Ion transport at the plant plasma membrane

Membrane transport plays a fundamental role in virtually every aspect of homeostasis, signalling, growth and development in plants. At the plasma membrane, the boundary with the outside world, ion and solute fluxes underpin inorganic mineral nutrient uptake, they trigger rapid changes in second messengers such as cytosolic"free Ca2+ concentrations and they power the osmotic gradients that drive cell expansion, to name just a few roles. Our understanding of the transporters" the ion pumps that generate an H+ electrochemical driving force, H+ ion"coupled symport and antiport systems and ion channels" now, more than ever, builds on developments in molecular genetics, genomics, protein chemistry and crystallography to gain insights into the fine structure and mechanics of these remarkable enzymes. Even so, it is the interface with the biophysical detail of ion transport that drives scientific enquiry in the field and will continue to be essential in informing both the most fundamental research as well as efforts to apply the knowledge gained in resolving some of the dilemmas that face society today.