title: Effect of phosphogypsum on growth, physiology, and the antioxidative defense system in sunflower seedlings.
abstract: Phosphogypsum (PG) is the solid waste product of phosphate fertilizer production and is characterized by high concentrations of salts, heavy metals, and certain natural radionuclides. The work reported in this paper examined the influence of PG amendment on soil physicochemical proprieties, along with its potential impact on several physiological traits of sunflower seedlings grown under controlled conditions. Sunflower seedlings were grown on agricultural soil substrates amended with PG at rates of 0, 2.5, and 5 %. The pH of the soil decreased but electrical conductivity and organic matter, calcium, phosphorus, sodium, and heavy metal contents increased in proportion to PG concentration. In contrast, no variations were observed in magnesium content and small increases were recorded in potassium content. The effects of PG on sunflower growth, leaf chlorophyll content, nutritional status, osmotic regulator content, heavy metal accumulation, and antioxidative enzymes were investigated. Concentrations of trace elements in sunflower seedlings grown in PG-amended soil were considerably lower than ranges considered phytotoxic for vascular plants. The 5 % PG dose inhibited shoot extension and accumulation of biomass and caused a decline in total protein content. However, chlorophyll, lipid peroxidation, proline and sugar contents, and activities of antioxidant enzymes such as superoxide dismutase and catalase increased. Collectively, these results strongly support the hypothesis that enzymatic antioxidation capacity is an important mechanism in tolerance of PG salinity in sunflower seedlings.
authors.affiliation: Laboratory of Water, Energy and Environment, Higher Institute of Biotechnology of Sfax, Sfax University, Sfax, Tunisia. nadaelloumi@yahoo.fr.
authors.forename: Nada
authors.initials: N
authors.lastname: Elloumi
authors.affiliation: Laboratory of Botany and Cryptogamy, Faculty of Pharmacy, University of Limoges, GRESE EA 4330, 2 rue du Docteur Marcland, F-87025, Limoges, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Zouari
authors.affiliation: Laboratory of Water, Energy and Environment, National Engineering School of Sfax, Sfax, Tunisia.
authors.forename: Leila
authors.initials: L
authors.lastname: Chaari
authors.affiliation: Laboratory of Plant Biodiversity and Dynamic of Ecosystems in Arid Area, Faculty of Sciences of Sfax, B.P. 1171, Sfax, 3000, Tunisia.
authors.forename: Ferjani Ben
authors.initials: FB
authors.lastname: Abdallah
authors.affiliation: Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 3UU, Scotland, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Woodward
authors.affiliation: Laboratory of Water, Energy and Environment, National Engineering School of Sfax, Sfax, Tunisia.
authors.forename: Monem
authors.initials: M
authors.lastname: Kallel
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D002133:Calcium Sulfate / Q000032:analysis / Q000494:pharmacology*; D002734:Chlorophyll / Q000378:metabolism; D006368:Helianthus / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress; D010758:Phosphorus / Q000032:analysis / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000494:pharmacology; D014131:Trace Elements / Q000378:metabolism
chemical_list: D000975:Antioxidants; D012987:Soil; D012989:Soil Pollutants; D014131:Trace Elements; C077769:phosphogypsum; D002734:Chlorophyll; D010758:Phosphorus; D002133:Calcium Sulfate
keywords: Antioxidant activities; Heavy metals; Phosphogypsum; Plant growth; Soil amendment; Sunflower