Effects of K$(86Rb) Transport and the Net H$ Efflux on Electrical Properties along Bean (Phaseolus mungo) Roots

The three-phase electric potential distribution along two-day-oldintact Phaseolus roots was investigated in relation to cellgrowth and K^$ and H^$ transports using tracer K^$(⁸⁶Rb) and pHexperiments. The activity of a radial electrogenic componentlocated between the cortical cells and the external solutionwas high in the elongating region and in the completely maturedregion. The activity of another radial electrogenic componentlocated between the cortical cells and the stele was maximalin the elongating region. Both potassium uptake from the externalsolution into the cortical cells and H^$ excretion took placemainly in these regions. (Received November 9, 1983; Accepted June 21, 1984)