Radial distribution of non-structural carbohydrates in Malaysian teak

Abstract

Non-structural carbohydrates are primary compounds whose distribution in the wood affects its properties. During the two last decades, a high variability of natural durability of plantation teak wood properties has been found with consequences for industry and consumers. In order to further investigate chemical traits for natural durability in Malaysian teak, we studied the radial distribution of main non-structural carbohydrates (NSC) from the sapwood to the inner heartwood. NSC were analysed by thin layer chromatography coupled to an enzymatic method. The main NSC were starch, glucose, fructose and sucrose. Stachyose and raffinose were also detected. Starch was the major NSC while sucrose was the less abundant. NSC were highly accumulated in sapwood and decreased drastically in heartwood. In our sampling, NSC distribution patterns were the same between trees but were different on a quantitative point of view. Our results suggested that NSC were stored as reserve materials in the sapwood and then were used in the sapwoodheartwood boundary for metabolic activities during heartwood formation process. Their involvement in heartwood formation was discussed.

Keywords: Tectona grandis, sapwood, heartwood, non-structural carbohydrates, starch.