近红外光谱技术在牧草育种研究中的应用前景

近红外光谱技术(NIRS)是一种快速、高效、无损的现代检测技术,已经在许多领域广泛应用.简要介绍了NIRS的基本原理、特点以及应用于牧草育种研究的意义,阐述了NIRS在牧草营养品质改良、次生代谢产物分析、病虫害抗性分析、抗逆能力评价等牧草育种方面的应用现状和前景.     

Infrared spectroscopic study of alkaline oxygen treatment of lignin with ATR technique in aqueous state 1: method for determining quantitative spectra of oxygen-degraded lignin

For the fundamental study of oxygen delignification of kraft pulp, structural changes of kraft lignin during alkaline oxygen treatment were investigated with the use of infrared measurement with attenuated total reflectance (ATR) technique. In the neutralized reaction mixture of alkaline oxygen-treated kraft lignin, there is a significant amount of NaCl, so that the spectral changes of water due to the coexistence of NaCl was investigated, and how to remove the huge absorption of NaCl solution is discussed. Sodium vanillate–NaCl solutions were employed as model solutions for the reaction mixture. Partial least square (PLS) regression was applied for the prediction of NaCl concentration, and the spectrum of NaCl solution was subtracted from the spectrum of sodium vanillate–NaCl solution as background measurement. This allowed us to obtain the vanillate spectra free from the absorption of NaCl solution. In addition, the mathematical method for reconstructing the spectrum of NaCl solution is discussed. The spectrum of NaCl solution is reconstructed as the linear combination of basic spectra calculated by singular value decomposition (SVD), and it was subtracted from that of the sodium vanillate–NaCl solution. By this procedure, the vanillate spectra were also obtained quantitatively, as has been demonstrated in PLS regression study. It was also confirmed that the quantitative spectra of high molecular weight fraction of alkaline oxygen-treated kraft lignin were obtained by the use of this reconstruction technique.Parts of this report were presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, Japan, April 2002 and the 12th International Symposium on Wood and Pulping Chemistry, Madison, USA, June 2003     

Spectrophotometrical characteristics in the near infrared region in beech (<Emphasis Type="Italic">Fagus crenata</Emphasis>) and pine (<Emphasis Type="Italic">Pinus densiflora</Emphasis>) litters at the various decomposing stages

We examined the relationships between the absorptional characteristics in the near infrared region and the chemical changes of decomposing beech (Fagus crenata) and pine (Pinus densiflora) litters. Spectra as well as the concentrations of chemical substances approached each other and converged with decomposition, although both initial characteristics differed markedly between beech and pine. This indicated that the fundamental chemical structures were almost the same, although their organochemical composition differed. Specific absorption bands for lignin, polysaccharide, and protein were identified at 2,140 and 1,670 nm, 2,270, 1,720, 1,590, and 1,216 nm, and 2,350 nm, respectively. Absorbance at 1,670 nm, peculiar band of aromatics, showed a positive correlation with lignin concentration, which suggested the relative increment of aromatics due to condensed lignin in decomposing litters. Absorbance at 2,140 nm, characterized as the C–H bond in HRC = CHR, showed a negative correlation with lignin concentration, which suggested the decrements of some structures such as side-chains in lignin polymers unrelated to aromatics. Absorbance at 2,270, 1,720, and 1,216 nm, specified to O–H/C–O/C–H bonds in saccharide, might reflect the change of polysaccharide during decomposition because they showed a positive correlation to polysaccharide concentration. In the same way, absorbance at 2,350 nm, identified to the C–H/CH₂ bonds in protein, showed a negative correlation to nitrogen concentration in decomposing litters, which might indicate that the C–H/CH₂ bonds in protein decreased with decomposition due to microbial consumption of carbon in protein. Our findings suggested the possibility that the spectral changes indicate the litter digestibility during decomposition and that also explain the compositional change in decomposing litters.     

Decomposition of needle/leaf litter from Scots pine, black cherry, common oak and European beech at a conurbation forest site

Litter decomposition was studied for 2 years in a mixed forest serving as a water protection area (Rhine-Neckar conurbation, SW Germany). Two experiments differing in initial dry weight equivalent in litterbags were set up: one to compare decomposition of European beech leaves (Fagus sylvatica) with common oak leaves (Quercus robur), and the other comparing decomposition of Scots pine needles (Pinus sylvestris) with black cherry leaves (Prunus serotina Ehrh.), respectively. Mass losses were greater for oak litter than for beech (75.0 versus 34.6%), and for cherry litter than for pine (94.6 versus 68.3%). In both experiments, a strong initial loss of soluble compounds occurred. The changes in litter N and P concentrations and the decrease in C-to-N ratio coincided with changes in residual mass. However, neither tannin and phenolic concentrations nor NMR could explain the pronounced variation in mass loss after 2 years. Differences in litter palatability and toughness, nutrient contents and other organic compounds may be responsible for the considerable differences in residual mass between litter types. The fast decay of black cherry leaves appears to play a major role in the present humus dynamics at the studied site. Since black cherry has a high N demand, which is mainly met by root uptake from the forest floor, this species is crucial for internal N cycling at this conurbation forest site. These effects together may significantly contribute to prevent nitrate leaching from the forest ecosystem which is subject to a continuous N deposition on an elevated level.     

醋酸水溶液处理对杉树材影响

为了研究醋酸水溶液处理给杉树材重量带来的变化,使用醋酸水溶液对杉树材进行了处理。结果发现处理后杉树材重量的减小量大约等于抽出物的重量,而且随着醋酸水溶液浓度的增加而增加。利用傅立叶变换红外光谱法对处理后的杉树材及抽出物进行了光谱分析。从处理后杉树材的光谱图可以观察到3400cm-1附近的OH伸缩振动及1510cm-1附近的木质素中苯环C=C伸缩振动的吸收强度有增加倾向。从醋酸水溶液抽出物光谱图可以发现用浓度30%醋酸水溶液处理时木质素被溶出。图2表2参6。     

Distribution of boron in wood treated with aqueous and methanolic boric acid solutions

The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)₃] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)₃ was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)₃ was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281     

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.     

稻草原料表面特性FTIR和XPS分析

运用红外光谱(IR)和X射线光电子能谱分析(XPS)法，考察了热磨处理对稻草表面特性的影响。结果表明：稻草秸秆内表面的活性基团数量和氧碳元素百分比都明显高于外表面；经热磨处理，稻草纤维表面的羟基、甲基、亚甲基等官能团含量显著增加，氧碳元素百分比相对秸秆表面有大幅度提高，证明热磨处理能增强稻草表面活性，为脲醛树脂稻草中纤板制造的技术可行性提供了依据。     

一种快速测定棕榈藤材材质特性的近红外光谱分析法

分析了棕榈藤生物质材料特点与近红外光谱关系；阐述了近红外光谱分析技术可以快速准确地预测棕榈藤材的材质特性，并详细介绍了其中包括藤材的选择及加工、藤材近红外光谱采集、藤材材性真值测量、多变量数据分析与模型建立的实验方法与操作步骤。