Root plasma membrane transporters controlling K+/Na+ homeostasis in salt-stressed barley.
Plant salinity tolerance is a polygenic trait with contributions from genetic, developmental, and physiological interactions, in addition to interactions between the plant and its environment. In this study, we show that in salt-tolerant genotypes of barley (Hordeum vulgare), multiple mechanisms are well combined to withstand saline conditions. These mechanisms include: (1) better control of membrane voltage so retaining a more negative membrane potential; (2) intrinsically higher H(+) pump activity; (3) better ability of root cells to pump Na(+) from the cytosol to the external medium; and (4) higher sensitivity to supplemental Ca(2+). At the same time, no significant difference was found between contrasting cultivars in their unidirectional (22)Na(+) influx or in the density and voltage dependence of depolarization-activated outward-rectifying K(+) channels. Overall, our results are consistent with the idea of the cytosolic K(+)-to-Na(+) ratio being a key determinant of plant salinity tolerance, and suggest multiple pathways of controlling that important feature in salt-tolerant plants.
Chen
Zhonghua
Z
School of Agricultural Science , University of Tasmania, Hobart, Tasmania 7001, Australia.
Pottosin
Igor I
II
Cuin
Tracey A
TA
Fuglsang
Anja T
AT
Tester
Mark
M
Jha
Deepa
D
Zepeda-Jazo
Isaac
I
Zhou
Meixue
M
Palmgren
Michael G
MG
Newman
Ian A
IA
Shabala
Sergey
S
D000222:Adaptation, Physiological; D002462:Cell Membrane / Q000378:metabolism*; D005838:Genotype; D006706:Homeostasis / Q000502:physiology; D001467:Hordeum / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D019441:Plant Epidermis / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism* / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism; D017494:Proton Pumps / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D054712:Salinity; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism*; D012979:Sodium Radioisotopes / Q000378:metabolism; D019789:Tetraethylammonium
D015221:Potassium Channels; D017494:Proton Pumps; D012979:Sodium Radioisotopes; D012965:Sodium Chloride; D019789:Tetraethylammonium; D012964:Sodium; D011188:Potassium