Microscopic biomineralization processes and Zn bioavailability: a synchrotron-based investigation of Pistacia lentiscus L. roots

• Published in: Environmental science and pollution research international Vol. 22; no. 24; pp. 19352 - 19361
• Main Authors: De Giudici, G, Medas, D, Meneghini, C, Casu, M. A, Gianoncelli, A, Iadecola, A, Podda, S, Lattanzi, P
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2015; Springer Nature B.V
• Subjects: Absorption spectroscopy; Alteration and Element Mobility at the Microbe-Mineral Interface; aluminum; Aluminum - analysis; Aluminum - chemistry; Aluminum - metabolism; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bioavailability; Biodegradation, Environmental; biomineralization; coatings; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Epidermis; fluorescence; Investigations; Italy; Microscopy, Electron, Scanning; Mine tailings; Mineralization; Minerals; Mining; Organic soils; Phytoremediation; Pistacia - metabolism; Pistacia lentiscus; plant adaptation; Plant Roots - metabolism; pollutants; polluted soils; Pollution control; Rhizosphere; Roots; Scanning electron microscopy; silicon; Silicon - analysis; Silicon - chemistry; Silicon - metabolism; Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soil Pollutants - metabolism; Soil pollution; soil-plant interactions; Spectrum analysis; Toxicity; Trace elements; Waste Water Technology; Water Management; Water Pollution Control; X-ray absorption spectroscopy; X-Ray Diffraction; X-ray fluorescence; X-rays; Zinc; Zinc - analysis; Zinc - chemistry; Zinc - metabolism; Sardinia; Italy; Italy, Sardegna; MED, Italy; Cameroon, Sud, Campo; Metal bioavailability; Silicon; Aluminium; XAS; L; Plant biomineralization; μ-XRF; Zinc; Pistacia lentiscus L
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-015-4808-9

Plants growing on polluted soils need to control the bioavailability of pollutants to reduce their toxicity. This study aims to reveal processes occurring at the soil-root interface of Pistacia lentiscus L. growing on the highly Zn-contaminated tailings of Campo Pisano mine (SW Sardinia, Italy), in order to shed light on possible mechanisms allowing for plant adaptation. The study combines conventional X-ray diffraction (XRD) and scanning electron microscopy (SEM) with advanced synchrotron-based techniques, micro-X-ray fluorescence mapping (μ-XRF) and X-ray absorption spectroscopy (XAS). Data analysis elucidates a mechanism used by P. lentiscus L. as response to high Zn concentration in soil. In particular, P. lentiscus roots take up Al, Si and Zn from the rhizosphere minerals in order to build biomineralizations that are part of survival strategy of the species, leading to formation of a Si-Al biomineralization coating the root epidermis. XAS analysis rules out Zn binding to organic molecules and indicates that Zn coordinates Si atoms stored in root epidermis leading to the precipitation of an amorphous Zn-silicate. These findings represent a step forward in understanding biological mechanisms and the resulting behaviour of minor and trace elements during plant-soil interaction and will have significant implications for development of phytoremediation techniques.