Change of Ni Tolerance Parameters by Light in Calli of a Ni Hyperaccumulator Plant Alyssum inflatum

Alyssum inflatum is an endemic of serpentine soils from western Iran and hypeaccumulates Ni. In this study، to investigate the mechanisms involved in the tolerance of high concentrations of Ni، a callus culture method was used to have a system with lower complexities in organ and tissue organization in compare to a whole plant. Calli were proliferated on MS medium containing of 1. 5 and 0. 1mg/l 2،4-D and kinetin respectively، treated by different concentrations of Ni (0،100، 200،300،400، 500 and 600) in light and dark conditions and different tolerance parameters including of growth، chlorophyll content and the activity of antioxidant enzymes were measured. The results showed that light both stimulates growth and higher Ni tolerance in calli. Among the other measured parameters، a positive relation was observed between increased tolerance and activity of catalyses while in that condition there were no increased activities in superoxide dismutase and ascorbate peroxides. Tissue culture methods could be used for study the tolerance of plants، avoiding of tissue and organ complexities. Conclusions from the current study based on the increment of tolerance observed at light، suggest the effect of cell differentiation on tolerance. The results of such simple systems could be reasonably extended to the whole plant.