title: Multiple metal accumulation within a manganese-specific genus.
abstract: OBJECTIVE
  Plants that strongly accumulate metals may be practically beneficial, and also serve as novel resources for increasing fundamental understanding of plant biology. Australian Gossia (Myrtaceae) species are delineated by a conspicuous affinity for the heavy metal manganese (Mn), which is a micronutrient crucial to photosynthesis. This genus includes several Mn hyperaccumulators such as G. bidwillii. Unusually, in G. bidwillii foliar Mn is most highly concentrated in photosynthetic cells, an observation thus far restricted to foliar-Mn accumulation in Mn hyperaccumulators. Recent discovery that several of these Gossia species accumulate other metals in addition to Mn will enable investigation as to whether primary sequestration of metals in photosynthetic tissues is restricted to Mn.
  
  
  METHODS
  Gossia species known to accumulate nickel (Ni) or aluminum (Al) in addition to Mn were sampled in the field. Complementary proton- and electron-probe data were combined to evaluate in vivo microdistribution patterns of excessively accumulated foliar metals.
  
  
  RESULTS
  It was discovered that in addition to Mn and Ni, Gossia fragrantissima accumulated foliar zinc (Zn) and cobalt (Co), with Mn, Ni, and Co most highly localized in mesophyll cells and Zn primarily located in the upper epidermis. In G. hillii, Mn and Al were highly concentrated in the palisade and epidermis, respectively.
  
  
  CONCLUSIONS
  This investigation provides evidence that the primary disposal of excess foliar metals in photosynthetic cells is not exclusive to Mn. It offers rare intrageneric perspective on metal compartmentation, pointing to significant variation among tonoplastal metal transporters associated with detoxification.
authors.affiliation: The Department of Botany, La Trobe University, Bundoora, Victoria 3086, Australia. d.fernando@latrobe.edu.au
authors.forename: Denise R
authors.initials: DR
authors.lastname: Fernando
authors.forename: Alan T
authors.initials: AT
authors.lastname: Marshall
authors.forename: Paul I
authors.initials: PI
authors.lastname: Forster
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hoebee
authors.forename: Rainer
authors.initials: R
authors.lastname: Siegele
mesh_terms: D008345:Manganese / Q000378:metabolism*; D058503:Mesophyll Cells / Q000378:metabolism*; D027822:Myrtaceae / Q000378:metabolism*; D019441:Plant Epidermis / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D008345:Manganese