This dataset contains data from an experiment described in the paper: "Miaomiao Wang, Guolei Li, Zhaozhong Feng, Yong Liu, Yansen Xu, Mercedes Uscola. Uptake of nitrogen forms by diploid and triploid white poplar depends on seasonal carbon use strategy and elevated summer ozone. Journal of Experimental Botany, erab317, https://doi.org/10.1093/jxb/erab317".

In the study, we investigated the mechanisms of N forms acquisition in response to developmental phase allowing us to analyze the plasticity in N forms preferences due to internal plant N demands that are modified by growth rates. As a second objective we evaluate the effects of O₃ enriched atmosphere during summer on the N forms uptake rates, which is a major air pollutant harmful to terrestrial vegetation and to human health. 

Main results of the experiments are that (1) Both ploidy levels had the physiological capacity to absorb intact glycine, and differed in growth, C and N acquisition patterns and N forms preferences. (2) Diploid, with six times higher RGR in spring than in summer, but similar absolute growth between seasons, showed plasticity on N forms preferences in response to seasons, shifting from no preferences in spring to strong preference on NO₃^- in summer. (3) Triploid, with only two times higher RGR in spring than in summer, but strongly higher absolute growth in summer than in spring, showed no plasticity among N forms in response to season and an overall preference for NO₃^-. (4) In response to O₃, both ploidy levels decreased their NO₃^- uptake rates as a consequence of C acquisition reduction. However, while diploid was not able to modify its preferences among N forms, and therefore decreased total N uptake rate, triploid was able to compensate the reduction in NO₃^- uptake by increasing NH₄⁺ and glycine acquisition, further decreasing the cost of N uptaken metabolism. (5) The different plasticity on N forms preferences across seasons and in response to elevated O₃ between ploidy levels was attributed to different C and N use strategy among nutrients functions in plants, i.e. mass growth, N uptake and metabolism and nutrient reserve, including repair or detoxication in response to O₃. Those strategies are deeply explored in the discussion.

The dataset was collected during a open top chamber study at Yanqing county in Beijing and has been processed by a series of generalized linear mixed models to produce a MS accepted for publication in Journal of Experimental Botany.

The readme file contains an explanation of each of the variables in the dataset and its measurement units. null =  none value.