Phytoextraction Efficiency of Lead by Arum (<i>Colocasia esculenta</i> L.) Grown in Hydroponics

Abstract

Lead (Pb) tolerance and phytoextraction efficiency of arum (Pani Kachu; Colocasia esculenta L . ) were investigated in hydroponics. Plants were grown for 60 days in nutrient solution after addition of Pb at the levels of 0, 50, 200 and 400 μM. The growth of different parts of arum was unaffected at low level of Pb concentration (50 μM Pb) compared with control treatment whereas it decreased gradually with the increase of metal concentration in nutrient solution. Concentration of metal in all parts of arum increased significantly with the levels of Pb in the growth media ( p < 0.05). In arum shoots, Pb concentration was 1121 mg &#183 kg &#45 1 , at its low level in solution. This concentration (50 μM Pb) did not cause any growth retardation which indicated that arum was a Pb hyperaccumulator plant. On an average, translocation of Pb from roots to shoots was 68% of total Pb which indicated that the major portion of Pb was translocated from roots to shoots. Transfer factor (TF) greater than one for this metal as found in the present experiment confirmed the hyperaccumulation characteristics of arum. Lead uptake in the shoots of arum without growth retardation and TF of Pb in arum indicated that this plant was a suitable candidate for the phytoremediation of soil and water contaminated with Pb.