The interaction of nitrogen assimilation with photosynthesis in nitrogen deficient cells of Chlorella.

Nitrogen-limited chemostat cultures of Chlorella fusca var. vacuolata, when given nitrogen in the inorganic forms of nitrate, nitrite and ammonium divert photo-generated electrons, from CO2 fixation to nitrogen assimilation. Addition of nitrate or nitrite, but not ammonium, stimulates rate of oxygen evolution. All but the most severely nitrogen-deficient culture have increased dark respiration rates after addition of inorganic nitrogen. The nitrite reduction step of nitrogen assimilation is the most light-dependent reaction.