Rhizotoxic effects of silver in cowpea seedlings

Blamey, F. Pax C., Kopittke, Peter M., Wehr, J. Bernhard, Kinraide, Thomas B. and Menzies, Neal W. (2010) Rhizotoxic effects of silver in cowpea seedlings. Environmental Toxicology and Chemistry, 29 9: 2072-2078. doi:10.1002/etc.236

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Author Blamey, F. Pax C.
Kopittke, Peter M.
Wehr, J. Bernhard
Kinraide, Thomas B.
Menzies, Neal W.
Title Rhizotoxic effects of silver in cowpea seedlings
Journal name Environmental Toxicology and Chemistry   Check publisher's open access policy
ISSN 1552-8618
0730-7268
Publication date 2010-09
Sub-type Article (original research)
DOI 10.1002/etc.236
Volume 29
Issue 9
Start page 2072
End page 2078
Total pages 7
Editor Calvin Herbert Ward
Place of publication Houston, TX, U.S.A.
Publisher SETAC Press
Collection year 2011
Language eng
Formatted abstract
Silver (Ag) is highly toxic to aquatic organisms, including algae, invertebrate animals, and fish, but little information exists  on Ag rhizotoxicity in higher plants. In two solution culture experiments with approximately 1,000 µMCa(NO3)2 and 5 µMH3BO3 (pH 5.4), 20 to 80% of added Ag (≤2µM) was lost from solution within approximately 30 min, with a further decrease after 48 h root growth. Using measured Ag concentrations at the start of the experiments, the median effective concentration (EC50) for root elongation rate of cowpea (Vigna unguiculata [L.] Walp. cv. Caloona) was 0.010 µM Ag in the first 4 h of exposure (0.021µM in the first 8 h). This demonstrates that Ag (as Ag+) is rapidly rhizotoxic to cowpea seedlings at concentrations similar to those that are toxic to freshwater biota. Rupturing of rhizodermal and outer cortical layers was evident after 48 h with 0.13 to 0.57µMAg initially in solution, being most severe at 0.13 or 0.25 µMAg. An additional experiment showed that ruptures were first evident after 20 h exposure to 0.17µMAg, with increased severity of rupturing over time. The rhizotoxic effects of Ag are similar to those of some other trace metals (e.g., Cu, Al, La) that bind strongly to hard ligands and weakly to soft ligands. The similarity of rupturing effects, despite the difference in strong binding to soft ligands by Ag and to hard ligands by the other metals, suggests a distinctive metabolic effect of Ag that binds only weakly to hard ligands.
© 2010 SETAC
Keyword Cowpea
Rhizotoxicity
Morphology
Silver
Toxicity
Rainbow trout
Toxicity
Aluminium
Inhibition
Mechanism
Transport
Chloride
Cations
Roots
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Agriculture and Food Sciences
 
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Citation counts: TR Web of Science Citation Count  Cited 6 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 12 Sep 2010, 00:05:12 EST