title: Simultaneous hyperaccumulation of nickel, manganese, and calcium in Alyssum leaf trichomes.
abstract: We have developed commercially viable phytoremediation/phytomining technologies employing Alyssum Ni-hyperaccumulator species to quantitatively extract Ni from soils. The majority of Ni is stored either in Alyssum leaf epidermal cell vacuoles or in the basal portions only of the numerous stellate trichomes. Here, we report simultaneous and region-specific localization of high levels of Ni, Mn, and Ca within Alyssum trichomes as determined by scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX). Plants were grown in high Ni soil, achieving up to 48 400 microg g(-1) Ni in total leaf concentration; however, Ca and Mn were not enriched in the experimental soils. The region-specific localization of hyperaccumulated Ca, Mn, and Ni occurred in three soil types, five Alyssum species/ecotypes, and over a wide range of soil Ni concentrations. The metal concentration in the trichome basal compartment was approximately 15-20% dry weight, the highest ever reported for healthy vascular plant tissue.
authors.affiliation: Animal Manure and Byproducts Laboratory, Animal and Natural Resources Institute, US Department of Agriculture, Henry A Wallace Agricultural Research Center, Beltsville, Maryland 20705, USA. broadhul@ba.ars.usda.gov
authors.forename: C Leigh
authors.initials: CL
authors.lastname: Broadhurst
authors.forename: Rufus L
authors.initials: RL
authors.lastname: Chaney
authors.forename: J Scott
authors.initials: JS
authors.lastname: Angle
authors.forename: Timothy K
authors.initials: TK
authors.lastname: Maugel
authors.forename: Eric F
authors.initials: EF
authors.lastname: Erbe
authors.forename: Charles A
authors.initials: CA
authors.lastname: Murphy
mesh_terms: D019607:Brassicaceae / Q000737:chemistry / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism*; D013052:Spectrometry, X-Ray Emission; D014617:Vacuoles / Q000378:metabolism
chemical_list: D008345:Manganese; D009532:Nickel; D002118:Calcium