Turf Quality and Physiological Responses to Summer Stress in Four Creeping Bentgrass Cultivars in a Subtropical Zone

Abstract

Cool-season creeping bentgrass (Agrostis stolonifera) has the ability to form fine sports turf, but high temperatures result in summer bentgrass decline (SBD), especially in transitional and subtropical zones. Physiological responses in combination with the alteration in turf quality (TQ) will contribute to a better understanding of SBD in a subtropical zone. Field experiments were conducted from 2017 to 2019 to test the adaptability to summer stress among four cultivars (13M, Penncross, Seaside II, and PA-1). A constant ambient high temperature above 30 °C significantly decreased the TQ of the four cultivars during the summer months in 2017, 2018, and 2019. Significant declines in the chlorophyll content, photochemical efficiency of photosystem II (Fv/Fm and PIABS), leaf relative water content (RWC), and osmotic potential (OP) were induced by summer stress, whereas gradual increases in water-soluble carbohydrates, proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), and electrolyte leakage (EL) were observed in the four cultivars during the summer months. The 13M and Penncross cultivars exhibited better performance than Seaside II and PA-1 in response to summer stress from 2017 to 2019, which is associated with better maintenance of photosynthesis, water status, WSC and proline accumulation, and cell membrane stability. The 13M and Penncross cultivars could be used as potential candidates for turf establishment in a subtropical zone. Physiological responses together with alterations in TQ also provided critical information for the breeding and development of germplasm with heat tolerance in creeping bentgrass species.

Foliar application of diethyl aminoethyl hexanoate (DA‐6) alleviated summer bentgrass decline and heat damage to creeping bentgrass

“…Leaf senescence is a classical symptom of SBD, which is distinguished by leaf chlorosis as a result of Chl degradation, water imbalance, and loss in cell membrane stability during high temperature stress (Li et al., 2022; Xu & Huang, 2004). Therefore, Chl content and fluorescence parameters as well as EL have been widely conducted to evaluate summer heat tolerance of different creeping bentgrass genotypes in field (Jespersen et al., 2018; Li et al., 2021, 2022). Many studies have confirmed that beneficial effects of DA‐6 have been attributed to mitigations of losses in Chl, Fv/Fm, and cell membrane stability in different plant species under drought, salt, or cold stress, but limited information is available in response to heat stress (Hassan et al., 2022; Lu et al., 2021; C. Zhang et al., 2016).…”

Assessing Heat Tolerance in Creeping Bentgrass Lines Based on Physiological Responses

“…Furthermore, our study also detected strong correlations of physiological factors plus MDA content with all fluorescence traits except for REo/ABS. As a reliable parameter commonly used in heat stress screening, it was not surprising that TRo/ABS showed the strongest associations with other factors [ 14 , 17 , 46 ]. Nevertheless, it’s noteworthy that DIo/ABS had the same correlation coefficients as TRo/ABS did, indicating its potential as another rapid and reliable measurement for thermotolerance evaluation in turfgrasses.…”

“…It not only contributes to increased osmotic adjustment but also improves the integrity of cellular membranes, helping relieve plants from heat-induced damages, which has been documented in creeping bentgrass [ 59 ] and other plant species [ 60 , 61 ]. Moreover, ESC turned out to accumulate more in creeping bentgrass cultivars with better summer performance [ 14 ]. The authors proposed that elevated temperature resulted in rapid loss of water, causing dehydration, as manifested by the declines in leaf relative water content and osmotic potential, while accumulation of sugars could produce positive effects on water homeostasis, thus explaining the higher sugar contents along with better leaf water status and osmotic adjustment abilities found in the more heat-tolerant cultivars.…”

“…A few defense pathways have been clarified to be common strategies responding to heat stress in turfgrasses, like enhanced ROS detoxification, greater maintenance of photosynthesis ability, or altered protein metabolism [ 7 ]. Nonetheless, it should be noted that the specific changes may differ between species, or even cultivars and genotypes, which plays a pivotal role in the wide divergence in thermotolerance [ 9 , 13 , 14 ]. Creeping bentgrass shows considerable intraspecific diversity among different lines for its tolerance to heat.…”

A bermudagrass variant exhibits strong tolerance to low temperature associated with enhanced sugar metabolism and cold‐responsive pathways

“…Total Chl content, Chl a content, and Chl b content were detected according to assay method of Arnon (1949). Determinations of Fv/Fm and PI ABS were conducted by using a Chl fluorescence system (Hansatech, UK) (Li et al., 2022b).…”