tration of ABA in seed, the smaller was the seed size. This suggests aparallel relationship between seed growth and the ABA concentra-tion in the cotyledon, although the relationship of ABA transportfrom the leaf to the seed and assimilate transfer is still unclear.Our experiments provide evidence for a promotive role of ABA inphotoassimilate accumulation in soybean seeds. ABA may stim-ulate rapid unloading of sucrose into the seed coat apoplast andmay enhance movement of sucrose into cotyledons during the seedfilling stage.It has been suggested