tolerance and accumulation of heavy metals by descurainia sophia l.

today, biosphere pollution has accelerated strongly with start of industrial revolution by toxicity of heavy metals. one of existing pollution is soil pollution. unfortunately, soil pollution by metals is as intensive environmental stress for plant hence for human. plants, which are able to store heavy metals in their organs, can be used for phytoremediation of polluted soils and utilization of these plants is effective for phytoremediation as a cheap and economic method. in this research, the absorption rate of cd (ii), ni (ii) by descurainia sophia was considered in hydroponic conditions. plants were grown in hoagland media containing different concentrations of cd (ii), ni (ii). an experiment in a completely randomized design with three replications was conducted. two weeks after treatment of plants the sample were gathered and metal concentration was measured by atomic absorption spectroscopy. besides, the content of chlorophyll and proline was measured. the results showed the chlorophyll content in high concentrations of the metals (cd (ii), ni (ii)) was decreased in plants that were sign of pigment degradation in presence of heavy metals. similarly, the proline content in plants was increased under stress which was sign of damage of heavy metal stress on plant and activation of defensive mechanisms in this condition. the effects of toxic concentration of nickel and cadmium on metal accumulation in these plants showed that roots were able to absorb more than shoots, which is sign of elements connection to root cell wall.