EFFECTS OF TEMPERATURE ON ENERGY-DEPENDENT FLUORESCENCE QUENCHING IN CHLOROPLASTS

Energy-dependent quenching of chlorophyll fluorescence and its reversi on in intact isolated spinach chloroplasts were recorded at temperatur es between 0 and 20-degrees-C. A temperature-dependence of the quenchi ng formation (and of quenching relaxation) corresponding to Q10 values between 2 and 3 was found. Long-term cold acclimation of the plants r esulted in a decrease of the fluorescence decline half-time. The final steady-state extent of quenching (q(E)) was not influenced by tempera ture shifts or cold acclimation.