Mechanisms Of Metal Tolerance In Higher Plants

Several heavy metals and metalloids, such as iron, manganese, zinc, copper, and molybdenum are essential micronutrients, whereas others such as aluminium, cadmium, arsenic, uranium, lead, thallium, chromium, mercury, silver, and gold are not. Nickel, cobalt, and vanadium may be essential for a limited number of species.1 A common characteristic of heavy metals in general, regardless of whether they are biologically essential or not, is that they may already exert toxic effects in low concentrations, compared with macro-nutrients.