The nucleotides present in the cambial tissue (primary wall tissue) and in the not yet fully differentiated secondary xylem (secondary wall tissue) of Larix decidua Mill. were extracted and characterized. The method of extraction best suited to the material was investigated and the problems involved in desalting of extracts and their effect on the final nucleotide pattern obtained are discussed. UDP-glucose was found to be the most important sugar nucleotide isolated from both cambial and young xylem tissue. UDP-galactose, UDP-arabinose, UDP-xylose, UDP-fructose, GDP-glucose, GDP-galactose, GDP-mannose, ADP-glucose, ADP-galactose, ADP-fructose, ADP-ribose and ADP-ribose phosphate (the last two compounds are the acid breakdown products of NADH and NADPH respectively) were also found in both extracts. UDP-galacturonic acid was identified only in the extract of the primary wall material. Several nucleotide oligosaccharides were obtained from both the extract of cambial tissue and that of the young xylem.
