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

KOTULA L; CLODE P; STRIKER GG; PEDERSEN O; LAUCHLI A; SHABALA S; COLMER TD

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 208 p. 1114 - 1125

0028-646X

O2 deficiency  associated  with  soil  waterlogging  adversely  impacts  root  respiration  and nutrient acquisition. We investigated the effects of O2deficiency and salinity (100 mM NaCl) on radial O2 concentrations and cell-specific ion distributionsin adventitious roots of barley. 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 cell-specific elemental concentrations of K, Na and 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 concentrationsof 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 aerated saline solution but was relatively high in all cell types in roots from stagnant saline solution.  O2 deficiency has a substantial impact on cellular ion concentrations. Both pericycle and xylem parenchyma cells are involved in energy-dependent K loading into the xylem as well as 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.