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.

Morpho-Physiological and Biochemical Attributes of Tall Fescue (Festuca arundinacea Schreb.) Inoculated with Pseudomonas fluorescens under Deficit Irrigation

“…It was found that inoculation with Pf caused enhancements in the physico-biochemical and morphological attributes of turfs under deficit irrigations in comparison with respective controls. There is ample research exploring the drought-resistant qualities of different cultivars of tall fescue (Mahdavi et al 2018). The findings of the previous literatures and the present study found that increases in drought stress cause a reduction in TQ, FW, and RWC.…”

“…Studies conducted on drought tolerance of various cultivars of tall fescue proved an increase in Pro concentration in response to increasing drought stress (Cao et al 2009;Ebrahimiyan et al 2013;Pirnajmedin et al 2015;Man et al 2011;Sarmast et al 2015). According to the findings of Mahdavi et al (2018) and the present research, tall fescue could be used as a model plant for SOD, superoxide dismutase; POX, peroxidase activity; In, greenhouse condition; Out 1st, outdoor environment in the 1st year; Out 2nd, outdoor environment in the 2nd year; TRTs, treatments; CTL, control; Pf, Pseudomonas fluorescens increasing Pro to deal with drought stress. This research also shows an increase in SOD and POX activity levels while dealing with drought stress.…”

“…Several researchers reported that a reduction in Chl content due to increasing drought stress in tall fescue which this reduction has not always been completely consistent due to the unique genetic features of each cultivar or as a result of differences in weather conditions and soil type. In the cases of initial stress or periods of mild stress, a temporal and sometimes irregular increase of stress showed reduction in Chl content by prolonging and intensifying the stress (Ebrahimiyan et al 2013;Fu and Huang 2001;Jiang and Huang 2001;Lee et al 2007;Mahdavi et al 2018;Pirnajmedin et al 2015;Sarmast et al 2015). Studies conducted on drought tolerance of various cultivars of tall fescue proved an increase in Pro concentration in response to increasing drought stress (Cao et al 2009;Ebrahimiyan et al 2013;Pirnajmedin et al 2015;Man et al 2011;Sarmast et al 2015).…”

“…Physico-biochemical properties of the soil and chemical analysis of the irrigation water used were carried out. Data is shown by Mahdavi et al (2018). The plastic pots used for the experiments held a volume of 25 L, and measured 36 cm in height and 33 cm in diameter.…”

“…Average day and night temperatures were between 30 ± 3°C and 24 ± 3°C, respectively, and the relative humidity was measured to be 50 ± 5% in the greenhouse. The following data concerning the climatic conditions are elaborated by Mahdavi et al (2018). Monthly temperatures were read at their maximum and minimum averages in July and March, which were recorded 25.76°C and 8.16°C, respectively.…”