Photoacoustic spectroscopy was used to study the effect of sulfite and SO2 on isolated corn mesophyll chloroplasts by monitoring the photochemical energy storage. Sulfite incubation of isolated chloroplasts, either in light or in darkness, caused a decrease in photochemical energy storage. The more pronounced decrease in light indicates a light-dependent sulfite inhibitory site(s) in chloroplasts. Also diphenylcarbazide caused a partial recovery of energy storage in sulfite treated chloroplasts indicating a possible site of damage at the water oxidizing system. Although the chloroplast membranes were found to be insensitive to high concentrations of SO2 for relatively short exposure periods (10 min) in light, exposure of chloroplasts to 28.5 ng cm-3 SO2 for 10 min caused a decrease in energy storage. An attempt was made to explain the mechanism of action of sulfite and SO2 in chloroplasts.
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis