title: Triticum aestivum shows a greater biomass response to a supply of aluminium phosphate than Lupinus albus, despite releasing fewer carboxylates into the rhizosphere.
abstract: The relationship between carboxylate release and the ability of plants to access phosphorus from AlPO4 and to detoxify aluminium was studied by comparing species with a low and high rate of carboxylate release, Triticum aestivum (wheat) and Lupinus albus (white lupin), respectively. Species were supplied with P at 10, 20, 40 or 100 mg P kg-1 sand in the form of sparingly soluble AlPO4 or soluble KH2PO4; control plants did not receive any P. Triticum aestivum was significantly better than L. albus at accessing P from AlPO4, despite accumulating fewer carboxylates in its rhizosphere. Rhizosphere pH of L. albus did not vary with form or level of P supply, while the rhizosphere pH of T. aestivum increased with the level of P supplied. Based on the evidence in the present study, a model is proposed to explain the poor performance of L. albus, whereby the release of carboxylates and associated protons reduces the chelating ability of exuded carboxylates, thus reducing P acquisition and increasing Al toxicity.
authors.affiliation: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. spearse@graduate.uwa.edu.au
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Pearse
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Veneklaas
authors.forename: Greg
authors.initials: G
authors.lastname: Cawthray
authors.forename: Mike D A
authors.initials: MD
authors.lastname: Bolland
authors.forename: Hans
authors.initials: H
authors.lastname: Lambers
mesh_terms: D017607:Aluminum Compounds / Q000378:metabolism*; D018533:Biomass; D002264:Carboxylic Acids / Q000378:metabolism*; D031297:Lupinus / Q000254:growth & development* / Q000378:metabolism; D008954:Models, Biological; D010710:Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D014908:Triticum / Q000254:growth & development* / Q000378:metabolism
chemical_list: D017607:Aluminum Compounds; D002264:Carboxylic Acids; D010710:Phosphates; D010758:Phosphorus; C012714:aluminum phosphate