title: How does NaCl improve tolerance to cadmium in the halophyte Sesuvium portulacastrum?
abstract: Sesuvium portulacastrum is a halophyte with considerable Cd tolerance and accumulation, especially under high salinity. The species seems a good candidate for phytoremediation of Cd-contaminated, saline soils. However, the mechanisms sustaining salt-induced alleviation of Cd toxicity remain unknown. Seedlings of S. portulacastrum were submitted hydroponically to different Cd concentrations (0, 25 and 50 μM Cd) in combination with low (0.09 mM), or high (200 mM) NaCl. Cadmium distribution within leaves and stems was assessed by total Cd, cell sap Cd, and Cd in different cell fractions. In plants with low salt supply (LS) Cd induced severe toxicity. The presence of 200 mM NaCl (HS) significantly alleviated Cd toxicity symptoms. HS drastically reduced both Cd-induced H2O2 production and membrane damage. In HS plants the reduced Cd uptake was only in part responsible for the lower Cd toxicity. Even at equal internal leaf Cd concentrations less Cd toxicity was observed in HS than in LS plants. In HS plants proportionally more Cd was bound in cell walls and proportionally less accumulated in the soluble fraction than in LS plants. Our results show that NaCl improves plant performance under Cd stress by both a decrease of Cd(2+) activity in the medium leading to less Cd uptake and a change of Cd speciation and compartmentation inside tissues. More efficient internal detoxification seems mainly brought about by preferential Cd binding to chloride and cell walls in plants treated with a high salt concentration.
authors.affiliation: Laboratoire des Plantes Extremophiles (LPE), Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia; Departamento de Fisiologia Vegetal, Facultad de Ciencias, Universidad Autonoma de Barcelona, E-08193 Bellaterra, Spain.
authors.forename: Wali
authors.initials: W
authors.lastname: Mariem
authors.affiliation: Laboratoire des Plantes Extremophiles (LPE), Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia.
authors.forename: Ben Rjab
authors.initials: BR
authors.lastname: Kilani
authors.affiliation: Departamento de Fisiologia Vegetal, Facultad de Ciencias, Universidad Autonoma de Barcelona, E-08193 Bellaterra, Spain.
authors.forename: Gunsé
authors.initials: G
authors.lastname: Benet
authors.affiliation: Laboratoire des Plantes Extremophiles (LPE), Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia.
authors.forename: Lakdhar
authors.initials: L
authors.lastname: Abdelbasset
authors.affiliation: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Lutts
authors.initials: L
authors.lastname: Stanley
authors.affiliation: Departamento de Fisiologia Vegetal, Facultad de Ciencias, Universidad Autonoma de Barcelona, E-08193 Bellaterra, Spain.
authors.forename: Poschenrieder
authors.initials: P
authors.lastname: Charlotte
authors.affiliation: Laboratoire des Plantes Extremophiles (LPE), Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia.
authors.forename: Abdelly
authors.initials: A
authors.lastname: Chedly
authors.affiliation: Laboratoire des Plantes Extremophiles (LPE), Centre de Biotechnologies de la Technopole de Borj Cedria, BP 901, Hammam Lif 2050, Tunisia. Electronic address: Tahar.ghnaya@gmail.com.
authors.forename: Ghnaya
authors.initials: G
authors.lastname: Tahar
mesh_terms: D035722:Aizoaceae / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D055049:Salt Tolerance; D055051:Salt-Tolerant Plants / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium; D012965:Sodium Chloride
keywords: Cadmium tolerance; Cd speciation; Chloride; Salinity; Sesuvium portulacastrum; Subcellular distribution