Impacts of fungi on chemical components and physical structure of Paulownia elongata wood

The objective of this study was to evaluate the impacts of fungi on components and structure of Paulownia elongata wood and to control wood stain more effectively.The chemical components and physical structure of P.elongata wood were studied using wood component analyses and infrared spectra of Fourier Transform Infrared Spectroscopy (FTIR) and Electron Spectroscopy for Chemical Analysis (ESCA) for stained and unstained wood.Comparing stained to unstained wood, hot water extracts increased from 5.01% to 5.87%, cold water extracts from 2.10% to 3.47%, and 1% NaOH extracts increased from 18.19% to 20.48%.Lignin was maintained at almost the same level, while holocellulose decreased from 77.60% to 76.10%, but alpha-cellulose in the holocellulose remained roughly at the same level.Pentosan decreased from 26.13% to 22.75%, suggesting that semi-cellulose decreased.Infrared spectra of FTIR showed that the intensity of 1 744 and 1 734 cm^-1 became weak compared with stained P.elongata wood with CK;these two peaks were related to the absorption of C=O vibration, which implied that changes of some semi-cellulose and a small amount of cellulose took place.The intensity of lignin characteristic absorption peaks of 1 508, 1 270 and 1 266 cm^-1 (G type) was relatively stable and only a little change occurred.The intensity of amylose characteristic absorption peaks of 1 200, 1 153 and 1 112 cm^-1 decreased a little in stained P.elongata wood.It was concluded that semi-cellulose was degraded to some extent by fungi.ESCA showed that the C_1s peak area of stained P.elongata wood increased from 68.91% to 73.92%, C₁ changed slightly from 15.11% to 15.02%, C₂ and C₃ decreased obviously from 15.98% to 11.06%, and O_1s/C_1s decreased when compared to CK.The results of ESCA were consistent with FTIR and quantitative chemical component analyses.