A field experiment was undertaken to investigate the effectiveness of arbuscular mycorrhizal (AM) fungi (Funneliformis mosseae) on nutrients uptake, biomass production, yield components, chlorophyll content and essential oil yield and composition in fenugreek (Trigonella foenum graecum L.), coriander (Coriandrum sativum L.) and nigella (Nigella sativa L.). All these medicinal plants were grown with or without AM fungi colonization. A randomized complete block design with three replications was employed to compare the treatments. Mycorrhiza colonization increased shoot P, Ca, Zn and Fe contents. However, K contents of fenugreek and nigella was not affected by AM colonization. AM colonization significantly increased the growth and yield components, chlorophyll content, and EO yield as compared to non-colonized plants. Changes in EO composition were detected in AM-colonized fenugreek, coriander and nigella plants. The contents of ether, limonene, carvone, iso-dihydrocarvone, myristicin, p-cymene, decanal, 2-decenal and n-dihydrocarvone were enhanced in EO obtained from AM-colonized plants, while AM colonization resulted in a lesser content of β-phellandrene, iso-dihydrocarveol, 1-decanol, cis-sabinol, pentadecanal, 2-pentadecanone,6,10,14-trimethyl, cis-9,17-octadecadienal, phytol and trans-2-dodecenal.
