Ethephon Application Research Articles

Effects of Ethephon treatments on Ripening and Uniformity of Fig Fruit (Ficus carica. L)

The current experiment was carried out to determine the effect of the application of ethephon on the maturation of “Peter” figs. Fig fruits were treated with three aqueous concentrations of ethephon (500, 1000, and 1500 ppm) during the developmental stage. The physic-chemical characteristics, such as fruit weight, fruit length, fruit diameter, total soluble solids (TSS), and fruit acidity were recorded and analysed. The results showed that ethephon application during the developmental period of the fig fruits significantly accelerated fruit ripening and enhanced the fruits’ uniformity. Fig fruits treated with ethephon showed increased TSS compared to untreated fruits, and the acidity of the treated fruit decreased compared to that of untreated fruits. Additionally, TSS/ acidity ratio was significantly higher in 1500 ppm treatment in comparison with other treatments. On the basis of our data, we conclude that the application of ethephon to fig fruit increases ripening and uniformity of the fruit.

Return bloom enhancement of low, medium and high flowering ‘Golden Delicious’ apple trees by the application of 1-naphthaleneacetic acid and ethephon

ISHS XIV International Symposium on Plant Bioregulators in Fruit Production Return bloom enhancement of low, medium and high flowering ‘Golden Delicious’ apple trees by the application of 1-naphthaleneacetic acid and ethephon

Summer applications of NAA and ethephon show little effect on return bloom, yield, tree growth, and juice quality of cider apple cultivars

Summer applications of NAA and ethephon show little effect on return bloom, yield, tree growth, and juice quality of cider apple cultivars

Using brassinolide and girdling combined application as an alternative to ethephon for improving color and quality of 'Crimson Seedless' grapevines

AbstractThe color of 'Crimson Seedless' berries is a major constraint in expanding marketing and export potential. The target of this investigation is to enhance the color and quality of 'Crimson Seedless' by using brassinolide (BL) and girdling treatments, individually and in combination, as an alternative to ethephon over two consecutive seasons. The obtained results revealed that the combined treatment BL at 2.0 mg/L and girdling recorded the highest significant yield values (17.78 ± 0.29 and 18.26 ± 0.23 kg/vine) in both seasons, respectively, in contrast to ethephon and girdling treatments which had no significant influence. Besides, BL 2.0 mg/L + girdling presented high levels of physicochemical characteristics of clusters and berries compared to the control. Concerning berry color assessment, ethepon followed by BL at 2.0 mg/L + girdling recorded the highest significant improvement in the red color, as indicated by Color Index of Red Grapes and visual assessment, and had similar and elevated levels of anthocyanin content. On the other hand, flavonoids (3.46 ± 0.03 and 3.66 ± 0.02 mg/100 g FW), and antioxidant capacity (2.37 ± 0.02 and 2.43 ± 0.06 IC50) were obviously increased with BL 2.0 mg/L + girdling, with a slight decrease than ethephon application. As for phenylalanine ammonia-lyase activity, the data show that it increased by ethephon (7.91 ± 0.02 and 8.01 ± 0.02 U mg−1protein) and BL 2.0 mg/L + girdling (7.77 ± 0.04 and 7.79 ± 0.07 U mg−1protein), compared to the control (3.69 ± 0.02 and 3.80 ± 0.01 U mg−1protein) in both seasons, respectively. In terms of polyphenol oxidase activity, the increase in PPO was closely associated with PAL. Moreover, BL 2.0 mg/L + girdling was the most effective treatment for increasing dormant season parameters in both seasons, while ethephon spraying had no influence. All these confirmed that the combined treatment BL 2.0 mg/L + girdling exhibited a synergistic effect in improving the color and quality of 'Crimson Seedless'.

Foliar application of ethephon induces bud dormancy and affects gene expression of dormancy- and flowering-related genes in ‘Mauritius’ litchi (Litchi chinensis Sonn.)

A previous study showed that foliar application of ethephon to litchi trees with mature shoots and dormant terminal buds during autumn successfully inhibited new vegetative shoot growth prior to floral induction thereby promoting carbohydrate accumulation and flowering. However, the functional mechanisms of ethylene, the breakdown product of ethephon, in the leaves and terminal buds of litchi and its involvement in the flowering process is largely unknown. Therefore, this study aimed to investigate the phenological, physiological and molecular changes underlying ethephon application and its associations with bud dormancy and flowering in litchi. Ethephon was applied as a single full canopy spray at a concentration of 1000 mg⋅L−1 to ‘Mauritius’ litchi trees with mature vegetative shoots and dormant terminal buds during late autumn of 2018 (mid-April; Southern Hemisphere). Untreated trees served as a control. Phenological characteristics, such as bud dormancy and panicle development, leaf chlorophyll (as an indicator of shoot maturity), ethylene evolution, gene expression levels of flowering- (LcFT2, LcFLC and LcAP1), dormancy- (LcSVP1 and LcSVP2) and ethylene pathway-related (LcEIN3) genes and non-structural carbohydrates were determined in terminal buds, leaves and/or shoots. Ethephon application induced bud dormancy, significantly delayed panicle emergence and promoted pure floral panicle development under more favorable inductive conditions. Ethylene evolution increased sharply 2 h after application in both leaves and terminal buds, but decreased rapidly thereafter in the leaves, while remaining high in terminal buds for seven days before gradually declining. Ethephon application significantly increased relative expression of LcEIN3 and LcFLC in terminal buds one day after application, while LcFT2 expression in leaves and LcAP1 expression in terminal buds were significantly increased at the bud break stage. Significant treatments differences were also observed for various carbohydrate metabolites in leaves and shoots at the bud break or floral initiation stage. Our study provided evidence that ethephon application plays an important role in the physiological and molecular regulation of bud dormancy of litchi. By influencing the time of bud break, ethephon application can be a useful tool to manage panicle emergence under less inductive conditions.

Exogenous application of ethephon regulates flower abscission, shoot growth, and secondary metabolites in Camellia sinensis

Tea plant (Camellia sinensis (L.) O. Kuntze) consumes a large amount of nutrients and water during the flowering stage, which compromises the tea growth and yield. Ethylene is an important plant hormone that plays pivotal roles in regulating plant growth and flowering. but there are few studies on flowering and growth of tea plants regulated by this plant hormone. Here, we investigated the effects of exogenous ethephon application on the abscission of flowers and flower buds in tea plants. The results showed that application of ethephon induced the production of endogenous ethylene and the peak of ethylene production occurred three days post ethephon spraying on the tea plants. Ethephon treatment induced the abscission of tea flowers and flower buds, leading to reduced amount of flowers in the tea plantations. Ethylene receptors (ETRs) play critical roles in ethylene-mediated cellular responses, and we found that there was a certain correlation between the effect of ethephon on the flower abscission and the expression of several CsETRs, including CsETR3, CsETR4, CsETR5, and CsETR6. Ethephon also induced the high activities of superoxide dismutase, peroxidase, and catalase three days after treatment. In addition, ethephon obviously reduced the tea polyphenol content and enhanced the caffeine content in tea plants. Treatment with ethephon (3000 mg L–1) significantly increased tea shoot length and production in the tea plantations in the following early spring. Overall, ethephon, in a range of concentrations, could effectively suppress the tea plant blooming and improve tea yield and quality to a certain extent.

Fall Applications of Ethephon Modulates Gene Networks Controlling Bud Development during Dormancy in Peach (Prunus Persica).

Ethephon (ET) is an ethylene-releasing plant growth regulator (PGR) that can delay the bloom time in Prunus, thus reducing the risk of spring frost, which is exacerbated by global climate change. However, the adoption of ET is hindered by its detrimental effects on tree health. Little knowledge is available regarding the mechanism of how ET shifts dormancy and flowering phenology in peach. This study aimed to further characterize the dormancy regulation network at the transcriptional level by profiling the gene expression of dormant peach buds from ET-treated and untreated trees using RNA-Seq data. The results revealed that ET triggered stress responses during endodormancy, delaying biological processes related to cell division and intercellular transportation, which are essential for the floral organ development. During ecodormancy, ET mainly impeded pathways related to antioxidants and cell wall formation, both of which are closely associated with dormancy release and budburst. In contrast, the expression of dormancy-associated MADS (DAM) genes remained relatively unaffected by ET, suggesting their conserved nature. The findings of this study signify the importance of floral organogenesis during dormancy and shed light on several key processes that are subject to the influence of ET, therefore opening up new avenues for the development of effective strategies to mitigate frost risks.

N-Methyltransferase CaASHH3 Acts as a Positive Regulator of Immunity against Bacterial Pathogens in Pepper.

Proteins with conserved SET domain play a critical role in plant immunity. However, the means of organization and functions of these proteins are unclear, particularly in non-model plants such as pepper (Capsicum annum L.). Herein, we functionally characterized CaASHH3, a member of class II (the ASH1 homologs H3K36) proteins in pepper immunity against Ralstonia solanacearum and Pseudomonas syringae pv tomato DC3000 (Pst DC3000). The CaASHH3 was localized in the nucleus, and its transcript levels were significantly enhanced by R. solanacearum inoculation (RSI) and exogenous application of salicylic acid (SA), methyl jasmonate (MeJA), ethephon (ETH), and abscisic acid (ABA). Knockdown of CaASHH3 by virus-induced gene silencing (VIGS) compromised peppers’ resistance to RSI. Furthermore, silencing of CaASHH3 impaired hypersensitive-response (HR)-like cell death response due to RSI and downregulated defense-associated marker genes, including CaPR1, CaNPR1, and CaABR1. The CaASHH3 protein was revealed to affect the promoters of CaNPR1, CaPR1, and CaHSP24. Transiently over-expression of CaASHH3 in pepper leaves elicited HR-like cell death and upregulated immunity-related marker genes. To further study the role of CaASHH3 in plant defense in vivo, CaASHH3 transgenic plants were generated in Arabidopsis. Overexpression of CaASHH3 in transgenic Arabidopsis thaliana enhanced innate immunity against Pst DC3000. Furthermore, CaASHH3 over-expressing transgenic A. thaliana plants exhibited upregulated transcriptional levels of immunity-associated marker genes, such as AtNPR1, AtPR1, and AtPR2. These results collectively confirm the role of CaASHH3 as a positive regulator of plant cell death and pepper immunity against bacterial pathogens, which is regulated by signaling synergistically mediated by SA, JA, ET, and ABA.

Rapid Multiplication of Sugarcane Seedlings of PSJT 941 Variety from Tissue Culture Using Ethephon and Paclobutrazol

<p>Indonesia's sugar self-sufficiency was targeted since 2014 but the target has not been reached yet. One of the major constraints is the limited healthy seedlings available for new sugarcane area expansion. The mass production of healthy sugarcane seedlings may be achieved by rapid multiplication of tissue culture-derived seedlings using plant growth regulators (PGR) applied in the nursery house. The aim of this study was to determine the effect of ethephon and pacloburazol (PBZ) on the growth and seedling multiplication of sugarcane PSJT 941 variety. The research was carried out in the nursery house at Pasuruan Experimental Station, Indonesian Sugarcane Research Center. This study was arranged using a randomized block design with three replications. The treatments included (a) 3.5 ml/l ethephon, (b) 7.0 ml/l ethephon, (c) 1.5 ml/l PBZ, (d) 3.0 ml/l PBZ, and (e) control (without application of neither ethephon nor PBZ). The results showed that the highest number of shoots per clump was obtained from 3.0 ml/l PBZ treatment (8.7 shoots/clump) after 3 months of application. In the contrary, PBZ reduced the plant height compared with control and ethephon. Ethephon and PBZ treatments improved seed multiplication 8–52 times, much higher than the control that produced seed multiplication value six times. Further study is necessary to obtain optimal PBZ concentration for better stem height by decreasing the PBZ inhibition effect on stem growth.</p>

Quality of ‘Baigent’ apples as a function of pre-harvest application of aminoethoxyvinylglycine and ethephon stored in controlled atmosphere

– The objective of this work was to evaluate the effects of pre-harvest application on ‘Baigent’ apple trees cultivated under black anti-hail nets with aminoethoxyvinylglycine (AVG), in a single or split dose, combined or not with ethephon, on the quality, the antioxidant activity, and the content of phenolic compounds of the fruits after storage in controlled atmosphere (CA). The pre-harvest applications of AVG alone, both at a dose of 0.125 g L−1, as well as in split dose and at a dose of 0.0625 g L−1, reduced the rate of ethylene production, showed less yellowing fruits and a lower incidence of cracks, maintaining high flesh firmness, texture attributes, and fruit acidity, without causing negative effects on the incidence of mealiness and decay. The pre-harvest applications of AVG at a dose of 0.125 g L−1 and in split dose combined with ethephon also contributed to the reduction of the ethylene production rate and yellowing, showed high flesh firmness and texture, however, it showed a high incidence of decay and cracking when ethephon was combined with AVG at a dose of 0.125 g L−1. In the skin, application of AVG only at a dose of 0.125 g L−1 reduced the total phenolic compounds values, however, total antioxidant activity was reduced with any form of AVG application. In the flesh, there was no effect of pre-harvest application of AVG. Regardless of the dose and form of application, AVG reduced the contents of chlorogenic acid, phloridizin, and epicatechin in the skin of fruits harvested at commercial harvest.

Effect of Preharvest 1-MCP Treatment on the Flesh Firmness of ‘Rojo Brillante’ Persimmon

This study investigated the effect of preharvest 1-MCP treatment on maintaining ‘Rojo Brillante’ persimmon firmness. Early in the season, preharvest 1-MCP was applied 1, 7 and 10 days after ethephon treatment. The fruit firmness was evaluated during three different harvests and after the commercialization period of 3 d at 3 °C, plus 6 d at 20 °C. Late in the season, 1-MCP was applied 3 days before harvest in the fruit treated with gibberellic acid (GA) and then cold-stored for up to 60 days, plus a 6-day shelf life at 20 °C. The results showed that preharvest 1-MCP delayed the fruit softening induced by ethephon during the harvest period, and was the most effective treatment when performed 1 day after ethephon application. Therefore, preharvest 1-MCP extended the harvest period of ethephon-treated fruit. At the end of the season, preharvest 1-MCP had the same effect on maintaining the fruit firmness as the commercial postharvest application.

Involvement of ethylene in glutamate-mediated tomato fruit resistance to Alternaria alternata

Recent progress showed the potential of glutamate to regulate stress responses by affecting phytohormones homeostasis, but much remains to be explored. To decipher the role of ethylene in glutamate-induced resistance to Alternaria alternata, ethephon application, ethylene perception inhibitor (1-MCP) experiment and ethylene measurement were pursued. Concurrently, temporal alteration in ethylene biosynthesis and signaling pathways were transcriptionally analyzed in tomato fruit. Our data exhibited that ethylene conferred tomato fruit susceptibility rather than resistance to Alternaria alternata. The enhanced resistance in glutamate treatment was related to decreased ethylene production during the early stages of interaction, accompanied by lower expression levels of SlACS1, SlACS2 and SlACO1 relative to the control. Interestingly, 1-MCP induced amounts of resistance similar to that observed in glutamate treatment, while ethylene receptors (SlETR3 and SlETR4), mitogen-activated protein kinase SlMPK3 and ethylene response factor SlERF1 were down-regulated by glutamate during infection. Collectively, antagonizing the ethylene biosynthesis or signaling might play a pivotal role in glutamate-induced resistance to the necrotrophic pathogen Alternaria alternata.

Maximizing seedhead suppression of Poa annua L. in Michigan through use of growing degree‐days to predict optimum application timing for ethephon and ethephon plus trinexapac‐ethyl

AbstractResearch was conducted from 2002 to 2006 to determine optimum application timings for the chemical seedhead suppression of annual bluegrass (AB) [Poa annua L. var. reptans (Hauskins) Timm.] by single applications of the plant growth regulators ethephon (EP) (2‐chloroethylphosphonic acid) or EP plus trinexapac‐ethyl (TE) [4‐(cyclopropyl‐alpha‐hydroxymethylene)‐3, 5‐dioxo‐cyclohexanecarboxylic acid ethyl ester]. The objectives were to evaluate AB seedhead suppression from single applications of EP and EP plus TE, and to evaluate the simple average‐calculated growing degree‐days (GDD) and Baskerville–Emin GDD models for their reliability to predict best application timing dates from year to year. Plots were established on a 10‐ to 15‐yr‐old AB fairway maintained at 1.5 cm and receiving 0.5 to 0.6 cm daily automatic irrigation throughout the growing season and 120 kg N ha–1 yr–1 from 2002 to 2006. The soil type is a Marlette sandy loam (fine‐loamy, mixed, semiactive, mesic Oxyaquic Glossudalf). Plant growth regulators were applied at 3.74 and 0.08 kg a.i. ha–1 for EP and TE, respectively, between 24 March and 13 May. Ethephon interacted with application timing in 2002 and 2003. Ethephon plus TE interacted with application timing in 2004, but not 2005 or 2006. Ethephon and EP plus TE did not provide less than 10% seedhead cover in 2003 or 2006, respectively. For EP and EP plus TE, application timing affected seedhead control in 3 of 5 yr.

Exogenously-Sourced Ethylene Positively Modulates Photosynthesis, Carbohydrate Metabolism, and Antioxidant Defense to Enhance Heat Tolerance in Rice.

The effect of exogenously-applied ethylene sourced from ethephon (2-chloroethyl phosphonic acid)was studied on photosynthesis, carbohydrate metabolism, and high-temperature stress tolerance in Taipei-309 and Rasi cultivars of rice (Oryza sativa L.). Heat stress increased the content of H2O2 and thiobarbituric acid reactive substances (TBARS)more in Rasi than Taipei-309. Further, a significant decline in sucrose, starch, and carbohydrate metabolism enzyme activity and photosynthesis was also observed in response to heat stress. The application of ethephon reduced H2O2 and TBARS content by enhancing the enzymatic antioxidant defense system and improved carbohydrate metabolism, photosynthesis, and growth more conspicuously in Taipei-309 under heat stress. The ethephon application enhanced photosynthesis by up-regulating the psbA and psbB genes of photosystem II in heat-stressed plants. Interestingly, foliar application of ethephoneffectively down-regulated high-temperature-stress-induced elevated ethylene biosynthesis gene expression. Overall, ethephon application optimized ethylene levels under high-temperature stress to regulate the antioxidant enzymatic system and carbohydrate metabolism, reducing the adverse effects on photosynthesis. These findings suggest that ethylene regulates photosynthesis via carbohydrate metabolism and the antioxidant system, thereby influencing high-temperature stress tolerance in rice.

Ethephon Reduces Maize Nitrogen Uptake but Improves Nitrogen Utilization in Zea mays L.

Increasing use of plant density or/and nitrogen (N) application has been introduced to maize production in the past few decades. However, excessive planting density or/and use of fertilizer may cause reduced N use efficiency (NUE) and increased lodging risks. Ethephon application improves maize lodging resistance and has been an essential measure in maize intensive production systems associated with high plant density and N input in China. Limited information is available about the effect of ethephon on maize N use and the response to plant density under different N rates in the field. A three-year field study was conducted with two ethephon applications (0 and 90 g ha−1), four N application rates (0, 75, 150, and 225 kg N ha−1), and two plant densities (6.75 plants m−2 and 7.5 plants m−2) to evaluate the effects of ethephon on maize NUE indices (N agronomic efficiency, NAE; N recovery efficiency, NRE; N uptake efficiency, NUpE; N utilization efficiency, NUtE; partial factor productivity of N, PFPN), biomass, N concentration, grain yield and N uptake, and translocation properties. The results suggest that the application of ethephon decreased the grain yield by 1.83–5.74% due to the decrease of grain numbers and grain weight during the three experimental seasons. Meanwhile, lower biomass, and fluxes in xylem bleeding sap, and total N uptake were observed under ethephon treatments. These resulted in lower NAE and NUpE under the ethephon treatment at a corresponding N application rate and plant density. The ethephon treatment had no significant effects on the N concentration in grains, and it decreased the N concentration in stover at the harvesting stage, while increasing the plant N concentration at the silking stage. Consequently, post-silking N remobilization was significantly increased by 14.10–32.64% under the ethephon treatment during the experimental periods. Meanwhile, NUtE significantly increased by ethephon.

Effect of Ethephon Application on Seed Yield and Yield Components of Two Faba Bean (Vicia faba L.) Cultivars

The aim of present study was to determine the effects of different ethephon doses on grain yield and yield components of two faba bean cultivars. The experiment was established in 2019/2020 and 2020/2021 cropping season at Research Area of Field Crops Department, Agriculture of Faculty, Cukurova University Adana, Turkey. The field experiment was laid out in randomized complete blocks design (RCBD) with three replications on the basis split plot design with cultivars (Luz de Otono and Histal) in main plots and ethephon doses (0, 500, 1000, 1500 g ha-1) in sub plots. Plant height (cm), branches per plant, pods per plant, seeds per plant, seed yield per plant (g), 100 grain weight (g), seed yield (kg ha-1) were investigated. Differences among the cultivars and ethephon applications were significant for seed yield and it varied from 1782 to 3388 kg ha-1 in the mean of the years. Seed yield also decreased with increasing ethephon doses. Seed yield was higher in 2019/2020 (3355 kg ha) than 2020/2021 (1841 kg ha-1) where low rainfed and high temperature. The present results suggested that ethephon applications at inititation of flowering were not useful for seed production of faba bean.

Influence of Environmental Parameters, Pinching, and Ethephon Application on Growth and Branching of Potted Stevia

Stevia (Stevia rebaudiana) is an herb grown commercially for the extraction of intensely sweet-tasting, non-caloric, steviol glycosides produced primarily in the leaves and used as a sugar substitute. While most stevia production occurs as an industrial field crop, more recently, consumer demand for stevia for home gardens and patio containers has increased. Research on how environmental inputs impact growth, branching, and flowering of stevia under greenhouse conditions for potted plant production is currently lacking. A series of experiments was conducted to quantify how methods to promote branching, fertilizer concentration, photoperiod and temperature impact branch production, growth and development, and flowering of stevia. Both manual decapitation and ethephon application increased lateral branch production, though hard pinching (cutting plants back to leave four nodes) yielded a more desirable plant architecture. Neither temperature nor fertilizer concentration impacted the number of branches produced by plants given a hard pinch. Shoot dry biomass was similar at fertilizer concentrations (applied at each watering) of 50, 100, and 200 mg⋅L−1 N, but decreased at 300 or 400 mg⋅L−1 N. Stevia responded to photoperiod as a facultative short-day plant, with earliest flowering occurring, both in days to flower and the number of nodes produced before flowering, at photoperiods <13 hours. The number of nodes produced on the longest branch increased as temperature increased from 17 to 26 °C. Plant height and longest branch length were shorter at 17 °C than at higher temperatures. The results of these studies indicate that for potted plant production, stevia should be grown under a photoperiod of 14 hours or longer with moderate nutrient levels, a minimum temperature of 20 °C, and plants should receive one or more manual pinches to promote branching.

Alleviation of Vascular Bundle Browning in the Japanese Pear ‘Rinka’ by Preharvest Application of Ethephon

Alleviation of Vascular Bundle Browning in the Japanese Pear ‘Rinka’ by Preharvest Application of Ethephon

Effect of Ethephon Application on Fruit Quality at Harvest and Post-harvest Storage of Japanese Plum (Prunus salicina) cv. Fortune

HIGHLIGHTS Several ethephon concentrations were applied in pre-harvest on Japanese plums. The quality characteristics of the plums prior and after cold storage were evaluated. Ethephon use hastened the ripening of the fruits, with no effect in overall yield. Some quality characteristics were influenced by ethephon, both in harvest and after storage.

Ripening and fruit quality of ‘Fortune’ plums treated by pre-harvest application of ripening stimulants

The use of plant growth regulators that increase ethylene production is a common strategy to anticipate fruit ripening, increase peel color, and reduce the number of collections to complete the harvest of the fruits. Besides, this strategy may come true as a helping technique for the farmers to reduce costs with manpower, increasing overall profitability. This work aimed to evaluate the application of several concentrations of ethephon, associated with boric acid, on the anticipation of ripening of ‘Fortune’ plums, cultivated in Serra Gaúcha region, South Brazil. The study was carried out in a commercial orchard during the 2018-2019 and 2019-2020 harvests. It was used a completely randomized design with six treatments and four replicates; each replicate was composed of four plants. The following parameters were evaluated: the amount of fruits collected in each harvest, average fruit mass, diameter, length, firmness, soluble solids content, titratable acidity, SS/TA ratio, total phenolic compounds, and total anthocyanins. According to the results, the application of ethephon was capable of hastening and homogenizing partially plum ripening, but it also caused a reduction of anthocyanin and phenolic compounds contents and fruit firmness. On the other hand, the application of boric acid increased fruit firmness. From an economic standpoint, the pre-harvest application of ethephon may be interesting to reduce manpower requirements during harvest by an earlier harvest and by reducing the number of harvest cycles.