Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton.
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.
Shandong Academy of Agricultural Sciences, Jinan, People's Republic of China.
Xiangqiang
X
Kong
Zhen
Z
Luo
Hezhong
H
Dong
A Egrinya
AE
Eneji
Weijiang
W
Li
D001692:Biological Transport / Q000502:physiology; D003368:Gossypium / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D052585:Phloem / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology; D024301:Plant Bark / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D030821:Plants, Genetically Modified; D011188:Potassium / Q000032:analysis / Q000378:metabolism; D054712:Salinity; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D012964:Sodium / Q000032:analysis / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013312:Stress, Physiological / Q000502:physiology; D014867:Water / Q000502:physiology*
D017923:Sodium-Hydrogen Exchangers; D014867:Water; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium