Zhong, H.Zhou, J.Azmi, A.Arruda, A.J.Doolette, A.L.Smernik, R.J.Lambers, H.Gibson, D.2020-10-182020-10-182021Journal of Ecology, 2021; 109(1):246-2590022-04771365-2745http://hdl.handle.net/2440/1285451. Hundreds of Proteaceae species in Australia and South Africa typically grow on phosphorus (P)-impoverished soils, exhibiting a carboxylate-releasing P-mobilizing strategy. In the Southwest Australian Biodiversity Hotspot, two Xylomelum (Proteaceae) species are widely distributed, but restricted within that distribution. 2. We grew Xylomelum occidentale in hydroponics at 1 μM P. Leaves, seeds, rhizosheath and bulk soil were collected in natural habitats. 3. Xylomelum occidentale did not produce functional cluster roots and occupied soils that are somewhat less P-impoverished than those in typical Proteaceae habitats in the region. Based on measurements of foliar manganese concentrations (a proxy for rhizosphere carboxylate concentrations) and P fractions in bulk and rhizosheath soil, we conclude that X. occidentale accesses organic P, without releasing carboxylates. Solution 31P-NMR spectroscopy revealed which organic P forms X. occidentale accessed. 4. Xylomelum occidentale uses a strategy that differs fundamentally from that t ypical in Proteaceae, accessing soil organic P without carboxylates. We surmise that this novel strategy is likely expressed also in co-occurring non-Proteaceae that lack a carboxylate- exuding strategy. These co-occurring species are unlikely to benefit from mycorrhizal associations, because plant-available soil P concentrations are too low. 5. Synthesis. Our findings show the first field evidence of effectively utilizing soil organic P by X. occidentale without carboxylate exudation and explain their relatively restricted distribution in an old P-impoverished landscape, contributing to a better understanding of how diverse P-acquisition strategies coexist in a megadiverse ecosystem.en2020 British Ecological SocietyCarboxylates; ecophysiology; manganese; phosphatases; Proteaceae; soil organic P; solution ³¹P-NMR; XylomelumJournal article100002539010.1111/1365-2745.134680005605502000012-s2.0-85089549352544752Doolette, A.L. [0000-0002-7504-9920]Smernik, R.J. [0000-0001-6033-5855]