Leaf phosphorus allocation and photosynthesis in native Australian plants differs between soil parent material types

Abstract Background and aims There is considerable interest in how plants allocate phosphorus (P) and how this varies by environment. How leaf P fractions change with soil P supplies and soil type is essential to understand the roles of P in storage, structure and biochemistry including photosynthesis. Here, we contrasted the P allocation patterns for native woody plants in south-eastern Australia on soils derived from either P-poor sedimentary or P-rich igneous parent materials. Methods We measured total leaf P and four leaf P fractions: inorganic phosphate (P i ), metabolite P, nucleic acid P, and lipid P for 33 native species. We also measured photosynthetic capacity ( A sat ) for species across four sites with contrasting soil P and parent material types: high total soil P from basalt versus low total soil P in sands. Results The leaf P i fraction scaled consistently with total leaf P within and across the high-P versus low-P sites. Species growing on high P soils from basalt tended to have similar P fractions of total P to those of species on low P soils, except for the lipid P fraction which was greater for species at high P sites. There was a substantial reduction in P allocated to the lipid fraction for species on low P soils, especially in Proteaceae species. Leaf photosynthetic P-use efficiency was significantly higher with lower leaf P concentration. Conclusion The adaptive strategy of reducing phospholipids in leaves occurs in multiple species in low-P environments, including non-Proteaceae. This resulted in species from more than one plant family maintaining lower leaf P concentrations on sedimentary-derived soils than on igneous soils, thus achieving more efficient P use in photosynthesis at low P.