Science Inventory

In Situ Distribution And Speciation Of Toxic Copper, Nickel, And Zinc In Hydrated Roots Of Cowpea

Citation:

Kopittke, P. M., N. W. Menzies, M. D. de Jonge, B. A. McKenna, E. Donner, R. I. Webb, D. J. Paterson, D. L. Howard, C. G. Ryan, C. J. Glover, K. G. SCHECKEL, AND E. Lombi. In Situ Distribution And Speciation Of Toxic Copper, Nickel, And Zinc In Hydrated Roots Of Cowpea. PLANT PHYSIOLOGY. American Society of Plant Biologists, Rockville, MD, 156:663-673, (2011).

Impact/Purpose:

To investigate the in situ distribution and speciation of Cu, Ni, and Zn in roots of a non-hyperaccumulator (cowpea, Vigna unguiculata (L.) Walp.) following short periods of exposure (1 to 24 h) to toxic, but environmentally relavant, levels of trace metals.

Description:

The phytotoxicity of trace metals is of global concern due to contamination of the landscape by human activities. Using synchrotron-based X-ray fluorescence microscopy and X-ray absorption spectroscopy, the distribution and speciation of Cu, Ni, and Zn was examined in situ using hydrated roots of cowpea (Vigna unguiculata (L.) Walp.) exposed to 1.5 µM Cu, 5 µM Ni, or 40 µM Zn for 1 to 24 h. After 24 h exposure, most Cu was bound to polygalacturonic acid of the rhizodermis and outer cortex, suggesting that binding of Cu to walls of cells in the rhizodermis possibly contributes to the toxic effects of Cu. When exposed to Zn, cortical concentrations remained comparatively low with much of the zn accumulating in the meristematic region and moving into the stele; ca. 60 to 85% of the total Zn stored as Zn-phytate within 3 h of exposure. Whilst Ni concentrations were high in both the cortex and meristem, concentrations in the stele were comparatively low. To our knowledge, this is the first report of the in situ distribution and speciation of Cu, Ni, and Zn in hydrated (and fresh) plant tissues, providing valuable information on the potential mechanisms by which they are toxic.

URLs/Downloads:

In Situ Dist Spec Toxic Cu, Ni, Zn Hydrated Roots Cowpea   Exit

Website   Exit

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Product Published Date: 04/27/2011
Record Last Revised: 04/27/2012
OMB Category: Other
Record ID: 238320

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL RISK MANAGEMENT RESEARCH LABORATORY

LAND REMEDIATION AND POLLUTION CONTROL DIVISION

WASTE MANAGEMENT BRANCH