Translocation of uranin in the symplasm of staminal hairs of Tradescantia

Abstract

Translocation of uranin proceeds in the protoplasm of Tradescantia staminal hairs both in the acropetal and basipetal direction from a wound. A diffusion pattern is observed proportional to the square root of time. It is slower than physical diffusion in water. At any given time interval the number of cells traversed is almost equal whether transport is from the base or the tip. Consequently the distance from the base, where the cells are longer, is also longer. Translocation fits the calculation on a model in which the plasmodesmata in the interconnecting walls are almost occluded with solid obstructions or in which the plasmodesmata are under the influence of a more or less uniform negative charge. Resistance in the plasmodesmata seems to be the limiting factor in this case of symplasmic transport.