Cadmium Tolerance and Phytoextraction Efficiency of Arum (Colocasia antiqourum) Grown in Spiked Cd Contaminated Soil

Md. Abul Kashem; S M Imamul Huq; Shigenao Kawai; Bal Ram Singh
A pot experiment was conducted to investigate the cadmium tolerance and phytoextraction efficiency of arum (Colocasia antiqourum) grown in soil spiked with cadmium (Cd) levels of 0, 5, 10, 25, 50, and 100 mg kg-1. Arum plants were grown for 105 days in the Cd contaminated soil. After harvest, the plants were separated into leaves, stems, bulbs and roots and dry mass of those were recorded. Dry matter yield was not affected by the application of Cd but Cd concentration in plant parts increased linearly with Cd application rates in soil. Without growth retardation, Cd concentrations in arum increased from 8.3 to 75 mg kg-1 in the leaves, 40 to 262 mg kg-1 in the stems, 4.3 to 55 mg kg-1 in the bulbs and 166 to 912 mg kg-1 in the roots, when Cd levels increased from 5 to 100 mg kg-1 in the soil. In the shoots (leaves and stems) of arum, Cd concentration was 137 and 168 mg kg-1 at the 50 and 100 mg kg-1 Cd supply levels in soils respectively. Those values were above the accepted threshold level of Cd hyper accumulator plants. Similar to Cd concentration, Cd accumulation (concentration × dry weight of plant) increased in different parts of arum with Cd application rates in the soil.Cadmium accumulation in the whole plant increased from 2.2 to 16.2 mg plant-1 when Cd levels in the soil increased from 5 to 100 mg kg-1 Cadmium accumulation in different parts of arum decreased in the order: root > stems > bulbs > leaves. Cadmium translocation from root to shoot was about 50% of the total Cd, showing a moderate mobility of Cd in arum, however, this plant is easy to harvest with roots. The outcomes of this study confirm that this plant is a suitable candidate for the phytoremediation of Cd contaminated soil.
Cadmium; Hyperaccumulator; Contaminated Soil; Phytoremediation
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