**7. List of abbreviations**

DW, dry weight; F, fluorescence yield; Fm, maximal fluorescence yield in the dark adapted state; F0, minimal fluorescence yield in the dark adapted state; F'm, maximal fluorescence yield in the light adapted state; Fv, variable fluorescence; FW, fresh weight; LED, light-emitting diode; Nq, non-photochemical quenching; PAM, pulse amplitude modulation; PPFD, photosynthetic photon flux density; PS, photosystem; RWC, relative water content; TW, turgid weight; Y(II), effective PS II quantum yield.
