Chloride fluxes in cells of the isolated root cortex of zea mays

Abstract

Isolated maize root cortical tissue is used to eliminate stelar complications in measuring fluxes. Comparison of isolated cortex and whole root segments shows that the cortex is not damaged by separation from the stele, that the initial influx estimate of the plasmalemma influx in cortical cells of whole roots (Cram and Laties 1971) is not affected by the presence of the stele, but that the quasi-steady influx to the vacuole of cortical cells may be overestimated at high external salt concentrations and with short loading times due to stelar contents. It is pointed out that tests of the validity and accuracy of the flux measurements depend, as in more complex analyses, on knowing the kinetics of exchange of the system. The validity of fitting three exponential components to the 36Clloss curve from isolated maize root cortex is confirmed by the equality of the exponential rate constants fitting the log content v. time and the log rate of loss v. time curves. © 1973, CSIRO. All rights reserved.