Under salt/drought stress, to avoid excessive Na+ accumulation
in the cytosol and reach ion homeostasis, plant cells
exhibit three major mechanisms: restriction of Na+ permeation
and uptake catalyzed by Na+ transporters; sequestration of Na+
into the vacuole; and efflux of excess sodium, with symplastic
Na+ being transported back to the apoplast through plasma
membrane Na+/H+ antiporters