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

Mercury uptake, distribution and translocation mechanisms in plants of Trit icum durum were studied after treatments with Hg-203(NO3)(2) (mercuric nitr ate). Results show that the highest mercury levels are observed in the root s or in the leaves depending on the way by which mercury was subministrated to the plants (i.e. by water or air, respectively). Autoradiographic exper iments on histological sections show that mercury is preferentially bound t o the cell walls of the outer layers of the root cortical cylinder; moreove r, 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 epi dermal and stomatal cell walls and on parenchyma cell nuclei. DNA extracted from Hg-203-treated leaves was analyzed in Cs2SO4 gradients and it was obs erved that mercury is preferentially linked to certain DNA families. (C) 19 99 Elsevier Science B.V. All rights reserved.