Effects of CCCP on Photosynthesis and on Active and Passive Chloride Transport at the Plasmalemma of Hydrodictyon Africanum

This is the authors' abstract. We don't add key points for this paper.

SUMMARY CCCP inhibits photosynthetic CO 2 fixation more than photosynthetic O 2 evolution in Hydrodictyon africanum , while the photosystem two inhibitor, DCMU, inhibits the two processes equally. These results are consistent with CCCP acting as an uncoupler of photophosphorylation, thereby inhibiting CO 2 fixation, and the remaining O 2 evolution being associated with the ATP‐independent reduction of some (unknown) electron acceptor. Analysis of tracer chloride fluxes at the plasmalemma into active influx, exchange diffusion and passive uniport components supports previous conclusions, based on the assumption that all the tracer influx was due to active transport, that active chloride influx is relatively ATP‐independent. Some problems inherent in the occurrence of redox‐coupled active transport at the plasmalemma of eukaryotes are discussed, and a scheme which accounts for active chloride transport at the plasmalemma of H. africanum is proposed.