发生了改变，在 77 K 下测量的荧光光谱也显示出不同的峰值位置。在补充CO _{2 的情况}下，在 30 °C 下生长的细胞中观察到一种新的岩藻黄质叶绿素a / c结合蛋白复合物，但在其他三种类型的细胞中未观察到。由于4种细胞的产氧活性几乎没有变化，说明CO ₂补充和生长温度参与了C. gracilis光合捕光器的调控在不同程度上。基于这些观察，我们讨论了C. gracilis的有利生长条件。