Introduction . In dense plant habitats, such as crop fields, sunlight availability for photosynthesis can undergo massive changes on short time scales1 , 2. Strong light fluctuations induce regulatory mechanisms that synchronize the light reactions with carbon fixation. Non-photochemical quenching (NPQ) presents a key regulatory mechanism that acts on the light reactions. When absorbed light energy exceeds the energetic needs of carbon fixation, the fastest component of NPQ, the ...