Ethylene Release Research Articles

Preparation and application of chlorine dioxide gas slow-release fresh-keeping card based on polylactic acid

Blueberries are highly perishable after harvest, so a simple preservation method is needed to extend the shelf life of blueberries. In this study, sodium chlorite-loaded sepiolite was added to polylactide solution with tartaric acid to create a ClO2 gas slow-release fresh-keeping card. The fresh-keeping card absorbs moisture in the air, which causes tartaric acid to enter the sepiolite and react with sodium chlorite to release ClO2 gas slowly. The study investigated the impact of fresh-keeping cards on the quality attributes of blueberries, including appearance, decay rate, ethylene release rate, respiration rate, hardness, ascorbic acid content, and anthocyanin concentration. Low-field nuclear magnetic technology was used to analyze the water state and distribution of blueberries during storage. The results showed that the ClO2 gas released by the fresh-keeping card can destroy ethylene in the air and kill microorganisms in blueberries, thereby delaying fruit decay.

Short-term anaerobic treatment maintained the quality of Actinidia arguta by activating the antioxidant defense system.

This study aimed to investigate the effect of 6, 12, and 24 h short-term anaerobic treatment on kiwiberry quality and antioxidant properties at 5 °C. Short-term anaerobic treatment was found to delay ripening and softening in kiwiberries, evident from changes in ethylene release, total soluble solids, starch, protopectin, and fruit texture. The 24 h treatment group exhibited the lowest decay rate of 12% on day 49, a 38% reduction compared with the control group. Anaerobic treatment reduced flesh translucency and decay in the fruit. The 12 h and 24 h treatments enhanced the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, and increased the level of total phenolics, flavonoids, anthocyanins, and ascorbic acid. Moreover, it lowered oxidative damage in cell membranes, evidenced by reduced malondialdehyde content and relative conductivity. These results indicate that anaerobic treatment maintains the fruit quality by stimulating its antioxidant defense system. Therefore, short-term anaerobic treatment emerges as a promising method for kiwiberry storage. © 2024 Society of Chemical Industry.

Study on Design, Synthesis and Herbicidal Activity of Novel 6-Indazolyl-2-picolinic Acids.

Thirty-eight new 4-amino-3,5-dicholo-6-(1H-indazolyl)-2-picolinic acids and 4-amino-3,5-dicholo-6-(2H-indazolyl)-2-picolinic acids were designed by scaffold hopping and synthesized to discover potential herbicidal molecules. All the new compounds were tested to determine their inhibitory activities against Arabidopsis thaliana and the root growth of five weeds. In general, the synthesized compounds exhibited excellent inhibition properties and showed good inhibitory effects on weed root growth. In particular, compound 5a showed significantly greater root inhibitory activity than picloram in Brassica napus and Abutilon theophrasti Medicus at the concentration of 10 µM. The majority of compounds exhibited a 100% post-emergence herbicidal effect at 250 g/ha against Amaranthus retroflexus and Chenopodium album. We also found that 6-indazolyl-2-picolinic acids could induce the up-regulation of auxin genes ACS7 and NCED3, while auxin influx, efflux and auxin response factor were down-regulated, indicating that 6-indazolyl-2-picolinic acids promoted ethylene release and ABA production to cause plant death in a short period, which is different in mode from other picolinic acids.

Comparative study on mechanisms of gases release from Ca-alginate beads

Calcium alginate (Ca-alginate) beads have attracted considerable attention as carriers for the controlled release of volatile compounds due to their biocompatibility and tunable properties. This study aimed to compare the release of ethylene and carbon dioxide gas from Ca-alginate beads. Ca-alginate beads were prepared from a sodium alginate solution containing ethephon and calcium carbonate as the gas-forming agent. The resulting solution was then extruded into a calcium chloride solution. The gas release behavior was studied by monitoring the concentration of released gases over time using gas detectors. Extrusion tip diameter, alginate concentration and gas-releasing agent concentration were systematically varied to assess their effect on the gas release rate. The results indicated distinct release patterns for ethylene and carbon dioxide gas. Ethylene gas exhibited a relatively slower and sustained release, while carbon dioxide gas exhibited a more rapid release. Moreover, the bead size influenced the gas release, with larger beads displaying faster release rates for ethylene and carbon dioxide gas. The concentration of alginate also played a role in modulating the release kinetics, with higher alginate concentration resulting in slower gas release. The findings have implications for designing and optimizing Ca-alginate-based systems for agricultural applications, including plant hormone delivery and modified atmosphere packaging.

Proposals for gas-detection improvement of the FeMPc monolayer towards ethylene and formaldehyde by using bimetallic synergy.

Development and fabrication of a novel gas sensor with superb performance are crucial for enabling real-time monitoring of ethylene (C2H4) and formaldehyde (H2CO) emissions from industrial manufacture. Herein, first-principles calculations and AIMD simulations were carried out to investigate the effect of the Fe-M dimer on the adsorption of C2H4 and H2CO on metal dimer phthalocyanine (FeMPc, M = Ti-Zn) monolayers, and the electronic structures and sensing properties of the above adsorption systems were systematically discussed. The results show that the FeMPc (M = Ti, V, Cr, Mn) monolayers interact with C2H4 and H2CO by chemisorption except for the FeMnPc/H2CO system, while the other adsorption systems are all characterized by physisorption. Interestingly, the adsorption strength of C2H4 and H2CO can be effectively regulated by the bimetallic synergy of the Fe-M dimer. Moreover, the FeCrPc and FeMnPc monolayers exhibit excellent sensitivity towards C2H4 and H2CO, and have short recovery time (4.69 ms-2.31 s) for these gases at room temperature due to the effective surface diffusion at 300 K. Consequently, the FeCrPc and FeMnPc materials can be utilized as high-performance, reusable gas sensors for detecting C2H4 and H2CO, and have promising applications in monitoring the release of ethylene and formaldehyde from industrial processes.

Discovery of candidate genes involved in ethylene biosynthesis and signal transduction pathways related to peach bud cold resistance.

Background: Low temperature pose significant challenges to peach cultivation, causing severe damage to peach buds and restricting production and distribution. Ethylene, an important phytohormone, plays a critical role in enhancing plant cold resistance. Structural genes and transcription factors involved in ethylene biosynthesis and signal transduction pathways are associated with cold resistance. However, no research has specifically addressed their roles in peach cold resistance. Methods: In this study, we aimed for cold-resistance gene discovery in cold-sensitive peach cultivar "21Shiji" (21SJ) and cold-resistance cultivar "Shijizhixing" (SJZX) using RNA-seq and gas chromatography. Results: The findings revealed that under cold stress conditions, ethylene biosynthesis in "SJZX" was significantly induced. Subsequently, a structural gene, PpACO1-1, involved in ethylene biosynthesis in peach buds was significantly upregulated and showed a higher correlation with ethylene release rate. To identify potential transcription factors associated with PpACO1-1 expression and ethylene signal transduction, weighted gene co-expression network analysis was conducted using RNA-seq data. Four transcription factors: PpERF2, PpNAC078, PpWRKY65 and PpbHLH112, were identified. Conclusion: These findings provide valuable theoretical insights for investigating the regulatory mechanisms of peach cold resistance and guiding breeding strategies.

The interaction between CmPIF8 and CmACO1 under postharvest red light treatment might affect fruit ripening and sucrose accumulation in oriental melon fruit

Light and plant hormones are involved in regulating the growth, development and fruit quality formation. However, it remains unclear whether light regulates the fruit quality of oriental melon by affecting hormones. Sucrose is mainly accumulated in mature oriental melon fruit, and the accumulation of sucrose is closely related to ethylene. Here, the climacteric melon fruit ‘HS’ were treated with red and blue light at ethylene release initial stage (30 d after anthesis, DAA), and the results showed that the red light treatment enhanced the production of ethylene and the activity of 1-aminocyclopropane-1-carboxylate oxidase (ACO), as well as CmACO1 expression in melon fruit at postharvest stage. Red light also up-regulated the sucrose accumulation and the activity of sucrose phosphate synthetase (SPS) and CmSPS1 expression in postharvest melon fruit. Moreover, we found that PHYTOCHROME INTERACTING FACTOR 8 (PIF8), as a negative regulator of ethylene biosynthesis by directly binding to CmACO1 promoter. In summary, red light treatment at postharvest stage suppressed the expression of CmPIF8, and released the inhibitory effect of CmPIF8 on CmACO1, thereby promoting the ethylene production and fruit ripening, which indirectly increased the sucrose content in melon fruit.

Effects of Ethrel and auxin applications on date palm fruit abscission during development

'Medjoul' is a large semidry date cultivar that is marketed as a special elite product. Fruit size and quality are determined by fruit load, which is dependent on the level of fruit set, fruitlet thinning protocols and natural drop. Currently there is no information on the process of natural fruit abscission in date palms and specifically not on abscission of 'Medjoul'. In the present study abscission levels were characterized through fruit development in vivo and in vitro. Fruit abscise throughout development. During two stages, at an 'Early fruitlet drop' and a 'June drop' (at 25–45 and 80–100 days after pollination respectively), specifically high rates of abscission were observed. The level of fruit set and the fruit load affects these two peaks respectively. Ethrel treatment, an ethylene releasing chemical, significantly induced fruitlet drop while Auxin (2,4-D) treatment reduced the rate of natural fruit drop in vitro, especially during the developmental stages with high natural abscission. A specific abscission zone located at the base of the fruit, just between the calyx and spikelet was detected. Following Ethrel treatment, breaks and cracks in this tissue were detected. This data will enable better understanding of fruitlet and fruit abscission in date palm, which is extremely important for a high quality production of 'Medjoul' dates.

Enhanced shelf life quality of peaches (Prunus persica L.) using ethylene manipulating active packaging in e-commerce logistics

Ethylene manipulating active packaging can effectively maintain the quality of peaches during storage. To explore the effectiveness of ethylene manipulating active packaging during E-commerce logistics, 1-methylcyclopropene (1-MCP) paper cards and ethylene absorbent (EA) sachets were applied to the peaches. During the logistics process, the ambient temperature and the vibration intensity inside the packaging remain at a high level and fluctuates greatly. In comparison with the control group, 1-MCP and EA significantly reduced the respiration rate, delayed ethylene release, and maintained the firmness and volatile compounds in peaches under high temperature and vibration stress. Five days after storage, the peel firmness, flesh firmness, cohesiveness, and chewiness of 1-MCP treatment decreased by 0.15 N, 6.37 N, 0.10 and 0.78, respectively. The total lactone content of peaches in control group reached 3.79 % at 10th day of storage, which was 2.61 % and 2.44 % higher than 1-MCP and EA group respectively. Furthermore, 1-MCP and EA can inhibited the accumulation of MDA and maintained cell membrane integrity. Among them, 1-MCP was more effective than EA. In conclusion, peaches treated with 1-MCP paper cards during E-commerce logistics can maintain good quality and extend shelf life. Our results confirmed that ethylene manipulating active packaging could effectively prolong the shelf life of peaches during E-commerce logistics.

Phenyllactic acid treatment for controlling anthracnose disease (Colletotrichum musae) and preserving banana fruit quality during storage

Banana is considered climacteric fruit that undergoes rapid post-harvest senescence, making it highly susceptible to diseases such as anthracnose, leading to a decline in quality. To address this issue, researchers investigated the effects of phenyllactic acid (PLA), a novel natural bio-preservative with broad-spectrum antibacterial properties, on banana fruit after harvesting. The study revealed that PLA treatment resulted in improved attributes of postharvest quality, including reduced changes in peel color, soluble solids concentration, and firmness. Additionally, respiratory rate, ethylene release, and disease index were significantly decreased, indicating that the fruit's physiological processes were better regulated. Furthermore, PLA treatment enhanced the activity of disease-resistant enzymes β-1,3-glucanase and chitinase, and upregulated the expression of pathogenesis-related genes. Importantly, PLA demonstrated its efficacy in suppressing the growth of anthracnose-causing fungi (Colletotrichum musae) and reducing disease severity on harvested fruit. In conclusion, PLA treatment shows promise as a new approach to maintain the freshness and quality of harvested banana fruit by reducing disease development, regulating physiological processes, and enhancing disease resistance mechanisms.

The apple transcription factor MdZF-HD11 regulates fruit softening by promoting Mdβ-GAL18 expression.

Fruit ripening and the associated softening are major determinants of fruit quality and post-harvest shelf life. Although the mechanisms underlying fruit softening have been intensively studied, there are limited reports on the regulation of fruit softening in apples (Malus domestica). Here, we identified a zinc finger homeodomain transcription factor MdZF-HD11that trans-activates the promoter of Mdβ-GAL18, which encodes a pectin-degradation enzyme associated with cell wall metabolism. Both MdZF-HD11 and Mdβ-GAL18 genes were up-regulated by exogenous ethylene treatment and repressed by 1-methylcyclopropene treatment. Further experiments revealed that MdZF-HD11 binds directly to the Mdβ-GAL18 promoter and up-regulates its transcription. Moreover, using transgenic apple fruit calli, we found that overexpression of Mdβ-GAL18 or MdZF-HD11 significantly enhanced β-galactosidase activity, and overexpression of MdZF-HD11 induced the expression of Mdβ-GAL18. We also discovered that transient overexpression of Mdβ-GAL18 or MdZF-HD11 in 'Golden Delicious' apple significantly increased the release of ethylene, reduced fruit firmness, promoted the transformation of skin color from green to yellow, and accelerated ripening and softening of the fruit. Finally, the overexpression of MdZF-HD11 in tomato also promoted fruit softening. Collectively, these results indicate that ethylene-induced MdZF-HD11 interacts with Mdβ-GAL18 to promote the post-harvest softening of apple.

Impact of Preharvest Ethephon Foliar Spray on the Postharvest Fatty Acid Profile and Dietary Indicators of Macadamia Nuts

The use of ethephon, designed to stimulate nut detachment, initiates the release of ethylene, a well-established regulator of postharvest shelf-life in various agricultural products. This study aimed to assess the impact of ethephon application on individual fatty acids and dietary indicators in two macadamia nut cultivars, namely ‘788’ and ‘Beaumont,’ during postharvest storage. Nuts that naturally abscised and those detached through ethephon treatment were divided into two groups: the ethylene-treated group (ED) and the control group (CD). Nuts were stored at 25 °C and sampled at 0, 36, and 72 days for fatty profile analysis. Our findings indicated a significant increase in stearic acid content in ED nuts (24,622 µg/g) compared to CD nuts (16,764 µg/g) at the end of the storage period for the ‘Beaumont’ cultivar. Additionally, unsaturated fatty acids (USFAs), such as eicosatrienoic acid + erucic acid (C20:3n3 + C22:1) and eicosatrienoic acid + alpha-linolenic acid (C20:1 + C18:3n3), were notably reduced. Hierarchical clustering analysis revealed positive correlations between ethylene treatment and saturated fatty acids (SFAs) in both ‘Beaumont’ (0.78) and ‘788’ (0.80) cultivars. This also coincided with an increase in atherogenic indices, thrombogenic index, and saturation index and a decrease in the hypocholesterolemic/hypercholesterolemic ratio and arachidonic acid (C20:4n6) within the ED group of the ‘Beaumont’ cultivar, collectively potentially impacting nutritional quality negatively. Furthermore, our findings indicated that the PUFA:SFA ratio was higher in CD (0.51) compared to ED (0.45) on day 72 for the ‘Beaumont’ cultivar, revealing differences in fatty acid compositions between the two treatment groups. Conversely, for ‘788’, both ED and CD had a PUFA:SFA ratio below 0.45, indicating an increased risk of cardiovascular diseases. These results suggest that ethephon treatment increases SFA levels and reduces USFA levels in the ‘Beaumont’ cultivar, while the response to ethylene varies between the two cultivars. Thus, the study provides insight into the significant role of modifying ethephon treatment methods and careful cultivar selection in the attainment of optimal nutritional value and shelf-life of macadamia nuts.

Effect of calcium spray at flowering combined with post-harvest 1-MCP treatment on the preservation of grapes

These tests were carried out to find out how calcium and 1-MCP treatment affected the preservation of grapes, as grapes are highly susceptible to decay during post-harvest storage. The grapes were treated with 5 g/L calcium at the flowering stage, followed by 1 μL/L 1-MCP treatment after harvesting.When grapevines were treated with a combination of calcium and 1-MCP, the marketable fruit rate (At day 56 of storage, the 1-MCP + Ca2+ treatment group was still 93%, an increase of 29.03% compared to the control group.) and quality improved (At day 28 of storage, the VC content of the 1-MCP + Ca2+ treated group was 4.35 mg/100g, an increase of 25.01% compared to the control group.), while the fruit weight loss rate decreased (At day 56 of storage, the weight loss of the control group was 6.97%, an increase of 39.43% compared to the 1-MCP + Ca2+ treated group.).According to the experimental results, there are several reasons for this. First, in the early stages of fruit storage, the concentration of soluble pectin and soluble fiber, as well as the activities of pectinase and cellulase (related gene levels) were decreased. Secondly, the activity of antioxidant enzymes was increased, while MDA content was decreased. Third, during fruit storage, the respiratory intensity and ethylene release rate were reduced, as was the activity of energy metabolism enzymes. As a result, the aging and deterioration of the fruit during storage were delayed. Principal component analysis revealed that the calcium and 1-MCP combination therapy slowed the decline in grape berry quality, followed by the calcium-treated and 1-MCP-treated fruits. In contrast, grape berry quality declined the most rapidly in the control group.

Transcriptome sequencing reveals the senescence mechanism of ethylene-insensitive cut Rhododendron flowers

Cut rhododendron flowers have high ornamental value and are loved by consumers. It is important to clarify the senescence mechanism of cut rhododendron flowers to prolong their vase life. Transcriptome sequencing was used to investigate flower senescence in four stages of Rhododendron ‘Hong Shanhu.’ Using RNA sequencing, we generated approximately 100.17 Gb clean data and 173,502 annotated unigenes. Ethylene biosynthesis genes, ACOs , had different expression trends, and most ethylene signaling genes had low expression levels. The ethylene release rate and the activities of ACS and ACO were on the rise during cut flower development. The effects of 200 mg/L ethephon and 0.1 mM/L spermidine on vase life and fresh weight were limited. Most of the LEA and Dehydrin were upregulated with cut flower development and the fresh weight was decreased during fully flowering stage. Based on the different expression trends, differentially expressed genes were classified into 10 clusters. Cluster 2 showed significant upregulation between Z4 and Z3, suggesting that the genes in this cluster were upregulated, probably due to the senescence of cut flowers. The overall trend of Cluster 7 was positively correlated with the opening process of cut flowers. Cluster 9 had a peak at Z3, which indicated that the unigenes started the senescence process. bZIP53, RAP2.4, UIF1, HAT5, ILR3, DEAR3, SCL8, TZF10, MYB70, ERF5, ERF9, and CBF1 had higher expression levels than the other transcription factors in these clusters, indicating that they are probably the key transcription factors involved in petal senescence. Our results indicated that ‘Hong Shanhu’ cut flowers were ethylene-insensitive, and their senescence was probably related to water stress. These results contribute to understanding the mechanism of senescence in cut rhododendron flowers.

Exogenous BR delayed peach fruit softening by inhibiting pectin degradation enzyme genes.

Peach fruit deteriorates and senesces rapidly when stored at room temperature. Brassinosteroids (BRs) play an important role in regulating plant growth and development and maintaining fruit quality. However, little information is available on the effect of BRs on the senescence of harvested peach fruit. In this study, different concentrations of BR were used to treat 'Hongniang' peach fruit, and the results showed that 10 μM BR was the most beneficial concentration to delay the senescence of peach fruits. BR treatment delayed the decrease of fruit firmness, the release of ethylene, the increase in water-soluble pectin (WSP) and ionic-soluble pectin (ISP) content and the decrease in covalently bound pectin (CBP) content, inhibited the activities of pectin degradation enzymes, and inhibited the gene expression of PpPME1/3, PpPG, PpARF2, and PpGAL2/16. In addition, BR treatment also inhibited the expression of PpBES1-5/6. Cis-acting regulatory element analysis of pectin degradation enzyme promoters showed that many of them contained BES1 binding elements. All the above results showed that BR treatment had a positive effect on delaying the senescence of peach fruit and prolonging its storage period.

Exogenous Activation of the Ethylene Signaling Pathway Enhances the Freezing Tolerance of Young Tea Shoots by Regulating the Plant’s Antioxidant System

Tea plants (Camellia sinensis (L.) O. Kuntze) frequently suffer severe damage as a result of freezing temperatures in early spring, which severely affect tea quality and tea production in China. Emerging evidence has demonstrated that the ethylene signaling pathway plays an important role in tea plants’ freezing responses. However, how ethylene modulates the response to freezing in sprouting tea shoots is not clear. This study verified that the measurement of relative electrolyte leakage in young shoots after 1 h at −5 °C is a rapid way to evaluate their freezing tolerance in the laboratory. Further exploration of the mechanism involved in increasing tea-shoot freezing tolerance by monitoring changes in the transcription of ethylene-related genes and cold signaling-related genes, and the physiological and biochemical changes after the application of ethephon (2-chloroethylphosphonic acid, an ethylene release reagent), revealed that exogenous ethephon significantly increased the freezing tolerance of tea shoots within 3 days of treatment, while concomitantly altering the expression of the ethylene signaling pathway-related genes (i.e., CsETR1, CsETR2, and CsEBF1). Moreover, antioxidant enzyme activities, including superoxide dismutase, catalase, and peroxidase, were uniformly upregulated, which might constitute a major physiological change induced by ethylene signaling and may be responsible for the observed increase in freezing resistance. Nevertheless, soluble sugars and starch, trehalose metabolism, and cold signaling-related genes did not appear relevant to the freezing tolerance increase following ethephon application. This study demonstrated that the freezing tolerance of sprouting tea shoots can be rapidly increased by the exogenous activation of the ethylene signaling pathway and upregulation of the plant’s antioxidant system.

Effect of Red Visible Lighting on Postharvest Ripening of Bananas via the Regulation of Energy Metabolism

The mechanism by which LED red light irradiation regulates postharvest banana ripening was evaluated in this study by the continuous irradiation of banana fruits at the mature-green stage. In this study, a self-developed LED banana fresh-keeping container lid was used to continuously irradiate the immature banana fruit. The light wavelength was 655.0 ± 1.0 nm, the light intensity was 800.0 ± 10.0 LX, and the height between the LED lamp and the fruit was 15.0 ± 0.5 cm. Bananas stored under dark conditions were used as the negative control group, and bananas stored under dark conditions after spraying with 500.0 mg/L ethephon diluent were used as the positive control group. Changes in physiological parameters related to postharvest banana ripening, such as the respiration rate, ethylene release, texture, color, carotenoid content, chlorophyll content, adenosine triphosphate content, and energy metabolism-related enzyme activities, were measured during 8 days of storage at 20.0 ± 0.1 °C to analyze the key factors determining postharvest banana ripening in response to red light. The red light-irradiated bananas had higher total color differences and higher rates of chlorophyll degradation and carotenoid synthesis than those of the ethephon-treated group during the storage period. Red light irradiation promoted banana fruit ripening and senescence mainly by promoting carotenoid synthesis, capturing absorbed light energy, accelerating energy metabolism, effectively enhancing the activities of the respiratory and energy metabolism-related enzymes H+ adenosine triphosphatase, Ca2+ adenosine triphosphatase, succinate dehydrogenase, cytochrome C oxidase, and malic enzyme, and promoting organic acid degradation. In conclusion, LED red light can be used as a new physical ripening technology for bananas, with a similar effect to that of traditional ethephon treatment.

Salicylic acid treatment alleviates the loss of glucosinolates accompanying yellowing in harvested broccoli

Commercial value of broccoli is seriously affected by the deterioration of its organoleptical and nutritional quality after harvest. Here, we treated broccoli with salicylic acid (SA) to evaluate its impact on the yellowing process and its protective effect on glucosinolates content during shelf life. SA treatment visibly postponed the yellowing process, as evidenced by higher chlorophyll content and h◦ values as well as lower L* values and yellowing index. Meanwhile, higher levels of glucoraphanin, glucobrassicin, and neoglucobrassicin were accumulated in the treatment group. It was attributed to the activation of glucosinolates biosynthetic capacity by SA treatment, as evidenced by the up-regulated expressions of key regulators BoBCAT3, BoCYP83A1, BoCYP83B1, BoMYB28, BoMYB34, and BoMYB122. In addition, the treatment suppressed the increment of ethylene release while facilitating the biosynthesis of endogenous SA, brassinolide, and jasmonic acid. Statistical analysis provided evidence for SA treatment directly promoting glucosinolate biosynthesis in broccoli and indirectly mitigating glucosinolates loss through hormonal interactions.

Ozone mitigates the flesh discoloration in response to 1-methylcyclopropene by promoting anthocyanin biosynthesis in postharvest nectarines

The effects of combined treatments with 1-methylcyclopropene (1-MCP) and ethylene absorbent (EA) or ozone (O3) on the anthocyanins biosynthesis in nectarines stored at 0 °C were investigated during the storage period. The results indicated that 1-MCP+EA and 1-MCP+O3 effectively inhibited respiration and ethylene release. 1-MCP+EA reduced anthocyanins accumulation and inhibited the red coloration in pulp, whereas 1-MCP+O3 accelerated the red pigmentation. Contrasted to the 1-MCP group, 1-MCP+O3 exhibited higher anthocyanins contents, expression levels of PpPAL1, PpCHS, PpDFR, PpANS, PpUFGT, and PpMYB10.2 and activities of 4-coumarate coenzyme A ligase, flavanone 3-hydroxylase, dihydroflavonol 4-reductase, uridine diphosphate flavonoid 3-O-glucosyltransferase involved in the phenylpropanoid pathway. These results indicated that 1-MCP+O3 promoted the anthocyanins biosynthesis due to the up-regulation of enzymes activities and anthocyanins biosynthetic genes and transcription factor. This study may shed new light on improving quality and color development and optimizing 1-MCP application for postharvest preservation of fruit.

Physiology and Application of Gibberellins in Postharvest Horticultural Crops

Gibberellins (GAs) are plant hormones indispensable in regulating the growth and development of fruits. Recent studies have shown that GAs play important roles in delaying horticultural crop ripening and senescence, enhancing the internal and external quality of horticultural crops and resistance to stress and disease. We reviewed the role of GAs in the postharvest physiology of fruits in recent years. GAs are closely related to their ability to retard fruit senescence. GAs could effectively improve fruit storage quality and significantly increase flesh hardness, reduce respiration intensity, inhibit the release of endogenous ethylene, and effectively inhibit fruit softening and ripening. It can also improve the intrinsic and extrinsic quality of fruit storage by improving fruit shape, regulating color, delaying the reduction of soluble solids, promoting sugar accumulation, and delaying vitamin loss. GAs also play a role in postharvest biotic and abiotic stress resistance. The GA treatment effectively reduces the cold damage index, reduces the production and accumulation of superoxide anion(O2−), improves the antioxidant capacity of fruits, and maintains the integrity of cell membranes during low-temperature storage. Moreover, GAs could effectively control some postharvest fruit diseases. In conclusion, GAs play an important role in the physiological regulation of postharvest fruits and have important application prospects in postharvest fruits.