Abstract
Higher plants have multiple mechanisms to cope with environmental changes. In photosystem II, absorption of excessive light energy induces thermal dissipation, which can be detected as nonphotochemical quenching (NPQ). To characterize the molecular mechanism of the adaptation to fluctuating environments, Arabidopsis thaliana plants were treated with continuous low-temperature or fluctuating-temperature conditions. The fluctuation of temperature modified the light-intensity-dependence of NPQ. Based on this information, mutants defective in the regulation of photosynthetic electron flow under fluctuating temperature were screened using chlorophyll fluorescence imaging, resulting in identification of candidates. We also characterized the effect of continuous light or fluctuating-light conditions and found the similar strategy of plants of modifying light-intensity-dependence of NPQ.
