Light-induced chemiluminescence of luminol in spinach chloroplast fragments : Reaction of O_2^- with electron transfer components

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Chemiluminescence of luminol (CLL) was induced by illuminated spinach chloroplast fragments. CLL was diminished by superoxide dismutase or under anaerobic conditions and increased by an autoxidizable electron acceptor, methyl viologen. The optimum pH for CLL was 10.0-10.5. Ferredoxin and cytochrome c reducing substance (CRS) did not affect the intensity of CLL, but accelerated the dark decay in the absence of methyl viologen. In the presence of methyl viologen, ferredoxin and CRS lowered the intensity and accelerated the dark decay. 3-(4-Chlorophenyl)-1,1-dimethylurea diminished CLL. Carbonyl-cyanide m-chlorophenylhydrazone accelerated the initial rate of CLL increase at low concentration and inhibited it at high concentration. Half-decay time of CLL after the cessation of light was shortened by inhibiting electron transfer on the oxidizing side of photosystem II. We conclude that most of the CLL observed in illuminated chloroplasts is dependent on O_2-. The results also suggest that O_2- is reduced by reduced ferredoxin or CRS and oxidized on the oxidizing side of photosystem II. The half life of O_2- in illuminated chloroplasts was estimated from the half-decay time of CLL to be a few sec.
日本植物生理学会の論文