Translocation of Labelled Assimilates in the Soybean II. The Pattern of Translocation in Intact and Defoliated Plants

Abstract

The distribution of He·labelled assimilate in the soybean has been studied, emphasis being placed on the expanding leaf as the major apical sink. The expanding leaf imports assimilate from leaves below, this import rising to a maximum and then falling to almost zero when the leaf is half-expanded. At this stage in the growth of the leaf, it has begun exporting assimilate to the younger leaves. Export, both to younger leaves and down the stem to the root, increases until the leaf is fully expanded