Algae. 2002; 17(2): 83-87.
Photosynthetic Characteristics and Cell Quota of Nitrogen and Phosphorus in Scenedesmus quadricauda under P Limitation
Chi-Yong Ahn, Hee-Sik Kim, Byung-Dae Yoon, Hee-Mock Oh
Biomolecular Process Engineering Laboratory, Korea
Research Institute of Bioscience and Biotechnology
Photosynthetic parameters of Scenedesmus quadricauda, such as the maximum photosynthetic rate (Pmax), photosynthetic efficiency (α) and the initial saturation intensity of irradiance for photosynthesis (Ik), were obtained using photosynthesis-irradiance (P-I) curve in a phosphorus-limited chemostat. S. quadricauda exhibited no photoinhibition until at 200 μmol?m-2?s-1. Pmax (r = 0.963, P = 0.002) and Ik (r = 0.904, P = 0.013) showed linear relationships with growth rate. Chlorophyll-a concentration and cell dry weight decreased at higher growth rates, but chlorohyll-a content per cell dry weight increased. The increase in photosynthetic rates at higher growth rates was due to the increase of Pmax and Ik which was caused mainly by the increase in the absolute amount of chlorophyll-a rather than the increased photosynthetic efficiency of individual chlorohyll-a. The α did not show a significant relationship with growth rate (r = 0.714, P = 0.111). The cell quota of carbon (r = 0.554, P = 0.254) was not correlated with growth rate, but cell quota of nitrogen (r = 0.818, P = 0.047) and phosphorus (r = 0.855, P = 0.030) exhibited linear correlations with growth rate.
Keywords : cell quota, chemostat, photosynthesis, P-I curve, P limitation, Scenedesmus quadricauda