The effect of short-term treatments (10 days) by a high salt level (150 mm NaCl) on vegetative and reproductive development was investigated in tomato plants (Solanum lycopersicum L. cv. Ailsa Craig) at two developmental stages. Salinity applied during flowering transition reduced shoot biomass and delayed the appearance of the first inflorescence. Both shoot and root biomasses were reduced when salt was applied during the development of the first inflorescence. At both stages, areas of young leaves decreased and time to first anthesis increased, while total number of flowers in the first inflorescence was not affected. Flower abortion, reduction of pollen number and viability were higher when salinity was applied during inflorescence development. Na⁺ accumulated in all organs while K⁺ decreased. Laser ablation inductively coupled plasma mass spectrometry microanalysis revealed that Na⁺ accumulated in style, ovaries and anther intermediate layers but not in the tapetum nor in the pollen grains when salinity was applied during inflorescence development. K⁺ was not significantly affected in these structures. Soluble carbohydrates dramatically increased in leaves and decreased in the inflorescence under salt stress conditions. The failure of inflorescence to develop normally under salt stress can be better explained in terms of altered source–sink relationships rather than accumulation of toxic ions.