Co-Authors:
Yermiyahu, U., Agricultural Research Organization, Gilat Research Center, D.N. Negev 285280, Israel
Kinraide, T.B., Appalachian Farming Systems Research Center, Agricultural Research Service, United States Department of Agriculture, Beaver West, VA 25813-9423, United States
Abstract:
An important feature of the biogeochemistry of trace elements in the rhizosphere is the interaction between plant root surfaces and the ions in the soil solution. These ions may accumulate in the aqueous phases of cell surfaces external to the plasma membranes (PMs). In addition, ions may bind to the cell wall (CW) components or to the PM surface with variable strength. The chapter describes the distribution of ions among the extracellular phases using electrostatic models (i.e., Gouy-Chapman-Stem and Donnan-plus-binding models) for which parameters are now available. Many plant responses to ions correlate well with computed PM-surface activities, but only poorly with activities in the soil solution. These responses include ion uptake, ion-induced intoxication, and the alleviation of intoxication by other ions. The chapter illustrates the technique for the quantitative resolution of multiple ion effects by inserting cell-surface activities into nonlinear equations. © 2005 Elsevier B.V. All rights reserved.