Effect of the Shoot on the Transmembrane Potentials of Root Cortical Cells of Sunflower

摘要: Transmembrane potentials (PD) of root cortical cells were measured between the vacuole and external solution while roots remained attached to plants. External con centration was varied by using a range dilutions balanced nutrient solution. In all cases PD more negative than that due diffusion alone indicating presence an elec trogenic or metabolically derived component. This component contributed additional —80 mV relatively independent concentration. The metabolic eliminated inhibitors, placing shoot in darkness, ringing phloem, severing rootlet from ; it restored again removing inhibitor, light, or, case severance, adding 25 ml sucrose medium. magnitude electrogenic dependent on antecedent light intensity way reminiscent translocation itself.