THE NATURE OF PHOTOSYNTHATE IN PINUS STROBUS SEEDLINGS
Representatives of C14-labelled sugars, amino acids, and organic acids were placed on several different kinds of exchange resins and their absorption and elution from such resins was determined. From the data obtained, a combination of IR 120 in the H+ form and IRA 400 in the formate form was selected for the initial separation of pine extracts into their sugar, amino acid, and organic acid fractions. These fractions were resolved further by two-dimensional paper chromatography.Two-year-old Pinus strobus seedlings were illuminated in C14O2 for 8 hours either at 2500 or 250 ft-c. Then their shoots were extracted with 80% ethanol and the distribution of C14 in various components of the photosynthate was determined, as described above.The results obtained were essentially the same for seedlings illuminated either with 2500 or 250 ft-c. Not more than 10% of the absorbed C14 were found in the ethanol-insoluble residue. About 98% of the ethanol-soluble C14 were found in the sugar fraction, with the remaining 2% being about equally divided between the amino and organic acids. Sucrose formed about 75% of the sugar fraction, with glucose and fructose making up additional 20%. Only small amounts of raffinose were found.