Endogenous Ethylene Research Articles

Postharvest treatment of navel oranges with fluroxypyr, 2-methyl-4-chlorophenoxyacetic acids, and 2,4-dichlorophenoxyacetic maintains physiological quality during ambient storage

Two batches of Green mature Navel oranges with calyxes attached were obtained from a farmer from Juaben Municipality in the Ashanti region of Ghana and were dipped for 2 minutes with fluroxypyr, and 2-methyl-4-chlorophenoxyacetic acid (MCPA), were assessed against the commercial 2,4-D at 0.1 and 0.2 mmol L-1 stored under ambient conditions (24±2 °C and 55-60% RH) for 4 weeks. The results showed that pre-storage dipping with fluroxypyr was the most effective in suppressing endogenous ethylene production and respiration rate, reduced calyx changes, and fruit rot, and retained fruit sensory attributes compared with MCPA 2,4-D, or untreated fruit at the end of storage life of four weeks. The effect of 2,4-D and MCPA on fruit rot, calyx browning, abscission, and fruit internal quality, was similar; which was not significantly different during storage. Dipping fruit with 0.1 mmol L-1 fluroxypyr was more effective in maintaining the quality of oranges and could be a substitute for current commercial 2,4-D.

Surface Molding Hydrogel Film Initiated by ZIF-8 with Ethylene Adsorption Performance for Preserving Perishable Fruits.

The quality deterioration of postharvest fruits is greatly influenced by ethylene, leading to food wastage worldwide. Therefore, it is urgent to develop an efficient packaging strategy to reduce ethylene concentration and prolong the shelf life of perishable fruits. In this work, a surface-molding hydrogel film was created using ZIF-8 in combination with carboxymethyl starch (CMS) and carboxymethyl chitosan (CMCS). Specifically, ZIF-8 is first anchored on CMS and then rapidly cross-linked in situ with CMCS, forming ZIF-8@CC on the fruit surface (within 10 s). The perfect tight-fitting effects of ZIF-8@CC were observed on various fruit surfaces with different roughness (Ra: ranges from 102 to 308 nm). ZIF-8@CC could absorb 57.3% endogenous ethylene from bananas, and the interaction mechanism between ethylene and ZIF-8 was studied by molecular dynamics simulations, providing insights into the ethylene adsorption capacity of ZIF-8@CC. Moreover, ZIF-8@CC presented excellent antibacterial properties and achieved satisfactory ultralong preservation effects on both nonclimatic and climatic fruits (12 days for strawberries and 14 days for bananas) at room temperature. Importantly, ZIF-8@CC is easily removed, washed, and degradable. These findings offer an efficient and potential food packing material with multifunctional properties for preserving perishable fruits.

Can endogenous ethylene glycol production occur in humans? A detailed investigation of adult monozygotic twin sisters

Introduction To the best of our knowledge, clinically significant endogenous ethylene glycol production has never been reported in humans, very seldom reported in other animals or microorganisms, and then only under rare and specific conditions. We describe the detailed investigations we undertook in two adult monozygotic twin sisters to ascertain whether they were producing endogenous ethylene glycol. Methods Two previously healthy monozygotic adult twin sisters presented with recurrent episodes of apparent ethylene glycol poisoning beginning at age 35, requiring chronic hemodialysis to remove ethylene glycol and its metabolites as well as to restore metabolic homeostasis. The sisters denied ingestion or exposure to ethylene glycol. At their request, they were admitted to hospital under strict supervision to exclude surreptitious ingestion of ethylene glycol and to evaluate the need for treatment. Hemodialysis was withheld during this prospective study. Twin A was admitted for 14 days and twin B for 11 days. Serial biochemical analyses were performed in blood and urine. Clinical exome sequencing and mitochondrial deoxyribonucleic acid sequencing were also completed. Results In both twins, ethylene glycol was detected in urine, along with intermittent increases in concentrations of lactate, glycolate, and glycine in blood and/or urine. Blood ethylene glycol concentrations, however, remained <62 mg/L (<1 mmol/L) but became positive soon after discharge. The oxalate concentration remained normal in blood and urine. Plasma and urine amino acid profiles showed intermittent small increases in glycine, serine, taurine, proline, and/or alanine concentrations. Exome sequencing and mitochondrial deoxyribonucleic acid sequencing were non-diagnostic. Neither twin has been admitted with metabolic acidosis nor ethylene glycol poisoning since chronic hemodialysis was started. Twin A developed a calcium oxalate dihydrate lithiasis. Discussion Mitochondrial disease, methylmalonic/propionic/isovaleric aciduria, primary hyperoxaluria, and analyte error were all excluded in these twins, as were obvious common environmental exposures. Conclusion Detailed investigations were performed in adult monozygotic twin sisters to ascertain whether they were producing endogenous ethylene glycol. Alternative explanations were excluded to the very best of our efforts and knowledge. Global metabolomics, gut microbiome analyses, and whole genome sequencing are pending.

Ethylene and hydrogen sulfide regulate hexavalent chromium toxicity in two pulse crops: Implication on growth, photosynthetic activity, oxidative stress and ascorbate glutathione cycle

Sustainable agriculture has become prime importance to feed growing population. To achieve this goal application of exogenous hormones and signaling molecules are gaining important. In this context, we have investigated potential of ethylene (25 μM ethephon; donor) and H2S (10 μM NaHS; donor) in mitigating hexavalent chromium [Cr (VI), 50 μM] toxicity in two pulse seedlings: black bean and mung bean. Cr(VI) declined growth and gas exchange parameters (photosynthetic rate, stomatal conductance, sub cellular CO2 concentration, and transpiration level) which was accompanied by intracellular accumulation of Cr in both pulse crops and the damaging effect was greater in mung bean seedlings. The suppression in the growth and related parameters was occurred due to higher buildup of oxidative stress markers; O2•‾, H2O2, lipid peroxidation (as malondialdehyde, MDA equivalents) and membrane injury in leaf and root of both pulse crops. Cr induced disturbance in AsA-GSH cycle (reduction in the activity of glutathione reductase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase, and the amount of ASA and GSH) could be one of the reasons for greater accumulation of H2O2. Further, exogenous application of ethylene and H2S significantly ameliorated Cr toxicity on growth and photosynthetic activity by significantly lowering the intracellular Cr accumulation and oxidative biomarkers, and also by strengthening the activity of AsA-GSH cycle. The exogenous application of biosynthesis inhibitors of ethylene (AVG) and H2S (PAG) caused greater damaging effect on these parameters due to more accumulation of Cr(VI), thereby suggesting that the endogenous levels of these regulators are critical for Cr(VI) tolerance. Interestingly, ET did not rescue adverse effects of Cr(VI) in absence of endogenous H2S, while H2S could do so even without endogenous ethylene, suggesting that H2S played downstream signaling to ethylene in regulating Cr(VI) toxicity. Hence, being cheap and easily available theses growth regulators may be considered for sustainable agriculture.

Asymmetric bulges within hairpin RNA transgenes influence small RNA size, secondary siRNA production and viral defence.

Small RNAs (sRNAs) are essential for normal plant development and range in size classes of 21-24 nucleotides. The 22nt small interfering RNAs (siRNAs) and miRNAs are processed by Dicer-like 2 (DCL2) and DCL1 respectively and can initiate secondary siRNA production from the target transcript. 22nt siRNAs are under-represented due to competition between DCL2 and DCL4, while only a small number of 22nt miRNAs exist. Here we produce abundant 22nt siRNAs and other siRNA size classes using long hairpin RNA (hpRNA) transgenes. By introducing asymmetric bulges into the antisense strand of hpRNA, we shifted the dominant siRNA size class from 21nt of the traditional hpRNA to 22, 23 and 24nt of the asymmetric hpRNAs. The asymmetric hpRNAs effectively silenced a β-glucuronidase (GUS) reporter transgene and the endogenous ethylene insensitive-2 (EIN2) and chalcone synthase (CHS) genes. Furthermore, plants containing the asymmetric hpRNA transgenes showed increased amounts of 21nt siRNAs downstream of the hpRNA target site compared to plants with the traditional hpRNA transgenes. This indicates that these asymmetric hpRNAs are more effective at inducing secondary siRNA production to amplify silencing signals. The 22nt asymmetric hpRNA constructs enhanced virus resistance in plants compared to the traditional hpRNA constructs.

Anthocyanin physiology and biochemistry in fleshy fruit species: Mangosteen as a model

AbstractMangosteen (Garcinia mangostana L.) is a popular, common tropical fruit grown in Southeast Asian countries. The pericarp contains a high anthocyanin content and various other bioactive compounds that are associated with medicinal and pharmaceutical properties. In marked contrast, the white edible aril contains no anthocyanins. The anthocyanins are the major pigments in the pericarp and produce red‐to‐purple coloration, which serves as a maturity index when fruit are ripe. The major anthocyanins consist mainly of cyanidin‐sophoroside and cyanidin‐glucoside. The synthesis of anthocyanin in mangosteen involves the coordinated expression of many genes with at least eight genes encoding enzymes and three transcription factors having been identified. Ripening‐induced anthocyanin accumulation is regulated by endogenous ethylene that controls the expression of key genes. Comparisons are made between anthocyanin synthesis in mangosteen and other fruit species under various conditions including light and temperature and the influence of plant growth regulators.

Responses of Ethylene Emission, Abscission, and Fruit Quality to the Application of ACC as a Chemical Thinner in ‘Flatbeauti’ Peach

Peach (Prunus persica (L.) Batsch) trees are prone to heavy cropping, but crop load management options are limited. 1-aminocyclopropane-1-carboxylic acid (ACC) has been suggested to reduce crop load and improve fruit quality in peaches, but many questions remain concerning the role of endogenous ethylene in the abscission response and other side effects. Here, the use of ACC as a chemical thinner in peach trees was studied at different rates (350, 500, and 750 mg L−1) and timings [at full bloom (FB) and after petal fall (AP) when the fruit was approximately 15–20 mm in diameter] by comparing the results to those of an untreated control and a hand-thinning treatment as a reference. The abscission response and ethylene emission were related to the ACC concentration. ACC-induced ethylene production, as well as some degree of defoliation, was time-dependent, with the highest ethylene emission peaks and the lowest defoliation degree occurring when ACC was applied at FB. On the other hand, the intra-annual differences in the abscission response between the FBs and APs varied depending on the season. AP-treated fruits produced more endogenous ethylene than did untreated fruits up to harvest, which could have influenced fruit color. Finally, our results indicate that ACC in the range of 500 and 350 mg L−1 can be used in ‘Flatbeauti’ peaches at FB and AP, respectively, to induce adequate levels of fruit crop load without or with minor undesired effects.

A self-heating gas sensor for online monitoring of endogenous ethylene of post-harvest cut chrysanthemums

The decay of post-harvest cut chrysanthemums (PHCCs) during storage and shipment results in enormous loss, and the accumulated endogenous ethylene is one of the main reasons. However, it is challenging for current technologies to onsite monitoring of endogenous ethylene of PHCCs whose concentration is very low. Here, we propose a ethylene sensor with high performances enabled by self-heating capability. Specifically, laser-induced graphene (LIG) patterns are in-situ fabricated on the upper and lower sides of a polyimide substrate. The upper LIG is coated with chemo-resistive SnO2 for ethylene sensing and the lower LIG serves as heater for self-heating. The working temperature is well tuned by the heater and effectively transferred to SnO2. Owing to the self-heating capability, the sensor displays outstanding ethylene detection performances, such as ultra-low limit of detection (1.654 ppb), wide detection range (0.05–100 ppm), high sensitivity (0.2249 ppm−1), high detection linearity (0.9925), and long-term stability (>14 days). Moreover, the sensor is integrated with a data acquisition circuit and connected to a mobile application, realizing online monitoring of endogenous ethylene of PHCCs. The results demonstrate that the decay of PHCCs is accelerated as the endogenous ethylene accumulates. This work would promote the online monitoring of endogenous ethylene of plants.

Transcriptomic and metabolomic analyses reveal the importance of ethylene networks in mulberry fruit ripening

Mulberry (Morus alba L.) is a climacteric and highly perishable fruit. Ethylene has been considered to be an important trigger of fruit ripening process. However, the role of ethylene in the mulberry fruit ripening process remains unclear. In this study, we performed a comprehensive analysis of metabolomic and transcriptomic data of mulberry fruit and the physiological changes accompanying the fruit ripening process. Our study revealed that changes in the accumulation of specific metabolites at different stages of fruit development and ripening were closely correlated to transcriptional changes as well as underlying physiological changes and the development of taste biomolecules. The ripening of mulberry fruits was highly associated with the production of endogenous ethylene, and further application of exogenous ethylene assisted the ripening process. Transcriptomic analysis revealed that differential expression of diverse ripening-related genes was involved in sugar metabolism, anthocyanin biosynthesis, and cell wall modification pathways. Network analysis of transcriptomics and metabolomics data revealed that many transcription factors and ripening-related genes were involved, among which ethylene-responsive transcription factor 3 (MaERF3) plays a crucial role in the ripening process. The role of MaERF3 in ripening was experimentally proven in a transient overexpression assay in apples. Our study indicates that ethylene plays a vital role in modulating mulberry fruit ripening. The results provide a basis for guiding the genetic manipulation of mulberry fruits towards sustainable agricultural practices and improve post-harvest management, potentially enhancing the quality and shelf life of mulberry fruits for sustainable agriculture and forestry.

Hypoxia in tomato (Solanum lycopersicum) fruit during ripening: biophysical elucidation by a 3D reaction-diffusion model.

Respiration provides energy, substrates and precursors to support physiological changes of the fruit during climacteric ripening. A key substrate of respiration is oxygen that needs to be supplied to the fruit in a passive way by gas transfer from the environment. Oxygen gradients may develop within the fruit due to its bulky size and the dense fruit tissues, potentially creating hypoxia that may have a role in the spatial development of ripening. This study presents a three-dimensional reaction-diffusion model using tomato (Solanum lycopersicum) fruit as a test subject, combining the multiscale fruit geometry generated from magnetic resonance imaging and micro-computed tomography with varying respiration kinetics and contrasting boundary resistances obtained through independent experiments. The model predicted low oxygen levels in locular tissue under atmospheric conditions and the oxygen level was markedly lower upon scar occlusion, aligning with microsensor profiling results. The locular region was in a hypoxic state, leading to its low aerobic respiration with high CO2 accumulation by fermentative respiration, while the rest of the tissues remained well oxygenated. The model further revealed that the hypoxia is caused by a combination of diffusion resistances and respiration rates of the tissue. Collectively, this study reveals the existence of the respiratory gas gradients and its biophysical causes during tomato fruit ripening, providing richer information for future studies on localized endogenous ethylene biosynthesis and fruit ripening.

Effects of ethephon on heartwood formation and related physiological indices of Dalbergia odorifera T. Chen

IntroductionDalbergia odorifera T. Chen, known as fragrant rosewood, is a rare and endangered tree species. Studies have shown that plant growth regulators can effectively promote heartwood formation. This study aimed to investigate the effects of ethephon (ETH) on heartwood formation and the influence of ethephon and hydrogen peroxide (H2O2) on the physiological characteristics in D. odorifera.MethodsD. odorifera branches underwent treatment with 2.5% plant growth regulators, including ETH, jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), H2O2, and inhibitors such as ascorbic acid (AsA) to inhibit H2O2 synthesis, and (S) -trans 2-amino-4 - (2-aminoethoxy) -3-butene (AVG) to inhibit ethylene synthesis. After a 14-day period, we conducted an analysis to evaluate the impact of these plant growth regulators on elongation distance, vessel occlusion percentage, and trans-nerol content. Additionally, the effects of ETH and H2O2 on endogenous plant hormones, H2O2 content, soluble protein content, and enzyme activity were investigated within 0-48 h of treatment.ResultsAfter treatment with ETH for 14 days, the extension distance of the heartwood material was 15 cm, while the trans-nerolol content was 15 times that of the ABA group. ETH and H2O2 promoted endogenous ethylene synthesis; Ethylene content peaked at 6 and 18 h. The peak ethylene content in the ETH group was 68.07%, 12.89%, and 20.87% higher than the initial value of the H2O2 group and ddH2O group, respectively, and 29.64% higher than that in the AVG group. The soluble protein content and activity of related enzymes were significantly increased following ETH treatment.DiscussionETH exhibited the most impact on heartwood formation while not hindering tree growth. This treatment effectively triggered the production of endogenous ethylene in plants and enhanced the activity of essential enzymes involved in heartwood formation. These findings serve as a valuable reference for future investigations into heartwood formation.

Sensitivity Consequences of Ethylene in Determining the Vase Life of Eremurus spectabilis and E. persicus

Foxtail lily (Eremurus), as a medicinal-ornamental geophyte, has recently emerged in the cut flower market as a novel, commercially significant specialty cut flower (SCF). However, there is limited information about the sensitivity to ethylene of foxtail lily species for managing the ethylene-mediated senescence to prolong the vase life and maintain the ornamental quality of this flower. The purpose of the current study was to compare the ethylene production rates and patterns, as well as the responses to exogenous ethylene and ethylene inhibitors, between two species, E. spectabilis and E. persicus, to better understand the role of ethylene in Eremurus inflorescence senescence. The results revealed that exogenous ethylene (10 μL L−1), as a pulsing or continuous method, dramatically accelerated petal wilting in E. spectabilis and petal abscission in E. persicus. Furthermore, the rate and patterns of endogenous ethylene production varied significantly among the two investigated species. Interestingly, E. persicus exhibited a higher rate of ethylene production than E. spectabilis on the first day after harvesting, but the reverse was true at the end of the vase life (Day 4 of the vase period). The results revealed that the treatments with ethylene inhibitors considerably improved the water relations and vase longevity of both foxtail lily species. The vase life of E. spectabilis was dramatically enhanced by silver thiosulfate complex (STS) treatment (0.2 mM pulse for 24 h) from 5 d (control) to 7 d. Furthermore, 1-methylcyclopropene (1-MCP) at 0.5 and 1.0 μL L−1 markedly improved water uptake, relative fresh weight, and water balance and extended the vase life of cut inflorescences by ~2 d in E. spectabilis and E. persicus, compared with those of control cut inflorescences, respectively. This research revealed that ethylene is involved in controlling the senescence of foxtail lily flowers, and two tested species exhibited distinct forms of ethylene sensitivity, including abscission type in E. persicus and wilting-type in E. spectabilis. Collectively, these findings suggest that ethylene is involved in the senescence of cut foxtail lily inflorescence and that ethylene inhibitors can prolong vase life.

Ethylene inhibitors improve crop productivity by modulating gene expression, antioxidant defense machinery and photosynthetic efficiency of Solanum lycopersicum L. cv. Pusa Ruby grown in controlled salinity stress conditions

Tomato is an important horticultural crop of global importance but its susceptibility to salinity stress significantly retards growth and thereby its yield. The impact of gaseous hormone, ethylene, accentuates the effect of salinity stress by negatively regulating various growth and developmental processes. Ethylene overproduction and ionic imbalance triggered by salinity stress exhibit upregulation of 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and downregulation of NHX1, SOS1 and HKT1;2 under salinity stress conditions that negatively affect proline content, ROS scavenging machinery, morphometric and physiological attributes. Variation in the proline content, activation of ROS scavenging machinery, affected morphometric and physiological attributes are some discernible points in response to salinity stress induced ethylene production. Therefore, the experiment was designed to study the role of ethylene inhibitors silver nitrate (AgNO3) and cobalt chloride (CoCl2) in mitigating the negative effects of ethylene over production under salinity stress. Tomato seedlings were treated with 0 mM NaCl, 250 mM NaCl and 250 mM NaCl + 100 µM AgNO3, 250 mM NaCl + 100 µM CoCl2 for three days. The gene expression of ACS2, NHX1, SOS1 and HKT1;2, and ACS activity, endogenous ethylene level, Na+ and K+ ions concentration, proline content, antioxidant enzymes activity, photosynthetic efficiency and different morphological and yield parameters were assessed in tomato plants treated with salinity stress, and ethylene inhibitors at 45 DAS and 90 DAS. Results revealed that ethylene inhibitors might be playing the role in minimizing the ethylene and ACC load. The ACS enzyme activity and ethylene content were considerably decreased due to application of AgNO3and CoCl2. Further, the endogenous proline and K+ content, and K+/Na+ ratio were considerably increased in response to ethylene inhibitors treatment. Also, antioxidant enzymesviz., SOD, CAT, APX and GR, growth matrices, photosynthetic efficiency and yield attributes were significantly improved in treated tomato plants (salinity with ethylene inhibitors).

Spermidine enhances chilling tolerance of kale seeds by modulating ROS and phytohormone metabolism.

Chilling stress is an important constraint for kale seed germination and seedlings establishment. It is vital to develop an effective approach to enhance kale seed germination ability under chilling stress. The present study reported that spermidine (Spd) could improve seed chilling tolerance in two kale cultivars 'Nagoya' (MGW) and 'Pigeon' (BB) during germination. The results showed that MGW was cold tolerant with a 90.67% germination percentage (GP) under chilling stress, while BB was cold sensitive with a 70.67% GP under chilling stress. Spd content in MGW and BB seeds during seed germination were up-regulated and down-regulated by chilling stress, respectively. Besides, chilling stress apparently decreased the gibberellin (GA) and ethylene (ET) contents, while increased the levels of abscisic acid (ABA) and reactive oxygen species (ROS) in MGW and BB seeds during germination. Exogenous Spd application increased GA, ET contents and decreased ABA content through regulating the gene expressions of metabolic-related enzymes, thus effectively alleviating the low temperature damage on kale seed germination. Besides, Spd significantly increased the activities of superoxide dismutase (SOD) and peroxidase (POD), and reduced the levels of hydrogen peroxide (H2O2) and superoxide anion (O2·-). The present study demonstrated that endogenous Spd metabolism plays an important role in kale seed germination under chilling stress. The effect of exogenous Spd on the metabolism of endogenous Spd, GA, ABA, ET and antioxidant enzymes might be the important reason for promoting the kale seed vigor at low temperature.

A Small Compound, HYGIC, Promotes Hypocotyl Growth Through Ectopic Ethylene Response.

Plant seedlings adjust the growth of the hypocotyl in response to surrounding environmental changes. Genetic studies have revealed key players and pathways in hypocotyl growth, such as phytohormones and light signaling. However, because of genetic redundancy in the genome, it is expected that not-yet-revealed mechanisms can be elucidated through approaches different from genetic ones. Here, we identified a small compound, HYGIC (HG), that simultaneously induces hypocotyl elongation and thickening, accompanied by increased nuclear size and enlargement of cortex cells. HG-induced hypocotyl growth required the ethylene signaling pathway activated by endogenous ethylene, involving CONSTITUTIVE PHOTOMORPHOGENIC 1, ETHYLENE INSENSITIVE 2 (EIN2) and redundant transcription factors for ethylene responses, ETHYLENE INSENSITIVE 3 (EIN3) and EIN3 LIKE 1. By using EBS:GUS, a transcriptional reporter of ethylene responses based on an EIN3-binding-cis-element, we found that HG treatment ectopically activates ethylene responses at the epidermis and cortex of the hypocotyl. RNA-seq and subsequent gene ontology analysis revealed that a significant number of HG-induced genes are related to responses to hypoxia. Indeed, submergence, a representative environment where the hypoxia response is induced in nature, promoted ethylene-signaling-dependent hypocotyl elongation and thickening accompanied by ethylene responses at the epidermis and cortex, which resembled the HG treatment. Collectively, the identification and analysis of HG revealed that ectopic responsiveness to ethylene promotes hypocotyl growth, and this mechanism is activated under submergence.

Carotenoid biosynthesis in durian pulp

AbstractDurian (Durio zibethinus Murray) is an important economic crop in Southeast Asian countries. Analysis of the composition of durian pulp indicates that it has high nutraceutical value that is related to the presence of bioactive antioxidant compounds, with carotenoids being one of the important constituents. The major carotenoids are β‐ and α‐carotene, with the minor carotenoids being lutein and zeaxanthin. Carotenoid biosynthesis in durian pulp involves the coordinated expression of many genes with at least nine genes encoding enzymes having been identified. Carotenoid accumulation increases as fruit maturity advances and is highest in ripe fruit. The concentration of carotenoids in ripe durian pulp varies among cultivars. Ripening‐induced carotenoid accumulation is regulated by endogenous ethylene that controls the expression of key genes.

Ethylene enhanced waterlogging tolerance by changing root architecture and inducing aerenchyma formation in maize seedlings

Waterlogging negatively affects maize growth and yield. In this study, we found that ethylene played a vital role in plant adaptation to waterlogging. ET promotes better growth in seedlings under waterlogging conditions by altering root architecture and increasing lateral root formation by 42.1%. What's more, plants with high endogenous ethylene levels exhibited reduced sensitivity to waterlogging stress. ET also induced the formation of aerenchyma, a specialized tissue that facilitates gas exchange, in a different pattern compared to aerenchyma formed under waterlogging. Aerenchyma induced by ET was mainly located in the medial cortex of the roots and was not prone to decay. ethylene inhibited root elongation under normal conditions, but this inhibition was not alleviated under waterlogging stress. Upon activation of the ET signaling pathway, the transcription factor EREB90 promoted aerenchyma formation by enhancing the programmed cell death process. Overexpression of EREB90 resulted in increased waterlogging tolerance compared to wild type plants. Our findings suggest that pre-treatment of maize seedlings with ET before waterlogging stress can trigger the programmed cell death process and induce aerenchyma formation, thus improving waterlogging resistance.

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.

Morpho-biological and economically valuable traits of a new apple variety Aksyona

The breeders of the Sverdlovsk breeding station of horticulture created a new apple variety Aksyona, which was included in the State Register of Breeding Achievements of the Russian Federation, approved for use on the territory of the Russian Federation in the Volga-Vyatka region in 2022. The parents of this variety are the Ural summer variety Serebryanoye Kopyttse and the donor of immunity to scab 22-40-67, created at Russian Research Institute of Fruit Crop Breeding. Hybridization was carried out in 1993. Studies of the new variety were carried out in 2001 - 2021 on the territory of the Sverdlovsk breeding station of horticulture . The average yield for 4 years of testing the Aksyona variety on the clonal rootstock 62-396 was 226.6 q/ha. This variety is immune to scab (Rvi6 gene), all three QTL FBF7 markers are present in its genotype, which suggests its resistance to fire blight disease. Variety Aksyona is heterozygous for two genes Md-ACO1 and Md-ACS1 and is of interest as an initial form in breeding for a low level of endogenous ethylene biosynthesis, which affects the duration of fruit storage. This variety showed high winter hardiness over the years of testing, has fruits of medium size (110 g), one-dimensional, round, regular shape, with a smooth surface, attractive appearance. The main color is light yellow, the integumentary coloration of the fruit is orange-red, blurry-striped. The skin is dry, matte. The pulp is creamy, medium density, fine-grained, juicy, good sweet and sour taste, with aroma. The ripening period is early summer, the period of consumption is 25 days. The tree is medium-sized, with a rounded crown of medium density, skeletal branches depart from the trunk at an angle close to a right one. The variety is early-growing, comes into fruiting in the fourth year after grafting. Authors of the variety: L.A. Kotov, T.A. Makarova.

Ranunculus sceleratus as a Model Species to Decrypt the Role of Ethylene in Plant Adaptation to Salinity.

The aim of the present study was to develop an experimental system for an exploration of ethylene-dependent responses using intact growing Ranunculus sceleratus plants and to approbate the system for assessing the role of ethylene in salinity tolerance and ion accumulation. Plants were cultivated in sealed plastic containers in a modified gaseous atmosphere by introducing ethylene or 1-methylcyclopropene (1-MCP), a competitive inhibitor of ethylene action. High humidity inside the containers induced a fast elongation of the leaf petioles of R. sceleratus. The effect was ethylene-dependent, as 1-MCP completely blocked it, but exogenous ethylene further promoted petiole elongation. Exogenous ethylene decreased (by 48%) but 1-MCP increased (by 48%) the Na+ accumulation in leaf blades of NaCl-treated plants. The experimental system was further calibrated with ethylene and silica xerogel, and the optimum concentrations were found for inducing leaf petiole elongation (10 μL L-1 ethylene) and preventing leaf petiole elongation (200 g silica xerogel per 24 L), respectively. The second experiment involved a treatment with NaCl in the presence of 1-MCP, ethylene, or 1-MCP + ethylene, both in normal and high air humidity conditions. In high humidity conditions, NaCl inhibited petiole elongation by 25% and ethylene treatment fully reversed this inhibition and stimulated elongation by 12% in comparison to the response of the control plants. Treatment with 1-MCP fully prevented this ethylene effect. In normal humidity conditions, NaCl inhibited petiole elongation by 20%, which was reversed by ethylene without additional elongation stimulation. However, 1-MCP only partially inhibited the ethylene effect on petiole elongation. In high humidity conditions, ethylene inhibited Na+ accumulation in NaCl-treated plants by 14%, but 1-MCP reversed this effect. In conclusion, the stimulation of endogenous ethylene production in R. sceleratus plants at a high air humidity or in flooded conditions reverses the inhibitory effect of salinity on plant growth and concomitantly inhibits the accumulation of Na+ in tissues. R. sceleratus is a highly promising model species for use in studies regarding ethylene-dependent salinity responses and ion accumulation potential involving the manipulation of a gaseous environment.