Abstract
An autoradiographic study of the rooted shoots of Tradescantia viridis (=T. albiflora Kunth emend. Brueckn.) showed a high speed translocation of 86Rb applied to a leaf for short periods of time (5 to 2.5 min). The speed of this translocation (between 840 and 1.440 cm h-1) speaks for the existence of a very rapid phloem component translocating ions to an active sink, represented here by the growing roots. Pretreatment with cycloheximide (48 h, 50 mg l-1) decreases the quantity of this long distance transport but not the velocity.