PHYTOREMEDIATION POTENTIAL OF RAPHANUS SATIVUS (L.), BRASSICA JUNCEA (L.) AND TRITICUM AESTIVUM (L.) FOR COPPER CONTAMINATED SOIL

Phytoremediation is an emerging technology that employs the use of higher plants for the clean up contaminated environment. Phyto extraction, the use of plants to extract toxic metals from contaminated soils, has emerged as a cost-effective, environment-friendly clean up alternative. The present study aimed to find a suitable plants species for use in cleaning up the soil in industrial regions. In this work we were studied crop species, which are cultivated by farmers of North-India. The effects of different concentration of copper were studied in two varieties of wheat (T. aestivum L., var. UP 2338 and var. PBW 373), mustard (Brassica juncea L.) and radish (Raphanus sativus L.) plants. The study included an assessment of heavy metal accumulation in root, shoot and leaf, effect of copper stress on growth parameter (root length, root and shoot dry weight), photosynthetic pigment content, bioaccumulation coefficient (BAC) and the activity of anti-oxidant enzymes. Results demonstrated that plant species were differ significantly in Cu uptake and translocation. Efficient Cu uptake was observed by the roots in all plants. A high metal content in roots, due to localization of ions in the apoplasm. The highest Cu++ ions accumulated in the roots of radish plant. Root growth was higher in brassicaceae plants (i.e. mustard and radish), as compared to the plants of poaceae family (T. aestivm). High concentration of copper (50-100 µM) had a negative effect on growth of all plants. Copper exposure also influenced biochemical and physiological parameters. Administration of excess of copper was followed by an increase of Cu accumulation in leaves, and associated symptoms of toxicity. Typical symptoms of Cu toxicity developed 30 days after the beginning of treatment. Chlorophyll concentration was decreased in response to heavy metal toxicity. Activity of anti-oxidative enzymes e.g. peroxidase and catalase were increased in response to oxidative stress. Atomic absorption spectrophotometer (AAS) was used for analysis of heavy metal in soil and plant samples. Tested plant species were grouped on the basis of their accumulation capability of heavy metal. The results of this research showed that radish and mustard plants of family brassicaceae are hyper accumulator plants that can concentrate heavy metals in their different parts, thus they can be used for remediation of polluted area. Study also showed that potential of metal accumulator plants for extraction of metal from soil occur up to a certain level of concentration, after that when the concentration of metal increased the phyto extraction rate of metal or bioaccumulation coefficient (BAC) were decreased