Premium
THERMOLUMINESCENCE AND TEMPERATURE EFFECTS ON DELAYED LIGHT EMISSION (CORRECTED FOR CHANGES IN QUANTUM YIELD OF FLUORESCENCE) IN DCMU‐TREATED ALGAE *
Author(s) -
JURSINIC P.
Publication year - 1972
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1972.tb06244.x
Subject(s) - dcmu , arrhenius plot , quantum yield , arrhenius equation , thermoluminescence , analytical chemistry (journal) , chemistry , atmospheric temperature range , yield (engineering) , reaction rate constant , temperature jump , fluorescence , luminescence , activation energy , materials science , thermodynamics , photosystem ii , kinetics , optics , photosynthesis , physics , organic chemistry , optoelectronics , biochemistry , quantum mechanics
—1 The simultaneous measurements of delayed light emission (DLE) and chlorophyll (Chl) fluorescence yield in DCMU§ treated Chlorella were made in the time range of 1 to 10 sec at various temperatures from 0 to 50°C. Similar measurements were made for DCMU treated thermophilic strain of Synechococcus in the temperature range of 0 to 75°C. 2 Using the basic assumption that DLE is produced by the back reaction of primary photoproducts of system II, and that two such reactions are required for it, a linear relationship between J ‐1/2 (where J is energy per unit time available for DLE) and time after illumination was derived. This second‐order relationship was confirmed experimentally at several temperatures (2°, 5°, 10° and 15°C). From these analyses, reaction rate decay constants, at specific temperatures, were calculated. 3 An Arrhenius plot was made for these calculated rate constants. Its slope (8–10 kcal/mole) agreed well with previous reports; however, it had a region of zero slope which occurred at the physiological temperature of the organisms used. 4 Thermoluminescence or temperature jump delayed light emission (TDLE) was measured using various temperature conditions and it was found that not only the magnitude of the temperature jump (Δ T ), but the initial and final temperatures of the sample were important. For example, a temperature jump of 8°C from 2 to 10°C gave much higher TDLE than from 12 to 20°C. 5 Many properties e.g., magnitude, temperature dependence and time independence of TDLE could be explained by the DLE decay data (corrected for changes in fluorescence yield) and the kinetic analysis. 6 It is suggested that, in addition to the back reaction of Z + (the primary oxidized photoproduct of system II) with Q ‐ (the primary reduced photoproduct of system II), a reducing entity, beyond the sites of DCMU and antimycin a action, is somehow involved in the production of slow DLE.