Assessment of Arbuscular Mycorrhizal Fungi Associated with three species of Astragalus L. (Astragalus squarrosus, Astragalus effusus and Astragalus podolobus )

Arbuscular mycorrhizal fungi are one of the most essential components in natural ecosystems, because these organisms can enhance plant growth, plant reproduction, plant resistance to water stress, and plant health through antagonistic and competitive effects on pests and pathogens. Mycorrhizal symbiosis improves the resilience of the plants against environmental stresses such as nutrient deficiencies, drought and soil authority. Identifying arbuscular mycorrhizal fungi and examining their coexistence with plant species can help us use these fungi to increase the ability of plants to grow and increase their tolerance to environmental stresses. This study focuses on identification of: spore population abundance, diversity pattern, determination of colonization index as well as arbuscular mycorrhizal fungal species morphological diversity in with three species of Astragalus L. (Astragalus squarrosus, Astragalus effusus and Astragalus podolobus). The study was conducted in Trud and Joshlobar regions, Semnan province, Iran at the beginning and end of the growing season on the soil (rhizosphere). Mycorrhizal symbiosis was observed in all three species. Results showed that the highest symbiosis percentage was on A. podolobus (62%), A effusus (50.25%) and A. squarrosus (12.75%), also the spores number per gram of soil in the rhizosphere, regardless of their types, for A. squarrosus is 7.62, A. effusus 25 and A. podolobus 5.36. The predominant fungal species of A. squarrosus include Ambispora callosa (Sieverd.) C. Walker, Vestberg & Schuessler, Funneliformis mosseae (T.H.Nicolson & Gerd.) C.Walker & A.Schüßler, Dentiscutata reticulate Koske, D.D. Mill. & C. Walker, the predominant fungal species of the two common species A. podolobus, A. effusus common and includes Funneliformis mosseae (THNicolson & Gerd.) C.Walker & A.Schüßler, Funneliformis badium (Oehl, D.Redecker & Sieverd.) C.Walker & A.Schüßler and Glomus hoi Berch & Trappe.