Abstract:
Cadmium is a toxic heavy metal for humans, animals and plants which enters the environment mainly from anthropogenic sources including smelters and by applications of fertilizers and sewage sludge. Effective and economical technologies are needed to remediate cadmium from contaminated terrestrial and aquatic environment. Phytoremediation is a novel, cost-effective, eco-friendly 'green' remediation technology for remediation of heavy metals from contaminated environment. Researchers have observed that some plant species endemic to metalliferous soils can tolerate greater than usual amounts of heavy metals and accumulate them in their aerial biomass. In the present study, the uptake of cadmium by alfalfa (Medicago sativa L.) was studied under in vitro culture conditions. Plants initially grown in liquid media containing Murashige & Skoog's medium were transferred to Hoagland's medium spiked with cadmium as Cd (NO3)2.4H20. The concentrations of cadmium used in this study were 0, 5, 10, 20 and 50 ppm and the experiments carried out upto a period of 21 days. After 21 days of treatment, the cadmium content in plant tissues was quantified using Atomic Absorption Spectroscopy. The results showed that 80-85% of cadmium from solution (50 ppm) was remediated by alfalfa plants within 21 days of culture. Most of the cadmium i.e.12360 lg gm-1 was accumulated in roots, while 1920 ig gm-1 was translocated to shoots. The present study that alfalfa plants could remediate cadmium will be useful to remediate cadmium from contaminated solutions.
