Arbuscular mycorrhizal symbiosis of Thymus kotschyamus Boiss. & Hohen. in relation with soil elements during spring and autumn in Noujian Watershed (Lorestan province)

Arbuscular mycorrhizal fungi (AMF) are the most important microorganisms of soil having an important role in soil fertility. In this research, the correlation between soil nutrient elements and Arbuscular mycorrhizal fungi colonization and spore numbers in the rhizosphere of Thymus kotschyamus Boiss. & Hohen. growing in the three regions (Taf, Vark and Kohkala) of Noujian watershed were studied during spring and autumn. Influence of arbuscular mycorrhizal symbiosis were also determined on vegetative characteristics and essential oil yield of T. kotschyamus.The results indicated that magnesium significant positive correlation with arbuscular mycorrhiza fungi spore density (.84) and percentage colonization (.92). Soil organic matter no significant linear correlation with arbuscular mycorrhiza fungi spore density and percentage colonization. Potassium negatively correlated with spore density and percentage colonization respectively; -0.85 and -0.90. Arbuscular mycorrhizal fungi colonization significant linear correlation with dry weight (.79). Essential oil yield of T. kotschyamus positively correlated with that of spore density and percentage colonization respectively; .93 and .91. Given the importance of mycorrhizal symbiosis and compilation this with soil elements, this information can be useful for development of medicinal plants in agricultural ecosystems.