Variation in the Essential Oil Composition and Morphological Parameters of Thymus daenensis Clack. with Two Species of Mycorrhizal Fungi Under Water Deficit Conditions

Abstract

To investigate the effects of arbuscular mycorrhizal fungi (AMF) and drought stress on essential oil (EO) and chemical composition of Thymus daenensis Clack, an experiment was conducted at Shahrekord, Iran in 2017.The experiment was arranged as a factorial pattern in a randomized complete design with three replications. Factors were consisted of four irrigation regimes and two inocula. The first factor included four irrigation regimes, consisted of well-watered (A: absence of stress), irrigation after depletion of 20-25 % of field capacity (FC) (L: low stress), irrigation after depletion of the 35-40 % of FC (M: mild stress) and irrigation after depletion of the 55-60 % of FC (S: severe stress). The second factor included two mycorrhizal fungus treatments, non-inoculation with AMF (C: control) and inoculation with AMF (M: Funneliformis mosseae, Rhizophagus intraradices). The results showed that use of AMF and water stress at low rate increase some morphological characters and these increases were more evident at root part. Application of AMF did not have any significant effects on EO but, low water stress had significant effects on it. Interaction of AMF and water stress at low rate showed increases on root mycorrhization but did not have any positive significant effect on EO. Separate application of AMF and water stress had significant effects on 16 and 18 components of EO, respectively. Interaction of AMF and water stress significantly affect on 16 EO components especially thymol and carvacrol, two important components of T. daenensis EO.

Key words:

• Thymus daenensis Celak
• essential oil
• arbuscular mycorrhizal fungi
• drought stress