A micro-analytical approach to the carbohydrate chemistry of compression wood

摘要

Severe compression wood is readily detected by its visual appearance, but there are differences of opinion concerning visual detection of mild forms. We adapted a micro-analytical method for carbohydrate analysis and assessed it for use on two different scales: (a) micro-scale studies within growth rings, (b) macroscopic studies integrated over entire discs. Wood fragments were hydrolysed, derivatised and analysed by gas-liquid chromatography. Mole ratios, relative to glucose, were measured with a standard error of 0.005. Galactose was the most useful marker for compression wood, with galactose/glucose ratios typically 0.05 in pale early- or latewood, 0.11 in brown latewood, up to 0.13 in pale earlywood adjacent to red discolouration, and 0.22 in red earlywood. Galactose/glucose ratios, integrated over entire discs, showed a strong correlation with compression wood severity graded according to visual schemes.