Proton and copper adsorption to maize and soybean root cell walls. [Zea mays L. Glycine max (L. ) Merr. cv Dare]

Journal Article · Wed Mar 01 00:00:00 EST 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.89.3.823· OSTI ID:5129700

Allan, D L; Jarrell, W M ^[1]

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1. Univ. of California, Riverside (USA)

A surface complexation model which has been used to describe inner-sphere complexation on metal oxide surfaces was applied to the adsorption of Cu by isolated cell walls of 4-day and 28-day-old maize (Zea mays L. cv WF9 {times} Mo17) and 21-day-old soybean (Glycine max (L.) Merr. cv Dare) roots. Concentration dependence of the titration data prevented the determination of unique pK and capacitance values for the 4-day maize cell walls, though mean values obtained for the intrinsic pK of the titratable carboxyl groups were 3.0 (4-day maize), 3.6 (28-day maize), and 3.0 (21-day soybean)as determined by potentiometric titration with either NaOH or HCl in 20 millimolar NaCl. The constant capacitance model was applied to Cu sorption data from rapid batch equilibrium experiments in an ionic medium of 20 millimolar NaClO{sub 4}. Speciation calculations indicated that the formation of bidentate surface complex was sufficient to describe the experimental data for all three types of plant material, with only one value for the pK and capacitance density. The intrinsic constants of Cu complexation by a neutral site are: log K = -0.3 {plus minus} 0.1, -0.2 {plus minus} 0.3, and 0.9 {plus minus} 0.1 for 4-day and 28-day maize, and 21-say soybean, respectively. The integral capacitance density parameter, which describes the relationship between surface charge density and electrical potential, is several times larger than for crystalline mineral surfaces.

• OSTI ID: 5129700
• Journal Information: Plant Physiology; (USA), Vol. 89:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CELL WALL
ION EXCHANGE
COPPER
ADSORPTION
GLYCINE HISPIDA
PHYSIOLOGY
MAIZE
CHARGE DENSITY
ELECTRIC POTENTIAL
EXPERIMENTAL DATA
ROOTS
CELL CONSTITUENTS
CEREALS
DATA
ELEMENTS
GRASS
INFORMATION
LEGUMINOSAE
LILIOPSIDA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METALS
NUMERICAL DATA
PLANTS
SORPTION
TRANSITION ELEMENTS
551000* - Physiological Systems