| Abstract: | The vacuole is the largest compartment of a mature plant cell and serves as an internal reservoir of metabolites and nutrients. In the last years transport of solutes across the tonoplast has been intensively investigated. It was shown that two different proton pumps reside in the tonoplast. These pumps generate an electrochemical gradient which can be used as an energy-source to accumulate solutes. Cation uptake is driven by an H+ antiport mechanism. Anions are accumulated in response to the inside positive membrane potential. In addition, the existence of ion channels was shown using the patch clamp technique. The aim of this review is to compare and to discuss the present state of our knowledge of solute transport across the tonoplast. |
