A novel proxy to examine interspecific phosphorus facilitation between plant species

Here, we use leaf manganese concentration ([Mn]) as a proxy for rhizosheath carboxylate concentration to explore novel mechanisms of complementarity mediated by phosphorus (P) facilitation. In pot experiments, we showed that mixtures involving efficient P-mobilizing species exhibited a greater biomass and relative complementarity effect. Both leaf [Mn] and [P] of inefficient P-mobilizing species increased when neighbored with a facilitator, i.e. interspecific P facilitation via carboxylates, which was confirmed by a meta-analysis. Phosphorus facilitation enhanced the relative complementarity effect, relating to the greater plasticity of several root morphological traits of facilitated species.