Back to Search
Start Over
The water permeability of Arabidopsis plasma membrane is regulated by divalent cations and pH.
- Source :
-
Plant Journal . Apr2002, Vol. 30 Issue 1, p71-81. 11p. 2 Charts, 9 Graphs. - Publication Year :
- 2002
-
Abstract
- Summary Mechanisms that regulate water channels in the plant plasma membrane (PM) were investigated in Arabidopsis suspension cells. Cell hydraulic conductivity was measured with a cell pressure probe and was reduced 4-fold as compared to control values when calcium was added in the pipette and in bathing solution. To assess the significance of these effects in vitro , PM vesicles were isolated by aqueous two-phase partitioning and their water transport properties were characterized by stopped-flow spectrophotometry. Membrane vesicles isolated in standard conditions exhibited reduced water permeability (P f ) together with a lack of active water channels. In contrast, when prepared in the presence of chelators of divalent cations, PM vesicles showed a 2.3-fold higher P f and active water channels. Furthermore, equilibration of purified PM vesicles with divalent cations reduced their P f and water channel activity down to the basal level of membranes isolated in standard conditions. Ca2+ was the most efficient with a half-inhibition of P f at 50–100 µm free Ca2+ . Water transport in purified PM vesicles was also reversibly blocked by H+ , with a half-inhibition of P f at pH 7.2–7.5. Thus, both Ca2+ and H+ contribute to a membrane-delimited switch from active to inactive water channels that may allow coupling of water transport to cell signalling and metabolism. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ARABIDOPSIS
*CELL membranes
*CATIONS
*HYDROGEN-ion concentration
Subjects
Details
- Language :
- English
- ISSN :
- 09607412
- Volume :
- 30
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Plant Journal
- Publication Type :
- Academic Journal
- Accession number :
- 6494470
- Full Text :
- https://doi.org/10.1046/j.1365-313X.2002.01268.x