Aims Ferula L. is one of the largest genera from Apiaceae family with about 180 species, which grow in semi-arid rangelands. One of the challenges associated with this genus in their natural habitats is drought and additionally in case of Ferula haussknechtii H. Wolff ex Rech.f. species is allelopathy caused by companion with Artemisia persica Boiss. Materials & Methods The present study aimed to investigate the roles of Arbuscular Mycorrhizal (AM) fungi in the growth, physiological characteristics, nutrient uptake, and survival of Ferula haussknechtii H. Wolff ex Rech. F. grown under the interactive influences of drought and allelopathy stress conditions. Four levels of allelopathy stress, three levels of drought stress, and two mycorrhizal treatments (AM and Non-AM) were applied to the pots in a completely randomized design with a factorial arrangement. Findings Based on ANOVA results (p≤5%), the survival capacities of the Non-AM inoculated plants were significantly less than those of the AM inoculated plants for all allelopathic and drought stress levels. The maximum values of survival capacity were seen in AM×FC×A1 treatment as 75% and the lowest survival capacity was observed in Non-AM×30%FC×A4 as 29%. In general, AM fungi inoculation significantly increase the root:shoot ratios and mycorrhizal dependency values (p≤5%). Based on ANOVA results, the highest and lowest values for root:shoot ratios were observed as 0.71 and 0.27 for Non-AM×30%FC×A4 and AM×FC×A1 treatments, respectively. Drought stress and allelopathic conditions have a destructive effect on total chlorophyll content. The maximum and minimum proline content (0.21 and 0.04) was observed in treatment of AM incubated with highest level of drought and allelopathic and in Non-AM incubated with lowest level of drought and allelopathic, respectively. Conclusions AM fungi inoculation had a significant positive effect on total nitrogen and phosphorus content in plant tissues but a significant negative effect
