Plant δ15N correlates with the transpiration efficiency of nitrogen acquisition in tropical trees
Journal Publication ResearchOnline@JCUAbstract
Based upon considerations of a theoretical model of 15N/14N fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant δ15N (δP) should vary as a function of the transpiration efficiency of nitrogen acquisition (FN/v) and the difference between δP and root δ15N (δP − δR). We tested these hypotheses with measurements of several tropical tree and liana species. Consistent with theoretical expectations, both FN/v and δP − δR were significant sources of variation in δP, and the relationship between δP and FN/v differed between non-N2-fixing and N2-fixing species. We interpret the correlation between δP and FN/v as resulting from variation in mineral nitrogen efflux-to-influx ratios across plasma membranes of root cells. These results provide a simple explanation of variation in δ15N of terrestrial plants and have implications for understanding nitrogen cycling in ecosystems.
Journal
Plant Physiology
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N/A
Volume
151
ISBN/ISSN
1532-2548
Edition
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Issue
3
Pages Count
10
Location
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Publisher
American Society of Plant Biologists
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EISSN
N/A
DOI
10.1104/pp.109.145870