Mineral phases and element composition of the copper hyperaccumulator lichen Lecanora polytropa

Abstract

Mineral phases and element localization were investigated in the vivid turquoise-coloured lichen, Lecanora polytropa, sampled from a psammite boulder in a wall supporting mine spoil at the abandoned copper mine, Riddarhyttan Kopparverke, southern Sweden. Normally pale yellowish (usnic acid), the lichen is turquoise coloured internally with bluish inclusions. X-ray mapping shows that Cu occurs on and within the lichen and does not coincide with P or S, suggesting that it is indeed associated with carbon or other elements not detected (or reported) using X-ray mapping. Scanning electron microscopy in back-scatter mode confirmed that the greatest Cu concentrations occur in the form of crystalline aggregates in coloured inclusions below the major internal turquoise layer with smaller Cu contents. X-ray diffraction with a position-sensitive detector (XRD-PSD) confirmed coloured crystalline aggregates consisted of the copper oxalate, moolooite. The study confirms the value of XRD-PSD as a non-destructive tool to characterize small (~50 μm) metal oxalate inclusions obtained from within lichen samples.

Compartmentation and complexation of metals in hyperaccumulator plants

“…One such example are anthocyanins, which have been shown to be associated with molybdenum accumulation (Hale et al, 2001). Another such case is oxalate, which was first shown to bind copper in copper (Cu)-tolerant lichens and fungi (Chisholm et al, 1987; Fomina et al, 2005; Purvis et al, 2008) and also has been reported [by X-ray absorption spectroscopy (XAS) studies] to be the major ligand for manganese in Phytolacca acinosa Roxb. and Phytolacca americana (Phytolaccaceae; Dou et al, 2009; Xu et al, 2009).…”

Phytoremediation of Copper-Contaminated Soil

“…The most interesting plants include Lecanora polytropa ( Purvis et al 2008 ), Polycarpaea longifl ora , Hyptis capitata, and Nicotiana tabacum (Nedelkoska and Doran 2000 ), Elsholtzia haichowensis (Lou et al 2004 ), Crassula helmsii (Küpper et al 2009 ), Helianthus annuus L. and Kalanchoe serrata L. (Wilson-Corral et al 2011 ) as well as the moss Scopelophila cataractae (Nakajima et al 2011 ), which have very many unique genetic and biochemical properties. The use of different hyperaccumulating plant species in decontamination of Cu-polluted areas is considerably limited by the generally too low biomass of these plants (Miransari 2011 ), but in our opinion when we are able to identify hyperaccumulating genes and make use of them in relation to high biomass-producing plants, this situation will change.…”

Phytoremediation

“…The most interesting plants include Lecanora polytropa ( Purvis et al 2008 ), Polycarpaea longifl ora , Hyptis capitata, and Nicotiana tabacum (Nedelkoska and Doran 2000 ), Elsholtzia haichowensis (Lou et al 2004 ), Crassula helmsii (Küpper et al 2009 ), Helianthus annuus L. and Kalanchoe serrata L. (Wilson-Corral et al 2011 ) as well as the moss Scopelophila cataractae (Nakajima et al 2011 ), which have very many unique genetic and biochemical properties. The use of different hyperaccumulating plant species in decontamination of Cu-polluted areas is considerably limited by the generally too low biomass of these plants (Miransari 2011 ), but in our opinion when we are able to identify hyperaccumulating genes and make use of them in relation to high biomass-producing plants, this situation will change.…”