Na plus transport in glycophytic plants: what we know and would like to know

Soil salinity decreases the growth rate of plants and can severely limit the productivity of crop plants. The ability to tolerate salinity stress differs widely between species of plants as well as within species. As an important component of salinity tolerance, a better understanding of the mechanisms of Na+ transport will assist in the development of plants with improved salinity tolerance and, importantly, might lead to increased yields from crop plants growing in challenging environments. This review summarizes the current understanding of the components of Na+ transport in glycophytic plants, including those at the soil to root interface, transport of Na+ to the xylem, control of Na+ loading in the stele and partitioning of the accumulated Na+ within the shoot and individual cells. Using this knowledge, strategies to modify Na+ transport and engineer plant salinity tolerance, as well as areas of research which merit particular attention in order to further improve the understanding of salinity tolerance in plants, are discussed.