title: Phragmites sp. physiological changes in a constructed wetland treating an effluent contaminated with a diazo dye (DR81).
abstract: The role of Phragmites sp. in phytoremediation of wastewaters containing azo dyes is still, in many ways, at its initial stage of investigation. This plant response to the long-term exposure to a highly conjugated di-azo dye (Direct Red 81, DR81) was assessed using a vertical flow constructed wetland, at pilot scale. A reed bed fed with water was used as control. Changes in photosynthetic pigment content in response to the plant contact with synthetic DR81 effluent highlight Phragmites plasticity. Phragmites leaf enzymatic system responded rapidly to the stress imposed; in general, within 1 day, the up-regulation of foliar reactive oxygen species-scavenging enzymes (especially superoxide dismutase, ascorbate peroxidase (APX), glutathione peroxidase (GPX) and peroxidase) was noticed as plants entered in contact with synthetic DR81 effluent. This prompt activation decreased the endogenous levels of H₂O₂ and the malonyldialdehyde content beyond reference values. Glutathione S-transferase (GST) activity intensification was not enough to cope with stress imposed by DR81. GPX activity was pivotal for the detoxification pathways after a 24-h exposure. Carotenoid pool was depleted during this shock. After the imposed DR81 stress, plants were harvested. In the next vegetative cycle, Phragmites had already recovered from the chemical stress. Principal component analysis (PCA) highlights the role of GPX, GST, APX, and carotenoids along catalase (CAT) in the detoxification process.
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: Renata Alexandra
authors.initials: RA
authors.lastname: Ferreira
authors.forename: Joana Gouveia
authors.initials: JG
authors.lastname: Duarte
authors.forename: Pompilio
authors.initials: P
authors.lastname: Vergine
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Antunes
authors.forename: Filipe
authors.initials: F
authors.lastname: Freire
authors.forename: Susete
authors.initials: S
authors.lastname: Martins-Dias
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism; D001391:Azo Compounds / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002374:Catalase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D018384:Oxidative Stress; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000378:metabolism; D006109:Poaceae / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D015854:Up-Regulation; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification; D053833:Wetlands
chemical_list: D001391:Azo Compounds; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C062246:Direct Red 81; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase