Low-temperature Treatment Research Articles

Postharvest CO2 treatment and cold storage for Drosophila suzukii (Diptera: Drosophilidae) fruit infestation control.

The invasive pest, spotted wing drosophila (Drosophila suzukii (Matsumura, 1931)or SWD), damages various soft-skinned fruits, severely impacting orchards and vineyards economically. Current sorting practices in commercial production may overlook early-stage SWD infestations, as visible signs take a few days to appear. Our study focused on managing SWD infesting fruits (blueberry, cherry, and raspberry) without visible signs using an artificial atmosphere with elevated CO2 and low temperature. We hypothesized that these factors affect SWD survival and possibly interact, with potential variations among different soft- or stone-fruit species or varieties. High CO2 concentrations and cold storage both negatively affected SWD development. A 24-h 100% CO2 fumigation, without cold storage, significantly reduced SWD infestations in all 3 fruit species studied. On the other hand, 10% CO2 without cold storage did not cause a significant infestation reduction in cherries. Cold storage alone was too slow to be considered effective. Concurrent low-temperature treatment and CO2 treatment reduced the insecticidal efficacy of CO2 fumigation. Optimal fruit sanitation was achieved with a 3-h 100% CO2 treatment at ambient temperature before cold storage. Raspberries were the most suitable host for SWD development, with over a 5-fold higher SWD development compared to blueberries and over 50 times more than in cherries. We discussed the observed interactions between CO2 fumigation and chilling and suggested a simple postharvest SWD management protocol using optimal CO2 levels, exposure times, and chilling periods-achievable without complex equipment.

Molecular identification and expression patterns of sweet cherry HIPPs and functional analysis of PavHIPP16 in cold stress.

The HIPP proteins are involved in low-temperature stress, the growth of sweet cherry, and may be potential targets for genetic improvement. PavHIPP16 improved cold resistance in Arabidopsis. In response to abiotic stressors, the heavy metal-associated isoprenylated plant protein (HIPP) proteins play a crucial regulatory role. Although the function of HIPP has been identified in some plants, there have been fewer systematic studies conducted on sweet cherry (Prunus avium L.). Therefore, we performed a comprehensive analysis and expression profiling of PavHIPPs using bioinformatics, RT-PCR, and qRT-PCR techniques. Our findings revealed that 28 PavHIPP genes were unevenly distributed across eight chromosomes. We predicted nine motifs in PavHIPP proteins and observed similar gene structures among highly homologous proteins. The promoter sequences of PavHIPPs contained numerous regulatory elements associated with an adversity of stress. The expression levels of some members showed varying degrees of change under low-temperature treatment. These genes were differentially expressed during flower and fruit development. Arabidopsis overexpressing the PavHIPP16 (OE) gene showed significantly lower relative conductivity and malondialdehyde (MDA) content compared with the wild-type (WT) plants under cold environment. Conversely, peroxidase (POD) activity, superoxide dismutase (SOD) activity, and proline content were significantly higher in OE Arabidopsis than in WT plants. Overall, our results suggest that PavHIPP16 OE Arabidopsis thaliana exhibited enhanced adaptability compared to WT plants under cold conditions. This study provides a foundation for future investigations of the pathways regulating sweet cherry growth and development mediated by the HIPP genes.

Overexpression of the Kiwifruit Transcription Factor AaMYB44 Decreases the Cold Tolerance in Arabidopsis thaliana

Cold stress is one of the main abiotic stresses that affect the development and growth of kiwifruit (Actinidia arguta). Herein, we analyzed the transcriptomic data of A. arguta dormant shoots in response to low-temperature treatment, identified 52 MYB genes, and constructed a phylogenetic tree based on the encoded protein sequences. Then, the effect of one MYB gene on cold tolerance was analyzed. This gene had an open reading frame of 837 bp long and encoded 279 amino acids. Sequence alignment and phylogenetic analysis revealed that this gene belongs to the R2R3-MYB family and was named AaMYB44 based on its homology to other MYB family members. Quantitative real-time PCR revealed that AaMYB44 expression was significantly induced by low temperatures but exhibited the opposite trend in cold-tolerant genotypes. Subcellular localization assays revealed the nuclear localization of the AaMYB44 protein. Furthermore, AaMYB44 was transformed into Arabidopsis thaliana (A. thaliana) via inflorescence infection, and physiological and biochemical tests revealed that the cold resistance and antioxidant capacity of the transgenic A. thaliana were lower than those of wild-type plants. Overall, AaMYB44 might play a negative regulatory role in response to cold stress, providing new insight into the mechanism of cold tolerance.

Synergistic regulation of nano-precipitates and reversed austenite in titanium-free maraging steel by low-temperature solution treatment and double aging treatment

To synergistically enhance the strength and toughness of titanium-free maraging steel, a multi-scale characterization method was used to illustrate the effects of low-temperature solution treatment and double aging treatment on the microstructure of titanium-free maraging steel in this paper. After the low-temperature solution treatment and the double aging treatment, the tensile strength of titanium-free maraging steel increased from 1954 MPa to 2160 MPa and the elongation increased by 8.95 %. By the low-temperature solution treatment, the original austenite grain size of the titanium-free maraging steel was refined to 0.69 μm. The double aging treatment promoted the diffusion of Mo and Ni elements, increased the volume fraction of ω phase, Ni3Mo nano-precipitation phase and reversed austenite, and refined the size of ω phase and Ni3Mo by 14.2 % and 7.9 %, respectively. The nanoparticles of titanium-free maraging steel mainly include the ω phase, Ni3Mo and Laves phase. The strengthening mechanism of nanoparticles was quantitatively evaluated from the shear mechanism and Orowan dislocation loop mechanism. The mechanism shows that the ω phase is the main contributor to the overall precipitation strengthening. Therefore, low-temperature solution treatment and double aging treatment provide a potential solution for achieving high strength and high toughness in maraging steel.

Modification mechanism of caking property of polystyrene waste using low-temperature pyrolysis and its use in coal-blending coking

Polystyrene (PS) waste was depolymerized using a low-temperature pyrolysis treatment (LTPT) to increase its caking index. The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy, thermogravimetric (TG) analysis, pyrolysis-gas chromatography with mass spectrometric detection, and solid-state 13C nuclear magnetic resonance spectroscopy. The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index (PS300) or raw PS. Some properties of the resultant cokes were also analyzed. It was demonstrated that the caking index of PS dramatically increased by LTPT; however, exceeding 300 °C did not yield any benefit. The caking index increased due to the formation of the caking components, whose molecules are medium in size, caused by LTPT. Additionally, the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1% relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter, suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.

Efficient removal of nitrate and ammonium by strain Pseudomonas poae EH-E3 under acidic pH and low-temperature conditions

The combined effect of low temperature and an acidic environment may restrict the growth and metabolic activity of microorganisms involved in nitrogen removal. To overcome poor biological nitrogen removal efficiency during low-temperature treatment of acidic wastewater, a novel pure strain of Pseudomonas poae EH-E3 was successfully isolated and screened based on its strong heterotrophic nitrification and aerobic denitrification capacity. Strain EH-E3 could completely eliminate inorganic nitrogen sources of nitrate within 30h and ammonium within 20h at 15 °C and pH 5.0, with corresponding removal efficiencies for total nitrogen of 95.13% and 91.35%, respectively. Nitrogen balance testing indicated that strain EH-E3 removed 43.25% of ammonium, 45.72% of nitrate, and 51.20% of nitrite in the form of gaseous products. Enzyme activity assays revealed that the specific activities of ammonia monooxygenase, nitrate reductase, and nitrite reductase were 0.533, 0.956, and 0.011 U/mg proteins, respectively. These findings suggest that strain EH-E3 has strong potential for use in low-temperature treatment of acidic wastewater.

Efficient low-temperature wastewater treatment by Pseudomonas zhanjiangensis sp. nov.: a novel cold-tolerant bacterium isolated from mangrove sediment.

A novel heterotrophic, cold-tolerant bacterium, designated Pseudomonas zhanjiangensis 25A3ET, was isolated from mangrove sediment and demonstrated excellent efficiency in cold wastewater treatment. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain 25A3ET within the genus Pseudomonas, showing the highest similarity (98.7%) with Pseudomonas kurunegalensis LMG 32023T. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were below the species delineation thresholds (70% for dDDH, 95% for ANI), indicating that strain 25A3ET represents a novel species. This strain demonstrated high efficiency in removing nitrogen (N) and organic pollutants under low-temperature conditions. Specifically, it achieved 72.9% removal of chemical oxygen demand (COD), 70.6% removal of ammoniacal nitrogen (NH4 +-N), and 69.1% removal of total nitrogen (TN) after 96 h at 10°C. Genomic analysis identified key genes associated with cold adaptation, nitrogen removal and organic matter degradation. These findings indicate that Pseudomonas zhanjiangensis 25A3ET holds significant potential for application in cold temperature wastewater treatment, offering a promising solution for environmental remediation in regions with low ambient temperatures.

Spraying KH2PO4 Alleviates the Damage of Spring Low-Temperature Stress by Improving the Physiological Characteristics of Wheat Flag Leaves.

The low-temperature stress (LTS) in spring results in tremendous yield loss in wheat production, and the application of potassium dihydrogen phosphate (KH2PO4) can alleviate stress-induced damage. However, the underlying effect of spraying KH2PO4 on the physiological characteristics of wheat flag leaves under spring LTS remains unclear. In this study, we investigated the effect of spraying KH2PO4 on flag leaf physiological traits and yield under spring LTS, including treatments at 15 °C and spraying H2O (CK), treatment at -4 °C and spraying H2O (LT1), and treatment at -4 °C and spraying KH2PO4 (LT2). The results showed that spraying KH2PO4 significantly increased the activities of the superoxide dismutase (SOD), the peroxidase (POD), and the catalase (CAT), and reduced malondialdehyde (MDA) content in the flag leaves. Compared to LT1, the SOD, POD, and CAT activities in the flag leaves of the Yangnong19 (YN19) and Xinmai26 (XM26) via LT2 increased by 5.5%, 10.9%, and 3.9%, and 5.4%, 9.2%, and 4.4%, respectively, and the MDA content of the YN19 and XM26 decreased by 10.5% and 9.1%, respectively, at 0-12 d after low temperature treatment (DALTT). Spraying KH2PO4 appreciably alleviated damage to the leaf cell morphology and tissue integrity, and increased the accumulation of proline and soluble protein, the chlorophyll content, and the activities of Ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxykinase. The net photosynthetic rate in the flag leaves of the YN19 and XM26 via LT2 increased by 37.9% and 35.9%, respectively, at 0-12 DALTT, compared to LT1. Moreover, spraying KH2PO4 reduced the yield loss rate of the YN19 and XM26 by 13.06% and 16.72%, respectively. The present study demonstrates that spraying KH2PO4 can enhance wheat resistance to spring LTS and maintain the photosynthetic capacity of flag leaves, alleviating the negative effects of LTS on grain yield.

Surface Activation of Cotton Fabric with Low-Temperature Air Plasma Treatment for Metallic Printing

In this investigation, air plasma treatment was utilised to activate the surfaces of 100% grey and bleached cotton fabrics in preparation for metallic pigment printing. The study delved into the surface morphology, wettability, and surface chemistry properties. Scanning electron microscopy (SEM) revealed roughness and grooves in the treated samples. The contact angle witnessed a 29% and 41% increase for grey and bleached fabrics, respectively, compared to their untreated counterparts. Surface chemistry analysis using FTIR and XPS provided crucial insights into the functional polar groups, such as OH and C=O, along with significantly elevated O1 peaks in both plasma-treated grey and bleached cotton fabrics. These findings contributed to the enhanced surface free energy of the fabrics, preparing them for the subsequent pigment printing process. The study explores the impact of plasma treatment on the colour fastness of grey and bleached cotton fabrics printed with gold and silver metallic pigments. Untreated fabrics exhibited poor durability, with low colour change and staining-resistance ratings, particularly for gold pigments. Plasma treatment significantly improved colour retention, adhesion, and resistance to staining for both metallic pigments, with silver outperforming gold. Rubbing fastness tests revealed that plasma treatment moderately enhanced durability, though gold remained susceptible to friction damage. Light fastness was excellent for both pigments, and plasma treatment further improved performance. Perspiration tests showed that plasma treatment bolstered resistance, particularly for gold. These findings suggest that plasma treatment enhances the stability of metallic pigments, offering potential applications in the textile industry for improved product quality and durability.

Response of Different Exogenous Phytohormones to Rice Yield Under Low-Temperature Stress at the Filling Stage

This paper aims to clarify the effects of different exogenous phytohormones on the physiological traits of rice (Oryza sativa L.) at the early stage of irrigation under low-temperature stress. In this study, two types of rice varieties with different temperature sensitivities screened out previously, namely, a cold-tolerant variety (Nan Jing 9108) and a low-temperature-sensitive variety (Hui Liang You 898), were used in pots to simulate the process of low-temperature stress in rice at the early stage of grouting (6–9 days after anthesis) with artificial low-temperature treatments. The experimental treatments were 450 mg L−1 Methyl jasmine acid (MJ), 46 mg L−1 Melatonin (MT), 69 mg L−1 Salicylate (SA), 40 mg L−1 Erythromycin (GA3), 25 mg L−1 Zeatin (Z), 145 mg L−1 Spermidine (SPD), and 5 mg L−1 Abscisic acid (ABA) sprayed on rice before low-temperature stress, while low-temperature treatment without spraying (DK) and conventional planting without spraying (CK) were added as the control. The results showed that compared with the room temperature control (CK, sprayed with deionized water), the low-temperature control (DK, low-temperature treatment, and sprayed with deionized water) all significantly reduced the rice grain yield. Different exogenous hormones sprayed before low-temperature stress could increase rice yield, among which, Z and SPD spraying treatments had a better effect on the yield of Hui Liang You 898, while different exogenous hormone treatments increased the yield of Nan Jing 9108 in an average manner. The Z and SPD treatments increased the yield of Hui Liang You 898 by 24.87% and 26.16% and that of Nan Jing 9108 by 15.87% and 17.80%, respectively. This was mainly attributed to the significant increase in thousand-grain weight and fruiting rate, while there was no significant difference in the number of spikes and number of grains. The different exogenous hormone treatments were able to delay leaf senescence, enhance the photosynthetic production capacity of plants by increasing leaf chlorophyll content, and thus increase the accumulation of photosynthetic assimilation products and population growth rate after flowering. Among them, both Z and SPD treatments resulted in a population growth rate of more than 30% from spike flushing to maturity, which led to a higher dry matter accumulation of the plant at maturity. In addition, in the dry matter distribution of the plant at maturity, the seeds occupied a higher accumulation amount and proportion compared with the respective DK; the SPD treatment resulted in the maximum distribution rate of seeds at maturity of Hui Liang You 898, with an increase of 8.27%, and the Z treatment resulted in the maximum distribution rate of seeds at maturity of Nan Jing 9108, with an increase of 7.34%. At the same time, the Z treatment significantly increased the activities of adenosine diphosphate glucose phosphorylated enzyme (AGP) and starch branching enzyme (SBE) in the grains of both varieties, which resulted in the accumulation of more starch and ultimately increased the rice grain yield. The results verified that different exogenous phytohormones could be used to regulate the insufficiency of grouting caused by low-temperature stress during the grouting and fruiting stages of rice and enriched their agronomic and physiological traits in response at the same time.

Effect Of The Composition Of The Etching System MF-HCl (M = Li+, Na+, NH4+) on the gas-sensitive properties of Ti3C2Tх/Tioх nanocomposites

The influence of the nature of MF-HCl etching systems (M = Li+, Na+, NH4+) on the process of synthesis of Ti3C2Tx MXenes on the basis of Ti3AlC2 MAX-phase, microstructure, phase purity, interlayer distance, composition of functional surface groups, thermal behavior and yield of the obtained products has been studied. The room temperature sensing properties of Ti3C2Tx receptor layers deposited by microplotter printing were studied with respect to a wide range of gas analytes (H2, CO, NH3, NO2, NO2, O2, benzene, acetone, methane and ethanol). Increased sensitivity to ammonia was revealed for the MXenes obtained by exposure to hydrochloric acid solutions of sodium and ammonium fluorides and to carbon monoxide for the sample synthesized using the LiF-HCl system. High responses (~20–30% to 100 ppm NO2) were observed for all three receptor materials, but sensor recovery processes were significantly hampered. To improve the sensing characteristics, Ti3C2Tx sensing layers were subjected to relatively low-temperature heat treatment in an air atmosphere to form Ti3C2Tx/TiOx nanocomposites. It was found that a high and selective oxygen response at very low operating temperatures (125-175°C) was observed for the MXenes partially oxidized, which is particularly characteristic of the material produced using the HCl-NaF system.

Resource stock, age structure, and seed prediction of ferula sinkiangensis K.M. Shen

Ferula sinkiangensis K.M. Shen (FS) is an endemic species in Xinjiang, China. It has extremely high economic and medicinal value but is on the brink of extinction. A comprehensive survey of the distribution area of FS was conducted to study its resource stock, age structure and yielding capacity of seeds. Results show that there is one existing distribution area of FS with an area of 322.84 hm2 and a total plant quantity of 907,100. The age structure of FS population is reasonable showing a growing type of population. After low-temperature treatment and indoor germination of the seeds of FS, the utilization efficiency of seeds was increased by 15.45 times and 1165.81 times respectively. The establishment of the original habitat protection zone has played a huge role in promoting the recovery of the population of FS and the indoor germination of seeds would greatly alleviate the problem of seeds shortage of FS. Bangladesh J. Bot. 53(3): 765-772, 2024 (September) Special

Chlorophyll and Carotenoid Metabolism Varies with Growth Temperatures among Tea Genotypes with Different Leaf Colors in Camellia sinensis

The phenotype of albino tea plants (ATPs) is significantly influenced by temperature regimes and light conditions, which alter certain components of the tea leaves leading to corresponding phenotypic changes. However, the regulatory mechanism of temperature-dependent changes in photosynthetic pigment contents and the resultant leaf colors remain unclear. Here, we examined the chloroplast microstructure, shoot phenotype, photosynthetic pigment content, and the expression of pigment synthesis-related genes in three tea genotypes with different leaf colors under different temperature conditions. The electron microscopy results revealed that all varieties experienced the most severe chloroplast damage at 15 °C, particularly in albino cultivar Baiye 1 (BY), where chloroplast basal lamellae were loosely arranged, and some chloroplasts were even empty. In contrast, the chloroplast basal lamellae at 35 °C and 25 °C were neatly arranged and well-developed, outperforming those observed at 20 °C and 15 °C. Chlorophyll and carotenoid measurements revealed a significant reduction in chlorophyll content under low temperature treatment, peaking at ambient temperature followed by high temperatures. Interestingly, BY showed remarkable tolerance to high temperatures, maintaining relatively high chlorophyll content, indicating its sensitivity primarily to low temperatures. Furthermore, the trends in gene expression related to chlorophyll and carotenoid metabolism were largely consistent with the pigment content. Correlation analysis identified key genes responsible for temperature-induced changes in these pigments, suggesting that changes in their expression likely contribute to temperature-dependent leaf color variations.

Compositing of rGO to TiO2 by Low-Temperature Treatment and Their Photocatalytic Properties

Reduced graphene oxide (rGO)/TiO2 nanocomposites were prepared by low-temperature and low-pressure heat treatment. The structure and photocatalysis performance of the composites were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and UV-visible diffuse reflectance spectrum (UV-Vis DRS). The photocatalytic degradation performance of methyl orange (MO) by composites with different raw material ratios was studied under simulated solar-irradiation conditions. Results indicated that graphene oxide (GO) was reduced to graphene during heat treatment and bonded well with TiO2. Compared with TiO2, GO addition greatly improved its photocatalytic efficiency. Under simulated sunlight irradiation, the samples exhibited good photocatalysis performance. Within 50[Formula: see text]min, MO can be rapidly degraded by TiO2/40% rGO composite.

Evaluating the effects of short-term low temperature on the growth and development of Trichopria drosophilae based on the age–stage two-sex life table

BackgroundThe effects of low temperatures on parasitic wasps are crucial for maintaining farmland biodiversity and enhancing biological control, especially given the implications of global warming and frequent extreme cold events.MethodsWe studied the effects of different low temperatures (−8 ± 1 °C, −4 ± 1 °C, 0 ± 1 °C, 4 ± 1 °C, and 8 ± 1 °C) on the mating frequency and duration of male adults of Trichopria drosophilae and the number of pupae beaten by female adults, and constructed the age–stage two-sex life table of T. drosophilae.ResultsThis study found that male T. drosophilae adults exposed to low temperatures for 12 h significantly altered their mating behavior, peaking between 15:00 and 17:00. As the temperature dropped during the exposure, both the mating frequency of T. drosophilae and the duration of pupal beating were affected. The survival rate of female adults dropped from 39.55% at 8 °C to just 21.17% at −8 °C. Low-temperature treatment shortened the development period and lifespan for T. drosophilae adults. They developed 4.71 days faster and had a total lifespan that was 10.66 days shorter than those in the control group after being exposed to −8 °C. Furthermore, the average number of eggs laid by females at −8 °C was 4.46 less than that at 8 °C and 6.16 less than that in the control group, which laid an average of 21.55 eggs. The net reproductive rate (R0) of T. drosophilae decreased with lower temperatures, reaching a low of 23.64 at −8 °C. Conversely, the intrinsic growth rate (rm) actually increased as temperatures dropped, with the lowest value being 0.21 at −8 °C.ConclusionsThe findings indicate that short-term exposure to low temperatures hampers the growth and population increase of T. drosophilae, thereby reducing their effectiveness as biological control agents.Graphical

Low-temperature-induced disruption of reproductive axis and sperm vitality via stress axis in Monopterus albus

The ricefield eel (Monopterus albus) is inherently timid and highly sensitive to stress. Our previous studies have shown that low-temperature weather could significantly affect the sperm vitality of ricefield eels. This study aims to investigate the regulatory mechanism of low-temperature effects on testicular function and sperm vitality in ricefield eels. The ricefield eels were initially reared at low (10 °C) and normal (25 °C) temperatures for 24 h. Low temperatures were found to induce the expression of pituitary pro-opiomelanocortin (POMC) and testes insulin-like growth factor-binding protein 1 (IGFBP1) mRNA expression, suggesting that the reduction in sperm vitality could be attributed to the activation of the stress axis. Moreover, the results indicated a significant decrease in sperm occupancy and count in the testes, along with a reduced percentage of motile sperm. Subsequent transcriptome analysis showed substantial inhibition of reproductive hormone genes (gnrh1, lh, and fsh) in the brain and pituitary, and downregulation of meiosis-related genes (dmc1, rec8, and sycp3) in the testes. These findings suggest that low temperatures might disrupt testicular development and spermatogenesis by inhibiting the reproductive axis. Metabolomics analysis then demonstrated a significant reduction in the levels of metabolites related to glycolysis, fatty acid metabolism, and the tricarboxylic acid (TCA) cycle in the testes after low-temperature treatment. Interestingly, the expression of zona pellucida sperm-binding proteins 3 and 4 (ZP3 and ZP4), which may affect sperm vitality and spermatogenesis, was significantly induced by low temperatures in the testes. In conclusion, these findings suggested that low temperatures might affect testicular function and sperm vitality by simultaneously activating the stress axis and inhibiting the reproductive axis and energy metabolism in the testes.

VvbZIP22 regulates quercetin synthesis to enhances cold resistance in grape

Grapes are one of the important fruit crops widely cultivated in the world, with high nutritional and economic value. However, with the intensification of global warming, extreme low temperature has seriously affected the development of the grape industry. Quercetin is a highly antioxidant active substance that can enhance the tolerance of plants to external environmental stress, but its function and mechanism in response to low-temperature stress in grapes are still unclear. Here, we found that grapes accumulate more quercetin under low-temperature stress, and exogenous quercetin can significantly improve the cold resistance of grapes. The key quercetin synthesis gene VvFLS1 (flavanol synthase 1) is up-regulated after low-temperature treatment, and overexpression of VvFLS1 increases quercetin content and enhances the cold resistance of grape. Yeast one-hybrid and dual luciferase reporter systems demonstrate that VvbZIP22 (basic-leucine zipper 22) directly binds to the VvFLS1 promoter, and VvbZIP22 has cold-induced expression characteristics. Overexpression of VvbZIP22 significantly improves the cold resistance of grape. The above results indicate that quercetin plays an important role in the response of grapes to low-temperature stress. Under low temperature, VvbZIP22 can mediate quercetin synthesis through regulating VvFLS1, alleviate oxidative damage, and improve the cold resistance of grapes.

Low-temperature treatment optimization for diesel-contaminated kaolin: Mutual impacts of generated pyrolytic carbon and particle agglomeration

Efficiency improvement in low-temperature treatment for diesel-contaminated sites is urgent because changes in soil properties and the generation of new substance during the remediation process can influence the duration and energy utilization. This paper focuses on low-temperature treatment optimization based on the mutual impacts of pyrolytic carbon and kaolin aggregation. Results reveal that the peak mass loss rate occurred between 100–150°C, with minimal loss beyond 200°C. Samples thermally treated at 150–200°C exhibited darker colors, indicating pyrolytic carbon formation, corroborated by x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), and three-dimensional fluorescence spectrum (3D-EEM) analyses. Additionally, diesel contamination influenced the fractal dimension of aggregates by influencing adhesion forces (<10000 mg/kg) and forming liquid bridges (≥10000 mg/kg) in untreated kaolin, resulting in an initial increase and subsequent fall in fractal dimension with increasing concentration. Decline rates of pollutant gas concentration were closely correlated with fractal dimension changes under thermal conditions due to pollutant volatilization and pyrolytic carbon formation. Based on the consistency between fractal dimension and decline rate, two critical remediation concentrations (C0) and temperatures (T0) indices were identified to optimize the low-temperature remediation.

Effects of different low-temperature pyrolysis treatments on the biotoxicity of biochar derived from tobacco stalks

The pyrolytic treatment of tobacco stalk (TS) waste results in the production of a large amount of biochar, which is usually used for environmental remediation. However, little attention has been given to the effects of different pyrolysis methods on the biotoxicity of TS biochar. This study examined the effects of three different pyrolysis methods at 350 °C (fast pyrolysis, slow pyrolysis, and low-temperature carbonization) on the biotoxicity of TS biochar (Escherichia coli (E. coli) growth and wheat germination). The results revealed that the dissolved organic matter (DOM) of the three types of biochar promoted the growth of E. coli, and the maximum growth of E. coli was ranked as DOM-F350 > DOM-S350 > DOM-350. However, the DOM inhibited the growth of the wheat seeds, with the growth index (below 0.8) of the wheat seeds ranked as DOM-350 > DOM-F350 > DOM-S350. The alkali metal content, pH and humus-like substance content of biochar may be responsible for the biotoxicity of biochar through various mechanisms. In addition, TS-S350 exhibited greater biotoxicity than did TS-F350 because of the greater content of toxic nitrogen-containing organic compounds. These findings can provide reliable theoretical guidance for the effective management and safe utilization of TS waste.

The effect of low-temperature heat treatment on hydrogen embrittlement of sheared edge in advanced high-strength steels

Hydrogen embrittlement (HE) has become an important issue in ultra-strong automotive steel applications. This study investigated the HE mechanism of the sheared edge in complex phase (CP) steel and examined the HE improvement achieved via low-temperature soaking (150 °C). To this end, changes in the microstructures of both the steel matrix and sheared edge were analyzed, and various mechanical properties were evaluated before and after soaking. In addition, the HE resistances of the steel and sheared edges were evaluated using slow-strain-rate tensile and immersion tests, respectively. Before soaking, the CP microstructure comprised of tempered martensite and lath bainite with island-shaped polygonal bainite. After soaking, the overall microstructure remained largely unchanged, the yield strength and fracture toughness increased, and uniform localized nanohardness was achieved through carbon redistribution. The intrinsic resistance to HE is enhanced by carbon clustering or carbide precipitation, which impedes hydrogen diffusion. Immersion tests revealed that HE occurred only in the sheared edge with a burr upward, indicating the cut-edge condition significantly affected HE susceptibility. H-induced cracks in the CP microstructure before soaking propagated along interfaces between the island bainite and the matrix, where stress concentration occurred because of large differences in nanohardness. After soaking, cracks penetrated the island bainite, suggesting a reduced stress concentration caused by the more uniform nanohardness across phases. Overall, soaking improved the HE resistance of the sheared edge by altering crack propagation behavior. The enhanced fracture toughness improved damage tolerance to pre-existing defects and enhanced the resistance to HE, along with reduced H diffusivity.