Ethylene Production Rate Research Articles

Could an Early Treatment with GA and BA Impact Prolonged Cold Storage and Shelf Life of Apricot?

Application of plant growth regulators (PGRs) in apricot orchards is a common practice with a goal of improving yield and/or quality of fruits at harvest. However, the question of whether such treatment alters postharvest properties is seldom answered. The effects of an early application of PGRs on postharvest changes on apricots were investigated on cultivar NS-4, grown on Myrobalan rootstock with blackthorn interstock in a 5-year-old orchard. PGR treatments included 50 and 100 ppm of benzyladenine (BA) and 200 ppm of gibberellic acid (GA3), which were applied when the green ovary was surrounded by dying a sepal crown, at the stage where sepals beginning to fall. Apricots at the stage of commercial ripeness were used for the postharvest experiments. Analysis was performed at harvest, after 21 days of cold storage (at 1 ± 1 °C and 80 ± 10% RH), and after 3 days of shelf life (24 ± 2 °C). At harvest, significant differences were observed between treated and untreated fruits regarding flesh firmness, color, ethylene production and respiration rate, flavonoid, carotenoid and citric acid content, while application of BA100 changed TA and TSS. Prolonged cold storage reduced the initial differences in firmness, respiration rate, flavonoid and carotenoid contents, but new differences in fructose, malic and succinic acid contents began to appear. Shelf life reduced the difference in citric acid, but differences in TA, TSS, phenol and flavonoid content appeared. There is no difference in the sensory properties of treated and non-treated fruit after cold storage and shelf life.

Effect of Preharvest and Postharvest Application of 1-MCP on the Quality of Gala Schniga® SchniCo Red(s) Apples during Long-Term Storage

Fruit growers are looking for effective solutions to preserve the high quality of apples after storage. Therefore, the aim of this study was to assess the impact of pre- and postharvest use of 1-MCP on the quality of ‘Gala Schniga® SchniCo Red(s)’ apples harvested at the optimal harvest date and at a delayed harvest date and stored for 9 months under conditions similar to DCA (0.6% CO2 and 0.6% O2). Four treatments: control (1-MCP untreated), 1-MCP treated 7 days before harvest (Harvista™), 1-MCP treated 7 days after harvest (Smart-Fresh™), and 1-MCP treated before and after harvest (Harvista™ + SmartFresh™) were used, respectively, for each of the above harvest dates. After 5, 7, and 9 months of storage and after an additional 7-day shelf-life period, the following properties were determined: flesh firmness, soluble solids content, titratable acidity, and ethylene production rate. The harvest date and the 1-MCP application date affected ethylene production rate which was reflected in fruit flesh firmness and acidity (p < 0.05). Apples collected at the optimal harvest date from trees sprayed with Harvista™ before harvest retained high firmness (>55 N) after 7 days of shelf-storage at 20 °C, even if previously stored for 9 months. Apples collected later showed firmness similar to the best preferred by consumers only if treated with 1-MCP after harvest.

Potential of Released Essential Oils from Active Packaging to Reduce Refrigeration Needs of Fruit and Vegetables

The energy efficiency of fruit and vegetables refrigeration facilities can be increased through the reduction of heat generated by produce (in kWh/kg). Ethylene production in fruit and vegetables is closely linked to their respiration rates. Clean technologies that can reduce ethylene production of fruit and vegetables are needed to relax (increase) the setpoint temperature of cold rooms. The heat produced may be reduced by up to 50% when ethylene concentrations surrounding the produce are reduced from 0.1–1 to 0.001–0.01 μL L−1 during the storage of some vegetables. There is a need to find green alternatives to ethylene scavenging techniques (of high cost and chemical origin) such as, for example, active packaging with encapsulated essential oils. Hence, respiration and ethylene production rates of flat peaches and broccoli were reduced by up to 30–50% with active packaging with essential oils. It would imply a lower produce heat generation of 14–30% with the consequent energy savings in the refrigeration systems of horticultural facilities. Consequently, the potential of essential oils released from active packaging to reduce the energy consumption related to respiratory heat of produce is hereby firstly reviewed and proposed as a clean technology to extend the postharvest life of fruit and vegetables.

Potensi Radiasi Gelombang Elektromagnetik Extremely Low Frequency (ELF) Guna Meningkatkan Ketahanan Usia Simpan Buah-Buahan

Fruits are included in foodstuffs that provide many benefits for the body, but fruits have a relatively short shelf life. ELF (Extremely Low Frequency) magnetic field radiation is radiation with a low frequency of around 0–300 Hz with non-ionizing properties or no effect on the atoms of a material it is subjected to and non-thermal or does not cause an increase in temperature when interacting with a material. In addition, Extremely Low Frequency (ELF) magnetic field radiation can be used for food tenacity. This study aims to determine how much influence ELF radiation has on the shelf life of various types of fruits. The method used in this study is the journal review method, the number of journals reviewed is 11 journals. The journal in question can be in the form of scientific articles and other journals that support and are relevant to the research title. The results of this study indicate that exposure to the ELF magnetic field can maintain the content of vitamin C, maintain the physical condition of the fruits, and increase the shelf life of fruits by maintaining pH by slowing down or increasing the pH, this is done by killing acid-forming microorganisms, In addition, exposure to the ELF magnetic field can reduce the respiration rate and the rate of ethylene production in fruits, this has an impact on extending the shelf life of fruits. The intensity and duration of exposure to the ELF magnetic field must be adjusted to the type and character of the fruit itself. Thus, it can be concluded that exposure to Extremely Low Frequency (ELF) magnetic fields are able to maintain vitamin C content, maintain the physical condition of fruits, and increase the shelf life of fruits.

Chitosan nano-biopolymer/Citrus paradisi peel oil delivery system enhanced shelf-life and postharvest quality of cherry tomato

Grapefruit peel essential oil (CpEO) was loaded on chitosan (Cs) nano-biopolymer by ionic gelation method and its effect on physicochemical properties of cherry tomatoes was evaluated during 18 days of storage at 10 °C. The highest loading capacity and encapsulation efficiency were obtained from the weight ratio of 1:0.25 Cs to oil. TEM, DLS and FTIR were used to characterize the nanoparticles. The release of the oil from the nanoparticles followed the Fickian diffusion model. CpEO-CsNPs-CO and CpEO-CsNPs-RE treatments reduced ethylene production and respiration rate and indicated a significant and promising effect on increasing the level of antioxidant enzymes (CAT and POD), slowing down the loss of ascorbic acid and total phenolic content and consequently, maintaining antioxidant capacity. These treatments prevented a rapid decline in TSS and TA and an increase in lycopene and MDA level, and maintained the firmness, weight, and color of the fruits throughout storage period.

Quality of Goji Berry Fruit (Lycium barbarum L.) Stored at Different Temperatures.

Goji berries are widely known for their outstanding nutritional and medicinal properties; they are usually found in the market as dried fruit or as juice because the fruit has a short shelf-life, and little information is available about its postharvest behavior at low temperatures. This study aimed to determine the storage performance of goji berry fruit by evaluating physicochemical, and sensorial attributes during storage at three different temperatures (0, 5, and 7 °C) for 12 days in a range that has not been extensively studied before. In addition, fruit respiration and ethylene production rates were also measured at the three temperatures. Fruit stored at 0 °C showed the lowest respiration rate and ethylene production (5.8 mg CO2 kg-1h-1 and 0.7 µg C2H4 kg-1h-1, respectively); however, at this temperature, the incidence and severity of pitting and electrolytic leakage were the highest. In contrast, 5 °C was found to be the best storage temperature for goji berry fruit; the fruit appeared fresh and healthy, had the highest scores during sensory analysis with an acceptable general impression, and had the lowest amount of damage attributable to chilling injury, with 17.1% fruit presenting with shriveling, 12.5% pitting, 6.7% mold, and 35% electrolytic leakage on day 9 of storage. Storage of goji berries at 7 °C resulted in the lowest marketability and the highest incidence of decay. Significant differences were also found in the phytochemical attributes, vitamin C content, soluble solid content (SSC), titratable acidity (TA), SSC/TA ratio, total polyphenol content, 2,2-diphenylpicrylhydrazy (DPPH), and anthocyanin content. This study revealed that a storage temperature of 5 °C for 9 days is recommended to maintain the quality of fresh goji berry. Thus, broadening the existing knowledge of the postharvest behavior of fresh goji berries; our results can help improve the commercial life of goji berries and ensure high-quality attributes throughout distribution.

Proanthocyanidin delays litchi peel browning by inhibiting ethylene biosynthesis, respiratory metabolism, and phenol oxidase activities

Proanthocyanidin (PA) promotes antioxidant capacity and enhances resistance against oxidative stress-induced senescence in fruits after harvest. However, the effects of PA on the postharvest physiology of litchi fruit remain unclear. This study aimed to determine the effect of PA on ethylene and respiration physiology, and on browning enzymes of ‘feizixiao’ litchi stored at 25 °C for 8 d. Proanthocyanidin treatment delayed peel browning and color change, maintained higher peel lightness, and reduced ethylene production and respiration rates in litchi fruit. Subsequently, the key genes and/or enzymes involved in the ethylene biosynthesis pathway and respiration metabolism were determined. The PA-treated fruit exhibited lower levels of 1-aminocyclopropanecarboxylic acid (ACC) content, ACC synthase (ACS) and ACC oxidase (ACO) activity, and an inhibition of LcACS7/9 and LcACO1/2 genes on the peel and pulp compared to that of the control. In addition, the application of PA reduced respiration rate by downregulating the expression of LcAtpB, LcAOX1, LcUCP1, LcAAC1, and LcSnRK2. Furthermore, the phenol oxidase including peroxidase (POD), polyphenol oxidase (PPO), and laccase (LAC), were inhibited during litchi peel browning and senescence. Therefore, the process of PA-delayed browning of litchi may occur by delaying ethylene production and respiratory rate and inhibiting phenol oxidase activities in litchi fruit.

The HY5 transcription factor negatively regulates ethylene production by inhibiting ACS1 expression under blue light conditions in pear

Ethylene is the main factor controlling fruit ripening of pear (Pyrus ussuriensis). Ethylene production rate is negatively correlated with fruit shelf life; therefore, it is important to decrease the ethylene levels for optimal fruit storage. Here, we observed that blue light treatment could inhibit ethylene production and promote the expression of ELONGATED HYPOCOTYL 5 (PuHY5), a basic leucine zipper domain (bZIP) transcription factor. The following studies showed that PuHY5 could bind to the promoter of ACC synthase 1 (PuACS1), a rate-limiting enzyme in ethylene biosynthesis, and inhibit its expression. For pears in which PuHY5 was silenced, the ethylene production and PuACS1 expression were much higher than those in the control fruit. These results demonstrated that blue light inhibited ethylene production through the induction of PuHY5 in pear. Our finding provides a new method for prolonging fruit shelf life.

Melatonin and 1-Methylcyclopropene Improve the Postharvest Quality and Antioxidant Capacity of ‘Youhou’ Sweet Persimmons during Cold Storage

ABSTRACT The objective of this study was to identify the effects of 100 μM melatonin (MT), 1 μL/L 1-methylcyclopropene (1-MCP), and their combination treatments on the postharvest characteristics, nutritional quality, and antioxidant capacity of ‘Youhou’ persimmons during cold storage at 0°C. Compared with the control fruit, all three treatments suppressed ethylene production and respiration rate, leading to delayed softening, reduced peel discoloration, and soluble solid content loss. These treatments increased plasma membrane stability by inhibiting lipoxygenase activity and decreasing H2O2, electrolyte leakage, and malondialdehyde concentrations, resulting in higher tolerance to chilling injury (CI). At the end of storage, the CI index of fruit treated with MT, 1-MCP, and MT+1-MCP respectively exhibited 54.67%, 14.57%, and 5.54%, which were significantly lower than the control ones (78.36%). In addition, the phenolics, flavonoids, and ascorbic acid contents were also improved by the above treatments, which contributed to higher antioxidant activity than the control fruit at the late stage of storage. The combination of MT and 1-MCP treatment was more effective in improving the postharvest quality and preserving high antioxidant ability levels than either treatment alone, indicating a promising measure to preserve sweet persimmons up to 70 d.

Fumigation with lemon and cinnamon oils suppresses ethylene production and maintains the fruit quality of controlled atmosphere-stored organic apples

This work investigated the effects of lemon and cinnamon oil fumigation on quality parameters and ethylene production of organic apples when kept for 100 and 180 d in a controlled atmosphere condition. Apples were fumigated with 3, 4 or 5 μM of lemon or cinnamon oils in 60 L sealed plastic barrels for 24 h at room temperature (∼20 °C) and untreated apple fruit was considered as a control. Following 180 d storage, both lemon and cinnamon oil fumigations significantly decreased the climacteric ethylene production rates, maintained higher quality parameters and reduced superficial scald disorder in both cultivars in comparison with the control fruit. Also, fumigated apples exhibited an increased in firmness up to 26 %, titratable acidity up to 92 %, total phenol up to 130 %, ascorbic acid up to 92 % and total antioxidants up to 104 % when compared with control. Respiration climacteric peaks were reduced in both cultivars stored for 180 d as well. Therefore, through ethylene inhibition, lemon and cinnamon oils have the potential for use in organic apple production to maintain postharvest apple quality.

Aroma volatiles as predictors of chilling injury development during peach (Prunus persica (L) Batsch) cold storage and subsequent shelf-life

As peaches ripen and deteriorate quickly, cold storage is used to extend their marketability. However, peach cold storage is limited by the development of physiological disorders, such as chilling injury (CI), that express during subsequent shelf-life. The aim of this research was three-fold: first, to determine CI incidence in the melting flesh ‘Red Haven’ peach stored at different temperatures throughout postharvest; secondly, to characterize and compare differences among these fruit with regards to ethylene production rates, physicochemical properties, flesh texture, and aroma volatile profiles; and thirdly, to assess correlations among CI incidence and all the evaluated features, and identify potential key aroma volatile compounds that could predict early stage peach CI development during storage. Fruit were harvested at optimal maturity and stored at 0 °C, 5 °C, and 20 °C for up to 30 d. Evaluations were conducted at harvest (0) and after 1, 3, 5, 15, and 30 d of storage, with and without 3 d shelf-life period. Fruit stored at 5 °C were sensitive to CI displaying impaired capacity for ethylene production, and alterations in fruit textural properties, including reduced expressible juice contents and failure to soften. Chilling-injured fruit decreased accumulation of fruity note lactones, esters and terpenoids (i.e., linalool), and increased production of aldehydes and alcohols, as compared to sound fruit. Furthermore, multivariate regression identified thirteen potential key volatiles that could predict peach CI. These volatiles could be used as markers to discriminate chilling-injured from sound fruit at early stages of development of the disorder, optimizing cold storage and fruit handling practices, while decreasing loss and waste.

Fruit bagging reduces the postharvest decay and alters the diversity of fruit surface fungal community in ‘Yali’ pear

BackgroundFruit bagging is an effective technique for fruit protection in the orchard management. Bagging can create a micro-environment for fruit growth and affect fruit quality during storage, in which the diversity of microorganisms may play an important role. Therefore, various methods including biochemistry, analytical chemistry, and bioinformatics methods were used to reveal the influences of fruit bagging on postharvest fruit quality, physiological characters, decay and surface fungal community of ‘Yali’ pear fruit were investigated in this study.ResultsFruit bagging significantly decreased the postharvest decay after 15 days of ambient storage. There were no significant differences in fruit firmness, titratable acid and ethylene production rate between the fruit-bagging and non-bagging group after 15 days of storage, while the soluble solids contents (SSC) and respiration rate in non-bagging fruit was significantly higher than that in fruit-bagging after 15 days of storage. Furthermore, the surface microbes of pear were collected and determined by the new generation sequencing technology. The alpha diversity of fungi in non-bagging fruit decreased significantly after 15 days of storage, while there were no significant changes in bagging fruit. Ascomycota and Basidiomycota were the two major phyla detected in the bagging fruit, and the dominant fungal genera were Alternaria (23.7%), Mycosphaerella (17.25%), Vishniacozyma (16.14%), and Aureobasidium (10.51%) after 15 days of storage. For the non-bagging pear, Ascomycota was the only phylum detected, and the dominant genera was Pichia (83.32%) after 15 days of storage. The abundance of Pichia may be regarded as the biomarker to indicate the degree of fruit decay.ConclusionsThis study showed that fruit bagging could significantly reduce postharvest fruit decay and respiration rate of ‘Yali’ pear. Significant differences were found in fungal composition between bagging and non-bagging pear after storage for 0 or 15 days. Fruit bagging maintained the diversity of fungi on the fruit surface, increased the abundance of non-pathogenic fungi, and even antagonistic fungi such as Aureobasidium, Vishniacozyma, and Mycosphaerella. A reduction in the abundance of pathogenic fungi and incidence of postharvest decay during the storage of ‘Yali’ pear were also recorded. In conclusion, fruit-bagging changed the fungal diversity on fruit surface of ‘Yali’ pear, which had significant effect on reducing postharvest fruit decay, and thus prolong the storage period of ‘Yali’ pears. The future thrust of this study will focus on the isolation of fungi or bacteria from pear fruit surface and identify their roles in causing fruit decay and changing fruit quality during storage.

Development of a novel ethylene scavenger made up of pumice and potassium permanganate and its effect on preservation quality of avocados

The purpose of this research was to develop a novel ethylene scavenger by combining pumice and potassium permanganate (KMnO 4 ) to preserve fruit and vegetables. The study showed that pumice with smaller particle sizes and lower relative humidity (RH) were favorable to ethylene adsorption. The optimal ratio was 1 g of pumice (<5 μm) to 100 mg of KMnO 4 with approximately 620 μL/g of ethylene adsorption capacity within 24 h at lab room RH (30%). Further, this novel ethylene scavenger restricted the ethylene production rate of avocados to 0 μL/kg/h for nine days, and simultaneously, the carbon dioxide (CO 2 ) production rate remained below 25 mL/kg/h. In addition, the firmness of avocados preserved by the novel ethylene scavenger was 4.04 × 10 5 N/m 2 on the 9th d. The results confirmed that the shelf life of avocados was extended by one week at 25 °C under the preservation of the novel ethylene scavenger. • Smaller particle size and lower relative humidity favored ethylene removal. • Pumice physically adsorbed ethylene and KMnO 4 oxidized ethylene. • Ethylene and CO 2 production rate were restricted by the ethylene scavenger. • The ethylene scavenger could extend shelf life of avocados by one week.

Bamboo Fruit Storage Chamber (FSC) Equipped with Ethylene-Degrading Manganese Doped Titanium Oxide Nanomaterial as Storage for Banana (Musa acuminata)

As a climacteric fruit, banana undergoes rapid ripening induced by the hormone ethylene, which is produced by autocatalytic reactions. Titanium dioxide is a photocatalytic compound with the ability to degrade ethylene to water and carbon dioxide. This compound can be used to control the concentration of ethylene inside storage chambers to delay the ripening process of bananas in storage. A passive modified atmosphere is another method to delay ripening by using storage spaces with limited air flow. This study attempts to investigate the performance of TiO2-Mn and bamboo fruit storage chamber (FSC) to delay the ripening of bananas by measuring characteristic physiological changes for 7 days which included ethylene accumulation in storage space, rate of ethylene production, rate of respiration, starch content, and soluble sugar content. The results show that the use of FSC in combination with TiO2-Mn can be used to delay the ripening of bananas. This study also investigated the effect of volumetric occupation to the efficacy of FSC by varying the number of banana fingers in storage and varying the volume of the chamber. While the volume of the FSC did not produce a significant difference in performance, the number of bananas stored in each FSC greatly influenced the delay-ripening ability of FSC with TiO2-Mn. At the end of the study, a profile plotted with MATLAB is presented to show the relationship of ethylene concentration in FSC in respect to storage time and number of fingers stored.

Metal–Nitrogen–Carbon Single‐Atom Aerogels as Self‐Supporting Electrodes for Dechlorination of 1,2‐Dichloroethane

AbstractSingle‐atom catalysts (SACs) have received widespread interest for their high atomic efficiency, enriched active sites, excellent catalytic performance, and low cost. However, the agglomeration of single metal atoms and the use of inactive additives for affixing powdery SACs on planar electrodes may reduce the density of active sites, diminish the charge transport to active sites, and thus suppress their performance. Herein, a series of metal–nitrogen–carbon single‐atom aerogels (M‐SAAs, M: Cu, Ni, Au, Ru) are synthesized via a universal strategy, in which the merits of metal organic frameworks and carbon aerogels are perfectly combined to prevent the agglomeration of single metal atoms and overcome the problem of poor electrical conductivity. The as‐prepared M‐SAAs can be directly employed as self‐supporting electrodes for the electrochemical dechlorination of 1,2‐dichloroethane, and outstanding activity and stability are observed. Significantly, the Cu‐SAA with abundant Cu−N4 sites shows an extraordinarily high ethylene production rate of 446 µmol h−1, with a selectivity of 99% and Faradaic efficiency of 64%. Moreover, theoretical calculations are performed to demonstrate the selectivity and activity of different metal active sites. This study provides a new strategy to exploit highly effective SACs and offers an intensive insight into the mechanism of electrochemical dechlorination reactions.

A 1-aminocyclopropane-1-carboxylic-acid (ACC) dipeptide elicits ethylene responses through ACC-oxidase mediated substrate promiscuity.

Plants produce the volatile hormone ethylene to regulate many developmental processes and to deal with (a)biotic stressors. In seed plants, ethylene is synthesized from 1-aminocyclopropane-1-carboxylic acid (ACC) by the dedicated enzyme ACC oxidase (ACO). Ethylene biosynthesis is tightly regulated at the level of ACC through ACC synthesis, conjugation and transport. ACC is a non-proteinogenic amino acid, which also has signaling roles independent from ethylene. In this work, we investigated the biological function of an uncharacterized ACC dipeptide. The custom-synthesized di-ACC molecule can be taken up by Arabidopsis in a similar way as ACC, in part via Lysine Histidine Transporters (e.g., LHT1). Using Nano-Particle Assisted Laser Desoprtion/Ionization (Nano-PALDI) mass-spectrometry imaging, we revealed that externally fed di-ACC predominantly localizes to the vasculature tissue, despite it not being detectable in control hypocotyl segments. Once taken up, the ACC dimer can evoke a triple response phenotype in dark-grown seedlings, reminiscent of ethylene responses induced by ACC itself, albeit less efficiently compared to ACC. Di-ACC does not act via ACC-signaling, but operates via the known ethylene signaling pathway. In vitro ACO activity and molecular docking showed that di-ACC can be used as an alternative substrate by ACO to form ethylene. The promiscuous nature of ACO for the ACC dimer also explains the higher ethylene production rates observed in planta, although this reaction occurred less efficiently compared to ACC. Overall, the ACC dipeptide seems to be transported and converted into ethylene in a similar way as ACC, and is able to augment ethylene production levels and induce subsequent ethylene responses in Arabidopsis.

Effect of harvest maturity stage and ripening remediation agents on the shelf life and biochemical quality attributes of tomato (Solanum lycopersicon) fruits

Tomato fruit is highly perishable because of the characteristic high rate of ethylene production and respiration during ripening. Delayed ripening could be achieved through the use of ripening remediation agents (RRa) that either absorb or block ethylene binding to the fruit receptor. The effects of ripening remediation agents on shelf life and biochemical quality attributes were evaluated on tomato fruits harvested at three maturity stages (breaker, turning and full-ripe). In 2018 and 2019, harvested fruits were stored under seven ripening remediation treatments: 0.1 µL/L 1-MCP, 0.3 µL/L 1-MCP, 0.5 µL/L 1-MCP, 5% KMnO4, 10% KMnO4, 10 g of Zeolite and 20 g of Zeolite and an open shelf condition as the control. At the end of the storage period, fruits were assessed for shelf life as well as total soluble solids (TSS), titratable acids (TA), ascorbic acid, and lycopene contents. There was significant (p≤0.05/0.01) influence of ripening remediation treatments on fruits for all the measured parameters. Fruits stored with RRAs consistently out-performed those stored in the open shelf. RRAs 0.3 µL/L1-MCP, 0.5 µL/L1-MCP and 5% KMnO4 solution media had longer shelf life and higher values of total soluble solids, titratable acidity, lycopene and ascorbic acid contents. The use of 1-MCP and 5% KMnO4 is recommended as effective scavenger of ethylene for extending the shelf-life and maintaining some quality attributes of stored tomato fruits.

Reevaluation of ethylene role in Arabidopsis cauline leaf abscission induced by water stress and rewatering.

It was previously reported that cauline leaf abscission in Arabidopsis is induced by a cycle of water stress and rewatering, which is regulated by the complex of INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), HAESA (HAE), and HAESA‐LIKE2 (HSL2) kinases. However, the involvement of ethylene in this process was ruled out. Because this conclusion contradicts the well‐established role of ethylene in organ abscission induced by a cycle of water stress and rewatering, our present study was aimed to reevaluate the possible involvement of ethylene in this process. For this purpose, we examined the endogenous ethylene production during water stress and following rewatering, as well as the effects of exogenous ethylene and 1‐methylcyclopropene (1‐MCP), on cauline leaf abscission of Arabidopsis wild type. Additionally, we examined whether this stress induces cauline leaf abscission in ethylene‐insensitive Arabidopsis mutants. The results of the present study demonstrated that ethylene production rates increased significantly in cauline leaves at 4 h after rewatering of stressed plants and remained high for at least 24 h in plants water‐stressed to 40 and 30% of system weight. Ethylene treatment applied to well‐watered plants induced cauline leaf abscission, which was inhibited by 1‐MCP. Cauline leaf abscission was also inhibited by 1‐MCP applied during a cycle of water stress and rewatering. Finally, no abscission occurred in two ethylene‐insensitive mutants, ein2‐1 and ein2‐5, following a cycle of water stress and rewatering. Taken together, these results clearly indicate that ethylene is involved in Arabidopsis cauline leaf abscission induced by water stress and rewatering.Our results show that ethylene is involved in Arabidopsis cauline leaf abscission induced by water stress and rewatering, similar to leaf abscission in other plants.

Highly Stable Doped Barium Niobate Based Electrocatalysts for Effective Electrochemical Coupling of Methane to Ethylene

AbstractMethane conversion into value‐added products such as olefins and aromatics is gaining increased attention in the wake of new natural gas reserve discoveries. Electrochemical oxidative coupling of methane (E‐OCM) provides better product selectivity as the product distribution can be controlled by applied potential as well as the oxide ion flux. Here a new catalyst based on Mg and Fe codoped barium niobate perovskites is reported. The prepared perovskites show excellent chemical stability in CH4‐rich environments up to 925 °C while showing methane activation properties from 600 °C. E‐OCM measurements indicate an ethylene production rate of 277 µmol cm−2 h−1 with a faradaic efficiency of 20% at 1 V and durable operation for six continuous days. X‐ray photoelectron spectroscopic measurements indicate significant Nb valency reorganization that can be the reason for its chemical stability. Nevertheless, the surface area of the catalyst is significantly lower and requires improvements in synthesis methodologies to improve catalytic activity further. The exceptional chemical stability of this perovskite material under methane exposure at high temperatures has significant importance as this material can be used as a catalyst and/or support in a wide variety of applications relevant for efficient energy conversion and storage.

Highly efficient electrocatalytic deuteration of acetylene to deuterated ethylene using deuterium oxide

Deuterated ethylene is an important building block for manufacturing various deuterated polyolefins and chemicals. However, low-cost and large-scale production of deuterated ethylene still remain a great challenge. Herein, with D2O as the D source, we first propose an electrocatalytic deuteration strategy for continuous production of deuterated ethylene from acetylene under ambient conditions. Specially, Ag nanoparticles exhibit a very high deuterated ethylene Faradic efficiency of up to 99.3% at –0.6 V vs. reversible hydrogen electrode. Meanwhile, Ag nanoparticles achieve a deuterated ethylene production rate of 3.72 × 103 mmol h–1 gcat–1 and an excellent long-term stability with deuterated ethylene Faradaic efficiencies of ∼95% in a two-electrode flow cell, which substantially outperform state-of-the-art values for previously reported deuterated alkenes. In-situ electrochemical Infrared absorption and Raman spectroscopies reveal superior acetylene absorption and formation of deuterated ethylene on Ag nanoparticles. This efficient electrocatalytic deuteration strategy opens a new window for continuous and economic production of deuterated alkenes.