[en] Plants were grown in a controlled environment chamber and fed with a modified Hoagland solution containing nitrate as nitrogen source (N+ medium). Soybeans, 33 days old (flowering stage), 45 and 56 days old (pods formation and filling stages) were used for experimentation. In each experiment, the eight trifoliated leaf (F₈) was exposed to ¹⁴CO₂ (10 μCi; 400 vpm), in the light (80 W x m^-2) for 30 min. After a 6 h chase period (22 - 25⁰C; 80 W x m^-2), the radiocarbon distribution among plant parts was determined and labelled compounds were identified. (orig.)