Effects of heavy metals on some proximate composition of Eichhornia crassipes

Effects of 8 heavy metals (Ag, Cd, Cr, Cu, Hg, Ni, Pb and Zn) on the total chlorophyll, foliar proline, and protein and starch contents of Eichhornia crassipes was investigated. Plantlets were grown in quarterstrength Hoagland’s solution and supplemented with 0, 0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 mM of each of the metals for 3 weeks. There was a significant reduction (p≤0.05) in total chlorophyll, protein and starch contents, while foliar proline increased significantly. These effects were however dependent on the nature of the metal, its concentration and duration of exposure.