Effects of doubled atmospheric CO₂ concentration on the photosynthesis and growth of Chlorella pyrenoidosa cultured at varied levels of light

Abstract

Chlorella pyrenoidosa was cultured with 350 and 700 p. p. m. v. CO₂ at varied levels of light to see the impacts of doubled atmospheric CO₂ concentration on its growth and photosynthesis. The CO₂ enrichment did not affect the growth rate (μ), but significantly increased the cell density when light was sufficiently supplied. The CO₂ enrichment significantly depressed light-saturated photosynthesis and dark respiration in the cells grown under a high-light regime, but not those under a low-light regime. The light-saturating point for photosynthesis and photosynthetic efficiency was not affected by the CO₂ enrichment under either the high-light or low-light conditions.