Sugar uptake and translocation in the castor bean seedling : III. An autoradiographic study of the absorption pathway.

Radioactive sucrose entering the cotyledons of germinating castor bean seedlings has been partly localised with the aid of microautoradiography. Complete penetration of these organs was achieved in twenty minutes from 0.1M aqueous sucrose. Radioactive material was found to occur predominantly in the vicinity of cell walls and in intercellular spaces. It is suggested that this region offers a diffusion pathway by which solutes can gain access to the vascular system from an external source.