Mercury uptake, distribution and DNA affinity in durum wheat Triticum durum Desf./ plants

Mercury uptake, distribution and translocation mechanisms in plants of Triticum durum were studied after treatments with 203Hg NO . mercuric nitrate.. Results show that the highest mercury levels are observed in the 3 2 roots or in the leaves depending on the way by which mercury was subministrated to the plants i.e. by water or air, respectively.. Autoradiographic experiments on histological sections show that mercury is preferentially bound to the cell walls of the outer layers of the root cortical cylinder; moreover, labeling is also observed in the outer layer of the central cylinder and in the parenchyma cell nuclei. In the leaf, mercury is incorporated on epidermal and stomatal cell walls and on parenchyma cell nuclei. DNA extracted from 203Hg-treated leaves was analyzed in Cs2SO4 gradients and it was observed that mercury is preferentially linked to certain DNA families.