Nitrate-dependent sodium uptake for osmotic adjustment

Arabidopsis plants take up sodium to decrease the water potential and keep their water content. Sodium uptake depends on nitrate although some other anions can substitute for nitrate in certain conditions.

 

Arabidopsis plants take up sodium to decrease the water potential and keep their water content. Sodium uptake depends on nitrate although some other anions can substitute for nitrate in certain conditions.


Under saline conditions, two nitrate-dependent transport systems in series that take up and load Na+ into the xylem constitute the major pathway for the accumulation of Na+ in Arabidopsis shoots; this pathway also functions with chloride at high concentrations. Arabidopsis plants exposed to an osmotic potential of −1.0 MPa (400 mOsm) for 24 h show high water loss and wilting in sorbitol or Na/MES, where Na+ cannot be accumulated. In contrast, in NaCl the plants accumulate Na+, lose a low amount of water, and only suffered transitory wilting. We conclude that root Na+ uptake and tissue accumulation of Na+ fulfill the primary function of osmotic adjustment, even if these processes lead to long-term toxicity.

zoom

 

Original Paper:

Álvarez-Aragón, R; Rodríguez-Navarro, A. 2017. "Nitrate-dependent shoot sodium accumulation and osmotic functions of sodium in Arabidopsis under saline conditions". Plant Journal. DOI: 10.1111/tpj.13556".


Print