Phytotoxicity of trace metals (Cu & Cd) to Gram (Cicer arientinum) and Mung (Phaseolus mungo)

A simple, quantification of the inhibitory effects of Cu & Cd on germination and root elongation of mung (var. K-851) and gram (var. Uday), was carried out. From the data obtained in the presence of different concentration of metals, Germination Index (GI), Metal Tolerance Index (MTI), and Percent Phytotoxicity was calculated. Results showed that both the plants species had a reduced seed germination and root growth with increasing concentration of both the selected metals. In treated samples, maximum germination recorded was 98.8% (Cu) and 93.3% (Cu) and the minimum was 57.7% (Cd) and 17.7% (Cd) with mung and gram, respectively. The percent phytotoxicity was found in the range of 62.8 to 78.7 for Cu and 77.6 to 93.1 for Cd in case of gram whereas in case of mung percent phytotoxicity was found to be 85.0 to 96.0 and 79.5 to 89.5 for Cu and Cd respectively. The maximum metal tolerance index was found to be 37.16 (Cu) & 14.94 (Cu) and minimum was 6.76 (Cd) & 3.96 (Cu) for gram and mung respectively. The maximum germination index was found to be 3.2 (Cd) and 1.61 (Cu) and minimum was 0.11 (Cd) and 0.33 (Cu) for gram and mung respectively. These bio-assay techniques may be helpful in identifying the suitable tolerant and resistant plant species and toxicity assessment of contaminated water.