STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: IX. RADIOACTIVITY OF WHEAT FOLLOWING INJECTION OF FORMATE-C14 AND GLYCINE-1-C14 WITH SPECIAL REFERENCE TO SERINE LABELLING

Abstract

Formate-C14 and glycine-1-C14 were injected into the stems of wheat plants 71 days after seeding and the distribution of carbon-14 in the plants 102 days after seeding (full maturity) was studied. Large losses of formate carbon from the plant were observed. The most active kernel component isolated after formate-C14 injection was protein, the methyl carbon of the methionine and carbon-3 of serine being especially radioactive. The gluten protein of wheat kernels labelled with glycine-1-C14 was also comparatively radioactive, more than one half of the carbon-14 occurring in the carboxyl carbons of glycine and serine. The results suggest that the radioactive serine was formed largely by way of the condensation of formate, or a "one carbon fragment," with carbon-2 of glycine.