Changes in hexoses and salicin endogenous content during water deficit and after re-hydration have been measured. Control plant endogenous content in measured hexoses and salicin did not vary significantly all along the experiment, since statistical tests [23] showed that the probability of rejection of the true null hypothesis was higher than the significant level (i.e. P > 0.05). Galactose level was estimated at 6.5±2.4mol g−1 of dry weight, fructose and glucose were quantified at higher levels with respectively 39.2±8.2 and 47.7±8.2mol g−1 DW. Salicin was the major carbohydrate in P. euphratica with an average content of 111.7±26.8mol g−1 DW. Variations of the carbohydrate levels, normalized to the control, are presented in Fig. 6. Various trends could be observed during the assay: fructose (Fru) and galactose (Gal) contents were higher during drought stress and after re-hydration than in control conditions. This accumulation is probably due to the increase of osmoprotectants needed for drought resistance [24,25]. Furthermore, galactose content decreased after plant watering and plant recovery. Glucose (Glu) accumulated during the first days of the stress and returned to the control level afterwards. Plant watering led to a secondary glucose accumulation. Salicin (Sal) accumulated at the end of the drought treatment, when glucose content returned to a control level. This may indicate that glucose is used, under prolonged water deficit stress, for the synthesis of salicin, thus leading to its accumulation. These modulations in compounds taking part in the osmoregulation during drought exposure may reveal adjustment needs for the responses to resist to drought for a long period.