Na(+)/H(+) antiporter that extrudes sodium in exchange for external protons. Mostly expressed in mature and senescent leaves, and, to a lower extent, in seeds, roots, shoots, flowers and developing siliques. Decreased biomasses and lower chlorophyll levels after sodium feeding. Increased Na(+) levels in chloroplasts in high sodium chloride conditions but impaired photosynthetic performance. Altered levels of phenylalanine and tyrosine. Belongs to the NhaD Na(+)/H(+) (TC 2.A.62) antiporter family.