关键词: 木材形成, 木材形成组织, FTIR, XRD

Abstract: [Objective] This paper aimed to reveal the chemical features in early-stage wood forming tissue of some main commercial wood species, and its differences among species were also analyzed. [Method] Both FTIR and XRD were employed to investigate the spectrum properties in early-stage wood forming tissue of ten commercial tree species. [Result] The results showed that the principal differences were found in finger region with the wave number from 900 cm^-1 to 2000 cm^-1 of FTIR. The peaks at 1735 cm^-1 for unconjugated CO in xylans exhibited significantly lower relative intensities in softwoods than hardwoods species. The absorption bands at 1511 cm^-1 for aromatic skeletal in lignin showed obviously in softwoods, especially in Larix gmelinii and Picea jezoensis. Both in softwoods and hardwoods, the different intensities and broad peaks at 1630-1660 cm^-1 attributed to vibration of amide compounds in protein peptides. After infrared spectroscopy treated by second derivative, conifer showed significant peaks at 1266 cm^-1 due to ring plus CO vibration in guaiacyl but not in hardwood. However, hardwood showed obviously peaks at 1245 cm^-1 which resulted from syringyl ring and C-O stretch I lignin. X-ray diffraction spectrogram showed the relative high intensities at I₀₀₂, but no obvious peaks at I_am, especially in hardwood. Therefore, it is suggested that the differences should be exist in crystal form, crystal cell or size of crystalline region between early-stage wood forming tissue and mature wood. [Conclusion] The results indicated that there were differences in lignin and hemicellulose deposition in wood formation between softwoods and hardwoods. All these would be helpful to reveal the change patterns of chemicals and structure in wood cell wall development.

Key words: wood formation, wood forming tissue, FTIR, XRD