Heat Tolerance of Kentucky Bluegrass as Affected by Trinexapac-ethyl

Abstract

Heat accumulation during storage of sod may reach lethal temperatures within 4 days, decreasing sod quality. Treatment with trinexapac-ethyl reduces heat accumulation during sod storage. However, heat tolerance of grasses treated with trinexapacethyl has not been documented. Our objectives were to: 1) determine the lethal temperatures for Kentucky bluegrass (Poa pratensis L.); and 2) identify the effect of a single application of trinexapac-ethyl on heat tolerance. Experimental design was a randomized complete block with three replications and a two (trinexapac-ethyl vs. control) × × × × × two (cultivars) factorial arrangement of treatments. Ten days after chemical treatment, Kentucky bluegrass sprigs were exposed to heat stress for 4 days in a temperature gradient block under low vapor pressure deficit. Treatment with trinexapac-ethyl at 0.23 kg·ha -1 reduced heat tolerance. Temperature needed to kill 50% of the population was 35.5 °C for treated vs. 36.1 °C for nontreated grass. Trinexapac-ethyl is in the same chemical family as the cyclohexanedione herbicides that interfere with lipid syntheses in grasses. This may be a reason for the slight decrease in heat tolerance. The practical value of trinexapac-ethyl treatment in reducing heat accumulation during storage of sod may be partially negated by a decrease in heat tolerance. Chemical name used: [(4cyclopropyl-α α α α α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] (trinexapac-ethyl).

Chemical plant protectants and plant growth regulator effects on annual bluegrass survival of ice cover

“…It has been shown to reduce grass clipping yield in multiple grass species including Kentucky bluegrass ( Poa pratensis ), perennial ryegrass, creeping bentgrass and ABG (Ervin & Koski, , ; Kreuser & Soldat, ; Landry & Murphy, ). The chemical TE has been shown to decrease tolerance to heat stress in Kentucky bluegrass (Heckman, Horst, Gaussoin, & Young, ). However, TE has also been shown to play a role in improving heat tolerance when combined with drought stress in creeping bentgrass (McCann & Huang, ).…”

“…Heckman et al. () concluded that it could have been due to TE being in the same class as cyclohexanedione, which interrupts lipid synthesis. Effects on lipid synthesis are relevant to the FA results found here.…”

Trinexapac‐ethyl and Paclobutrazol Affect Kentucky Bluegrass Single‐Leaf Carbon Exchange Rates and Plant Growth

“…The effect of PGRs on turfgrass CERs are generally measured on turfgrass canopies rather than single leaves due to the tedious nature of turfgrass leaf area measurements. However, gibberellin‐inhibiting PGRs have been reported to increase turfgrass canopy density through increasing tillering, widening leaf blades, and delaying leaf senescence (Heckman et al, 2001; Ervin and Koski, 2001; Ervin and Koski, 1998; Wiles and Williams, 1985). Therefore, calculation of turfgrass CERs on a ground area basis without taking into account changes in leaf area may not accurately reflect the effects of PGRs on single plant and/or sward CERs.…”

Effects of Trinexapac‐Ethyl and Daconil Action (Acibenzolar‐S‐Methyl and Chlorothalonil) on Heat and Drought Tolerance of Creeping Bentgrass

“…Previous studies with plant growth regulators such as TE have found beneficial effects on plant stress tolerance (Heckman et al, 2001; Zhang et al, 2003; McCann and Huang, 2008; Bian et al, 2009; Xu and Huang, 2010). To our knowledge, our study is the first to examine the combined effects of a plant growth regulator with a fungicide that has plant health benefits under field conditions.…”

“…This ultimately results in plants having reduced height, increased density, and improved canopy characteristics (McCullough et al, 2007; Wherley and Sinclair, 2009). Furthermore, TE has also been implicated in improving the abiotic stress tolerance of turfgrasses (Heckman et al, 2001; Zhang et al, 2003). These effects of TE on abiotic stress tolerance have been studied in creeping bentgrass ( Agrostis stolonifera L.), with the applications of TE improving drought tolerance by maintaining leaf hydration, leaf growth, and photosynthetic parameters (McCann and Huang, 2008), as well as increasing osmotic adjustment (Bian et al, 2009).…”