Water scarcity in the Mediterranean basin, especially in countries in arid zone appears as one of the main factors limiting agricultural development. In order to overcome water shortages, the use of water of low quality is becoming important in many countries. The use of saline water is a promising alternative. Mycorrhizal colonization is often thought to increase the ability of salt tolerance in certain plant species. It is difficult to identify potential AM fungal effects on plant function that are not directly related to mycorrhizal enhancement of plant P nutrition. There is, however, increasing evidence that AM fungi stimulate root growth independent of P nutrition. The mechanisms by which this fungus alleviated salt stress appeared to be based on physiological processes. Therefore, the objective of this book was intended to study the effect of different water salinity levels on the morphology, physiology and anatomy of sour orange and Volkamer lemon seedlings. Moreover, the study aimed to elucidate the efficiency of the endomycorrhizal fungus (AM) on controlling the various hazards accompanying salinity stress.