Abstract Leaves at nodes 4 or 8 of greenhouse grown beans, Phaseolus vulgaris L., cv. Puelba 152, were briefly exposed to 14 CO 2 at 35, 48, 63, or 70 days after planting. Prior to flowering, over 85% of the recovered 14 C-activity translocated in 24 hours from node 4 was in roots, nodules, and lower stem. At flowering, radioactivity translocated to the lower stem decreased but correspondingly increased in nodules. Roots sequestered 45% of translocated- 14 C throughout the life of the node-4 leaf. About 80% of the 14 C-activity exported from node 8 at flowering was in middle and upper stem sections, but during pod-fill over 85% moved into the pods and less than 1% to the nodulated root system. Starch concentration in the lower stem increased continuously from flowering, but in other plant parts declined after early pod-fill. At mid pod-fill, the concentration of soluble sugars in nodules and roots declined and reached a common value in stem sections. Nitrogen (C 2 H 2 ) fixation decreased rapidly after peaking at early pod-fill. This decline, which was accompanied by loss of lower leaves, occurred in the presence of a high concentration of starch in the stem.