Genome-Wide Exploration of the Grape GLR Gene Family and Differential Responses of VvGLR3.1 and VvGLR3.2 to Low Temperature and Salt Stress

Grapes,one of the oldest tree species globally,are rich in vitamins.However,environmental conditions such as low temperature and soil salinization significantly affect grape yield and quality.The glutamate receptor(GLR)family,comprising highly conserved ligand-gated ion channels,regulates plant growth and development in response to stress.In this study,11 members of the VvGLR gene family in grapes were identified using whole-genome sequence analysis.Bioinformatic methods were employed to analyze the basic physical and chemical properties,phylogenetic trees,conserved domains,motifs,expression patterns,and evolutionary relationships.Phylogenetic and collinear analyses revealed that the VvGLRs were divided into three subgroups,showing the high conservation of the grape GLR family.These members exhibited 2 glutamate receptor binding regions(GABAb and GluR)and 3-4 transmembrane regions(M1,M2,M3,and M4).Real-time quantitative PCR analysis demonstrated the sensitivity of all VvGLRs to low temperature and salt stress.Subsequent localization studies in Nicotiana tabacum verified that VvGLR3.1 and VvGLR3.2 proteins were located on the cell membrane and cell nucleus.Additionally,yeast transformation experiments confirmed the functionality of VvGLR3.1 and VvGLR3.2 in response to low temperature and salt stress.Thesefindings highlight the significant role of the GLR family,a highly conserved group of ion channels,in enhancing grape stress resistance.This study offers new insights into the grape GLR gene family,providing fundamental knowledge for further functional analysis and breeding of stress-resistant grapevines.

Effects of Low Temperature Stress on Germination and Physiological Characteristics of Different Sweet Maize Varieties

[Objectives]The paper was to explore the effects of low temperature stress on germination and physiological characteristics of different sweet maize varieties.[Methods]Taking Taitian 264,Zhexuetian 1 and Chaotian 4 as the research objects,the changes in germination potential,germination index,plant height,biomass,and antioxidant enzyme activity of maize seeds were studied under optimal temperature conditions(25℃)and low temperature stress conditions(10℃).[Results]Under 10℃stress,the germination rate and germination index of Taitian 264 were higher than that of Zhexuetian 1 and Chaotian 4.Under low temperature stress,Taitian 264 exhibited the least reduction in height and biomass,while Zhexuetian 1 had the most reduction.Additionally,the SOD and POD activities of Taitian 264 were higher than that of Zhexuetian 1 and Chaotian 4 under both temperature conditions,while the MDA content of Taitian 264 was lower.Taitian 264 showed strong germination ability against low temperature stress.[Conclusions]This study provides a basis for timely sowing practices of sweet maize in agricultural production.

Advances in Molecular Regulatory Mechanisms of Fruit Trees under Low Temperature Stress

The most recent research findings on the tolerance of fruit trees to cold stress are reviewed from a molecular perspective,including the perception and transduction of low temperature calcium signaling,CBF-dependent molecular regulatory mechanisms,non-CBF-dependent molecular regulatory mechanisms,and so forth.The objective is to provide a reference basis for further improving the cold resistance of fruit trees and cultivating new varieties of hardy plants.

De Novo Transcriptome Analysis in Hevea brasiliensis to Unveil Genes Involved in Low Temperature Stress Response

Low temperature is one of the adversities threatening the growth and development and reduces the yield of rubber trees.However,molecular mechanisms toward rubber trees in response to low temperature are largely unclear.In this study,7,159 and 7,600 differentially expressed genes(DEGs)were identified in‘Reyan 73397’rubber trees.Through GO analysis,the catalytic activity was the representative of the GO term in the only DEGs at the two studied temperatures(room temperature and 4°C,respectively),while KEGG analysis showed that carbon metabolism was the most important grouping under the comparison of these two temperatures.In addition,expression of 9 members of transcription factor MYB family genes were further verified by qRT-PCR,and MYB family genes may play important roles in the regulation of rubber trees under low temperature stress.This study provided a theoretical foundation for(1)revealing the molecular mechanisms of rubber trees in response to low temperature and(2)breeding of tolerant varieties of rubber trees.

Analysis of microRNA Expression Characteristics Related to Low Temperature Stress in Chewing Cane

[Objectives]To explore microRNA expression characteristics related to low temperature stress in chewing cane.[Methods]The research on miRNA under abiotic stress of sugarcane at home and abroad mainly focused on the types and regulation of miRNA under cold,heat,drought,high salt,and mechanical stress.However,there are few studies on miRNA under low temperature stress in chewing cane.The target genes of miR394 and miR825 in chewing cane were predicted and functionally analyzed by bioinformatics technology.[Results]The results showed that the target genes of miR394 and miR825 were mainly members of the WRKY transcription factor family,involved in plant growth,development and stress resistance.Real-time fluorescence quantitative PCR analyzed the expression characteristics of target miRNA in different tissues of chewing cane at different periods of low temperature stress.[Conclusions]The results showed that the expression of chewing cane miR394 and miR408 had temporal and spatial specificity and tissue specificity,both of which could respond to low temperature stress with significant differential expression.

Effects of Low Temperature Stress on Physiological and Biochemical Characteristics of Podocarpus nagi

[Objective] The paper was to study the effect of low temperature stress on physiological and biochemical characteristics of Podocarpus nagi. [Method] Through the determination of physiological indices such as plasma membrane permeability, free proline content, soluble sugar content, malondialdehyde （MDA） content and chlorophyll content, the change law of these indices of P. nagi seedlings under natural conditions and artificially controlled low temperature conditions within the continuous 5 d was studied. [Result] The soluble sugar content, free proline content, MDA content and plasma membrane permeability of P. nagi seedlings were slightly in- creased compared with control; the chlorophyll content gradually decreased with the prolongation of low temperature stress. P. nagi seedlings produced active response to low temperature stress, so the low temperature injury P. nagi seedlings suffered was reduced. [Conclusion] The study provided theoretical basis for winter management in P. nagi cultivation in Hanjiang plain area.

Effect of Low Temperature Stress on Sweet Potato S-Adenosyl Methionine Synthetase Gene Expression

[Objective] The mRNA expression level changes of S-adenosylmethionine synthetase （SAMS） under low temperature stress was studied. [Method] Total RNA were extracted from leaves, stem and earthnut of sweet potato 0,12,24,48 and 72 h after low temperature treatement, mRNA expression level was analyzed by reverse expression and Real-time PCR technique. [Result] The expression quality of the gene extracted from leaves, stem and earthnut increased and the expression quality reached the peak point 24,72 and 72 h after low temperature treatment respectively. The expression change of earthnut was the biggest. [Conclusion] Low temperature was good for increasing mRNA expression of relevart genes.

Screening Index for Low Phosphorus Tolerance at Seedling Stage

[Objective] Simple and reliable identification criteria used in screening phosphorus efficiency of soybean at seedling stage was discussed.[Method] Using the high and low phosphorus soil pot experiment,the soybean seedling stage＇s 5 criteria including RPH,RAW,RRW,RAPC and RRPC were studied.[Result] Low phosphorus stress had the low effects on relative plant height,the coefficient of variation was only 9.07%,has not achieved the remarkable level with its its criteria＇s relevance;Low phosphorus stress had the higher effects on relatively above-ground dry weight and relative dry weight of root,relatively above-ground phosphorus concentration and relative root phosphorus concentration,its coefficient of variation was also big,in turn is 26.67%,22.68%,24.01% and 15.87%,The correlation coefficient among the indicators had significantly or extremely significantly positive correlation.[Conclusion] Relatively above-ground dry weight and relative dry weight of root,relatively above-ground phosphorus concentration can be used as an important indicator of comprehensive evaluation of screening phosphorus efficiency of soybean at seedling stage,while the relative root phosphorus concentration can be used as secondary screening index.

Physiological Responses of Actinidia arguta (Seib.et.Zucc.) to Low Temperature Stress

[Objective] To study the ecophysiological effects of low temperature stress on Actinidia arguta （Seib.et.Zucc.）, and provide a theoretical basis for the introduc- tion and breeding of cold resistant varieties. [Method] A. arguta as the test material was processed at room temperature of 4 ℃ to determine the contents of chloro- phyll, water soluble sugar, water soluble protein, free proline, MDA, and antioxidant enzymes （POD activity, SOD activity, CAT activity） with the treatment at 25℃ as the control. [Results] The results indicated that with the prolonging of stress time, the content of chlorophyll was first increased and then decreased, and the content of MDA was increased; soluble sugar content of seedling leaf decreased gradually, while the soluble protein and proline content of seedling leaves were first increased and then decreased; the activities of SOD and POD were displayed a decline trend, meanwhile the activities of CAT was first increased and then decreased. [Conclu- sion] The various indicators showed that under low temperature stress, the chloro- phyll content decreased accompanied with membrane lipid peroxidation and MDA accumulation, and soluble sugar, soluble protein, free proline and antioxidant en- zymes play a protective role in different degrees.

Differentiation of Barley Genotypes with High Phosphorus Efficiency under Low Phosphorus Stress

[Objective] This study aimed to investigate differences in phosphorus effi-ciency between two-rowed barley and multiple-rowed barley and differences in phos-phorus efficiency among various agronomic traits, and to explore the relationship be-tween agronomic traits and row type with phosphorus efficiency. [Method] Under available phosphorus mass fractions of 1.32 and 36.6 mg/kg, 172 barley varieties, including 79 two-rowed foreign barley, 22 multiple-rowed foreign barley, 58 two-rowed Chinese barley and 13 multiple-rowed Chinese barley, were selected to com-pare differences in phosphorus efficiency-related agronomic traits. Plant height, spike length, number of unfil ed grains, number of unfil ed grains, main panicle weight, to-tal panicle weight, total stem weight, weight of aerial part and heading stage were surveyed for statistical analysis. [Result] The results showed that, various agronomic traits were larger under fertilization condition than under non-fertilization condition ex-cept number of unfil ed grains and heading stage. Plant high, spike length, weight of aerial part and heading stage varied greatly under non-fertilization condition; number of fil ed grains, number of unfil ed grains and total stem weight varied greatly under fertilization condition. In two-rowed barley, plant height and number of fil ed grains of Chinese varieties were higher than those of foreign varieties, while other agronomic traits such as spike length, number of unfil ed grains, main panicle weight, total panicle weight, total stem weight, weight of aerial part and heading stage of foreign varieties were higher than those of Chinese varieties. Spike length and weight of aerial part in multiple-rowed and two-rowed foreign barley were higher than those in Chinese barley. In multiple-rowed barley, plant height, number of unfil ed grains, total panicle weight and total stem weight of foreign varieties were higher under non-fer-tilization condition and lower under fertilization condition compared with those of Chi-nese varieties; number of fil ed grains, main panicle weight and heading stage of foreign varieties were lower under non-fertilization condition and higher under fertil-ization condition compared with those of Chinese varieties. [Conclusion] Heading stage, number of fil ed grains, number of unfil ed grains and total stem weight are more sensitive to phosphorus efficiency. Multiple-rowed barley is more sensitive to phosphorus efficiency than two-rowed barley.

Effect of Acute Low Temperature Stress on Oxygen Consumption Rate and Respiration Frequency in Silurus meridionalis and Pelteobag vachelli

The objective of the study was to explore the effect of acute low temperature stress on VO2 and Vf of Silurus meridionalis and Pelteobag vachelli after 10 minutes cold water bath with different temperature.The investigation was operated under the temperature of 24 ℃.It was found that the VO2 and Vf of Silurus meridionalis after 6 and 0 ℃ stress showed a decrease-increase-decrease trend while other groups showed a rapid increase then slowly recovery trend.The VO2 and Vf of Pelteobag vachelli after 0 ℃stress showed a decrease-increase-decrease trend while other groups showed an increase then slowly recovery process.It was suggested that Pelteobag vachelli was more adaptive to acute cold stress,but it cost more energy adapting to cold stress compared to Silurus meridionalis.

Analysis of Phosphorus Nutrition Efficiency of Soybean Genotypes with Different Phosphorus Efficiency at Blooming Stage under Low Phosphorus Stress

[Objective] This study aimed to investigate the phosphorus nutrition effi- ciency of different soybean genotypes at blooming stage under low phosphorus stress. [Method] By using four ＂low phosphorus efficiency＂ soybean genotypes （D03, D05, D17 and D18） and four ＂high phosphorus efficiency＂ soybean genotypes （D31, D34, D37 and D38） as experimental materials, soil culture experiment was conduct- ed with two treatments of high phosphorus （＋P） and low phosphorus （-P）, to analyze the relationship between phosphorus content, phosphorus uptake, phosphorus use efficiency and phosphorus efficiency of soybean genotypes with different phos- phorus efficiency. [Result] Under low phosphorus conditions, four soybean genotypes with high phosphorus efficiency showed significant advantage in phosphorus uptake at seedling stage, to be specific, D34 showed relatively high phosphorus absorption capacity but no advantage in adaptability of phosphorus use efficiency, while only D37 showed relatively high phosphorus absorption capacity and phosphorus use ca- pacity. Correlation analysis and path analysis showed that the level of phosphorus efficiency of soybean at blooming stage under （-P） and （＋P） treatments was mainly determined by phosphorus absorption capacity, and that under （-P） treatment was significantly greater than （＋P） treatment. Phosphorus uptake and phosphorus use ef- ficiency under （-P） and （＋P） treatments both showed great direct effects on phos- phorus efficiency, and phosphorus uptake made greater contribution; however, the indirect effects were relatively low, Under low phosphorus stress, the mechanisms for various soybean genotypes with high phosphorus efficiency to adapt to low phospho- rus stress were different, and phosphorus absorption efficiency （phosphorus uptake） was the main variation source of the phosphorus efficiency of various soybean genotypes at blooming stage. [Conclusion] This study revealed the contribution made by phosphorus absorption efficiency and phosphorus use efficiency to phosphorus efficiency of soybean.

ANovel Non-Isolated Cubic DC-DC Converter with High Voltage Gain for Renewable Energy Power Generation System

In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.

Changes in Physiological Indexes of SPDS Transgenic Potato Plants under Low Temperature Stress

Using potato plants overexpressing spermidine synthase（SPDS） gene as experimental materials, changes in chlorophyll content, malondialdehyde（MDA） content and superoxide dismutase（SOD） activity of potato leaves under low temperature stress were determined. According to the results, chlorophyll content of experimental plants showed a decreasing trend; MDA content of 01-47 was significantly higher than that of Atlantic; MDA content of 01-6 and 01-49 was significantly lower than that of Atlantic; SOD activity of 01-6 and 01-47 was higher than that of Atlantic. Potato lines 01-6 and 01-47 can be further cultivated to breed new cold-resistant potato varieties.

Gene Expression and Activities of SOD in Cucumber Seedlings Were Related with Concentrations of Mn^(2+),Cu^(2+),or Zn^(2+) Under Low Temperature Stress

Effects of increasing Mn^2＋, Cu^2＋, or Zn^2＋ on SOD expressions were studied in cucumber seedlings under low temperature stress. Both gene expressions and activities of Cu/Zn-SOD and Mn-SOD in cucumber seedling leaves were induced by increasing Mn^2＋, Cu^2＋, or Zn^2＋ under low temperature stress, especially 48 h afterwards. The activities of Cu/Zn-SOD and Mn-SOD at 0 and 48 h after treatment were in accordance with their gene expression levels, which implied that the transcriptional regulation plays key roles in regulating their activities at the early stage of low temperature stress. Gene expressions of Cu/Zn-SOD and Mn-SOD declined at 96 h, but Cu/Zn-SOD and Mn-SOD activities still remain high, which suggested that Cu/Zn-SOD and Mn-SOD activities might be regulated by other factors after transcription at the later stage of low temperature stress. Therefore, we concluded that the increasing Mn^2＋, Cu^2＋, or Zn^2＋ could increase the capacity of scavenging ROS in cucumber seedlings under low temperature stress by inducing gene expressions of Cu/ Zn-SOD and Mn-SOD, elevating activities of Cu/Zn-SOD, Mn-SOD, or regulating other factors after transcription.

In vitro Anthocyanin Induction and Metabolite Analysis in Malus spectabilis Leaves Under Low Nitrogen Conditions

Anthocyanins are the most widely produced secondary metabolites in plants,and they play an important role in plant growth and reproduction.The nitrogen source is an important factor affecting anthocyanin production,but the nitrogen concentrations on metabolism and the underlying genetic basis remain unclear.In this study,in vitro anthocyanin induction was conducted on Malus spectabilis.The leaf explants were cultivated in media containing different nitrogen concentrations.The results suggested that when the nitrogen contents decreased in limit,the color of leaf explants turned from green to red,and increased anthocyanin accumulation led to a change in phenotype.Furthermore,the content of other flavonoids,such as dihydroquercetin,epicatechin,and catechin,increased under low nitrogen conditions.The transcription levels of the general flavonoid pathway genes,from phenylalanine ammonia lyase(PAL)to anthocyanidin synthase(ANS),were associated with the concentration of corresponding flavonoid compounds and phenotype changes.In particular,the expression level of ANS increased substantially under a low nitrogen treatment,which was significantly and positively correlated with the anthocyanin levels(R2=0.72,P<0.05).The increased expression patterns of anthocyanin pathway genes were similar to that of the transcription factor MYB10.We further verified MYB10 played an important role in the anthocyanin pathway in leaves of Malus spectabilis.These results suggested that we can improve the desirable ornamental plant phenotypes by controlling nitrogen content.This process may offer clues to further development of new agricultural practices.

Regulation of Calcium on Peanut Photosynthesis Under Low Night Temperature Stress

The effects of different levels of CaCl 2 on photosynthesis under low night temperature（8°C） stress in peanuts were studied in order to find out the appropriate concentration of Ca2＋through the artificial climate chamber potted culture test.The results indicated that Ca2＋,by means of improving the stomatal conductivity of peanut leaves under low night temperature stress,may mitigate the decline of photosynthetic rate in the peanut leaves.The regulation with 15 mmol L-1CaCl 2（Ca15） was the most effective,compared with other treatments.Subsequently,the improvement of Ca2＋on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15,Ca2＋chelator（ethylene glycol bis（2-aminoethyl） tetraacetic acid; EGTA） and calmodulin antagonists（trifluonerazine; TFP）.And CaM（Ca2＋-modulin） played an important role in the nutritional signal transduction for Ca2＋mitigating photosynthesis limitations in peanuts under low night temperature stress.

Low temperature stress on the hematological parameters and HSP gene expression in the turbot Scophthalmus maximus

To study the effect of low temperature stress on hematological parameters and HSP gene expression in the turbot （Seophthalmus maximus）, water temperature was lowered rapidly from 18 to 1℃. During the cooling process, three individuals were removed from culture tanks at 18, 13, 8, 5, 3, and 1℃. Blood samples and tissues were taken from each individual, hematological indices and HSP gene expression in tissues were measured. The red blood cell count, white blood cell count, and hemoglobin concentration decreased significantly （P〈0.05） as temperature decreased. Enzyme activities of plasma alanine transaminase and creatine kinase increased as temperature decreased, whereas aspartic transaminase and γ-glutamyl transpeptidase activities displayed no obvious changes above 1℃ and lactate dehydrogenase activity increased first and then decreased. Blood urea nitrogen and uric acid levels were highest at 8℃, and creatinine concentration was highest at 3℃. The concentrations of plasma cortisol, cholesterol, and triglyceride all increased significantly （P〈0.05） as temperature decreased. The serum glucose concentration increased first and then decreased to the initial level. The HSP70 mRNA expression showed various patterns in different tissues, whereas HSP90 mRNA expression showed the same tendency in all tissues. Overall, these results indicate that temperature decreases in the range of 8 to 5℃ may induce a stress response in S. maximus and that temperature should be kept above 8℃ in the aquaculture setting to avoid damage to the fish.

Response of Nitrate Metabolism in Seedlings of Oilseed Rape(Brassica napus L.) to Low Oxygen Stress

In order to understand the response of nitrate metabolism in seedlings of oilseed rape （Brassica napus L.） to low oxygen stress （LOS）, two cultivars were studied at different light, LOS time and exogenous nitrate concentrations under hydroponic stress. Results show that N-uptake and dry matter of rape seedlings were decreased after LOS stress while nitrate accumulation （NA） under LOS was induced by darkness. Nitrate accumulation peaked at 3 d while root activity （RA, deifned as dehydrogenase activity） decreased with prolonged waterlogging exposure. Exogenous nitrate signiifcantly elevated NA and RA. Tungstate （TS） and LOS inhibited nitrate reductase （NR） activity while NR transcription and activity were enhanced by exogenous nitrate. Low oxygen stress stimulated the activity of superoxide dismutase （SOD） and peroxidase （POD） slightly, but inhibited that of catalase （CAT）. B. napus L. Zhongshuang 10 （ZS10）, a LOS tolerant cultivar, displayed smaller decrease upon dry matter under LOS, higher NA in darkness and lower NA in light than B. napus L. Ganlan CC （GAC）, a LOS sensitive variety. ZS10 had lower NA and higher RA after waterlogging and exogenous nitrate treatment, and higher NR activity under TS inhibition than GAC, but the activity of antioxidant enzymes did not change under LOS. The results indicate that nitrate metabolism involved tolerance of rape seedlings to LOS, with lower accumulation and higher reduction of nitrate being related to higher LOS tolerance of rape seedlings exposed to waterlogging.

Low stress no distortion welding for aerospace shell structures

To fit in with the strict geometrical integrity and ensure dimensionally consistent fabrication of the welded aerospace structures. the low stress no distortion(LSND)welding, a technique for thin materials, was poineered and developed to provide an ininprocess active control of welding distortion. Satisfactory distortion free results were achieved in both welding of jet engine cases of heat-resistance alloys and rocket fuel tanks of aluminuim alloys, and there need no. reworking operations for post-weld distortion correction. Based on the 'static' method a newly developed method for dvnamic in-process control is also discussed in this paper. Both methods provide quanutiative in-process control of incompatible strains in weld zone and low stress no distortion welding results.