ABSTRACT
Changes in the fluorescence characteristics and molecular photophysical parameters induced by disaggregation of light-harvesting chlorophyll a/b complexes isolated from pea were studied. Disaggregation was achieved by increasing the concentration of the detergent triton X-100 (concentration range 0-230 microM, chlorophyll concentration 2.45 microg/ml). Laser fluorimetry methods were used to measure the molecular photophysical parameters. It was shown that the decrease in aggregate size is accompanied by a decrease in fluorescence at 700 nm at 77 K, a fall of the singlet-singlet annihilation rate (by more than two orders), and the growth of fluorescence life time (from 160 ps to 3.2 ns).
Subject(s)
Chlorophyll/chemistry , Light-Harvesting Protein Complexes/chemistry , Octoxynol/chemistry , Pisum sativum/chemistry , Plant Proteins/chemistry , Chlorophyll A , Cold Temperature , Spectrometry, FluorescenceABSTRACT
The possibilities of diagnosis of the state of the phytoplankton photosynthetic apparatus by the method of nonlinear laser fluorimetry (saturation fluorimetry), which can be realized in remote sensing mode, were investigated. A procedure for the determination of the nonsaturated fluorescence parameter phi0, which is proportional to the concentration of chlorophyll a molecules, and the parameter A, which is a product of three photophysical parameters of chlorophyll a molecule in native chloroplast, was elaborated. Laboratory experiments with the axenic culture of eurihaline Thalassiosira weissflogii showed that the parameter A depends on the state of the photosynthetic apparatus of the alga, which was varied by either DCMU treatment or exposure to actinic light.
