Physiological Responses of Two Cool-season Grass Species to Trinexapac-ethyl under Traffic Stress

Abstract

<jats:p>Traffic stress is one of the major abiotic stresses that limits grass growth in lawn fields. The severity of losses depends on several factors, including the number of events per season, the athletic field size, and the soil moisture content during the traffic incident. Trinexapac-ethyl (TE) is considered to influence plant tolerance to traffic stress. Therefore, the physiological responses of the wheatgrass <jats:italic>(Agropyron desertorum</jats:italic> L.) and tall fescue (<jats:italic>Festuca arundinacea</jats:italic> L. cv. Rebel) species to different levels of TE and traffic stress were investigated. A factorial experiment including combination of TE application and traffic stress treatments was performed based on a randomized complete block design (RCBD) with three replications in 2014 and 2015. The treatments, including traffic stress (traffic and nontraffic stress) and TE at three levels (0, 0.25, and 0.5 kg·ha<jats:sup>−1</jats:sup>), were applied once every 3 weeks. The simulated traffic stress was imposed using a Brinkman traffic simulator (BTS). The results showed that traffic stress reduced the turf quality, relative water content (RWC), total chlorophyll content, and antioxidant activity and increased electrolyte leakage (EL), soluble sugar content (SSC), and malondialdehyde (MDA) in both species. Conversely, TE increased the turf quality, RWC, SSC, and total chlorophyll and resulted in less EL and MDA in both species. Furthermore, TE application increased the superoxide dismutase (SOD) (EC 1.15.1.1), ascorbate peroxidase (APX) (EC 1.11.1.11), and peroxidase (POD) (EC 1.111.1.7) activities, especially under traffic stress conditions. TE application enhanced the resistance to traffic stress in both species by improving the osmotic adjustment and antioxidant activity.</jats:p>

Establishment and traffic stress response of tall fescue as affected by Mycorrhiza fungi and Trinexapac-ethyl

“…Wear injury would damage turf grass canopy parts (crowns, leave and stem) by physical compaction and abrasion that may decrease RWC (Christians et al, 2004). Also, Ervin and Koski (2001) and Mohamadi et al (2017) indicated that traffic stress condition decreased RWC, however, TE treatment increased RWC along with evapotranspiration rate and leaf growth rate decreasing, and all of these are consistent with this study results. Although, other studies found that applying TE significantly increased the leaf RWC under traffic stress (Mohamadi et al, 2017), but our results demonstrated that RWC significantly decreased under TE (200 g 100 m -2 ) application and traffic stress.…”

“…TE was not absorbed after high traffic stress and interaction between TE and Traffic stress considerably diminished the turf quality in 2017, because of high traffic stress and crown compaction (Figure 2E). Therefore, this study findings do not support the controversial claims in the study accomplished by Mohamadi et al, (2017). Fagerness and Penner (1998) claimed that the plant base (crown) being the greater site of absorption for TE, on the other hand traffic stress injures crowns by compressing which in turn may result in TE absorption loss.…”

“…Turfgrass wear tolerance can be increased applying several methods. Higher weartolerance cool-season turfgrass genus selecting (Trappe et al, 2009) and also plant growth retardants application are two important methods for eliminating traffic stress (Mohamadi et al, 2017).…”

“…Trinexapac-ethyl (TE) is a popular plant growth substances (Gibberellic acid inhibitor) in the turf grass industry and could efficiently increase the chlorophyll content and turf quality , however, it reduces the leaf elongation and clipping production (Ervin and Koski, 2001). Hereafter, TE can enhance both drought and wear tolerance (Mohamadi et al, 2017). Moreover, TE increased the quality of turf and wear tolerance of bermudagrass under simulated traffic stress (Williams et al, 2010).…”

Mechanisms of Environmental Stress Tolerance in Turfgrass

“…Tolerance to this stress is associated with a high vascular bundle number, wide leaves, high leaf angle, and high root length density [169,170]. Physiological changes in turfgrass species were detected under traffic stress, such as a decrease in RWC, shoot density, root length, leaf Chl concentration, non-structural carbohydrates content, and POD activity, while the cell membrane permeability was increased in both warm-season and cool-season turfgrass species after traffic stress treatment [171][172][173]. Both lignin and carbohydrate concentrations proved to be important factors related to the wear resistance of turfgrass [174].…”