Bioaccumulation and phyto-translocation of Nickel by Medicago sativa in a calcareous soil of Iran

Nickel is a heavy metal distributed ubiquitously in nature. It accumulates in soil as a result of human activities, including mining and industries development. It may be poisonous to plants, humans, animals and microorganisms. The present study was implemented as a factorial experiment with a Randomized Complete Block Design (RCBD), of three replications in calcareous soils of Karaj and in greenhouse conditions for detection of the effect of nickel polluted soil, Ni125, Ni250, Ni500, Ni1000 (mgkg?1) in comparison with control (Ni0). The inoculant of resistant native bacteria to nickel in three levels, of: control (B0), Bacillus mycoides M1(B1), Micrococcus roseus M2 (B2) were examine on nickel phytoremediation in alfalfa (Medicago sativa L.). Results demonstrated that by increasing the polluted nickel concentration in soil, its absorption by the alfalfa have increased significantly (P 0.05). The plant growth and biomass accumulation severely decreased by increasing nickel concentration in soil. Application of native inoculant (B1 and B2) resistant to nickel significant increased the nickel concentration in plant shoot compared to control, and also increased the concentration of iron, zinc, copper and manganese in plant shoots. The highest nickel uptake occurred with B2 inoculant and during the second cutting of the plant growth, which was 350 µgPot?1