Abbreviations -A, net photosynthetic assimilation rate; APX, ascorbate peroxidase; CAT, catalase; Chl a, chlorophyll a; Chl b, chlorophyll b; Chl a/Chl b, ratio between Chl a and Chl b; E, transpiration rate; ETR, electron transport rate; ETR/A, electron transport to oxygen molecules; F0, initial fluorescence; Fv/fm, potential quantum yield of photosystem II; g s , stomatal conductance; H 2 O 2 , hydrogen peroxide; HS, hydrogen sulphide; LDM, leaf dry matter; MDA, malondialdehyde; MWHC, maximum water holding capacity; NPQ, non-photochemical quenching coefficient; POX, peroxidase activity; PP, potassium phosphite; RDW, root dry weight; REL, rate of electrolyte leakage; RWC, relative water content; SDM, shoot dry matter; SOD, superoxide dismutase; TDM, total dry matter; WD, water deficit; WUEg, intrinsic water use efficiency; WW, well-watered; ZS, zinc sulphate; Ψ s , osmotic potential; Ψ w , water potential; Φ PSII , effective quantum yield of photosystem II.