title: Phytoextraction of contaminated urban soils by Panicum virgatum L. enhanced with application of a plant growth regulator (BAP) and citric acid.
abstract: Lead (Pb) contamination in soil represents a threat to human health. Phytoextraction has gained attention as a potential alternative to traditional remediation methods because of lower cost and minimal soil disruption. The North American native switchgrass (Panicum virgatum L.) was targeted due to its ability to produce high biomass and grow across a variety of ecozones. In this study switchgrass was chemically enhanced with applications of the soil-fungicide benomyl, chelates (EDTA and citric acid), and PGR to optimize phytoextraction of Pb and zinc (Zn) from contaminated urban soils in Atlanta, GA. Exogenous application of two plant hormones was compared in multiple concentrations to determine effects on switchgrass growth: indole-3-acetic acid (IAA), and Gibberellic Acid (GA3), and one PGR benzylaminopurine (BAP), The PGR BAP (1.0 μM) was found to generate a 48% increase in biomass compared to Control plants. Chemical application of citric acid, EDTA, benomyl, and BAP were tested separately and in combination in a pot experiment in an environmentally controlled greenhouse to determine the efficacy of phtyoextraction by switchgrass. Soil acidification by citric acid application resulted in highest level of aluminum (Al) and iron (Fe) in plants foliage resulting in severe phytotoxic effects. Total Pb phytoextraction was significantly highest in plants treated with combined chemical application of B + C and B + C + H. Suppression of AMF activities by benomyl application significantly increased concentrations of Al and Fe in roots. Application of benomyl reduced AMF colonization but was also shown to dramatically increase levels of septa fungi infection as compared to Control plants.
authors.affiliation: Georgia Highlands College, Cartersville Campus, 5441 Highway 20 NE, Cartersville, GA 30121, USA; Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, 370 Paulding Ave. NW, Kennesaw, GA 30144, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Aderholt
authors.affiliation: Department of Molecular and Cellular Biology, Kennesaw State University, 370 Paulding Ave. NW, Kennesaw, GA 30144, USA.
authors.forename: Dale L
authors.initials: DL
authors.lastname: Vogelien
authors.affiliation: Department of Chemistry and Biochemistry, Kennesaw State University, 370 Paulding Ave. NW, Kennesaw, GA 30144, USA.
authors.forename: Marina
authors.initials: M
authors.lastname: Koether
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, 370 Paulding Ave. NW, Kennesaw, GA 30144, USA. Electronic address: sgreipss@kennesaw.edu.
authors.forename: Sigurdur
authors.initials: S
authors.lastname: Greipsson
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D019343:Citric Acid / Q000494:pharmacology; D005875:Gibberellins / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D007854:Lead / Q000032:analysis / Q000493:pharmacokinetics; D019216:Metals, Heavy / Q000032:analysis / Q000493:pharmacokinetics; D008897:Panicum / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D005875:Gibberellins; D007210:Indoleacetic Acids; D019216:Metals, Heavy; D010937:Plant Growth Regulators; D012989:Soil Pollutants; D019343:Citric Acid; D007854:Lead; C030737:indoleacetic acid; C007842:gibberellic acid
keywords: Biomass production; Lead; Phytoextraction; Plant growth regulator; Soil acidification; Switchgrass