Global climate and nutrient controls of photosynthetic capacity

Abstract There is huge uncertainty about how global exchanges of carbon between the atmosphere and land will respond to continuing environmental change. A better representation photosynthetic capacity required for Earth System models simulate assimilation reliably. Here we use a leaf-trait dataset test whether quantitatively predictable from climate, based on optimality principles; explore this prediction modified by soil properties, including indices nitrogen phosphorus availability, measured in situ. The maximum rate carboxylation standardized 25 °C ( V cmax25 ) was found be proportional growing-season irradiance, increase—as predicted—towards both colder drier climates. Individual species’ departures predicted covaried with area-based leaf N area but community-mean unrelated , which turn C:N ratio. In contrast, leaves low P had (both within communities), increased total P. These findings do not support assumption, adopted some ecosystem models, that leaf-level depends supply. They do, however, previously-noted relationship photosynthesis