Storage carbohydrates and adenine nucleotides in trunks of fagus sylvatica L. in relation to discolored wood

Four Fagus sylvatica L. trunks (approximately 120 years old) showing discoloration in the centre, were separated into outermost sapwood (youngest growth ring), middle sapwood, older sapwood, sapwooddiscolored wood boundary and outer discolored wood and analyzed for storage carbohydrates and adenine nucleotides. Using TLC and enzymatic assay, fructose, glucose, sucrose, raffinosc/stachyose, starch, adenosine mono-, di- and triphosphatc were determined. In general, sugar concentrations were high in the sapwood but negligible in the discolored wood.The youngest growth ring showed the highest levels of raffinose/stachyose. Starch contents were highest in the peripheral sapwood and decreased in centripetal direction. No starch was present in the discolored wood. The outermost sapwood contained highest amounts of adenine nucleotides. The older sapwood zones exhibited more or less equal amounts of adenine nucleotides. The discolored wood was almost free of adenine nucleotides. The results show that discolored wood of Fagus sylvatica is not physiologically different from heartwood.