The effect of xanthoxylin (2-oxy, 4-6-dimethoxyacetophenone) on potassium-dependent acid: extrusion in wheat and maize root segments |
| |
Authors: | M. BELLANDO,G. ALLOATTI&dagger ,G. ROMANI&Dagger ,M. T. MARRÉ &Dagger |
| |
Affiliation: | Dipartiment di Biologia vegetale dell' Universitàdi Torino;Dipartiment di Biologia animale, Istituto di Fisiologia generale dell' Universitàdi Torino;Dipartiment di Biologia, Laboratorio di Fisiologia vegetale dell' Universitàdi Milano |
| |
Abstract: | Abstract. Xanthoxylin is a cytotoxic and fungicidal compound with the characteristics of a typical phytoalexin. At a concentration of 0.3 mol m−3 it inhibits K+-dependent acid extrusion and K+ net uptake (or uptake of equivalent alkaline cations such as Rb+ and CS+) by up to about 80% and hyperpolarizes by about 20% the membrane electrical potential. Its inhibition of the acid extrusion does not depend on altered ion exchange involving the anions in the media, a reduction of the metabolic energy available, or detectable changes in the permeability of the cell membrane to H+ ions. The drop in K+ net uptake depends on a decrease in the influx of K+ into the cell. In functional terms, xanthoxylin is an inhibitor of the K+ permeation mechanism and does not appear to interact with the mechanisms creating the electrochemical energy gradient. |
| |
Keywords: | xanthoxylin acid extrusion potassium uptake inhibition |
|
|