Leaf phosphorus fractions vary with leaf economic traits among 35 Australian woody species

Adaptations of plants to phosphorus (P) deficiency include reduced investment of leaf P in storage (orthophosphates in vacuoles), nucleic acids and membrane lipids. Yet, it is unclear how these adaptations are associated with plant ecological strategies. Five leaf P fractions (orthophosphate P, P_i ; metabolite P, P_M ; nucleic acid P, P_N ; lipid P, P_L ; and residual P, P_R ) were analysed alongside leaf economic traits among 35 Australian woody species from three habitats: one a high-P basalt-derived soil and two low-P sandstone-derived soils, one undisturbed and one disturbed by human activities with artificial P inputs. Species at the undisturbed low-P site generally exhibited lower concentrations of total leaf P ([P_total ]), primarily associated with lower concentrations of P_i , and P_N . The relative allocation of P to each fraction varied little among sites, except that higher P_L per [P_total ] (rP_L ) was recorded at the undisturbed low-P site than at the high-P site. This higher rP_L , reflecting relative allocation to membranes, was primarily associated with lower concentrations of leaf nitrogen at the undisturbed low-P site than at the high-P site. Associations between leaf P fractions and leaf nitrogen may provide a basis for understanding the variation in plant ecological strategies dependent on soil P availability.