Effects of salinity stress on water desalination, olive tree (Olea europaea L. cvs ‘Picholine’, ‘Meski’ and ‘Ascolana’) growth and ion accumulation

The effects of salinity, on three olive tree cultivars (‘Picholine’, ‘Meski’ and ‘Ascolana’), growing under greenhouse conditions, were studied through the following parameters: vegetative growth, stomatal density and ion accumulation (Na+, K+, Ca2+, and Cl−). Olive plants were subjected to three saline irrigation treatments: T0 (irrigated with tap water), T1 and T2 irrigated with 6 and 9g of NaCl·l1 solution respectively. As salinity increased, vegetative growth, stomatal density, root dry weight and root density of ‘Meski’ and ‘Ascolana’ declined sharply. Sodium accumulation was greater in leaves and roots with increased external NaCl concentration, but differently according to cultivars. In fact, Na+ concentration was higher in leaves than in roots for ‘Meski’ and ‘Ascolana’ cultivars. However, for ‘Picholine’ the highest content of Na+ was in roots. Generally, ‘Picholine’ accumulate less Na+ in leaves and were able to maintain higher K+/Na+ ratios compared to other cultivars. In leaves, ratios of K+/Na+ and Ca2+/Na+ between cultivars were lower in salinity treatments compared to control. ‘Meski’ and ‘Ascolana’ have a higher power of water desalination than ‘Picholine’. •Effect of irrigation with saline water was assessed on three olive cultivars.•Irrigation with saline affect growth, root density and stomatal density•Na+ concentration was higher in leaves than in roots.•Picholine seems to be most resistant cultivar to saline water.•Olive tree can be used as a desalination plant to valorise saline water.