K+ transport in plants: Physiology and molecular biology

SummaryPotassium (K+) is an essential nutrient and the most abundant cation in plant cells. Plants have a wide variety of transport systems for K+ acquisition, catalyzing K+ uptake across a wide spectrum of external concentrations, and mediating K+ movement within the plant as well as its efflux into the environment. K+ transport responds to variations in external K+ supply, to the presence of other ions in the root environment, and to a range of plant stresses, via Ca2+ signaling cascades and regulatory proteins. This review will summarize the molecular identities of known K+ transporters, and examine how this information supports physiological investigations of K+ transport and studies of plant stress responses in a changing environment.