NEAR INFRARED SPECTROSCOPY: RAPID AND ACCURATE ANALYTICAL TOOL FOR PREDICTION OF NON-STRUCTURAL CARBOHYDRATES IN WOOD

Abstract

The non-structural carbohydrate (NSC) reserves in the various organs of trees are associated with their growth and the mechanism of resilience when exposed to environmental stresses, especially the water deficit. The goal of this study was to develop multivariate models to estimate the amount of non-structural carbons (starch, sucrose, reducing sugars, total sugars and total non-structural carbons) based on near-infrared (NIR) spectra measured in solid wood and wood reduced to powder. Partial least squares regression was used to associate the amount of non-structural carbons obtained by conventional laboratory analysis with NIR spectral signatures. The best predictive models were obtained from the wood reduced to powder. Validity for the NSC prediction in an external set of data presented the following statistics: reducing sugars with R² = 0.91 and root mean square error (RMSE) of 2.39% dry matter, total sugars (R² = 0.90, RMSE = 2.57%), total NSC (R² = 0.87, RMSE = 2.89%), sucrose (R² = 0.82, RMSE = 0.06%) and starch (R² = 0.80, RMSE = 1.03%). The ability of the models to estimate the NSC concentration in the growth rings and under divergent environmental conditions demonstrates the potential of the NIR tool to study the physiological responses of plants to different environmental stresses.