ABSTRACT
I. Introduction .............................................................................................................................151 II. The Plasma Membrane (PM) H
-ATPase ..............................................................................152 A. Structure ............................................................................................................................152 B. Regulation of the PM H
-ATPase as a Response to Variations in the Conditions at the Rhizosphere ...............................................................................153 1. Energization of Nutrient Transport..............................................................................153 2. Nutrient Acquisition through Rhizosphere Acidification ............................................155 3. Response to Abiotic Stress ..........................................................................................156 4. Response to Rhizosphere Signals ................................................................................157
III. Ion Carriers .............................................................................................................................158 A. Anion Carriers...................................................................................................................158 B. Cation Carriers ..................................................................................................................162
IV. Channels ..................................................................................................................................164 A. Cation Channels ................................................................................................................164 B. Anion Channels.................................................................................................................165 C. Porinlike Channels ............................................................................................................165 D. Organic Anion Channels ...................................................................................................166
V. Concluding Remarks and Future Perspectives .......................................................................166 References ......................................................................................................................................167
Roots play an important role in the relationship between plant and soil, acting as anchoring organs and allowing the acquisition of water and nutrients. These functions are complicated by the nature of soil, which erects barriers of a mechanical, physical, chemical, and biological nature against the activities and development of the root system. These conditions determine numerous forms of anatomical, physiological, biochemical, and molecular adaptations by which the plant can modify, to its own advantage, the characteristics of the soil; it has been found that there are profound modifications — physical, chemical, and biological [1,2] — in the area immediately around the roots (rhizosphere).
