Nitrogen/phosphorus leaf stoichiometry and the scaling of plant growth

We adopted previous N:P stoichiometric models for zooplankton relative growth to predict the relative growth rates of the leaves μ_L of vascular plants assuming that annual leaf growth in dry mass is dictated by how leaf nitrogen N_L is allocated to leaf proteins and how leaf phosphorus P_L is allocated to rRNA. This model is simplified provided that N_L scales as some power function of P_L across the leaves of different species. This approach successfully predicted the μ_L of 131 species of vascular plants based on the observation that, across these species, N_L scaled, on average, as the 3/4 power of P_L, i.e. N_L ∝ P_L^3/4. When juxtaposed with prior allometric theory and observations, our findings suggest that a transformation in N:P stoichiometry occurs when the plant body undergoes a transition from primary to secondary growth.