Can arbuscular mycorrhizal fungi ameliorate the adverse effects of deficit irrigation on tall fescue (Festuca arundinacea Schreb.)?

Abstract: With increasing concerns over global warming, the shortage of water supplies has turned to be a disputable problem in the world. Drought stress is one of the most prevalent abiotic stresses that affect turfgrass growth and quality in landscapes of arid or semi-arid regions. Among the common cool-season turfgrasses, tall fescue can tolerate drought more than other grasses. Fungal bio-fertilizers, especially Arbuscular Mycorrhizal Fungi (AMFs) are able to alleviate the harmful effects of abiotic stresses in the plant. This study was conducted in two consecutive years, 2014 and 2015, to evaluate how two types of AMFs (Funneliformis mosseae and Rhizophagus irregularis) would affect the growth characteristics of two cultivars (‘H-d’ and ‘J-r’) of tall fescue (Festuca arundinacea Schreb.) in the greenhouse and field conditions. Three irrigation intervals were applied, i.e. 7, 14 or 21-days. Results showed that by irrigating less frequently, the visual quality of turfgrass decreased, and there were reductions in the fresh weight, chlorophyll content, and relative water content. However, there were increases in the amount of phosphorus in the shoots, root colonization, compatible solutes (proline and glycine betaine) and antioxidant enzymes (superoxide dismutase and peroxidase). However, these changes were more pronounced in turfgrasses that were treated with AMFs. Qualitative and quantitative characteristics were substantially more promising in the greenhouse than in the field. This is the first report on the morpho-physiological and biochemical responses of tall fescue to AMFs. Results of this investigation could inspire further such works on other turfgrasses, given that the inoculation of turfgrasses with AMFs is a new approach with uncharted potentials that aims at reducing water consumption in the landscape environment.