Investigation of the manganese stress on wheat plant by attenuated total reflectance Fourier transform infrared spectroscopy

The present paper deals with the investigation of the changes in chemical contents of the leaf of wheat seedling stressed by excess manganese using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR) technique. The infrared spectra of the leaves of control and manganese-treated wheat plants have been recorded in the spectral region 485-4000 cm(-1) at a resolution of 4 cm(-1). The recorded spectrum has been analyzed with the help of curve-fitting method for the quantitative estimation of chemical contents and conformational changes. The study indicated changes arising in the polysaccharide, lignin, amino acid, secondary structure of protein, and lipid in the leaves of control and manganese-treated wheat plants. Manganese treatment increased the amount of cellulose, lignin, and amide II till 200 mu M concentration, while a decrease was observed at 1000 mu M concentration. Manganese induced conformational changes in the secondary structure of protein which was indicated by shifting of the bands to the higher wavenumber and change in the beta sheet/alpha helix ratio. In addition, manganese stress decreased lipid content in the leaves of the wheat seedlings. The study demonstrates the potential of attenuated total reflectance FTIR for the non-invasive and rapid monitoring of the plants stressed with heavy metals.