A chlorophyll fluorescence (ChlF) assessment was carried out on oak seedlings (Quercus ilex L., Quercus pubescens Willd., Quercus frainetto Ten.) of Italian and Greek provenance, during the years 2017 and 2018, in a common garden in central Italy planted in 2017. This trial aimed to test the relative performances of the oak species in the perspective of assisted migration as part of the actions for the adaptation of forests to climate change. The assessment of the photosynthetic performance of the tree species included the analysis of the prompt chlorophyll fluorescence (PF) transient and the modulated reflection (MR) at 820 nm, leaf chlorophyll content, leaf gas exchange (net photosynthesis, stomatal conductance), plant growth (i.e., height) and mortality rate after 2 years from the beginning of the experiment. The assessment of the performance of the three oak species was carried out ‘in vivo’. Plants were generated from seeds and exposed to several environmental factors, including changing seasonal temperature, water availability, and soil biological and physical functionality. The results of PF indicate a stable functionality of the photosynthetic system PSII (expressed as F_V/F_M) across species and provenances and a decline in photochemistry functionality at the I–P phase (ΔV_IP) in Q. frainetto, thus indicating a decline of the content of PSI in this species. This result was confirmed by the findings of MR analysis, with the speed of reduction and subsequent oxidation of PSI (V_RED and V_OX) strongly correlated to the amplitude of ΔV_IP. The photosynthetic rates (net photosynthesis, P_N) and growth were correlated with the parameters associated with PSI content and function, rather than those related to PSII. The low performance of Q. frainetto in the common garden seems to be related to early foliar senescence with the depletion of nitrogen, due to suboptimal climatic and edaphic conditions. Chlorophyll fluorescence allowed discrimination of populations of oak species and individuation of the less (or/and best) suitable species for future forest ecology and management purposes.

中文翻译：

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气候变化下森林树木的选择：与PSII相比，PSI是否能更好地预测净光合作用和生长？

叶绿素荧光（ChlF）评估是在橡树幼苗上进行的（Quercus ilex L.，Quercus pubescens Willd。，Quercus frainetto10.在2017年和2018年期间，于2017年在意大利中部一个共同的花园种植意大利和希腊血统。该试验旨在从协助迁徙的角度测试橡树种的相对性能，作为行动的一部分使森林适应气候变化。对树种光合作用性能的评估包括瞬态叶绿素荧光（PF）瞬态分析和820 nm的调制反射（MR）分析，叶绿素含量，叶片气体交换（净光合作用，气孔导度），植物生长从实验开始2年后的身高（即身高）和死亡率。三种橡树种的性能评估是在“体内”进行的。植物是由种子产生的，并受到多种环境因素的影响，包括不断变化的季节性温度，水的可利用性以及土壤的生物学和物理功能。PF的结果表明光合系统PSII的功能稳定（表示为F _V / F _M）跨物种和种源，以及Q. frainetto的I–P相（ΔV _IP）的光化学功能下降，从而表明该物种中PSI含量下降。MR分析的结果证实了这一结果，PSI的还原速度和随后的氧化速度（V _RED和V _OX）与ΔV _IP的幅度密切相关。光合速率（净光合速率，P _ñ）和生长与与PSI含量和功能相关的参数相关，而不与与PSII相关的参数相关。由于气候和水土条件欠佳，普通花园里的Q. frainetto表现不佳似乎与早期叶片衰老和氮的消耗有关。叶绿素荧光可以区分橡树种的种群，并可以区分较小（或/和最佳）的橡树种，以用于未来的森林生态学和管理目的。