[High speed translocation of (86)Rb in the phloem of Tradescantia viridis].

An autoradiographic study of the rooted shoots of Tradescantia viridis (=T. albiflora Kunth emend. Brueckn.) showed a high speed translocation of (86)Rb 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.