Scaling Maximum Growth Rates Across Photosynthetic Organisms

1. This study provides evidence for the existence of general intrinsic patterns controlling the maximum growth rate of photosynthetic organisms, based on a compilation of data from more than 120 reports, the species ranging from unicellular algae to trees and thick-leaved desert plants. 2. We used thickness and nutrient concentration of the photosynthetic tissue to scale differences in maximum growth rate among plants, based on the demonstrated importance of these plant traits in regulating the maximum growth rates of particular plant groups. 3. The growth rate declined with increasing thickness of the photosynthetic structures and increased with increasing nitrogen and phosphorus concentration. The strong dependence of growth rate and nutrient concentrations on tissue thickness reflect broad-scale patterns and not the adaptive response of individual or closely related species of similar tissue thickness to varying environmental conditions. 4. The scaling of maximum growth rate is similar to the scaling of metabolic rate to animal size. Thickness of the photosynthetic structures therefore plays an important role in the environmental control of plant performance and evolution, setting thresholds for the growth and productivity of photosynthetic organisms.