Abstract
Osmoregulation in date palm seedlings (Phoenix dactylifera L. Cv Khedhri) was studied under salinity where NaCl was added to the nutrient solution. The concentrations of NaCl in the nutrient solution were 0.12 as control 6, 12, 20 and 30 g/L (as treatments). Seedlings (about 3 months old) were watered by these solutions for four weeks in the green house. When the osmotic potential of the external medium was decreased, the total potential of the tissue (psi-t) decreased proportionally (about 5 bars). Relative water content (RWC) had the same trend as that of (psi-t) where salinity treatment resulted in lower RCW (97%-89%). Of the compounds that accumulated in the tissue were Na+ and proline. Proline accumulation in plant was enhanced by the presence of NaCl in the medium. Other parameters, such as K, Mg, Ca, PO4, sugars and total amino acids did not show regular changes in their concentrations which indicate that they do not have a specific role in the osmoregulation of these seedlings.