Ecophysiological Response of Mycorrhizal Dragon's Head plants to Irrigation Levels

In order to evaluate the effect of mycorrhizae on the physiological characteristics and yield of medicinal plant ‘Dragon’s head’ under different irrigation regimes, a 2-year (2014 and 2015) split plot experiment was conducted based on randomized complete block design with three replications at the Agricultural Research Field of Shahid Beheshti college of Urmia. Treatments were irrigation after 40, 80, 120 and 160 mm of evaporation from pan class A as main plots and mycorrhizae (Glomus intraradices, G. versiformisand control) as sub plots. The effects of irrigation and mycorrhizae on the leaf chlorophyll (a, b and total), carotenoid, superoxid dismutase and malon dialdehyde were not significant. The highest total soluble carbohydrates (110.7 µmol/g fresh weight) and yield of essential oil (2.258 kg.ha-1) were respectively obtained from irrigation after 120 and 80 mm of evaporation. The maximum number of pod per plant (19.34), 1000-seed weight (3.081 g) and seed yield (589.7 kg.ha-1) belonged to inoculated plants (G. intraradices). The greatest number of nod per pant (12.5) and stem diameter (1.16 mm) were obtained from mycorrhizal (G. intraradices) plants irrigated after 80 mm of evaporation. The highest harvest index (26.84 %) and betaine glycine (51 µmol/g fresh weight) were respectively observed in irrigation after 80 and 160 mm of evaporation in mycorrhizal plants (G. versiformis). In conclusion irrigation of for 80 mm of evaporation from pan class A due to lower water use and higher performance in mycorrhizal Dragon's head plants was recommended.