The translocation of 14C photosynthate from leaves and pods in Phaseolus vulgaris

SUMMARY Field experiments were undertaken to study the pattern of distribution of photosynthate produced by the leaves and the pods of Phaseolus vulgaris (cv. Purley King) by means of the 14C technique. It was found that the UC photosynthate produced by a trifoliate leaf (38 days after anthesis) was shared almost equally between the leaf and the pod at its axil with 33–50% of the fixed 14C finding its way to the seeds in that pod. However, during the early stages of pod development (10 days after anthesis) some 13–14% of the fixed 14C was detected in the stem, indicating the inadequacy of the pod as a sink at that stage. When the pod was treated, virtually no 14C was detected in other parts of the plant. Of the 14C fixed by pod photosynthesis in the later stages (38 days after anthesis), 55–60% was translocated to the seeds within the same pod. These results indicate the importance of current photosynthesis during the pod fill stage in P. vulgaris as has been suggested in other grain legume crops.