Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton

J Exp Bot. 2012 Mar;63(5):2105-16. doi: 10.1093/jxb/err420. Epub 2011 Dec 26.


A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na(+) concentrations in leaves. The [Na(+)] in the '0' side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the '0' side phloem was girdled, suggesting that the increased [Na(+)] in the '0' side roots was possibly due to transportation of foliar Na(+) to roots through phloem. Plants under non-uniform salinity extruded more Na(+) from the root than those under uniform salinity. Root Na(+) efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na(+) efflux and H(+) influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na(+) extrusion was probably due to active Na(+)/H(+) antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na(+) concentration, transport of excessive foliar Na(+) to the low salinity side, and enhanced Na(+) efflux from the low salinity root.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Transport / physiology
  • Gossypium / growth & development
  • Gossypium / metabolism
  • Gossypium / physiology*
  • Phloem / growth & development
  • Phloem / metabolism
  • Phloem / physiology
  • Photosynthesis / physiology
  • Plant Bark / growth & development
  • Plant Bark / metabolism
  • Plant Bark / physiology
  • Plant Leaves / growth & development
  • Plant Leaves / metabolism
  • Plant Leaves / physiology
  • Plant Roots / growth & development
  • Plant Roots / metabolism
  • Plant Roots / physiology
  • Plant Transpiration / physiology
  • Plants, Genetically Modified
  • Potassium / analysis
  • Potassium / metabolism
  • Salinity
  • Seedlings / growth & development
  • Seedlings / metabolism
  • Seedlings / physiology
  • Sodium / analysis
  • Sodium / metabolism
  • Sodium Chloride / pharmacology*
  • Sodium-Hydrogen Exchangers / metabolism*
  • Stress, Physiological / physiology
  • Water / physiology*


  • Sodium-Hydrogen Exchangers
  • Water
  • Sodium Chloride
  • Sodium
  • Potassium