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Abscisic acid effects on intracellular pH and ion fluxes in barley leaf segments
Author(s) -
Beffagicoletta
Publication year - 1992
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1992.tb04770.x
Subject(s) - abscisic acid , dids , intracellular , hordeum vulgare , chemistry , efflux , intracellular ph , biophysics , ion transporter , diaphragm pump , membrane transport , biochemistry , membrane , biology , botany , poaceae , materials science , micropump , gene , nanotechnology
Changes in intracellular pH and in H + , K + and Cl − fluxes were evaluated in different experimental conditions in leaf segments of barley ( Hordeum vulgare cv. Georgie) incubated in the dark, at pH 5.5, in the presence or absence of abscisic acid (ABA), and a comparison was made between the effects of ABA and those of erythrosin B (EB), a plasmalemma H + ‐pump inhibitor. In all conditions tested, ABA induced a cell sap acidification, an alkalinization of the external medium, a decrease in K + intracellular contents, and an increase in the contents of Cl − . The ABA‐induced decrease in K + content was chiefly due to the inhibition of K + influx. On the contrary, ABA did not influence the uptake of Cl − , but inhibited Cl − efflux, the inhibition satisfactorily accounting for the larger Cl − content observed in the presence of the hormone. The intracellular acidification and the decrease in apparent outward net transport of H + observed with ABA were seemingly not associated with the activity of the proton pump, the transmembrane electrical potential difference, or K + transport. On the contrary, a correlation was evident with the changes in Cl − content. These results and, in particular, the similarity between the effects of ABA and those induced by 4,4 ‐diisothiocyano‐2,2‐disulfonic acid stilbene (DIDS), a Cl − channel‐blocking agent, suggest that the ABA‐induced changes in intracellular pH and in H + transport might depend on the capability of ABA to inhibit Cl − efflux, more than on a primary inhibition of the H + pump, and propose an important role for ABA in regulating the Cl − channels.