Barrier function of the cell wall during uptake of nickel ions

Russian Journal of Plant Physiology (Impact Factor: 0.95). 05/2011; 58(3):409-414. DOI: 10.1134/S1021443711030137


Cell walls were isolated from roots of six plant species to study their ion-exchange capacity for nickel ions (S
Ni) at Ni2+ concentration of 10−3 M. The S
Ni values varied depending on the plant species from 50 to 150 μmol Ni2+ per gram dry wt; the sorption capacity increased in a row: Poaceae < Chenopodiaceae < Fabaceae. At pH 5 the sorption capacity
of cell walls for nickel ions was determined by the presence of carboxyl groups of polygalacturonic acid in the polymeric
cell-wall matrix. In all cases the ion-exchange capacity of cell walls was higher at pH 8 than at pH 5, indicating that Ni2+ binds also to a carboxyl group different from that of polygalacturonic acid. Irrespective of plant species, the presence
of EDTA in the solution diminished drastically the absorption capacity of cell walls for Ni2+. It is concluded that the presence of 10−3 M EDTA weakens the defense properties of cell walls. The sequestration of Ni2+ in the cell wall can be considered as an effective means of plant cell defense against elevated concentrations of nickel
ions in the external medium.

Keywordshigher plants–cell walls–nickel ions–carboxyl groups–EDTA

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Available from: Nataly Robertovna Meychik,
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    • "The cell walls can work as a barrier and effectively sequestrate heavy metal ions (Macfie and Welbourn 2000; Latha et al. 2005; Meychik et al. 2011). Therefore, the cell walls could be a key factor in heavy metal exclusion mechanisms for fungi. "
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