THE EFFECT OF HEAVY METALS ZN AND NI ON GROWTH OF IN VITRO HAIRY ROOT CULTURES OF INDIAN MUSTARD Brassica juncea L

Roots are the plant parts which facilitate the primary contact between a plant and pollutant and culturing of genetically transformed hairy roots of hyperaccumulator plant sp.Brassica juncea L. grown in vitro was established to study the potential of in vitro hairy root cultures for the uptake and accumulation of heavy metals (Ni and Zn) for their growth and biomass from an aquatic environment. At elevated concentrations of Ni and Zn metals, hairy roots showed an exponential growth and accumulation. In lower concentrations, Zn might have no effect on growth of root biomass and also found to be it caused no dramatic decrease in root growth even they are accumulated. At higher concentrations of Zn, B. Juncea hairy roots was not only found to be tolerent to Zn and also had capacity to increase their root biomass and no growth retardation was seen. All concentrations of Ni showed a drastic change in root biomass growth irrespective of the duration of incubation periods. Ni in higher concentrations caused an exponential increase in root biomass growth and Ni showed no toxicity symptoms in hairy roots even at higher concentrations for longer time upto 8 weeks of our study period and Ni was found to be an essential micronutrient for the growth of hairy root biomass. From this study, it was cleared and concluded that hairy roots of in vitro grown hyperaccumulator plant culture system could be the useful and effective model (as it needs metals for their root biomass growth) to study the metal uptake and accumulation from an aquatic environments.