The cytosolic Na+ : K+ ratio does not explain salinity-induced growth impairment in barley: a dual-tracer study using 42K+ and 24Na+.

摘要: It has long been believed that maintenance of low Na+ : K+ ratios in the cytosol plant cells is critical to plant's ability tolerate salinity stress. Direct measurements such ratios, however, have few. Here we apply non-invasive technique compartmental analysis, using short-lived radiotracers 42K+ and 22Na+, intact seedlings barley (Hordeum vulgare L.), evaluate unidirectional plasma membrane fluxes cytosolic concentrations root tissues, under eight nutritional conditions varying levels supply. We show adjust significantly across tested, these are poor predictors growth response salinity. Our study further demonstrates subject rapid futile cycling at all supply, independently external K+, while influx reduced by Na+, from a similar baseline, extent, both high compare our results those other groups, conclude ratio not central survival NaCl offer alternative explanations for sodium sensitivity relation primary acquisition mechanisms K+.