Leaves of young corn plants were exposed to light and to C1402 for 24 hours. Root tips, stem tips and the remaining portions of these plants were separately extracted with solvents to yield 5 fractions. These were dried, weighed and their radioactivities measured with a Geiger counter. In the tip samples, the residual alcohol fraction (organic acids and sugars) and the ether soluble fraction (lipids and pigments) contained the most radioactivity, the principal nitrogenous fraction and the acid hydrolysate (largely starch) intermediate radioactivity, and the crude fiber the least radio-activity. In the remaining portions of the plant, the former fractions had less radioactivity while the crude fiber contained more. Microautoradiographs were made from 8-10 [mu] longitudinal sections of root tips prepared by standard histological procedures. Greatest autoradiographic density was found in the inner cortex, outer stelar regions and in the superficial cells. These areas may well have been translocation paths or the seat of active growth and metabolism. It may be concluded that translocation of C14-labeled metabolites from the leaves to the meristematic region of roots occurs largely in areas which are later destined to become the functional vascular and conducting cells of mature roots. The presence of relatively large amts. of C14-labeled sugars, organic acids and starch in certain areas of the meristematic region of corn roots suggests the existence of a spatial metabolic pattern.