PS 5-48
Elucidating the nutrient resorption in senescing plant tissues using metabolomics approach
Plants resorb ~50% of both nitrogen and phosphorus from the leaves during senescence. Thus, nutrient resportion is a fundamental ecosystem process that not only affects the fitness of perennial species but also influences ecosystem nutrient cycling through the chemical composition of senesced tissues. Currently nutrient resorption has been frequently evaluated using elemental ratios (C:N:P). However, the identity of compounds within this broader ratio is fundamental in deciding the fate of these compounds in soil. Climatic and edaphic conditions can largely affect resorption with climatic stress predisposing plants to produce and resorb compounds that favor the fitness of the species. We evaluated the nutrient resportion at a metabolic level in Quercus rubra seedlings subjected to a factorial combination of warming and altered precipitation at the Boston-Area Climate Experiment, Waltham, MA. The green and senesced leaf tissues were analyzed for both polar and non-polar metabolites using gas chromatography mass spectrometry platforms.
Results/Conclusions
Climate treatments induced changes in both production as well as resorption of metabolites in Q. rubra leaves. Plants exposed to drought with high warming treatments induced the production of nitrogen based metabolites such as amino acids while those exposed to wet precipitation treatment under ambient temperature invested more in carbon based compounds. Precipitation and warming treatments significantly altered the production and resorption of metabolites as indicated by the principal component analysis of 120 different metabolites. Both the production and resorption of metabolites plants exposed to wet precipitation treatments varied significantly from the dry and ambient treatments. Plants exposed to moisture stress induced by waming and or drought resulted in greater resorption of metabolites compared to those under wet precipitation treatments. These results will be further discussed with regard to plant fitness and soil nutrient cycling.