Biophoton Emission (Ultraweak Photoemission) From Dark Adapted Spinach Chloroplasts

Biophoton emission (ultraweak photoemission) is observable in isolated spinach chloroplasts, even after several hours of dark adaptation. This spontaneous light emission is oxygen dependent, decreased by respiratory inhibitors such as cyanide or salycilhydroxamic acid, suppressed by p‐benzoquinone and enhanced by NADPH. We suggest that the respiratory chain of chloroplasts is involved in the series of redox reactions leading to the dark excitation of the emitter of biophotons, presumably chlorophyll molecules. Biophoton emission is inhibited by superoxide dismutase, implying that the univalent reduction of molecular oxygen is associated with this process, in a yet unknown way.