Non-Destructive Assessment of the Impact of Selenium Treatment on the Biochemical Profile of the Leaves of Wheat Seedlings by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

Abstract

The study aims at exploring the potential of attenuated total reflectance Fourier transform infrared spectroscopy for the sensitive, nondestructive, rapid, and simultaneous multi-component pre-symptomatic toxicological assessment in terms of changes in the biochemical composition of leaves of the laboratory grown wheat seedlings induced by the exposure of selenium. The infrared spectra of the leaves of control and selenium treated wheat seedlings have been recorded in the spectral region from 4000 to 400 cm⁻¹. Principal component analysis applied on the infrared measurements reveals that there are significant biochemical differences between the control and selenium treated seedlings. The spectral analysis reveals that treatment with selenium alters the position and intensity of infrared spectral signatures of the leaves of the wheat seedlings. The treatment with selenium decreases the level of xyloglucan, cellulose, pectin, proteins, and lipids in the leaves of wheat seedlings. In addition, it also decreases the amount of carbonyl and lignin compounds at 0.2 to 0.6 mM selenium concentrations but a significant increase is observed in the level of these biochemicals  at 1.0 mM selenium concentration. The decrease in the amount of hemicellulose at 0.4 to 0.6 mM selenium treatment while an increase at 0.8 to 1.0 mM selenium treatment is observed with the shift in the spectral signature depict change in the molecular mass of hemicellulose. The obtained results in terms of spectral features are expected to increase the existing spectral database for the assessment of elemental stress in plants and provide a mechanistic overview of the changes taking place in plants as result of overdose of trace element exposure to crops.

Keywords:

• Attenuated total reflectance Fourier transform infrared spectroscopy
• biochemical analysis
• selenium
• wheat seedlings

Acknowledgements

The authors are thankful to UGC, New Delhi for providing financial assistance for creating attenuated total reflectance Fourier transform infrared spectroscopy facility under the UGC–CAS and DST-PURSE program to the Department of Physics, University of Allahabad, Allahabad. We are also grateful to Prof. M. M. Joshi and Prof. R. Gopal, former Head, Department of Physics, University of Allahabad, Allahabad for their keen interest in this work. One of us (Sweta Sharma) is also grateful to UGC, New Delhi for the financial assistance in form of SRF (NET, UGC) scholarship.