Substantial nutrient resorption from leaves, stems and roots in a subarctic flora: what is the link with other resource economics traits?

Abstract

*Nutrient resorption and leaching resistance, through their roles in reducing nutrient losses, are important determinants of plant nutrient economy. However, the contributions of fine-stem and fine-root resorption, as well as leaf leaching resistance, have largely been overlooked. *We quantified the relative contributions of these processes to nutrient depletion of these organs during their senescence using 40 subarctic vascular species from aquatic, riparian and terrestrial environments. We hypothesized that interspecific variation in organ nutrient resorption and leaf leaching would be linked to the species' nutrient acquisitive-conservative strategies, as quantified for a set of common-organ nutrient/carbon economics traits. *The subarctic flora generally had both high resistance to leaching and high internal nutrient recycling. Average nutrient resorption efficiencies were substantial for leaves (nitrogen (N), 66 +/- 3% SE; phosphorus (P), 63 +/- 4%), fine stems (N, 48 +/- 4%; P, 56 +/- 4%) and fine roots (N, 27 +/- 7%; P, 57 +/- 6%). The link between nutrient resorption and other nutrient/carbon economics traits was very weak across species, for all three organs. *These results emphasize the potential importance of resorption processes for the plant nutrient budget. They also highlight the idiosyncrasies of the relationship between resorption processes and plant economics, which is potentially influenced by several plant physiological and structural adaptations to environmental factors other than nutrient stress.