Kinetics studies of ultraweak luminescence induced by ascorbic acid in Characeae cells and their structures.

Abstract

Native non-stressed Nitellopsis obtusa cells emit low-intensity (10-10(4) photons s(-1) cm(-2)) electromagnetic radiation within the visible range. The intensity of emission by these cells is several times higher than the intensity of the environmental medium. This luminescence appears as a long-lived (observable not for hours but for a few days) spontaneous light emission, sensitized by chlorophyll. Cells exposed to ascorbic acid action emit ultraweak radiation, dependent on reagent concentrations. Ultraweak luminescence (UL) intensity increases with rise in concentration, reaching maximum for higher concentrations faster and also changing the kinetics of UL decay. Studies of UL kinetics for different substructures and fractions, as well as for intact cells, allow us to consider single- and double-exponential functions as decay curves, which could suggest two ways of ascorbic acid action in the cells. In the spectral distribution, the bands of chlorophyll, dimoles of singlet oxygen and NADH, FMN and Q(10), which are electron carriers of the respiration chain, can be taken into consideration. Ascorbic acid action shows an increase in the red part of spectrum, except 627 nm, and in these bands of emission, which can be associated with the electron carriers of the respiration chain and lipid peroxidation.