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This study
investigated the effect of toxic concentrations of nickel on
antioxidant enzymes in the root of soybean plant, and the
use of copper to ameliorate the adverse effect of nickel on
these antioxidant enzymes. Viable seeds were planted in soil
contaminated with 30PPmNi and also soil contaminated with
30ppmNi + 2OPPmCU and 30PPmNi + 40PPmCu for 2-4 weeks. The
results revealed a decrease in root weight when the soil was
contaminated with nickel. Superoxide dismutase, catalase and
glutathione peroxide were assayed for from week 2-4. For
week 2, at 30PPmNi the activity of Superoxide dismutase
increased (0.84 ± 0.004). The activity of Catalase (1.04±
0.01) and Glutathione peroxide (0.94 ± 0.01) also increased
in the second week. For the fourth week, the activity of
Superoxide dismutase, Catalase and Glutathione peroxide
increased remarkably at 30PPmNi. i.e Superoxide dismutase
(1.26±0.01), catalase (1.04 ± 0.01) and Glutathione peroxide
(0.94 ± 0.01). Copper (Cu) had an ameliorating effect on
nickel toxicity, it reduces the rate of lipid peroxidation.
At 30PPmNi + 20PPmCu, MDA value was (0.56 ± 0.01) compared
to 30PPmNi (0.66 ± 0.01). At 30PPmNi + 40PPmCu MDA value
further reduced to (0.45 ± 0.001) compared to 30PPm Ni
(0.66±0.001) for the week 2.This trend of reduction in MDA
valve increased in the 4th week. In conclusion, Cu can be
used as a means of reducing the toxicity of nickel in
farmland, which is detrimental to the plant. Cu
competitively inhibits the absorption to nickel by the plant
thus reducing the concentration
Key words: enzymes, nickel, copper, catalaseioxidant,
toxicity, soybean |
