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Nitrate‐dependent shoot sodium accumulation and osmotic functions of sodium in Arabidopsis under saline conditions
Author(s) -
ÁlvarezAragón Rocío,
RodríguezNavarro Alonso
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13556
Subject(s) - arabidopsis , wilting , turgor pressure , biology , shoot , xylem , salinity , nitrate , sodium , botany , horticulture , agronomy , chemistry , mutant , biochemistry , ecology , organic chemistry , gene
Summary Improving crop plants to be productive in saline soils or under irrigation with saline water would be an important technological advance in overcoming the food and freshwater crises that threaten the world population. However, even if the transformation of a glycophyte into a plant that thrives under seawater irrigation was biologically feasible, current knowledge about Na + effects would be insufficient to support this technical advance. Intriguingly, crucial details about Na + uptake and its function in the plant have not yet been well established. We here propose that 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 can also function with chloride at high concentrations. In nrt1 . 1 nitrate transport mutants, plant Na + accumulation was partially defective, which suggests that NRT 1.1 either partially mediates or modulates the nitrate‐dependent Na + transport. Arabidopsis plants exposed to an osmotic potential of −1.0 MP a (400 mO sm) for 24 h showed high water loss and wilting in sorbitol or Na/ MES , where Na + could not be accumulated. In contrast, in NaCl the plants that accumulated Na + lost a low amount of water, and only suffered transitory wilting. We discuss that in Arabidopsis plants exposed to high NaCl concentrations, root Na + uptake and tissue accumulation fulfil the primary function of osmotic adjustment, even if these processes lead to long‐term toxicity.