Summary The uptake of Cd2+ in maize root segments was studied. A preliminary characterization of this uptake was conducted to quantiry the Cd2+ influx across the root celi plasma membrane. Cd2+ influx depended on tissues integrity, was inhibited by low temperature and promoted by fusicoccin. Concentration-dependent Cd2+ influx in maize roots yielded saturating kinetic curve that was typical of the uptake of many minerai elements. Ca2+ influx, evaIuated using 4SCa2+, was similar to that of Cd2+ even if characterized by different kinetic constants. The presence of Ca2+ in the incubation medium reduced Cd2+ influx, affecting both Km and V . The slight effect of Cd2 + on transmembrane electric potentiaI (E.,) excluded a generalized toxicity of Cd2+ at plasmalemma leveL The presence of Ca2+ or Cd2+ +Ca2+ in the medium did not significantly affect the E",. The presence ofK+ reduced the Cd2+ influx, probably due to the depolarizing effect ofK+ on E",. These results suggest !hat the mechanism of Cd2+ influx is complex and that there are interactions between Cd2+ and Ca2+ influx at plasmalemma level in subapical maize root segrilents.
Mechanism of cadmium uptake in maize roots / A. Rivetta, N. Negrini, S. Lucchini, M. Cocucci - In: XXVII Annual Meeting of European Society for New Methods in Agricultural Research (ESNA) / joint organised with International Union of Radioecology (IUR)Ghent : University of Ghent, Faculty of Agricultural and Applied Biological Sciences, Department of Applied Analytical and Physical Chemistry, 1997. - pp. 40-46 (( Intervento presentato al 27. convegno Annual Meeting of ESNA tenutosi a Ghent nel 1997.
Mechanism of cadmium uptake in maize roots
A. RivettaPrimo
;N. NegriniSecondo
;M. CocucciUltimo
1997
Abstract
Summary The uptake of Cd2+ in maize root segments was studied. A preliminary characterization of this uptake was conducted to quantiry the Cd2+ influx across the root celi plasma membrane. Cd2+ influx depended on tissues integrity, was inhibited by low temperature and promoted by fusicoccin. Concentration-dependent Cd2+ influx in maize roots yielded saturating kinetic curve that was typical of the uptake of many minerai elements. Ca2+ influx, evaIuated using 4SCa2+, was similar to that of Cd2+ even if characterized by different kinetic constants. The presence of Ca2+ in the incubation medium reduced Cd2+ influx, affecting both Km and V . The slight effect of Cd2 + on transmembrane electric potentiaI (E.,) excluded a generalized toxicity of Cd2+ at plasmalemma leveL The presence of Ca2+ or Cd2+ +Ca2+ in the medium did not significantly affect the E",. The presence ofK+ reduced the Cd2+ influx, probably due to the depolarizing effect ofK+ on E",. These results suggest !hat the mechanism of Cd2+ influx is complex and that there are interactions between Cd2+ and Ca2+ influx at plasmalemma level in subapical maize root segrilents.
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