Ultrastructure of Dunaliella tertiolecta Cells Grown under Low and High CO2 Concentrations 1

The cells of Dunaliella tertiolecta grown under ordinary air (low-CO2 cells) had a well developed pyrenoid with many more starch granules than those grown under air enriched with CO2 (high-CO2 cells). The chloroplast was located close to the plasmamembrane in low-CO2 cells, while that in high-CO2 cells was located in the inner area of the cells. Chloroplast envelope was electronically denser in low-CO2 cells than in high-CO2 cells, while the opposite effect of CO2 was observed for the plasmamembrane.