title: Effects of organic ligands on Pb absorption and speciation changes in Arabidopsis as determined by micro X-ray fluorescence and X-ray absorption near-edge structure analysis.
abstract: Pb can pass through the food chain via plants and threaten human health, which has attracted widespread attention. Changes in Pb speciation affect its bioavailability in soils and water. However, whether organic ligands can change the uptake and mobility of Pb in plants and increase or decrease Pb bioavailability remains uncertain. To reveal the roles of organic and inorganic Pb in Pb metabolism in plants, the localization and speciation changes of Pb in Arabidopsis thaliana plants grown in organic and inorganic Pb were characterized by synchrotron radiation micro X-ray fluorescence and X-ray absorption near-edge structure, respectively. These results demonstrated that Arabidopsis absorbed more Pb from Pb(NO3)2than Pb(CH3COO)2at the same exposure concentration. A higher percentage of Pb-citrate was found in Arabidopsis exposed to inorganic Pb solution, which suggested that Pb-citrate was the main complex for root-to-shoot transportation in Arabidopsis exposed to inorganic Pb solutions. Pb complexed with the organic ligand CH3COO-significantly inhibited primary root growth and lateral root development, while, at the same time, Pb was blocked by root hairs, which represented another way to reduce Pb absorption and protect the plant from biotoxicity.
authors.affiliation: National Research Center of Geoanalysis, 26# Xicheng District, Beijing 100037, People's Republic of China.
authors.forename: Ya Ting
authors.initials: YT
authors.lastname: Shen
authors.affiliation: National Research Center of Geoanalysis, 26# Xicheng District, Beijing 100037, People's Republic of China.
authors.forename: Yu Fang
authors.initials: YF
authors.lastname: Song
mesh_terms: D017360:Arabidopsis / Q000737:chemistry*; D005453:Fluorescence; D007854:Lead; D008024:Ligands; D014965:X-Rays
chemical_list: D008024:Ligands; D007854:Lead
keywords: XANES; bioavailability; iron plaque; lead; lead acetate; plant; speciation; µ-XRF