Shomer, I., Department of Food Science, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Novacky, A.J., Department of Plant Pathology, University of Missouri, Columbia, MO 65211, United States
Pike, S.M., Department of Plant Pathology, University of Missouri, Columbia, MO 65211, United States
Yermiyahu, U., Gilat Research Center, Agricultural Research Organization, Negev 85280, Israel
Kinraide, T.B., Appalachian Farming Syst. Res. Ctr., Agricultural Research Service, U. States Department of Agriculture, Beaver, WV 25813-9423, United States
Electrical potentials in cell walls (ψWall) and at plasma membrane surfaces (ψPM) are determinants of ion activities in these phases. The ψPM plays a demonstrated role in ion uptake and intoxication, but a comprehensive electrostatic theory of plant-ion interactions will require further understanding of ψWall. ψWall from potato (Solanum tuberosum) tubers and wheat (Triticum aestivum) roots was monitored in response to ionic changes by placing glass microelectrodes against cell surfaces. Cations reduced the negativity of ψWall with effectiveness in the order Al3+ > La3+ > H+ > Cu2+ > Ni2+ > Ca2+ > Co2+ > Cd2+ > Mg 2+ > Zn2+ > hexamethonium2+ > Rb + > K+ > Cs+ > Na+. This order resembles substantially the order of plant-root intoxicating effectiveness and indicates a role for both ion charge and size. Our measurements were combined with the few published measurements of ψ Wall, and all were considered in terms of a model composed of Donnan theory and ion binding. Measured and model-computed values for ψ Wall were in close agreement, usually, and we consider ψ Wall to be at least proportional to the actual Donnan potentials. ψWall and ψPM display similar trends in their responses to ionic solutes, but ions appear to bind more strongly to plasma membrane sites than to readily accessible cell wall sites. ψWall is involved in swelling and extension capabilities of the cell wall lattice and thus may play a role in pectin bonding, texture, and intercellular adhesion.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
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תנאי שימוש
Electrical potentials of plant cell walls in response to the ionic environment
133
Shomer, I., Department of Food Science, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Novacky, A.J., Department of Plant Pathology, University of Missouri, Columbia, MO 65211, United States
Pike, S.M., Department of Plant Pathology, University of Missouri, Columbia, MO 65211, United States
Yermiyahu, U., Gilat Research Center, Agricultural Research Organization, Negev 85280, Israel
Kinraide, T.B., Appalachian Farming Syst. Res. Ctr., Agricultural Research Service, U. States Department of Agriculture, Beaver, WV 25813-9423, United States
Electrical potentials of plant cell walls in response to the ionic environment
Electrical potentials in cell walls (ψWall) and at plasma membrane surfaces (ψPM) are determinants of ion activities in these phases. The ψPM plays a demonstrated role in ion uptake and intoxication, but a comprehensive electrostatic theory of plant-ion interactions will require further understanding of ψWall. ψWall from potato (Solanum tuberosum) tubers and wheat (Triticum aestivum) roots was monitored in response to ionic changes by placing glass microelectrodes against cell surfaces. Cations reduced the negativity of ψWall with effectiveness in the order Al3+ > La3+ > H+ > Cu2+ > Ni2+ > Ca2+ > Co2+ > Cd2+ > Mg 2+ > Zn2+ > hexamethonium2+ > Rb + > K+ > Cs+ > Na+. This order resembles substantially the order of plant-root intoxicating effectiveness and indicates a role for both ion charge and size. Our measurements were combined with the few published measurements of ψ Wall, and all were considered in terms of a model composed of Donnan theory and ion binding. Measured and model-computed values for ψ Wall were in close agreement, usually, and we consider ψ Wall to be at least proportional to the actual Donnan potentials. ψWall and ψPM display similar trends in their responses to ionic solutes, but ions appear to bind more strongly to plasma membrane sites than to readily accessible cell wall sites. ψWall is involved in swelling and extension capabilities of the cell wall lattice and thus may play a role in pectin bonding, texture, and intercellular adhesion.
Scientific Publication