OSCILLATIONS OF THE TRIGGERED LUMINESCENCES OF ISOLATED CHLOROPLASTS PREILLUMINATED BY SHORT FLASHES*

Abstract— Four types of triggered luminescence of isolated lettuce chloroplast (HCl-induced, methanol-induced, sodium benzoate-induced and T-jump-induced) were examined after preillumination by a series (from 1 to 10) of short flashes. Oscillations were observed in the luminescence peaks, with a period of four flashes. These oscillations had maxima after the second and the sixth flash, similar to those of delayed light emission. The maxima were shifted forward two flashes by 50 μ M hydroxylamine, as in oxygen evolution, and were abolished by 5 μ M DCMU, as for delayed light. These results may show that the mechanism of triggered luminescence is influenced directly by the oxidation states ( S ₁) on the donor side of photo-system II.