Sodium (Na + ) is toxic to most plants, but the molecular mechanisms of plant Na + uptake and distribution remain largely unknown. Here we analyze Arabidopsis lines disrupted in the Na + transporter AtHKT1 . AtHKT1 is expressed in the root stele and leaf vasculature. athkt1 null plants exhibit lower root Na + levels and are more salt resistant than wild‐type in short‐term root growth assays. In shoot tissues, however, athkt1 disruption produces higher Na + levels, and athkt1 and athkt1 / sos3 shoots are Na + ‐hypersensitive in long‐term growth assays. Thus wild‐type AtHKT1 controls root/shoot Na + distribution and counteracts salt stress in leaves by reducing leaf Na + accumulation.

Altered shoot/root Na+ distribution and bifurcating salt sensitivity in Arabidopsis by genetic disruption of the Na+ transporter AtHKT1