Interactions among nitrogen fixation and soil phosphorus acquisition strategies in lowland tropical rain forests |
| |
Authors: | Megan K Nasto Silvia Alvarez‐Clare Ylva Lekberg Benjamin W Sullivan Alan R Townsend Cory C Cleveland |
| |
Institution: | 1. Department of Ecosystem and Conservation Sciences, University of Montana, , Missoula, MT, 59812 USA;2. MPG Ranch, , Missoula, MT, 59803 USA;3. Department of Ecosystem Conservation Sciences, University of Montana, , Missoula, MT, 59802 USA;4. Department of Natural Resources and Environmental Science, University of Nevada, , Reno, NV, 89557 USA;5. Nicholas School of the Environment, Duke University, , Box 90328 Durham, NC, 27708 USA |
| |
Abstract: | Paradoxically, symbiotic dinitrogen (N2) fixers are abundant in nitrogen (N)‐rich, phosphorus (P)‐poor lowland tropical rain forests. One hypothesis to explain this pattern states that N2 fixers have an advantage in acquiring soil P by producing more N‐rich enzymes (phosphatases) that mineralise organic P than non‐N2 fixers. We assessed soil and root phosphatase activity between fixers and non‐fixers in two lowland tropical rain forest sites, but also addressed the hypothesis that arbuscular mycorrhizal (AM) colonisation (another P acquisition strategy) is greater on fixers than non‐fixers. Root phosphatase activity and AM colonisation were higher for fixers than non‐fixers, and strong correlations between AM colonisation and N2 fixation at both sites suggest that the N–P interactions mediated by fixers may generally apply across tropical forests. We suggest that phosphatase enzymes and AM fungi enhance the capacity of N2 fixers to acquire soil P, thus contributing to their high abundance in tropical forests. |
| |
Keywords: | Arbuscular mycorrhizal fungi nutrient acquisition strategies phosphatase enzymes tropical forest |
|
|