Abstract
Phytoplankton accounts for nearly 50 % of primary production. The on-going global warming largely affects ecophysiology of phytoplankton, which recursively affests global warming itself. We have established a simple method to determine the dominant physiological paramters related to NPQ including the extent of ΔpH-dependent (qE) and redox-dependent (qT) quenching in Chlamydomonas cells by examining the fluorescence properties under fluctuation of light. By this method, we observed that similar abiotic stresses, high light (HL) conditions where excess energy is supplied and low CO2(LC) conditions where energy output is limited, induce different types of NPQ: HL conditions mainly induce qE-quenching that gradually increases with time and LC conditions mainly induce qT-quenching that attains a maximum in 20 min. It is apparent that HL and LC signals induce different physiological responses, suggesting that the acclimation by HL and LC was achieved through independent mechanisms. This work was in part supported by GERF.
