Non-structural carbohydrates mobilization throughout the stem of Tectona grandis: A strategy for enhancing the wood natural durability
B F Niamké, N Amusant, D Stien, A Amissa Adima, C Jay-Allemand
Non-structural carbohydrates (NSC) storage is an important feature of heartwood substances formation. Radial distributions of NSC before and after chemical (acid and basic) hydrolysis, were quantified using a spectrophotometric method after enzymatic reaction and the corresponding macromolecules of conjugated NSC analyzed by HPLC, were studied in teak stem with reference to wood in environmental condition. In sapwood, free NSC (starch, glucose, fructose and sucrose) content and that of conjugated NSC (glucose) decreased abruptly from sapwood to heartwood. In both sapwood and heartwood, NSC were bounded to two unidentified compounds HB1 and HB2 which were well-characterized by high performance liquid chromatography (HPLC)/diode array detector. Our results show that free (70%) and conjugated (30%) NCS mobilized in sapwood, underwent high catabolic activities in the transition zone leading to their drastic depletion in heartwood. In heartwood unmetabolized glucose was stored by glucosilation with HB1 and HB2 and probably with other molecules. These results indicate that NSC mobilization throughout the stem could be a strategy for long lasting species like teak with consequences on decay resistance of wood.