Replicate common gardens of Italian and Greek provenances of Quercus ilex, Q. pubescens, and Q. frainetto seedlings were established in 2017 in Italy, Greece, and Germany (here: also Q. robur) to assess their potential for plantations for future climate scenarios. The JIP-test was applied on saplings (2016) and in the summers of 2017-2019 to assess the efficiency of the photosynthetic apparatus. Seedlings from the nurseries differed in the tested JIP parameters from older plants in the field. Further, considerable inter-annual and between-sites variability of the parameters occurred. Q. pubescens revealed the most stable behavior across time and site, with the Greek provenance usually showing higher values of performance index and the probability of electron transport beyond QAthan the Italian provenance. In the German sites, Greek Q. pubescens revealed higher values of most of the tested JIP parameters than the local species, Q. robur. index on absorption basis; RC/ABS -density of active reaction centres; RIE -Frankfurt-Riedberg; SAN -Sant'Anatolia di Narco; SWA -Frankfurt-Schwanheim; ΔVIP -relative fluorescence increase between I and P step, i.e., indicator for the relative contribution of electron transport from the intersystem carriers to the electron end acceptors of PSI; φPo -quantum efficiency of reduction of QA; ΨEo -probability of electron transport beyond QA -.

Abbreviations: DOY -day of the year; gs -stomatal conductance; OLY -Olympiada/Greece; PIabs -performance index on absorption basis; PNmax -light-saturated net photosynthetic rate; RC/ABS -active reaction centers on absorption base; SWA -Schwanheim/ Germany; WUE -water-use efficiency; φP0 -Fv/Fm -maximum quantum efficiency of the reduction of QA; ψE0 -the probability that an absorbed photon leads to a reduction further than QA.