title: Ectomycorrhizal Pisolithus albus inoculation of Acacia spirorbis and Eucalyptus globulus grown in ultramafic topsoil enhances plant growth and mineral nutrition while limits metal uptake.
abstract: Ectomycorrhizal fungi (ECM) isolates of Pisolithus albus (Cooke and Massee) from nickel-rich ultramafic topsoils in New Caledonia were inoculated onto Acacia spirorbis Labill. (an endemic Fabaceae) and Eucalyptus globulus Labill. (used as a Myrtaceae plant host model). The aim of the study was to analyze the growth of symbiotic ECM plants growing on the ultramafic substrate that is characterized by high and toxic metal concentrations i.e. Co, Cr, Fe, Mn and Ni, deficient concentrations of plant essential nutrients such as N, P, K, and that presents an unbalanced Ca/Mg ratio (1/19). ECM inoculation was successful with a plant level of root mycorrhization up to 6.7%. ECM symbiosis enhanced plant growth as indicated by significant increases in shoot and root biomass. Presence of ECM enhanced uptake of major elements that are deficient in ultramafic substrates; in particular P, K and Ca. On the contrary, the ECM symbioses strongly reduced transfer to plants of element in excess in soils; in particular all metals. ECM-inoculated plants released metal complexing molecules as free thiols and oxalic acid mostly at lower concentrations than in controls. Data showed that ECM symbiosis helped plant growth by supplying uptake of deficient elements while acting as a protective barrier to toxic metals, in particular for plants growing on ultramafic substrate with extreme soil conditions. Isolation of indigenous and stress-adapted beneficial ECM fungi could serve as a potential tool for inoculation of ECM endemic plants for the successful restoration of ultramafic ecosystems degraded by mining activities.
authors: IRD, UR040 LSTM, TA A-82/J Campus International de Baillarguet, 34398 Montpellier Cedex 5, France. Electronic address: philippe.jourand@ird.fr.
authors: Philippe
authors: P
authors: Jourand
authors: IRD, UR040 LSTM, TA A-82/J Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
authors: Laure
authors: L
authors: Hannibal
authors: IRD, UR040 LSTM, TA A-82/J Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
authors: Clarisse
authors: C
authors: Majorel
authors: Université de Nouvelle-Calédonie, Laboratoire insulaire du vivant et de l'environnement, B.P. R4, 98851 Nouméa Cedex, New Caledonia.
authors: Stéphane
authors: S
authors: Mengant
authors: CIRAD, UR 82 LSTM, TA A-82/J Campus International de Baillarguet, 34398 Montpellier Cedex 5 France.
authors: Marc
authors: M
authors: Ducousso
authors: Université Montpellier 2, UMR28 LSTM, TA A-82/J Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
authors: Michel
authors: M
authors: Lebrun
mesh_terms: D000045:Acacia / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D000220:Adaptation, Biological; D001487:Basidiomycota / Q000502:physiology*; D005052:Eucalyptus / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D019216:Metals, Heavy / Q000378:metabolism*; D038821:Mycorrhizae / Q000502:physiology*; D019815:Oxalic Acid / Q000032:analysis; D053147:Plant Exudates / Q000737:chemistry; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology; D012987:Soil / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D053147:Plant Exudates; D012987:Soil; D013438:Sulfhydryl Compounds; D019815:Oxalic Acid
keywords: Acacia spirorbis; Ectomycorrhiza; Eucalyptus globulus; Pisolithus albus; Ultramafic topsoil