The transport of carbon-14 injected into the hollow stems of growing wheat plants in the form of sodium acetate-1-C14 and -2-C14 was studied. The labelling efficiency of the tracer and its distribution among components of the wheat kernels was markedly dependent upon the time of injection. Maximum incorporation of activity occurred with plants which were given the tracer about 80 days after seeding. Sodium acetate-1-C14 was less effective for producing labelled kernels and gave rise to more uniform distribution of carbon-14 among the components, very little carbon-14 being utilized for starch synthesis nearer maturity. A high percentage of the carbon-14 content of the gluten resided in the glutamic acid residues. Glutamic acid-C14 injected into the stems was an efficient source of labelling for the plant. The results are consistent with the view that acetate is utilized by way of the Krebs' citric acid cycle.