Concentration and biotransformation of arsenic by Prosopis sp. grown in soil treated with chelating agents and phytohormones
The aim of the present research was to study the effects of cysteine (Cys), cyclohexylenedinitrotetraacetic acid (CDTA), nitrilotriacetic acid (NTA), and kinetin (KN) on the arsenic (As) concentration and speciation in mesquite (Prosopis sp.) grown in soil containing 30 ppm (parts per million) of As III or 50 ppm of AsV. Inductively coupled plasmaoptical emission spectroscopy (ICP-OES) determinations revealed that, compared with As alone, roots of plants treated with 2.5 mM CDTA or 0.5 mM of Cys + 100 μM KN increased total As concentration from AsIII by ∼20 and 36% and from AsV by 100 and 65%, respectively. Liquid chromatographyinductively coupled plasmamass spectrometry (LC-ICP-MS) studies revealed that in roots, AsIII remained without change, whereas both AsIII and AsV were found in plants grown with As V. X-ray absorption spectroscopy (XAS) studies revealed that As within plants was mainly coordinated to three sulfur atoms, with interatomic distances of 2.26 Å. Results suggests that Cys + KN increased the mesquite tolerance to AsV, because plants grown in AsV had roots of similar size to plants grown without As. © CSIRO 2008.