[Effects of Cd stress on FTIR spectra and physiological traits of Hypnum fertile Sendtn].

In the present paper, Fourier transform infrared spectrometer was applied to gain the infrared spectra of Hypnum fertile Sendtn. samples with different concentration of Cd2+ for 7 days to study the changes in chemical components, and some physiological characteristics such as malondialdehyde (MDA), solubility sugar (SS) and solubility protein (Pr) were also studied. Malondialdehyde and solubility sugar were measured by anthrone colorimetry and solubility protein was measured by brilliant blue and commassie dye. The results showed that with the enhancement of Cd2+ concentration, the contents of solubility sugar and solubility protein were enhanced at first and then decreased. However, it was just the opposite for the content of malondialdehyde. Based on the indices of wave number-absorbance, the infrared spectra of samples with different concentration of Cd2+ were compared in terms of changes in the physiological characteristics. The two bands at 2 920 and 2 855 cm(-1) in the CH stretching region (3 000-2 800 cm(-1)) of the spectra denote the asymmetric and symmetric lipid CH2 stretching vibrations, whose band height's variety was related to the change in malondialdehyde content in plant. The distinctive amide-I band at 1 635 cm(-1) and amide-II band at 1 545 cm(-1) arise from endogenous proteins. In the region below 1 500 cm(-1), a variety of characteristic IR group frequencies can be observed that are difficult to assign but the shape of the spectra in this region is characteristic and can be used as a "finger print" of the tissue. The band at 1 036 cm(-1)-C-O, -C-C or CH stretching region of the spectra denotes the carbohydrate related to the content of solubility sugar. The results showed that there was good correspondence between the changes in the physiological characteristics and the changes of samples based on the indices of wave number-absorbance of FTIR spectra, and the FTIR was more sensitive and convenient. Therefore, Fourier transform infrared spectrometry can be accepted as a fast and effective method to study bryophytes for monitoring the pollution degree of heavy metal in environment.