Ethephon Induced Changes in Vegetative Growth of ‘Tifton 85’ Bermudagrass

Abstract

The establishment rate of warm-season turf and forage grasses propagated by sprigs or cuttings is of economic importance by determining not only how quickly an area may be utilized but also by influencing the extent of weed invasion. We monitored 'Tifton 85' bermudagrass [Cynodon dactylon (L.) Pers.] vegetative growth response to the application of ethephon (2-chloroethylphosphonic acid), an ethylene-producing compound, and how this treatment affected subsequent vegetative establishment. Responses of established Tifton 85 plants to ethephon treatment when compared with untreated plants included a 22% reduction in plant height, node swelling, bud swelling at the crown, terminal leaf necrosis, chlorotic striping of young developing leaves, and a 118% and 101% increase in leaf/stem fresh and dry weight ratios, respectively. Swelling of ethephon-induced buds appeared to be due to a transient arrest in sprouting. Swelled buds finally sprouted 9 d following ethephon treatment. In glasshouse experiments, vegetative cuttings taken from ethephon treated plants produced 112% more roots under a range of water stress conditions 8 d after cutting removal, and produced 10-fold higher number of tillers at 6 d after planting in soil than untreated cuttings. Tiller production in the soil establishment study was not statistically different between ethephon treated and untreated plants after 21 d. These glasshouse results indicated that it may be feasible to develop ethephon treatments that improve establishment rate and subsequent stand quality of Tifton 85 bermudagrass in field/commercial applications. M ANY ECONOMICALLY DESIRABLE warm-season grasses must be established via vegetative propagation. This includes many bermudagrass forage and turf cultivars and stargrasses (Cynodon sp.), St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and pangolagrass (Digitaria eriantha Stent.

‘TifEagle’ Bermudagrass Response to Plant Growth Regulators and Mowing Height

“…Enhancement of turf quality throughout this 2‐yr field study with low‐dose trinexapac‐ethyl treatments, compared to the control and other PGRs, provides further evidence as to why trinexapac‐ethyl is the most widely used PGR on intensely managed turfgrass. Acceptable turf quality (∼7) provided by ethephon was somewhat surprising though, as other studies have indicated negative effects on visual quality following ethephon treatment (Shatters et al, 1998; McCullough et al, 2004, 2005a, 2005b). The lower application rate of ethephon used in this study likely explains the higher visual quality achieved.…”

“…The release of ethylene within a plant signals stress or injury and reduces growth by inhibiting hypocotyl elongation and producing other physiological and morphological changes that help reduce the impact of injury or stress on plant survival (Bleecker and Schaller, 1996). However, actual responses following ethephon treatment can be highly variable and may depend on plant species, ethephon concentration, and duration of exposure (Shatters et al, 1998). Furthermore, response to ethylene may include stimulation or inhibition of root development, shoot elongation, seed germination, and flower development (Shatters et al, 1998).…”

“…However, actual responses following ethephon treatment can be highly variable and may depend on plant species, ethephon concentration, and duration of exposure (Shatters et al, 1998). Furthermore, response to ethylene may include stimulation or inhibition of root development, shoot elongation, seed germination, and flower development (Shatters et al, 1998). Thus, the impact of ethephon on plants is not as directly focused on reducing shoot growth and stem cell elongation as inhibitors of gibberellic acid biosynthesis.…”

“…Ethephon suppressed annual bluegrass ( P. annua L.) growth and seedhead production, allowing creeping bentgrass to spread into areas previously occupied by annual bluegrass (Eggens et al, 1989). Application of ethephon on ‘Tifton 85’ bermudagrass turf resulted in reduction in plant height but also caused necrosis of terminal leaves and necrotic‐clorotic striping of developing leaves (Shatters et al, 1998). Turf discoloration and thinning of creeping bentgrass following application of ethephon was reported by Kane and Miller (2003).…”

Effects of Various Plant Growth Regulators on the Traffic Tolerance of ‘Riviera’ Bermudagrass (Cynodon dactylon L.)

“…McCullough et al (2005b) reported a 22% reduction in growth (measured as clipping reduction) with sequential ethephon applications to 'TifEagle' hybrid bermudagrass; however, the researchers also reported linear reductions in bermudagrass quality with increasing rates of ethephon and as high as a 33% reduction in root mass. Although shoot density was not measured, both McCullough et al (2005b) and Shatters et al (1998) observed discolorations in bermudagrass leaf tissue and severe shoot thinning after treatment with ethephon. These responses suggest that ethephon may reduce bermudagrass traffic tolerance, but data describing the effects of ethephon on bermudagrass athletic field turf have not been reported.…”