[FTIR study of the endurance to Al of different soybean cultivars]

The spectra of root, stem, leaf of soybean samples with 0, 20, 40, 60 mg x L(-1) Al3+ were determined by Fourier transform infrared (FTIR) spectrometry with OMNI-sampler. Little difference was found in the spectra of leaf between two soybean cultivars, aluminum-resistant cultivar Zhechun NO. 2 and aluminum-sensitive cultivar Zhechun NO. 3, except the indices of wave number-absorbance from 928 to 1 200 cm(-1), and similar results were also observed in stem and root samples of the two soybean cultivars with 0 mg x L(-1) Al3+. However, results from the comparison of the spectra showed some distinguishable differences in the intensity and the shape of absorption peaks of their FTIR spectra from 721 to 3 366 cm(-1) of Al-stressed samples and control samples between the two soybean cultivars, and more evident differences of FTIR were exhibited in Al-stressed roots, stems and leaves with higher concentration of Al3+. The increased absorbance at 2 929 and 3 350 cm(-1) was found in root FTIR spectra with 20, 40, 60 mg x L(-10 Al3+, while roots got maximum absorbance at wave number of 1 375 cm(-1) with 20 mg x L(-1) Al3+, which decreased with higher concentration of Al3+, and the same results were showed at wave numbers of 1 410, 1 423, 1 549 and 1 645 cm(-1). Absorption peak showed maximum at wave numbers of 1 051, 2 850, 2 929 and 3 350 cm(-1) in stem FTIR spectra with 60 mg x L(-1) Al3+. There was little difference between the spectra of Al-stressed leaves and controls at wave numbers from 1 750 to 2 750 cm(-1), but visible difference in leaf spectra was exhibited at other wave number. Moreover, the results showed that the FTIR spectra of aluminum-sensitive cultivar Zhechun NO. 3 showed much more observable differences than aluminum-resistant cultivar Zhechun NO. 2 with different concentration of Al, implying that the material metabolic of aluminum-sensitive soybean was evidently affected by Al. Therefore, FTIR spectra could be used broadly for identification of the endurance of different soybean cultivars to Al.