Strategies underlying salt tolerance in halophytes are present in Cynara cardunculus

Cynara cardunculus L. is a robust thistle widespread in arid and semi-arid regions where high salinity is frequently present, but information about salt stress tolerance in this plant is almost null. This study examines the effect of salts (NaCl and KCl) on the growth, ion and other solutes accumulation and distribution through the plant. Moreover, Na+ and Rb+ (K+) uptake and translocation in the presence of specific water stress were determined. Moderately high concentrations of salt decreased the weight of the plant. However, a differential effect between NaCl and KCl was found. High concentrations of K+ produced higher deleterious effects than the same amounts of Na'. KCl was more toxic for the plant, probably because of the high accumulation of K+ ions in the plant. Osmotic adjustment was mainly due to inorganic ions and not to other organic solutes. Water stress promoted Na+ but not Rb+ (K) uptake and translocation to the shoot. It is proposed that strategies present in halophytic plants to cope with high salt can be found in C. cardunculus although this plant cannot be considered as a typical halophyte. (C) 2004 Elsevier Ireland Ltd. All rights reserved.