title: Response of Pistia stratiotes to heavy metals (Cr, Ni, and Zn) and phosphorous.
abstract: The effects of Cr, Ni, Zn, and P exposure on the root anatomic structure, growth, and chlorophyll a concentration of Pistia stratiotes L. were studied. Plastic aquaria containing 50 g of wet plants and 5 L of pond water added with the contaminant(s) were disposed. The treatments were: (1) Cr, (2) Ni, (3) Zn, (4) P, (5) Cr + Ni + Zn, (6) Cr + Ni + Zn + P, and (7) control. Contaminant additions were done seven times. In each addition, concentrations of 1 mg of metals or 5 mg of P per liter of water were added. Chlorophyll a was an indicator more sensitive to Zn and Cr toxicity than the relative growth rate. Ni and Cr + Ni + Zn treatments were the most toxic ones, in which biomass and the root anatomical parameters (root length, cross-sectional areas [CSAs] of root, stele, and metaxylem vessels) decreased significantly. The addition of P to the treatment with combined metals attenuated the decrease in plant growth and root length, and caused a significant increase in CSAs of total metaxylem vessels, suggesting that P increased the tolerance of P. stratiotes to metals. This fact has important implications for the use of this macrophyte in constructed wetlands for industrial wastewater treatment.
authors.affiliation: Química Analítica, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe (3000), Argentina. mmufarrege@fiq.unl.edu.ar
authors.forename: M M
authors.initials: MM
authors.lastname: Mufarrege
authors.forename: H R
authors.initials: HR
authors.lastname: Hadad
authors.forename: M A
authors.initials: MA
authors.lastname: Maine
mesh_terms: D029064:Araceae / Q000033:anatomy & histology / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D002857:Chromium / Q000633:toxicity; D019216:Metals, Heavy / Q000378:metabolism / Q000633:toxicity*; D009532:Nickel / Q000633:toxicity; D010758:Phosphorus / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015032:Zinc / Q000633:toxicity
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002857:Chromium; D002734:Chlorophyll; D010758:Phosphorus; D009532:Nickel; D015032:Zinc; D000077194:Chlorophyll A