title: Implication of organic acids in the long-distance transport and the accumulation of lead in Sesuvium portulacastrum and Brassica juncea.
abstract: The implication of organic acids in Pb translocation was studied in two species varying in shoot lead accumulation, Sesuvium portulacastrum and Brassica juncea. Citric, fumaric, malic and α-cetoglutaric acids were separated and determined by HPLC technique in shoots, roots and xylem saps of the both species grown in nutrient solutions added with 200 and 400 μM of Pb(II). The lead content of the xylem saps was determined by ICP-MS. Results showed that S. portulacastrum is more tolerant to Pb than B. juncea. Lead concentration in xylem sap of the S. portulacastrum was significantly greater than in that of B. juncea. For both species, a positive correlation was established between lead and citrate concentrations in xylem sap. However minor relationship was observed for fumaric, malic and α-cetoglutaric acids. In the shoots lead treatment also induced a significant increase in citric acid concentration. Both observations suggest the implication of citric acid in lead translocation and shoot accumulation in S. portulacastrum and B. juncea. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could explain its high potential to translocate and accumulate this metal in shoot suggesting their possible use to remediate Pb polluted soils.
authors.affiliation: Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia. tahar.ghnaya@gmail.com
authors.forename: Tahar
authors.initials: T
authors.lastname: Ghnaya
authors.forename: Hanen
authors.initials: H
authors.lastname: Zaier
authors.forename: Raoudha
authors.initials: R
authors.lastname: Baioui
authors.forename: Souhir
authors.initials: S
authors.lastname: Sghaier
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lucchini
authors.forename: Gian Attilio
authors.initials: GA
authors.lastname: Sacchi
authors.forename: Stanley
authors.initials: S
authors.lastname: Lutts
authors.forename: Chedly
authors.initials: C
authors.lastname: Abdelly
mesh_terms: D035722:Aizoaceae / Q000502:physiology*; D001692:Biological Transport; D019343:Citric Acid / Q000378:metabolism; D005650:Fumarates / Q000378:metabolism; D007854:Lead / Q000378:metabolism*; D009149:Mustard Plant / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism
chemical_list: D005650:Fumarates; D012989:Soil Pollutants; D019343:Citric Acid; D007854:Lead; C032005:fumaric acid