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The change in phosphorus and nitrogen content in a common geophyte spring species, Allium ursinum, is studied in alluvial forests in relation to three flooding histories related to river regulation: (1) annually flooded, (2) unflooded for 30 years, and (3) unflooded for 200 years. Flood suppression leads to a reduction of available P soil content as well as decreasing the biomass and the amount of phosphorus in plants, but has no significant effect on N plant content. Plant N:P ratio increases with the suppression of floods and is primarily driven by soil N:P ratios, in turn markedly linked to the total nitrogen in the soil. We highlighted a lower nutrient accumulation in leaves during plant growth in unflooded forests. Overall, our results suggest that P was the main limiting factor in unflooded forests while nitrogen was the main limiting factor in annually flooded forests. Flood suppression strongly affects the morphology and nutrient uptake by Allium ursinum and thus nutrient cycling in riverine forests. [ABSTRACT FROM AUTHOR]