Cell-specific responses of ion concentrations in barley roots during low oxygen and saline conditions

KOTULA L.; CLODE PL; STRIKER GG; PEDERSEN O; COLMER TD

Utrech

Simposio; International Workshop on Flooding 2015; 2015

Committee of the International Workshop on Flooding 2015 sponsored by New Phytologist

Oxygen deficiency restricts root respiration and impacts on energy-dependent ion transport with adverse consequences for nutrient acquisition. We investigated the effects of O2-deficiency and salinity (100 mM NaCl) on radial O2 concentrations and cell-specific ion concentrations in roots of barley (Hordeum vulgare L.). Severe O2 deficiency occurred in the stele and apical regions of adventitious roots reliant on internal O2 movement via aerenchyma when in de-oxygenated stagnant solution. X-ray microanalysis of root cross sections revealed that O2 deficiency in the stele reduced the concentrations of K+, Na+ and Cl- in the pericycle and xylem parenchyma cells at a subapical position. Nearer the root tip, 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. Oxygen deficiency has a substantial impact on ion transport and cellular distribution of ions across roots, which impacts on shoot nutrient status in waterlogged soils and ?exclusion? of the potentially-toxic Na+ from the shoot of plants in waterlogged saline soils.