Abstract
• • Our objective was to analyze and summarize data describing photosynthetic parameters and foliar nutrient concentrations from tropical forests in Panama in order to improve model representation of phosphorus (P) limitation of tropical forest productivity.
• Leaf gas exchange and nutrient content data were collected from the upper canopy of two forest sites in Panama, differing in species composition, rainfall, and soil fertility. Photosynthetic parameters were derived from analysis of assimilation rate vs. internal CO2 concentration curves (A/Ci), and relationships with foliar nitrogen (N) and P content were developed.
• The relationships between photosynthetic parameters and nutrients were of similar strength for N and P and robust across diverse species and site conditions. The strongest relationship expressed maximum electron transport rate (Jmax ) as a multivariate function of both N and P, and this relationship was improved with the inclusion of independent data on wood density.
• Models that estimate photosynthesis from foliar N content would be improved only modestly with the inclusion of additional data on foliar P, but doing so may increase the capability of models to predict future conditions in P-limited tropical forests, as long as there are reliable approaches for predicting foliar P from edaphic conditions or other environmental drivers.
