Mycorrhizal plants often have greater tolerance to drought than non-mycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on total protein, essential oil content and physiological traits of Glycyrrhiza glabra grown in a greenhouse under water stress condition. The experiment was conducted in factorial arrangement in a completely randomized design using 5 replications. 100, 80, 60, 40 and 20 % of field water capacity (as water stress levels) and two AM fungal levels were applied. Control (without inoculation) and inoculated (with AM fungi) were two mycorrhizal levels. The highest and lowest leaf area values were found in AM fungi Inoculated treatment with the lowest water stress (% FC) level and 20 % FC without AM inoculation. The maximum percentage values of shoots height and shoots dry weight have been seen in in AM fungi Inoculated treatment with the lowest water stress (% FC). While the maximum percentage values of root length and root dry weight were found in AM fungi Inoculated treatment with 80 % FC water stress. Essential oil content of plants significantly increased in AM fungi Inoculated treatment with 80 % FC water stress. There were significant differences found between essential oil contents of plants at various water stress and mycorrhizal treatments. There was significant difference between total protein content of plants in AM fungi inoculated treatment with FC and 80 % FC water stress and other treatments. Total protein content was reduced from 48 to 5 μM/g FW, for AM fungi inoculated treatment with FC and without AM inoculation treatment with the 20 % FC, respectively. The results suggest that Glycyrrhiza glabra could be used for arid and semi-arid lands economical use.
