[Studies on the physiological response of Phytolacca americana to manganese toxicity by FTIR spectroscopy].

A technique based on Fourier transform infrared (FTIR) spectrometry was used to detect the physiological changes in chemical composition of Phytolacca americana under a wide range of Mn2+ treatments (0, 0.125, 0.25, 0.5 and 1 g x kg(-1)). Using the roots, stems and leaves of phytolacca americana, absorption bands corresponding to carbohydrates, ester and proteins varied differently. The absorption band heights at 3 000 and 2 916 cm(-1) of stem tissues rose firstly and then decreased, indicating the exudation and transporting situation of organic substances which served as organic osmotic contents to enhance manganese tolerance under low treatments; Meanwhile, the band heights at 2 922 cm(-1) (roots) and 1 606 cm(-1) (leaves) which have different tendency in accordance with Mn treatments showed that the capability to chelate Mn decreased under higher manganese concentration. In addition, the changes of the bands at 1 732 and 1 026 cm(-1) (roots), 1 028 cm(-1) (stems), 1 052 and 967 cm(-1) (leaves) differed from each other, suggesting that under the conditions of severe Mn stress the ex-oxidation of membrane lipid increased; Otherwise, the band heights at 1 375 cm(-1) increased firstly and then decreased, representing that the cell wall improved Mn resistance by increasing cation-exchange capacity (CEC). The result also implied that it is practical to apply FTIR to the research comparing the chemical differences of phytoaccumulators under metal treatments.