Use of Plasma-Based Spectroscopy and Infrared Microspectroscopy Techniques to Determine the Uptake and Effects of Chromium(III) and Chromium(VI) on Parkinsonia Aculeata

Abstract

Chromium uptake and tolerance by Mexican Palo Verde (Parkinsonia aculeata) (MPV) was studied in a six-month experiment with Cr(III) and Cr(VI) at 60 and 10 mg kg⁻¹, respectively. Chromium and nutrient uptake were determined by ICP-OES and changes in macromolecules were studied by infrared microspectroscopy (IMS). In the Cr(VI)-treated plants, chromium concentration increased in the roots only through the third month, while translocation to stems increased constantly throughout the six months. Cr(III) applications decreased the amount of Zn in leaves and stems (p ≤ 0.05). Cr(VI) increased P and S in all plant tissues and increased Ca in roots, but decreased Ca in stems and leaves, and Mg in roots and stems. Cr(III) decreased P in stems and leaves, while both Cr ions decreased K in all MPV tissues. Relative to untreated plant tissue, the IMS revealed significant changes at 1730 cm⁻¹ and 845 cm⁻¹. Changes at 1730 cm⁻¹ indicated that the cortex and xylem of Cr-treated plants were more proteinaceous. Changes at 845 cm⁻¹ revealed higher lignifications in cortex. However, at the stem level, Cr(VI) decreased lignin deposition in xylem. The data showed that MPV could be useful in the phytoremediation of Cr in moderately impacted soils.

KEY WORDS:

• chromium
• Mexican Palo Verde
• phytoremediation
• FTIR Microscope
• ICP-OES

ACKNOWLEDGEMENTS

This material is based upon work supported by the National Science Foundation and the Environmental Protection Agency under Cooperative Agreement Number EF 0830117. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Environmental Protection Agency. J. Gardea also acknowledges the USDA grant # 2008-38422-19138, the LERR and STARs programs of the UT System, the Toxicology Unit of the BBRC (NIH NCRR Grant # 2G12RR008124-16A1), the NSF Grant # CHE-0840525, and the Dudley family for the Endowed Research Professorship in Chemistry.