ABSTRACT
Heavy metals are defined as metallic elements with atomic number higher than 20, but 12 of them are widely known as environmental pollutants due to their release by industry: Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, and Zn. Within this group Cd, Cu, Fe, Hg, Ni, Pb, and Zn are usually considered as potentially hazardous for plants and animals, despite the fact that most of them (Cu, Fe, Ni, and Zn) are known as essential elements necessary for plant and animal metabolism (1-3). In general, biodiversity in plant response to heavy metals will be discussed in this chapter. Nonetheless, some particularly important responses to A1-nonheavy, but well known as a very toxic metal-are also described. Some plants, like Arabidopsis sp. (a model organism in plant molecu lar biology), Thlaspi sp. (hyperaccumulator), or such popular experimental mate rial as Brassica sp., Lactuca sp., or Raphanus sp. belong to the Brassicaceae
family, and their responses to metals are described in detail by Di Toppi et al. in Chapter 8 of this book.
