Changes in Redox State of Cytochromes in Relation to Carbon Assimilation in Isolated Pea Chloroplasts

Abstract

The induction phase of photosynthesis, owing to the continuous change in conditions within the chloroplast (Edwards, Walker, 1983) represents a good model system for the investigation of interaction and regulation between the photochemical and biochemical reactions in photosynthesis. Measurements of chlorophyll a fluorescence changes have increasingly been used to this aim (cf. Walker et al. in these Proceedings) An other valuable monitor could be the redox state of photosynthetic cytochromes, especialy in relation to the problem of changing ATP demands during induction that could be mached by several alternative mechanisms. On the other hand, little is known about photosynthetic cytochromes under physiological and steady-state conditions (Heber et al. 1976) Therefore an analysis of the steady-state redox state of cytochromes in illuminated isolated chloroplasts was undertaken.