Ultrastructure of Dunaliella tertiolecta Cells Grown under Low and High CO2 Concentrations1

The cells of Dunaliella tertiolecta grown under ordinary air(low-CO₂ cells) had a well developed pyrenoid with many morestarch granules than those grown under air enriched with CO₂(high-CO₂ cells). The chloroplast was located close to the plasmamembranein low-CO₂ cells, while that in high-CO₂ cells was located inthe inner area of the cells. Chloroplast envelope was electronicallydenser in low-CO₂ cells than in high-CO₂ cells, while the oppositeeffect of CO₂ was observed for the plasmamembrane. ²On leave from Institute of Biology, University of Novi Sad,Novi Sad, Yugoslavia. (Received November 7, 1985; Accepted March 5, 1986)