A simple system for determining the phloem mobility of compounds using excised pods of lupin (Lupinus albus L.).

Lupin pods were isolated from the plant and the pedicels placed in solutions of either radiolabeled sucrose, glucose, abscisic acid, or gibberellin A9 (GA9). Phloem exudate was collected from the cut stylar ends of the pods and both quantitative and qualitative data were obtained on the activity in the sap. Fed sucrose, abscisic acid, and GA9 were found in phloem exudate, but labeled glucose was immobile as the monosaccharide and activity in exudate appeared in sucrose.