Abstract: The ecophysiological adaptive responses of some halophytes (Avicennia marina, Atriplex farinosa, Limonium axillare, Nitraria retusa, Arthrocnemum glaucum and Halocnemum strobilaceum) and wide ecological amplitude species (Salsola tetrandra) were studied under different habitat conditions of two regions (Red Sea and Sinai Peninsula) during winter and summer seasons. The changes in plant quaternary ammonium salts, proline, total soluble protein and protein pattern in relation to habitat conditions were discussed. Both of halophytes and species of wide ecological amplitude accumulated higher contents of quaternary ammonium compounds, proline and total soluble protein. Salt stress in the most studied species was associated with the formation of certain adaptive stress proteins, which may play a role in protecting the membranes.