Screening of Brassica species for hyper-accumulation of zinc, copper, lead, nickel and cadmium
2009
Purakavastha, T.J. | Bhadraray, S. | Chhonkar, P.K.
In a sand culture experiment five different species of Brassica, (1) B. juncea (Indian mustard) cv. Pusa Bold, (2) B. campestris (Yellow mustard) cv. Pusa Gold, (3) B. carinata (Ethiopian mustard) cv. DLSC-1, (4) B. napus cv. Early napus, (5) B. nigra cv. IC-247 were grown in a phytotron for screening possible hyper-accumulator of heavy metals, viz. Zn, Cu, Pb, Ni and Cd. The plants were grown with Hoagland solution (control) and Hoagland solution enriched with medium and high levels of heavy metals up to maximum vegetative stage. Results showed that all the heavy metal contents in stalks of Brassica species increased due to enrichment of Hoagland solution with heavy metals. The plant growth was affected at higher level of metal enrichment. Among the species, B. napus contained highest amount of Cu, Pb, Ni and Cd in stalks, while B. cannata alone and B. cannata jointly with B. juncea showed highest Zn contents in medium and high metal levels, respectively. This was reflected in highest Zn uptake by B. carinata followed by B. nap us. In case of Cu the trend interchanged among these two species. For Pb, Ni and Cd, B. nap us accumulated highest amount outperforming all the other species. The most novel aspect of current study remained in the fact that probably for the first time B. napus and B. carinata reported as promising accumulator of Zn, Cu, Ni, Pb and Cd; which performed better than otherwise most reported B. juncea. Succinic acid was characterized and quantified as one of the dominant organic acids in root exudates of promising Brassica species. In this respect the greater secretions of this acid by roots of B. napus reflected its probable role in metal acquision through complexation
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