Fig. 5.

Degradation of exogenously added H₂O₂ in the medium by photosynthesis mutants. Time course of degradation of H₂O₂ added to the medium of Chlamydomonas cultures in the light (white light, 55 μmol photons m⁻² s⁻¹) (open symbol) or in the dark (closed symbol). The rbcL and ΔpetD mutants were grown in very dim light (<10 μmol photons m⁻² s⁻¹) for 5 days and then diluted to 1 × 10⁶ cell ml⁻¹. The parental strain of the mutants (WTS34), named WT, was incubated with irradiation (white light, 55 μmol photons m⁻² s⁻¹) for 3 days and then diluted to 1 × 10⁶cell ml⁻¹. Right after dilution, H₂O₂ (final concentration 2 mM) was added. Samples were taken at the time points indicated and the H₂O₂ concentration in the media was determined as described in Sect. “Materials and methods”