Co-Authors:
Kinraide, T.B., Appalachian Soil/Water Conserv. R.L., Agricultural Research Service, U. States Department of Agriculture, Beaver, WV 25813-0400, United States
Yermiyahu, U., Inst. Soils, Water and Environ. Sci., Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel
Rytwo, G., Tel Hai College, Upper Galilee 12210, Israel
Abstract:
A Gouy-Chapman-Stern model has been developed for the compulation of surface electrical potential (ψ0) of plant cell membranes in response to ionic solutes. The present model is a modification of an earlier version developed to compute the Sorption of ions by wheat (Triticum aestivum L. cv Scout 66) root plasma membranes. A single set of model parameters generates values for ψ0 that correlate highly with published ζ potentials of protoplasts and plasma membrane vesicles from diverse plant sources. The model assumes ion binding to a negatively charged site (R- = 0.3074 μtmol m-2) and to a neutral site (P0 = 2.4 μmol m-2) according to the reactions R- + Iz ⇌ RIz~' and P0 + Iz ⇌ PIz, where Iz represents an ion of charge Z. Binding constants for the negative site are 21,500 M-1 for H+, 20,000 M-1 for Al3+, 2,200 M-1 for La3+, 30 M-1 for Ca2+ and Mg2+, and 1 M-1 for Na+ and K+. Binding constants for the neutral site are 1/180 the value for binding to the negative site. Ion activities at the membrane surface, computed on the basis of ψ0, appear to determine many aspects of plant-mineral interactions, including mineral nutrition and the induction and alleviation of mineral toxicities, according to previous and ongoing studies. A computer program with instructions for the computation of ψ0, ion binding, ion concentrations, and ion activities at membrane surfaces may be requested from the authors.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
