RUSSIAN JOURNAL OF PLANT PHYSIOLOGY Vol. 58 No. 3 2011
BARRIER FUNCTION OF THE CELL WALL DURING UPTAKE 413
Our results show that, regardless of plant species,
the presence of EDTA in the solution dramatically
reduces the sorption capacity of cell walls for nickel
ions (Fig. 4). The cell walls of chickpea roots were
characterized by the highest value of this parameter
moles per gram dry wt), while this parameter for cell
walls of other plant species did not exceed 7
Obviously, the low sorption capacity under these con
ditions was due to the reduced capacity of complex
formation by PGA carboxyl groups compared with
EDTA. Based on these results, we suppose that the
presence of EDTA in the medium weakens the protec
tive functions of the cell wall, which could lead to the
increased absorption by plant cells of Me
in the form
Thus, the cell wall of higher plant roots has a high
ability to adsorb nickel ions from aqueous solutions.
concentration in cell walls is determined by
the number of carboxyl groups in the cellwall poly
meric matrix. The selectivity of carboxyl groups is
independent of the plant species, while their cation
exchange capacity is solely determined by the number
of carboxyl groups capable of exchange reactions.
Based on our results we conclude that, among the
mechanisms preventing accumulation of heavy metal
ions in the cytoplasm to concentrations toxic for bio
chemical reactions, sequestering of Ni
into the cell
wall is an effective means to protect plant cells from
the impact of elevated concentrations of nickel ions in
This work was supported by the Russian Founda
tion for Basic Research (project nos. 040449379a
and 080401398a) and by the Federal targeted pro
gram Scientific and Scientific–Pedagogical Personnel
of Innovative Russia (subprogram Cell Technologies,
State Contract no. P403).
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) in cell walls isolated from plant roots.
) pH 5 (10
M acetate buffer); (
) pH 5 (10
M acetate buffer). Initial solutions contained 10
. Data represent mean values and standard deviations
obtained from 3–5 assays.