Divergent nitrogen and phosphorus allocation strategies in terrestrial plant leaves and fine roots: A global meta-analysis

The quantification of the allocation of nitrogen (N) and phosphorus (P) among plant organs is essential to improve our understanding of plant growth, life-history strategies and ecosystem nutrient and energy cycles. However, allocation strategies of N and P between terrestrial plant leaves and fine roots are unclear. Here, we compiled a global dataset comprising 807 terrestrial plant species to analyse the stoichiometric scaling of N and P between leaves and fine roots across species, families, plant groups, biomes and locations. We found that N and P, and N:P ratios manifest different scaling exponents (alpha-values) between leaves and fine roots. Specifically, overall alpha(N) and alpha(P) were >1 and <1, respectively, and alpha(N:P) = 1, indicating a higher proportional increase of N to fine roots and P to leaves. However, there were differences in alpha(N), alpha(P) and alpha(N:P) among major species, families, plant groups, biomes and locations. In addition, alpha(N) and alpha(N:P) increased with latitude; there was no clear trend for alpha(P). Mean annual temperature accounted for the greatest proportion of variation in alpha(N), whereas soil total P accounted for the greatest proportion of variation in alpha(P) and alpha(N:P). Synthesis. Our results demonstrate a divergent N and P allocation strategy between leaves and fine roots in terrestrial plants. This study improves our understanding of the effects of the environment (including changes in global climate and life-history strategies) on nutrient allocation patterns between these two important plant organs.

Automated summary

This study analyzes the nitrogen and phosphorus allocation strategies between leaves and fine roots in terrestrial plants using a global dataset. The results show divergent scaling relationships between N and P in different plant organs, improving our understanding of the effects of environmental changes and life-history strategies on nutrient allocation patterns between these two important plant organs.