Physiological responses of tagasaste to a progressive drought in its native environment on the Canary Islands

Photochemical efficiency of PSII (φPSII) followed the inverse pattern to that observed for the photosynthetic photon flux density (PPFD), decreasing at midday and recovering during the late afternoon. This recovering at the end of each day, and the constant values of the maximum quantum yield of PSII photochemistry (Fv/Fm) during the studied period, indicate that there was no permanent damage to the photosynthetic apparatus due to mild water stress.