Cell membrane surface potential (psi(0)) plays a dominant role in the phytotoxicity of copper and arsenate

Wang, Peng, Zhou, Dongmei, Kinraide, Thomas B., Luo, Xiaosan, Li, Lianzhen, Li, Dandan and Zhang, Hailin (2008) Cell membrane surface potential (psi(0)) plays a dominant role in the phytotoxicity of copper and arsenate. Plant Physiology, 148 4: 2134-2143. doi:10.1104/pp.108.127464

Author Wang, Peng
Zhou, Dongmei
Kinraide, Thomas B.
Luo, Xiaosan
Li, Lianzhen
Li, Dandan
Zhang, Hailin
Title Cell membrane surface potential (psi(0)) plays a dominant role in the phytotoxicity of copper and arsenate
Journal name Plant Physiology   Check publisher's open access policy
ISSN 0032-0889
Publication date 2008-12
Sub-type Article (original research)
DOI 10.1104/pp.108.127464
Volume 148
Issue 4
Start page 2134
End page 2143
Total pages 10
Place of publication Rockville, MD, United States
Publisher American Society of Plant Biologists
Language eng
Formatted abstract
Negative charges at cell membrane surfaces (CMS) create a surface electrical potential (ψ0) that affects ion concentrations at the CMS and consequently affects the phytotoxicity of metallic cations and metalloid anions in different ways. The ζ potentials of root protoplasts of wheat (Triticum aestivum), as affected by the ionic environment of the solution, were measured and compared with the values of ψ0 calculated with a Gouy-Chapman-Stern model. The mechanisms for the effects of cations (H +, Ca2+, Mg2+, Na+, and K +) on the acute toxicity of Cu2+ and As(V) to wheat were studied in terms of ψ0. The order of effectiveness of the ions in reducing the negativity of ψ0 was H+ > Ca 2+ ≈ Mg2+ > Na+ ≈ K+. The calculated values of ψ0 were proportional to the measured ζ potentials (r2 = 0.93). Increasing Ca2+ or Mg2+ activities in bulk-phase media resulted in decreased CMS activities of Cu 2+ ({Cu2+}0) and increased CMS activities of As(V) ({As(V)}0). The 48-h EA50{Cu2+}b ({Cu2+} in bulk-phase media accounting for 50% inhibition of root elongation over 48 h) increased initially and then declined, whereas the 48-h EA50{As(V)}b decreased linearly. However, the intrinsic toxicity of Cu2+ (toxicity expressed in terms of {Cu2+}0) appeared to be enhanced as ψ0 became less negative and the intrinsic toxicity of As(V) appeared to be reduced. The ψ0 effects, rather than site-specific competitions among ions at the CMS (invoked by the biotic ligand model), may play the dominant role in the phytotoxicities of Cu2+ and As(V) to wheat.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
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Created: Thu, 19 Sep 2013, 15:51:43 EST by Peng Wang on behalf of School of Agriculture and Food Sciences