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 mu(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 mu(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 proportional to 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.