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Simple Summary The study observed how plants adjust leaf turnover rates and nutrient allocation at the organ level to counter O3 damage. Various O3 treatments (ambient concentration, 1.5 x AA, 2.0 x AA) and fertilization levels (N: 0 and 80 kg N ha-1 y-1; P: 0 and 80 kg N ha-1 y-1) were applied to an O3-sensitive poplar clone in a FACE experiment. The results revealed significant effects of both fertilization and O3 on nutrient content, with increases in foliar C and N (+5.8% and +34.2%) and root Ca and Mg (+46.3% and +70.2%). Accelerated leaf turnover rates due to O3 exposure were observed, indicating its significant role in this physiological parameter. O3 fumigation influenced the overall allocation of primary and secondary elements across plant organs. These findings underscore the ecological implications of altered element allocation in plant leaves in response to elevated O3 levels.Abstract An excess of ozone (O3) is currently stressing plant ecosystems and may negatively affect the nutrient use of plants. Plants may modify leaf turnover rates and nutrient allocation at the organ level to counteract O3 damage. We investigated leaf turnover rate and allocation of primary (C, N, P, K) and secondary macronutrients (Ca, S, Mg) under various O3 treatments (ambient concentration, AA, with a daily hourly average of 35 ppb; 1.5 x AA; 2.0 x AA) and fertilization levels (N: 0 and 80 kg N ha-1 y-1; P: 0 and 80 kg N ha-1 y-1) in an O3-sensitive poplar clone (Oxford: Populus maximowiczii Henry x P. berolinensis Dippel) in a Free-Air Controlled Exposure (FACE) experiment. The results indicated that both fertilization and O3 had a significant impact on the nutrient content. Specifically, fertilization and O3 increased foliar C and N contents (+5.8% and +34.2%, respectively) and root Ca and Mg contents (+46.3% and +70.2%, respectively). Plants are known to increase the content of certain elements to mitigate the damage caused by high levels of O3. The leaf turnover rate was accelerated as a result of increased O3 exposure, indicating that O3 plays a main role in influencing this physiological parameter. A PCA result showed that O3 fumigation affected the overall allocation of primary and secondary elements depending on the organ (leaves, stems, roots). As a conclusion, such different patterns of element allocation in plant leaves in response to elevated O3 levels can have significant ecological implications.

来源平台：BIOLOGY-BASEL