The effect of different concentrations of nickel in the medium on the biomass production, nickel accumulation and the activity of anti-oxidative enzymes in some Pistacia species

Serpentine soils contain relatively high and toxic concentrations of heavy metals like nickel, chromium and cobalt. Nevertheless, in the most of these soils some plant species, such as Pistaacia atlantica, are grown which are metal tolerance. In this research, the effect of different concentrations of nickel supplied has been studied on dry biomass, nickel accumulation and the activity of some anti-oxidative enzymes in serpentine species of P. atlantica compared to non-serpentine P. vera and P. khinjuk. The results of dry biomass indicated the serpentine species of P. atlantica is more tolerant to increasing concentration of nickle than non-serpentine species of P. vera and P. khinjuk. It also appears that Pistacia species are some nickel excluders indicated by low nickel content in their shoots with increasing in the medium. The activity of anti-oxidative enzymes of catalase and ascorbate peroxidase increased in Pistacia species with increasing nickel supplied. Their activities were higher in shoots compared to roots, probably to protect photosynthetic systems against oxidative stress of nickel excess. Remarkably, increasing ascorbate peroxidase activity in the shoots of serpentine species, P. atlantica, was higher than non-serpentine species, P. vera and P. khinjuk, in response to increasing nickel concentration in the medium. This characteristic may be involved in the higher tolerance of P. atlantica, compared to P. vera and P. khinjuk, in serpentine soils.