Arbuscular Mycorrhizal Fungi Alleviate Soil Salinity Stress in Arid and Semiarid Areas

Soil salinization is an increasingly important problem in many parts of the world, particularly in the arid and semiarid areas. Soil salinity affects plant growth adversely, by disrupting their physiological mechanisms due to excessive Na+ and Cl− ions toxicity toward cells. The toxic effects include disruption of enzyme structure and other macromolecules, disruption of photosynthetic efficiency, gas exchange, membrane organization, and water status. Salinity may directly or indirectly inhibit plant cell division, development, and productivity. To overcome the detrimental effects and to improve plant tolerance to stresses, particularly salt stress, plants adopt a wide variety of strategies including symbiotic association with soil fungi such as the arbuscular mycorrhizal fungi (AMF). The use of arbuscular mycorrhizal fungi proved to be an interesting way for the management of native flora and restoration of natural habitats with minimal chemical inputs. Unfortunately, the knowledge about restoration of salt-affected ecosystems using AMF biofertilizer is limited. This chapter aims to review the impact of salinity stress on plants and on AMF life cycle and physiology and to describe the effect of AMF biofertilizers on plant development underlying physiological, biochemical, and molecular plant mechanisms within the context of salinity stress.