Investigation of a Bacterial and Arbuscular Mycoorhizal Fungus Spore Inoculation in Cultivation of Saffron

Saffron (Crocus sativus L.) is prized for its stigma, a valuable spice rich in bioactive compounds crucial for various industries and traditional medicine. Enriched with bioactive compounds crucial for numerous industries and traditional medicinal practices, saffron cultivation expansion hinges on assessing the vegetative process in soils with low organic content. Optimal fertilization, considering plant and soil conditions, is crucial. Leaves indicate vegetative status and serve as an agricultural byproduct. In this study, saffron was grown in clay loam soil (1.88% organic matter) with supplementation of the bacterium Rhodobacter sphaeroides, spores of an arbuscular mycorrhizal fungus Glomus iranicum var. tenuihypharum, and both. Sole bacterium application increased leaf fresh and dry weight by 25.5% and 36.8%, respectively, demonstrating growth promotion. Rhodobacter sphaeroides and AMF combination elevated leaf P, Mg, and Cu concentrations, while AMF alone increased Zn, Mn, and B accumulation. Rhodobacter sphaeroides reduced Fe, Zn, Mn, and B soil concentrations, with no corresponding increase in their accumulation in the plant, as observed with mycorrhiza and the combination of microorganisms, hinting at its applicability for saffron cultivation in environments contaminated with heavy metals. In summary, the findings underscore the importance of microorganism supplementation in saffron cultivation, offering insights into optimizing growth conditions.