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New Phytol. 2015 Dec;208(4):1114-25. doi: 10.1111/nph.13535. Epub 2015 Jun 22.

Oxygen deficiency and salinity affect cell-specific ion concentrations in adventitious roots of barley (Hordeum vulgare).

Author information

1
School of Plant Biology, Faculty of Science, The University of Western Australia, Crawley, WA, 6009, Australia.
2
Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA, 6009, Australia.
3
IFEVA-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.
4
Institute of Advanced Studies, The University of Western Australia, Crawley, WA, 6009, Australia.
5
Freshwater Biological Laboratory, University of Copenhagen, Copenhagen, 2100, Denmark.
6
Department of Land, Air and Water Resources, University of California, Davis, CA, 95616-8627, USA.
7
School of Land and Food, University of Tasmania, Hobart, TAS, 7001, Australia.
8
The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia.

Abstract

Oxygen deficiency associated with soil waterlogging adversely impacts root respiration and nutrient acquisition. We investigated the effects of O2 deficiency and salinity (100 mM NaCl) on radial O2 concentrations and cell-specific ion distributions in adventitious roots of barley (Hordeum vulgare). Microelectrode profiling measured O2 concentrations across roots in aerated, aerated saline, stagnant or stagnant saline media. X-ray microanalysis at two positions behind the apex determined the cell-specific elemental concentrations of potassium (K), sodium (Na) and chloride (Cl) across roots. Severe O2 deficiency occurred in the stele and apical regions of roots in stagnant solutions. O2 deficiency in the stele reduced the concentrations of K, Na and Cl in the pericycle and xylem parenchyma cells at the subapical region. Near the root apex, Na declined across the cortex in roots from the aerated saline solution but was relatively high in all cell types in roots from the stagnant saline solution. Oxygen deficiency has a substantial impact on cellular ion concentrations in roots. Both pericycle and xylem parenchyma cells are involved in energy-dependent K loading into the xylem and in controlling radial Na and Cl transport. At root tips, accumulation of Na in the outer cell layers likely contributed to reduction of Na in inner cells of the tips.

KEYWORDS:

O2 deficiency; X-ray microanalysis; barley (Hordeum vulgare); potassium (K); root aeration; salinity × waterlogging interaction; sodium (Na); stele hypoxia

PMID:
26094736
DOI:
10.1111/nph.13535
[Indexed for MEDLINE]
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