Xylem ionic relations and salinity tolerance in barley

Abstract

SUMMARYControl of ion loading into the xylem has been repeatedly named as a crucial factor determining plant salt tolerance. In this study we further investigate this issue by applying a range of biophysical [the microelectrode ion flux measurement (MIFE) technique for non-invasive ion flux measurements, the patch clamp technique, membrane potential measurements] and physiological (xylem sap and tissue nutrient analysis, photosynthetic characteristics, stomatal conductance) techniques to barley varieties contrasting in their salt tolerance. We report that restricting Na + loading into the xylem is not essential for conferring salinity tolerance in barley, with tolerant varieties showing xylem Na + concentrations at least as high as those of sensitive ones. At the same time, tolerant genotypes are capable of maintaining higher xylem K + /Na + ratios and efficiently sequester the accumulated Na + in leaves. The former is achieved by more efficient loading of K + into the xylem. We argue that the observed increases in xylem K + and Na + concentrations in tolerant genotypes are required for efficient osmotic adjustment, needed to support leaf expansion growth. We also provide evidence that K + -permeable voltage-sensitive channels are involved in xylem loading and operate in a feedback manner to maintain a constant K + /Na + ratio in the xylem sap.

De Novo Transcriptome Characterization, Gene Expression Profiling and Ionic Responses of Nitraria sibirica Pall. under Salt Stress

“…In this study, we also found that Ca, Cu, Fe, Mg, and K contents decreased in roots, stems and leaves under salt stress. Similar results have also been reported in which salt stress affects the uptake of Mg [27], Fe [30], Ca [72], and K [73], among others, by plants.…”

Tetraploid Black Locust (Robinia PseudoacaciaL.) Increased Salt Tolerance by Activation of the Antioxidant System

“…Usually, plant responses to salt stress are associated with generation of reactive oxygen species (RoS) (2,12,31,34,35,41). however, redundant RoS cause membranes damage, ion and water leakage, and protein turnover in plant cells (6).…”

The Potential Role of Osmotic Pressure to Exogenous Application of Phytohormones on Crop Plants Grown under Different Osmotic Stress

“…An overview of the many changes in the transcript abundance of cytokinin genes in Arabidopsis in response to environmental factors was given elsewhere [48]. Shabala et al (2010) [49] demonstrated that pants growth is impressed by biotic and abiotic stress inversely. There are many reports about proteins change level in salinity stress.…”