title: Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants (Solanum lycopersicum).
abstract: The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 micromol/L CdCl2 associated to different concentrations of ZnCl2 (10, 50, 100, and 150 micromol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cd-treated plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial effect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their effect on plant growth parameters and oxidative stress.
authors.affiliation: Unit of Research "Nitrogenized Nutrition and Metabolism and Stress Proteins" UR 99/09-20, Department of Biology, Faculty of Science, University of Tunis, Tunis 2092, Tunisia. jaouhra.cherif@yahoo.fr
authors.forename: Jaouhra
authors.initials: J
authors.lastname: Cherif
authors.forename: Chamseddine
authors.initials: C
authors.lastname: Mediouni
authors.forename: Wided
authors.initials: W
authors.lastname: Ben Ammar
authors.forename: Fatma
authors.initials: F
authors.lastname: Jemal
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D018533:Biomass; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D015032:Zinc / Q000378:metabolism / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D002104:Cadmium; D002734:Chlorophyll; D002338:Carotenoids; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D015032:Zinc