مشخصات پژوهش

Water-deficit stress is one of the most important limiting factors for field crops in arid and semi-arid regions [1]. Plant growth under stress conditions may be enhanced by the application of microbial inoculation including plant growth promoting rhizobacteria (PGPRs) and mycorrhizal fungi. These microbes can promote plant growth by regulating nutritional and hormonal balance, producing plant growth regulators, solubilizing nutrients and inducing resistance against plant pathogens [2]. In order to investigate the effect of water-deficit stress and the application of two biofertilizers on some growth traits and seed essential oil of fennel (Foeniculum vulgare Mill), an experiment was conducted as a split plots based on a randomized complete block design with three replications at the research farm, agricultural faculty of Azarbaijan Shahid Madani University, Tabriz-Iran in 2020. Factors were different levels of irrigation regimes including irrigation at the field capacity, 30% and 10% of total available moisture as the main plot and application of biofertilizers at three levels (control, Paenibacillus polymixa N179 and arbuscular mycorrhizal fungi) as a subplot. The results indicated that the application of biofertilizers had a significant effect on the studied morphological traits under water stressful conditions, such that water deficit stress caused to less impacts on plant growth using biofertilizres than the control treatment. Maximum main root length, number of secondary roots, plant height and number of sub-stems were obtained from plants under using arbuscular mycorrhizal fungi. Essential oil content increased in fennel seeds using biofertilizers particulary Paenibacillus polymixa N179 by increasing water-deficit stress condition in the soil compared with control. Totally, biofertilizers improved growth traits and essential oil content measured in fennel seeds under the severity of water stressful conditions.