Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable development.Based on eddy covariance measurements over Lak...Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable development.Based on eddy covariance measurements over Lake Vanajavesi in southern Finland,characteristics of energy fluxes and cold frontal effects on energy exchange were investigated.The lake acted as a heat sink in spring and summer and a heat source in winter.The latent heat flux reached its minimum value in the morning and peaked in the afternoon.The diurnal variation of sensible heat flux was opposite to that of latent heat flux.Impact factors for the sensible heat flux were mainly the lake-air temperature difference and the product of lake-air temperature difference and wind speed.The latent heat flux was mainly affected by the vapor pressure deficit and the product of vapor pressure deficit and wind speed.The annual mean values of bulk transfer coefficients for momentum,heat,and water vapor were 1.98×10^(-3),1.62×10^(-3),and 1.31×10^(-3),respectively.Bulk transfer coefficients for heat and water vapor were not equal,indicating that the parameterization of energy exchange in numerical models,where the assumption that the heat coefficient equals the water vapor coefficient needs improvement.During the ice-free season,cold fronts resulted in 28 sensible heat pulses and 17 latent heat pulses,contributing to 50.59%and 34.89%of sensible and latent heat exchange in Lake Vanajavesi.These results indicate that cold fronts significantly impact the surface energy budget and evaporation over lakes.展开更多
The generation of high-resolution data is increasingly important in understanding the complexities of coastal ocean and developing sound management strategies, especially in view of the long-term impact of severe weat...The generation of high-resolution data is increasingly important in understanding the complexities of coastal ocean and developing sound management strategies, especially in view of the long-term impact of severe weather systems. The impact of severe weather systems, when integrated over time, can be significant when compared with tidal oscillations. This paper presents a study of water transport out of Vermilion Bay in response to a short, intense event associated with a passing atmospheric cold front, and reports the application of an Acoustic Doppler Current Profiler （ADCP） mounted on an Automated Surface Craft （ASC）, known as the auto-boat or unmanned boat, developed in our lab at the Louisiana State University, to generate high resolution data accurately at a fraction of the cost of a manned boat. In our study, we used a manned boat and an unmanned boat, each for over 24 h to cover an entire diurnal tidal cycle, to measure flow velocity profiles to calculate the total transport. A stationary ADCP was deployed in the Southwest Pass of the Vermilion Bay from May 2009 to April 2012, providing data almost continuously （with only one major gap）, with a 717-day record of water transport between the northern Gulf of Mexico and Vermilion Bay, and demonstrates the importance of the pass in water transport.展开更多
The present study identifies wintertime cold fronts in Eurasia from gridded datasets using a new objective two-step identification scheme.The simple and classic conception of a front is adopted,where a cold front is i...The present study identifies wintertime cold fronts in Eurasia from gridded datasets using a new objective two-step identification scheme.The simple and classic conception of a front is adopted,where a cold front is identified as the warm boundary of the frontal zone with a suitable horizontal temperature gradient and cold advection.We combine the traditional thermal front parameter with temperature advection to first identify the cold frontal zone,and then its eastern and southern boundaries are objectively plotted as a cold front in Eurasia.By comparing different cold front identification methods,the results from this two-step cold front identification method and subjective analysis are more consistent,and the positions of the cold front identified with our method are more reasonable.This objective technique is also applied to a nationwide cold wave event over China.Results show that the horizontal extent and movement of the cold front are in good agreement with the related circulation and the associated cold weather.The proposed method and results in this study may shed light on the rapid identification of cold fronts in operational weather analysis and facilitate further research on the long-term activity characteristics of continental cold fronts.展开更多
In order to study the characteristics of cold frontal motion over the arbitrary topography, the velocity of cold frontal movement is derived by using the one layer shallow-water model. The results show that there exis...In order to study the characteristics of cold frontal motion over the arbitrary topography, the velocity of cold frontal movement is derived by using the one layer shallow-water model. The results show that there exist the retardation in upwind side and rapid descent in the lee slope when the cold front crosses the topography.展开更多
[Objective] The aim was to summarize the characteristics of refelectivity factors of Doppler radar of the cold front cloud system. [Method] Judging from the characteristics of reflectivity factors, by dint of the new ...[Objective] The aim was to summarize the characteristics of refelectivity factors of Doppler radar of the cold front cloud system. [Method] Judging from the characteristics of reflectivity factors, by dint of the new generation weather radar in Harbin from 2002 to 2007, the features of the reflectivity factors of the cold front cloud system were summarized. [Result] The cloud formed by the cold front was in banded form in general. However, there was void in the cloud and its intensity was uneven. Most fast moving cold front was long and narrow banded echo and basically the radial velocity turned from northwest wind to southwest. With the changes of month, the feature of the reflective rate also changed. In winter, the cold front cloud was in layer form. The feature of the reflectivity factors was weak and in large area. However, the structure was loose and there was space in the echo. Among them, there were several strong echoes. Strong convection cell echo formed in the two sides of the cold front, and it moved with the entire cloud belt. When the dry cold front moved, regional strong convective current formed, mainly by convective cloud and small echo area. Generally, the changes of the wind direction can not be expounded from the radial velocity. However, the intensity of the convection cell was distinct, 'three-body scattering', 'side lobe echo', and 'weak echo', as well as features of super convection cell. [Conclusion] The study provided positive role for the application of Doppler radar in the surveillance of weather in Heilongjiang Province.展开更多
The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non h...The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non hydrostatic large eddy simulation.Conversion between the frontogenesis and frontolysis of cold filament were created by the chang in the direction of secondary circulations.The changes in the direction of secondary circulation are induced by the Coriolis Effect regardless of wind direction and wave fields.The destructive action of the wind and wave fields on symmetry of the submesoscale flow fields becomes weak as the angle increases.The secondary downwelling jet induced by Stokes shear force is gradually close to that associated with secondary circulations as the angle changes fromθ=0°to 45°and then the downwelling jet is only created by secondary circulations forθ=67.5°and 90°.The frontogenetic intensity of cold filament may be impacted by the angle of the wind and wave fields and the filament axis.The reason is that firstly the odd-symmetry of secondary circulations enhances with the angle increasing,and secondary the secondary downwelling jet created the Stokes shear force gradually weakens and then disappears with the angle increasing.展开更多
The variations of the frontogenetic trend of a cold filament induced by the cross-filament wind and wave fields are studied by a non-hydrostatic large eddy simulation. Five cases with different strengths of wind and w...The variations of the frontogenetic trend of a cold filament induced by the cross-filament wind and wave fields are studied by a non-hydrostatic large eddy simulation. Five cases with different strengths of wind and wave fields are studied.The results show that the intense wind and wave fields further break the symmetries of submesoscale flow fields and suppress the levels of filament frontogenesis. The changes of secondary circulation directions—that is, the conversion between the convergence and divergence of the surface cross-filament currents with the downwelling and upwelling jets in the filament center—are associated with the inertial oscillation. The filament frontogenesis and frontolysis caused by the changes of secondary circulation directions may periodically sharpen and smooth the gradient of submesoscale flow fields.The lifecycle of the cold filament may include multiple stages of filament frontogenesis and frontolysis.展开更多
The frontogenetic processes of a submesoscale cold filament driven by the thermal convection turbulence are studied by a non-hydrostatic large eddy simulation.The results show that the periodic changes in the directio...The frontogenetic processes of a submesoscale cold filament driven by the thermal convection turbulence are studied by a non-hydrostatic large eddy simulation.The results show that the periodic changes in the direction of the cross-filament secondary circulations are induced by the inertial oscillation.The change in the direction of the secondary circulations induces the enhancement and reduction of the horizontal temperature gradient during the former and later inertial period,which indicates that the frontogenetical processes of the cold filament include both of frontogenesis and frontolysis.The structure of the cold filament may be broken and restored by frontogenesis and frontolysis,respectively.The magnitude of the down-filament currents has a periodic variation,while its direction is unchanged with time.The coupling effect of the turbulent mixing and the frontogenesis and frontolysis gradually weakens the temperature gradient of the cold filament with time,which reduces frontogenetical intensity and enlarges the width of cold filament.展开更多
Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this ...Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.展开更多
1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-...1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.展开更多
The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to bio...The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to biotic and abiotic stresses.However,the mechanism underlying the response of this module to cold stress and its role in flower development in wintersweet(Chimonanthus praecox)remains unclear.Through expression pattern analysis,calcium ion(Ca^(2+))concentration assays,correlation analysis,and linear regression analysis,we found that the[Ca^(2+)],along with CpCBL8 and CpCIPK9 expression levels in wintersweet flower buds(FBs),significantly decreased during the initial flowering stage when the chilling requirement reached 570 chill units(CU).Notably,there was a significant positive correlation between[Ca^(2+)]and CpCBL8 expression.Ca^(2+)increased the expression of Cp CBL8 and CpCIPK9 in FBs,causing a significant delay in the flowering of wintersweet.Furthermore,the function of CpCBL8 was studied using heterologous transformation.Overexpression of CpCBL8 significantly delayed flowering time and significantly reduced cold tolerance and altered the expression pattern of endogenous genes related to low-temperature stress and flower development in transgenic Arabidopsis thaliana.Additionally,transcriptome analysis of chilling-induced dormancy breaking and flower bud enlargement revealed that CpCBL8 and CpCIPK9 were negatively regulated by cold,and the expression pattern of endogenous genes related to flower development and cold stress in wintersweet were similar to that of in A.thaliana.Moreover,protein-protein interaction(PPI)analysis revealed that CpCBL8 and CpCIPK9 interacted in the plasma membrane and nucleus.On the basis of these findings,we speculated that the CpCBL8-CpCIPK9 module plays a crucial role in regulating responses to cold stress and flower development in wintersweet.This study elucidated molecular mechanisms through which the downregulation of the Ca^(2+)-induced CpCBL8-CpCIPK9 module results in dormancy breaking and enhances cold tolerance.This study provides valuable insights for the cultivation of new varieties of wintersweet with increased ornamental value and enhanced cold stress tolerance.展开更多
Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous ...Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous quantitative analyses often simplified the chorus dispersion relation by using the cold plasma assumption.However,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic disturbances.We here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to 2018.The statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma density.The region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density decreases.In addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus waves.Compared with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those below.Furthermore,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density.展开更多
A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the f...A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the first clear demonstration of what scientists call the“inheritance of acquired characteristics”-a phenomenon that biologists have debated for over two centuries.展开更多
The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-do...The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-dosage and high-efficiency CFIs for diesel,1,2,3,6-tetrahydrophthalic anhydride(THPA)was introduced as a third and polar monomer to enhance the depressive effects of alkyl methacrylatetrans anethole copolymers(C_(14)MC-TA).The terpolymers of alkyl methacrylate-trans anethole-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-TA-THPA)were synthesized and compared with the binary copolymers of C_(14)MC-TA and alkyl methacrylate-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-THPA).Results showed that C_(14)MC-THPA achieved the best depressive effects on the cold filter plugging point(CFPP)and solid point(SP)by 11℃and 16℃at a dosage of 1250 mg/L and monomer ratio of 6:1,while 1500mg/L C_(14)MC-TA(1:1)reached the optimal depressive effects on the CFPP and SP by 12℃and 18℃.THPA introduction significantly improved the depressive effects of C_(14)MC-TA.Lower dosages of C_(14)MCTA-THPA in diesel exerted better improvement effects on the CFPP and SP than that of C_(14)MC-TA and C_(14)MC-THPA.When the monomer ratio and dosage were 6:0.6:0.4 and 1000 mg/L,the improvement effect of C_(14)MC-TA-THPA on diesel reached the optimum level,and the CFPP and SP were reduced by 13℃and 19℃,respectively.A 3D nonlinear surface diagram fitted by a mathematical model was also used for the first time to better understand the relationships of monomer ratios,dosages,and depressive effects of CFIs in diesel.Surface analysis results showed that C_(14)MC-TA-THPA achieved the optimum depressive effects at a monomer ratio of 6:0.66:0.34 and dosage of 1000 mg/L,and the CFPP and SP decreased by 14℃ and 19℃,respectively.The predicted results were consistent with the actual ones.Additionally,the improvement mechanism of these copolymers in diesel was also explored.展开更多
Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively ...Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.展开更多
Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was desi...Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.展开更多
Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibit...Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.展开更多
Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress i...Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress impacts immune responses in these species,especially in relation to chromatin accessibility and epigenetic regulation,remain poorly understood.In this study,we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia(Oreochromis niloticus),a tropical fish of significant economic importance,under cold stress.By analyzing cis-regulatory elements in open chromatin regions and their associated transcription factors(TFs),we construct a comprehensive transcriptional regulatory network(TRN)governing immune responses,including DNA damage-induced apoptosis.Our analysis identifies 119 TFs within the TRN,with Stat1 emerging as a central hub exhibiting distinct binding dynamics under cold stress,as revealed by footprint analysis.Overexpression of Stat1 in immune cells leads to apoptosis and increases the expression of apoptosis-related genes,many of which contain Stat1-binding sites in their regulatory regions,emphasizing its critical role in immune cell survival during cold stress.These results provide insights into the transcriptional and epigenetic regulation of immune responses to cold stress in tilapia and highlight Stat1 as a promising target for enhancing cold tolerance in tropical fish species.展开更多
Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared wit...Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared with Vitis vinifera.However,metabolites that contribute to the cold tolerance of V.amurensis remain unknown.Here,the metabolomics of buds from V.amurensis‘Zuoshan-1'during cold acclimation(CA)were identified,and cold-sensitive cultivar(V.vinifera‘Jingzaojing')was used as the control.The buds were collected in October,November,and December in 2016 and 2018.The cold hardiness of the buds increased during CA in the two grapevines.However,browning was observed only in V.vinifera buds at temperature below-10℃.Among detected metabolites from buds,443 metabolites were overlapped between two years.Forty-four and thirty differentially accumulated metabolites(DAMs)were identified in V.amurensis and V.vinifera,respectively.Ten DAMs including monoacylglycerol(MAG,18:2)isomer 1,trehalose 6-phosphate,and D-glucose showed identical variations in the two grapevines,indicating conserved CA responses within the Vitis genus.Eighteen DAMs exhibited higher accumulation in V.amurensis than in V.vinifera.Maltotetraose,D-glucoronic acid,L-aspartic acid,azelaic acid,and 4-hydroxybenzoic acid were reported to accumulate during CA in other plants.Enhanced cold tolerance was detected in grapevine leaves with exogenous 5 mmol L^(-1)L-aspartic acid and 1%proanthocyanidins.Potential contributions of other DAMs found in V.amurensis such as Cyanidin 3-O-glucoside need to be further elucidated.Thus,eighteen metabolites accumulated in V.amurensis can be used for practical application in improvement of cold resistance in grapevine.Our findings provide new insights into understanding the cold hardiness of V.amurensis.展开更多
In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in...In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in cold-stress,confirmation through documented evidence was lacking.In this study,we transformed the MYB97 gene from Iris laevigata into tobacco,and discovered that the gene boosted photosynthesis,photoprotection and resilience to cold.The transgenic tobacco seeds exhibited enhanced germination and accelerated seedling growth.Moreover,these plants had decreased levels of MDA(Malondialdehyde)and relative conductance,coupled with elevated concentrations of proline and soluble sugars.This response was accompanied by heightened activity of antioxidant enzymes during periods of cold stress(4 and−2℃).Exposure to low temperatures(0–15℃)also reduced heights but accentuated primary root growth in transgenic tobacco plants.Additionally,tobacco leaves showed an increased growth along with higher chlorophyll levels,net photosynthetic rates,stomatal conductance,transpiration rates and non-photochemical quenching coefficient.This study shows that IlMYB97(The MYB97 genes in I.laevigata)improves cold-resistance,and enhances photosynthesis and photoprotective ability,and thus overall growth and development.These findings would offer the genetic resources to further study cold resistance and photosynthesis.展开更多
基金supported by funds from the National Natural Science Foundation of China(Grant Nos:42275079,41975017,42411530052,and 42161144010)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0105)。
文摘Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable development.Based on eddy covariance measurements over Lake Vanajavesi in southern Finland,characteristics of energy fluxes and cold frontal effects on energy exchange were investigated.The lake acted as a heat sink in spring and summer and a heat source in winter.The latent heat flux reached its minimum value in the morning and peaked in the afternoon.The diurnal variation of sensible heat flux was opposite to that of latent heat flux.Impact factors for the sensible heat flux were mainly the lake-air temperature difference and the product of lake-air temperature difference and wind speed.The latent heat flux was mainly affected by the vapor pressure deficit and the product of vapor pressure deficit and wind speed.The annual mean values of bulk transfer coefficients for momentum,heat,and water vapor were 1.98×10^(-3),1.62×10^(-3),and 1.31×10^(-3),respectively.Bulk transfer coefficients for heat and water vapor were not equal,indicating that the parameterization of energy exchange in numerical models,where the assumption that the heat coefficient equals the water vapor coefficient needs improvement.During the ice-free season,cold fronts resulted in 28 sensible heat pulses and 17 latent heat pulses,contributing to 50.59%and 34.89%of sensible and latent heat exchange in Lake Vanajavesi.These results indicate that cold fronts significantly impact the surface energy budget and evaporation over lakes.
基金The Louisiana Board of Regents EPSCoR(pFund)the Louisiana Board of Regents Traditional Enhancement Program under contract No.LEQSF(2016-17)-ENH-TR-05+1 种基金the North Pacific Research Board under contract No.1229the Louisiana Department of Wildlife and Fisheries under contract No.699775/514-100210
文摘The generation of high-resolution data is increasingly important in understanding the complexities of coastal ocean and developing sound management strategies, especially in view of the long-term impact of severe weather systems. The impact of severe weather systems, when integrated over time, can be significant when compared with tidal oscillations. This paper presents a study of water transport out of Vermilion Bay in response to a short, intense event associated with a passing atmospheric cold front, and reports the application of an Acoustic Doppler Current Profiler （ADCP） mounted on an Automated Surface Craft （ASC）, known as the auto-boat or unmanned boat, developed in our lab at the Louisiana State University, to generate high resolution data accurately at a fraction of the cost of a manned boat. In our study, we used a manned boat and an unmanned boat, each for over 24 h to cover an entire diurnal tidal cycle, to measure flow velocity profiles to calculate the total transport. A stationary ADCP was deployed in the Southwest Pass of the Vermilion Bay from May 2009 to April 2012, providing data almost continuously （with only one major gap）, with a 717-day record of water transport between the northern Gulf of Mexico and Vermilion Bay, and demonstrates the importance of the pass in water transport.
基金This work is supported by the National Key Research and Development Pro-gram of China under contract(Grant No.2019YFC1510201 and Grant No.2018YFC1505602).
文摘The present study identifies wintertime cold fronts in Eurasia from gridded datasets using a new objective two-step identification scheme.The simple and classic conception of a front is adopted,where a cold front is identified as the warm boundary of the frontal zone with a suitable horizontal temperature gradient and cold advection.We combine the traditional thermal front parameter with temperature advection to first identify the cold frontal zone,and then its eastern and southern boundaries are objectively plotted as a cold front in Eurasia.By comparing different cold front identification methods,the results from this two-step cold front identification method and subjective analysis are more consistent,and the positions of the cold front identified with our method are more reasonable.This objective technique is also applied to a nationwide cold wave event over China.Results show that the horizontal extent and movement of the cold front are in good agreement with the related circulation and the associated cold weather.The proposed method and results in this study may shed light on the rapid identification of cold fronts in operational weather analysis and facilitate further research on the long-term activity characteristics of continental cold fronts.
文摘In order to study the characteristics of cold frontal motion over the arbitrary topography, the velocity of cold frontal movement is derived by using the one layer shallow-water model. The results show that there exist the retardation in upwind side and rapid descent in the lee slope when the cold front crosses the topography.
文摘[Objective] The aim was to summarize the characteristics of refelectivity factors of Doppler radar of the cold front cloud system. [Method] Judging from the characteristics of reflectivity factors, by dint of the new generation weather radar in Harbin from 2002 to 2007, the features of the reflectivity factors of the cold front cloud system were summarized. [Result] The cloud formed by the cold front was in banded form in general. However, there was void in the cloud and its intensity was uneven. Most fast moving cold front was long and narrow banded echo and basically the radial velocity turned from northwest wind to southwest. With the changes of month, the feature of the reflective rate also changed. In winter, the cold front cloud was in layer form. The feature of the reflectivity factors was weak and in large area. However, the structure was loose and there was space in the echo. Among them, there were several strong echoes. Strong convection cell echo formed in the two sides of the cold front, and it moved with the entire cloud belt. When the dry cold front moved, regional strong convective current formed, mainly by convective cloud and small echo area. Generally, the changes of the wind direction can not be expounded from the radial velocity. However, the intensity of the convection cell was distinct, 'three-body scattering', 'side lobe echo', and 'weak echo', as well as features of super convection cell. [Conclusion] The study provided positive role for the application of Doppler radar in the surveillance of weather in Heilongjiang Province.
基金Supported by the National Natural Science Foundation of China (Nos.92158204,42176027,41876017,42076026)the project supported by Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2023SP240)+1 种基金the Open Research Project Program of the State Key Laboratory of Internet of Things for Smart City (University of Macao)(No.SKL-IoTSC (UM)-2021-2023/ORPF/A20/2022)the Postdoctoral Innovation Practice Base of Hezhu University and the Guangxi Yuchai New Energy Co.,Ltd.。
文摘The variations of the frontogenetic activity of cold filament driven by the different angle(θ=0°,22.5°,45°,67.5°,and 90°)of the wind and wave fields and the filament axis are studied by non hydrostatic large eddy simulation.Conversion between the frontogenesis and frontolysis of cold filament were created by the chang in the direction of secondary circulations.The changes in the direction of secondary circulation are induced by the Coriolis Effect regardless of wind direction and wave fields.The destructive action of the wind and wave fields on symmetry of the submesoscale flow fields becomes weak as the angle increases.The secondary downwelling jet induced by Stokes shear force is gradually close to that associated with secondary circulations as the angle changes fromθ=0°to 45°and then the downwelling jet is only created by secondary circulations forθ=67.5°and 90°.The frontogenetic intensity of cold filament may be impacted by the angle of the wind and wave fields and the filament axis.The reason is that firstly the odd-symmetry of secondary circulations enhances with the angle increasing,and secondary the secondary downwelling jet created the Stokes shear force gradually weakens and then disappears with the angle increasing.
基金supported by the National Natural Science Foundation of China (Grant Nos. 92158204, 41506001 and 42076019)a Project supported by the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant No. 311021005)。
文摘The variations of the frontogenetic trend of a cold filament induced by the cross-filament wind and wave fields are studied by a non-hydrostatic large eddy simulation. Five cases with different strengths of wind and wave fields are studied.The results show that the intense wind and wave fields further break the symmetries of submesoscale flow fields and suppress the levels of filament frontogenesis. The changes of secondary circulation directions—that is, the conversion between the convergence and divergence of the surface cross-filament currents with the downwelling and upwelling jets in the filament center—are associated with the inertial oscillation. The filament frontogenesis and frontolysis caused by the changes of secondary circulation directions may periodically sharpen and smooth the gradient of submesoscale flow fields.The lifecycle of the cold filament may include multiple stages of filament frontogenesis and frontolysis.
基金The National Key Research and Development Program of China under contract No.2022YFC3103400the National Natural Science Foundation of China under contract Nos 42076019 and 42076026the Project supported by Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2023SP240.
文摘The frontogenetic processes of a submesoscale cold filament driven by the thermal convection turbulence are studied by a non-hydrostatic large eddy simulation.The results show that the periodic changes in the direction of the cross-filament secondary circulations are induced by the inertial oscillation.The change in the direction of the secondary circulations induces the enhancement and reduction of the horizontal temperature gradient during the former and later inertial period,which indicates that the frontogenetical processes of the cold filament include both of frontogenesis and frontolysis.The structure of the cold filament may be broken and restored by frontogenesis and frontolysis,respectively.The magnitude of the down-filament currents has a periodic variation,while its direction is unchanged with time.The coupling effect of the turbulent mixing and the frontogenesis and frontolysis gradually weakens the temperature gradient of the cold filament with time,which reduces frontogenetical intensity and enlarges the width of cold filament.
基金financially supported by the National Natural Science Foundation of China(No.52071040 and 51871036)Natural Science Foundation of Shandong Province,China(No.ZR2022QE008)China Postdoctoral Science Foundation(No.2022M712984)。
文摘Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.
基金supported by the National Natural Science Foundation of China(No.52061135101 and 52001078)the German Research Foundation(DFG,No.448318292)+3 种基金the Technology Innovation Guidance Special Foundation of Shaanxi Province(No.2023GXLH-085)the Fundamental Research Funds for the Central Universities(No.D5000240161)the Project of Key areas of innovation team in Shaanxi Province(No.2024RS-CXTD-20)The author Yingchun Xie thanks the support from the National Key R&D Program(No.2023YFE0108000).
文摘1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.
基金funded by the Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0236)Fundamental Research Funds for the Central Universities(SWU-XDJH202308)Earmarked Funds for the China Agriculture Research System(CARS-26)。
文摘The complex of calcineurin B-like protein(CBL)and CBL-interacting protein kinase(CIPK)serves as key components in calcium-sensing,orchestrating various signals crucial for plant growth,development,and responses to biotic and abiotic stresses.However,the mechanism underlying the response of this module to cold stress and its role in flower development in wintersweet(Chimonanthus praecox)remains unclear.Through expression pattern analysis,calcium ion(Ca^(2+))concentration assays,correlation analysis,and linear regression analysis,we found that the[Ca^(2+)],along with CpCBL8 and CpCIPK9 expression levels in wintersweet flower buds(FBs),significantly decreased during the initial flowering stage when the chilling requirement reached 570 chill units(CU).Notably,there was a significant positive correlation between[Ca^(2+)]and CpCBL8 expression.Ca^(2+)increased the expression of Cp CBL8 and CpCIPK9 in FBs,causing a significant delay in the flowering of wintersweet.Furthermore,the function of CpCBL8 was studied using heterologous transformation.Overexpression of CpCBL8 significantly delayed flowering time and significantly reduced cold tolerance and altered the expression pattern of endogenous genes related to low-temperature stress and flower development in transgenic Arabidopsis thaliana.Additionally,transcriptome analysis of chilling-induced dormancy breaking and flower bud enlargement revealed that CpCBL8 and CpCIPK9 were negatively regulated by cold,and the expression pattern of endogenous genes related to flower development and cold stress in wintersweet were similar to that of in A.thaliana.Moreover,protein-protein interaction(PPI)analysis revealed that CpCBL8 and CpCIPK9 interacted in the plasma membrane and nucleus.On the basis of these findings,we speculated that the CpCBL8-CpCIPK9 module plays a crucial role in regulating responses to cold stress and flower development in wintersweet.This study elucidated molecular mechanisms through which the downregulation of the Ca^(2+)-induced CpCBL8-CpCIPK9 module results in dormancy breaking and enhances cold tolerance.This study provides valuable insights for the cultivation of new varieties of wintersweet with increased ornamental value and enhanced cold stress tolerance.
基金supported by the National Natural Science Foundation of China (NSFC) through Grant Number 42074193
文摘Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous quantitative analyses often simplified the chorus dispersion relation by using the cold plasma assumption.However,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic disturbances.We here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to 2018.The statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma density.The region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density decreases.In addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus waves.Compared with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those below.Furthermore,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density.
文摘A recent discovery in rice has revealed an elegant trick of nature:crops can teach their later generations to survive the cold through inherited memories written in chemical marks on the DNA letters,representing the first clear demonstration of what scientists call the“inheritance of acquired characteristics”-a phenomenon that biologists have debated for over two centuries.
基金supported from the Natural Science Foundation Project of Shanghai(Nos.23ZR1425300 and 22ZR1426100)Experimental Technical Team Construction Project of Shanghai Education Commission(No.10110N230080)+1 种基金National Natural Science Foundation of China(No.22075183)Research and Innovation Project of Shanghai Municipal Education Commission(No.2023ZKZD54).
文摘The addition of cold flow improvers(CFIs)is considered as the optimum strategy to improve the cold flow properties(CFPs)of diesel fuels,but this strategy is always limited by the required large dosage.To obtain low-dosage and high-efficiency CFIs for diesel,1,2,3,6-tetrahydrophthalic anhydride(THPA)was introduced as a third and polar monomer to enhance the depressive effects of alkyl methacrylatetrans anethole copolymers(C_(14)MC-TA).The terpolymers of alkyl methacrylate-trans anethole-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-TA-THPA)were synthesized and compared with the binary copolymers of C_(14)MC-TA and alkyl methacrylate-1,2,3,6-tetrahydrophthalic anhydride(C_(14)MC-THPA).Results showed that C_(14)MC-THPA achieved the best depressive effects on the cold filter plugging point(CFPP)and solid point(SP)by 11℃and 16℃at a dosage of 1250 mg/L and monomer ratio of 6:1,while 1500mg/L C_(14)MC-TA(1:1)reached the optimal depressive effects on the CFPP and SP by 12℃and 18℃.THPA introduction significantly improved the depressive effects of C_(14)MC-TA.Lower dosages of C_(14)MCTA-THPA in diesel exerted better improvement effects on the CFPP and SP than that of C_(14)MC-TA and C_(14)MC-THPA.When the monomer ratio and dosage were 6:0.6:0.4 and 1000 mg/L,the improvement effect of C_(14)MC-TA-THPA on diesel reached the optimum level,and the CFPP and SP were reduced by 13℃and 19℃,respectively.A 3D nonlinear surface diagram fitted by a mathematical model was also used for the first time to better understand the relationships of monomer ratios,dosages,and depressive effects of CFIs in diesel.Surface analysis results showed that C_(14)MC-TA-THPA achieved the optimum depressive effects at a monomer ratio of 6:0.66:0.34 and dosage of 1000 mg/L,and the CFPP and SP decreased by 14℃ and 19℃,respectively.The predicted results were consistent with the actual ones.Additionally,the improvement mechanism of these copolymers in diesel was also explored.
文摘Based on the high-altitude and ground observation data,as well as physical quantity field data,a cold wave weather process in Northeast China,North China and Inner Mongolia during January 1-6,2010 was comprehensively analyzed from the aspects of circulation background,circulation situation,influence system,dynamic conditions,water vapor conditions,etc.The results show that the cold wave weather process appeared during the transition of circulation pattern from zonal to meridional type in middle and high latitudes in the northern Hemisphere.Due to the development of the European trough,the strong warm advection was transported to the Ural Ridge,making it strongly developed.The strong northerly wind belt in front of the ridge moved southwards.The warm advection at the rear of the transverse trough and the cold advection in the southeast in front of the transverse trough on the northwest side of Lake Baikal caused the transverse trough to turn upright and moved southwards,and the longitude of the circulation increased continuously to guide cold air to move southwards,resulting in this strong cold air process.The large ground pressure gradient caused by strong cold air and the frontogenesis of strong surface cyclone led to the gale in North China.
基金supported by National Natural Science Foundation of China(Nos.51806092,52201410)Non-Carbon Energy Conversion and Utilization Institute under the Shanghai Class IV Peak Disciplinary Development Program,High-End Foreign Experts Recruitment Plan of China(G2022013028L).
文摘Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS-2024-00451587)supported by Post-plastic Specialized Graduate Program through the Korea Environmental Industry&Technology Institute(KEITI)funded by the Ministry of Environment(MOE).
文摘Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.
基金supported by the National Natural Science Foundation of China(32130109 and 32373113)the National Natural Science Foundation of Shanghai(23ZR1426800)SciTech Funding by CSPFTZ Lingang Special Area Marine Biomedical Innovation Platform.
文摘Temperature fluctuations challenge ectothermic species,particularly tropical fish dependent on external temperatures for physiological regulation.However,the molecular mechanisms through which low-temperature stress impacts immune responses in these species,especially in relation to chromatin accessibility and epigenetic regulation,remain poorly understood.In this study,we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia(Oreochromis niloticus),a tropical fish of significant economic importance,under cold stress.By analyzing cis-regulatory elements in open chromatin regions and their associated transcription factors(TFs),we construct a comprehensive transcriptional regulatory network(TRN)governing immune responses,including DNA damage-induced apoptosis.Our analysis identifies 119 TFs within the TRN,with Stat1 emerging as a central hub exhibiting distinct binding dynamics under cold stress,as revealed by footprint analysis.Overexpression of Stat1 in immune cells leads to apoptosis and increases the expression of apoptosis-related genes,many of which contain Stat1-binding sites in their regulatory regions,emphasizing its critical role in immune cell survival during cold stress.These results provide insights into the transcriptional and epigenetic regulation of immune responses to cold stress in tilapia and highlight Stat1 as a promising target for enhancing cold tolerance in tropical fish species.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000300)the National Natural Science Foundation of China(Grant Nos.32272691 and 32025032)+1 种基金the Grape Breeding Project of Ningxia(Grant No.NXNYYZ202101-04)the Major Program of Technological Innovation in Hubei Province(Grant No.2022BBA0022)。
文摘Cold tolerance is one of the important traits for grapevine,especially in regions with extremely low temperatures in winter.Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared with Vitis vinifera.However,metabolites that contribute to the cold tolerance of V.amurensis remain unknown.Here,the metabolomics of buds from V.amurensis‘Zuoshan-1'during cold acclimation(CA)were identified,and cold-sensitive cultivar(V.vinifera‘Jingzaojing')was used as the control.The buds were collected in October,November,and December in 2016 and 2018.The cold hardiness of the buds increased during CA in the two grapevines.However,browning was observed only in V.vinifera buds at temperature below-10℃.Among detected metabolites from buds,443 metabolites were overlapped between two years.Forty-four and thirty differentially accumulated metabolites(DAMs)were identified in V.amurensis and V.vinifera,respectively.Ten DAMs including monoacylglycerol(MAG,18:2)isomer 1,trehalose 6-phosphate,and D-glucose showed identical variations in the two grapevines,indicating conserved CA responses within the Vitis genus.Eighteen DAMs exhibited higher accumulation in V.amurensis than in V.vinifera.Maltotetraose,D-glucoronic acid,L-aspartic acid,azelaic acid,and 4-hydroxybenzoic acid were reported to accumulate during CA in other plants.Enhanced cold tolerance was detected in grapevine leaves with exogenous 5 mmol L^(-1)L-aspartic acid and 1%proanthocyanidins.Potential contributions of other DAMs found in V.amurensis such as Cyanidin 3-O-glucoside need to be further elucidated.Thus,eighteen metabolites accumulated in V.amurensis can be used for practical application in improvement of cold resistance in grapevine.Our findings provide new insights into understanding the cold hardiness of V.amurensis.
基金supported by the Science and Technology Basic Resources Investigation Program of China(2019FY100500)the Fun-damental Research Funds for the Central Universities(2572023CT18)the Natural Fund Project of Heilongjiang Province(LH 2020C 044).
文摘In northern China,light and temperature are major limiting factors for plant growth,particularly during seed production and seedling establishment.While previous studies suggested a possible role for the MYB97 gene in cold-stress,confirmation through documented evidence was lacking.In this study,we transformed the MYB97 gene from Iris laevigata into tobacco,and discovered that the gene boosted photosynthesis,photoprotection and resilience to cold.The transgenic tobacco seeds exhibited enhanced germination and accelerated seedling growth.Moreover,these plants had decreased levels of MDA(Malondialdehyde)and relative conductance,coupled with elevated concentrations of proline and soluble sugars.This response was accompanied by heightened activity of antioxidant enzymes during periods of cold stress(4 and−2℃).Exposure to low temperatures(0–15℃)also reduced heights but accentuated primary root growth in transgenic tobacco plants.Additionally,tobacco leaves showed an increased growth along with higher chlorophyll levels,net photosynthetic rates,stomatal conductance,transpiration rates and non-photochemical quenching coefficient.This study shows that IlMYB97(The MYB97 genes in I.laevigata)improves cold-resistance,and enhances photosynthesis and photoprotective ability,and thus overall growth and development.These findings would offer the genetic resources to further study cold resistance and photosynthesis.
