Influence of some chelators on the phytoextraction ability of sunflower, Helianthus annuus for cd and pb metals in polluted soil
2009
Lotfy; S.M. | Abdel Bary, S.A.A. | El-Naka, E.A. | Abdel Sabour, M.F.
Chelation and complexation of heavy metals were evaluated as practical ways to solubilize, detoxify, and enhance heavy metals accumulation by plants. Sunflower (Helianthus annuus) was selected as a potential heavy metals accumulator for metals in two selected soils different in texture and contamination levels. To enhance metals phyto-extraction, ammonium nitrate and organic chelators (EDTA, and citric acid) were added to soils at rates of 0 to 20 mmol kg. Pots experiment was run for 8 weeks. Plant dry matter production (biomass) and metals accumulation were varied with soil contamination levels, chelator form and rate, and soil type. The highest metals concentration of Cd and Ph was obtained in plants grown on clayey soil however, the lowest content was observed in the sandy soil. Addition of citric acids significantly increased metals accumulation and translocation to the shoots. Adding high rate of citric acid (20 mmol kg) to clayey soils increases metals accumulation in shoots several-fold of magnitude Citric acid was the most effective chelator of Cd and Pb metals that could enhance their accumulation in sunflower. Ammonium nitrate had low effect on metal translocation to shoots. In conclusion, the relationship between enhancing metal solubility in soils and plants, and feasible practices to minimize the risk of heavy metal leaching should be considered.
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