1. A web-accessible computer program for calculating electrical potentials and ion activities at cell-membrane surfaces.
- Author
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Kopittke, Peter, Wang, Peng, Menzies, Neal, Naidu, Ravi, and Kinraide, Thomas
- Subjects
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COMPUTER software , *ELECTRIC potential , *PLANT roots , *CELL membranes , *PLANT cell walls , *DONNAN equilibrium , *PHYSIOLOGY - Abstract
Aims: Increasing evidence indicates that plant responses to ions (uptake/transport, inhibition, and alleviation of inhibition) are dependent upon ion activities at the outer surface of root-cell plasma membranes (PMs) rather than activities in the bulk-phase rooting medium. Methods: A web-accessible computer program was written to calculate the electrical potential ( ψ) at the outer surface of root-cell PMs ( ψ). From these values of ψ, activities of ion I with charge Z ({ I}) can be calculated for the outer surface of the PM ({ I}). In addition, ψ and { I} in the Donnan phase of the cell walls ( ψ and { I}) can be calculated. Results: By reanalysing published data, we illustrate how this computer program can assist in the investigation of plant-ion interactions. For example, we demonstrate that in saline solutions, both Ca deficiency and Na uptake are more closely related to {Ca} and {Na} than to {Ca} and {Na} (activities in the bulk-phase media). Additional examples are given for Zn and P nutrition, Ni toxicity, and arsenate uptake. Conclusions: The computer program presented here should assist others to develop an electrostatic view of plant-ion interactions and to re-evaluate some commonly-held views regarding mechanisms of ion transport, toxicity, competition among ions, and other phenomena. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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