Plant Response to Saline Substrates VIII. Regulation of Ion Concentrations in Salt-Sensitive and Halophytic Species

Concurrent uptake and export of ions were measured in a very salt-sensitive species, Phaseolus vulgaris, and in a halophyte, Atriplex. In plants with high chloride and sodium § concentrations, the whole plants, shoots, and older leaves exported only a small percentage of previously absorbed ions. However, chloride retranslocation from older leaves was appreciable in plants of low chloride concentrations. Similar results were obtained previously for a salt-tolerant non-halophyte (Hordeum vulgare). Thus these halophytes and non-halophytes do not differ in the characteristics rneasured.