title: Foliar manganese accumulation by Maytenus founieri (Celastraceae) in its native New Caledonian habitats: populational variation and localization by X-ray microanalysis.
abstract: Hyperaccumulation by plants is a rare phenomenon that has potential practical benefits. The majority of manganese (Mn) hyperaccumulators discovered to date occur in New Caledonia, and little is known about their ecophysiology. This study reports on natural populations of one such species, the endemic shrub Maytenus founieri. Mean foliar Mn concentrations of two populations growing on ultramafic substrates with varying soil pHs were obtained. Leaf anatomies were examined by light microscopy, while the spatial distributions of foliar Mn in both populations were examined by qualitative scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). Plants growing on two different substrates were found to have very different mean dry weight (DW) foliar Mn concentrations. Light microscopy showed that the leaves had very distinct thick dermal structures, consisting of multiple layers of large cells in the hypodermis. In vivo X-ray microprobe analyses revealed that, in both populations, Mn sequestration occurred primarily in these dermal tissues. The finding here that foliar Mn is most highly localized in the nonphotosynthetic tissues of M. founieri contrasts with results from similar studies on other woody species that accumulate high Mn concentrations in their shoots.
authors.affiliation: School of Botany, University of Melbourne, VIC 3010, Australia.
authors.forename: D R
authors.initials: DR
authors.lastname: Fernando
authors.affiliation: School of Botany, University of Melbourne, VIC 3010, Australia.
authors.forename: I E
authors.initials: IE
authors.lastname: Woodrow
authors.affiliation: IRD Centre, Botany Laboratory, BPA5, 98848 Nouméa Cedex, New Caledonia.
authors.forename: T
authors.initials: T
authors.lastname: Jaffré
authors.affiliation: IRD Centre, Botany Laboratory, BPA5, 98848 Nouméa Cedex, New Caledonia.
authors.forename: V
authors.initials: V
authors.lastname: Dumontet
authors.affiliation: Analytical Electron Microscopy Laboratory, Faculty of Science and Technology & Engineering, La Trobe University, Melbourne VIC 3086, Australia.
authors.forename: A T
authors.initials: AT
authors.lastname: Marshall
authors.affiliation: School of Botany, University of Melbourne, VIC 3010, Australia.
authors.forename: A J M
authors.initials: AJM
authors.lastname: Baker
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D029753:Celastraceae / Q000737:chemistry / Q000378:metabolism*; D003710:Demography; D017753:Ecosystem; D004577:Electron Probe Microanalysis; D008345:Manganese / Q000032:analysis / Q000378:metabolism*; D009510:New Caledonia; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008345:Manganese; D002118:Calcium