Apples are one of the most important economic crops worldwide.Because of global warming and an aggravation of environmental,abnormally high temperatures occur frequently in fruit-growing season and seriously affect no...Apples are one of the most important economic crops worldwide.Because of global warming and an aggravation of environmental,abnormally high temperatures occur frequently in fruit-growing season and seriously affect normal fruit growth and reduce fruit quality and yield.We took five-year-old Ruixue’(Qinfu 1×Pink Lady;CNA20151469.1) fruits as test materials,and the ambient temperature during fruit development was monitored.The results showed that during the fruit-growing season,especially during the rapid growth stage (July to August),the maximum daily temperature exceeded 30℃ and lasted for more than 40 days.To determine the effects of high temperature stress on the apple fruit resistance,we treated expanding,veraison,and maturity-period fruits at different temperatures.It was found that the fruits of the expanding period showed strong resistance to high temperature stress,whereas during veraison and maturity,fruit resistance to high temperature stress decreased,and the fruit peel browning phenotype appeared.Meanwhile,the content of malonaldehyde (MDA),hydrogen peroxide (H_(2)O_(2)),and superoxide anion (O._(2)^(-)) in the peel gradually increased with increasing temperature.The content of total phenols,flavanol,and flavonoids in the peel decreased substantially at 45℃.Moreover,it was found that polyphenol oxidase gene (MdPPO1) was most sensitive to high temperature stress in apple.Furthermore,transient and stable MdPPO1 overexpression significantly promoted peel browning.The transgenic materials were more sensitive to high temperatures,and browning was more severe compared to non-genetically modified organism (WT).Stable MdPPO1 knockout calli obtained via clustered regularly interspersed short palindromic repeats (CRISPR/Cas9) gene knockout technology reduced the browning phenotype,and the resultant fruits were not sensitive to the effects of high temperature stress.Thus,MdPPO1 expression may be a key factor of high temperature-related changes observed in the browning phenotype that provides a scientific theoretical basis for the selection of high temperature-resistant varieties and apple cultivation and management in the future.展开更多
[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...[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.展开更多
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 unclea...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.展开更多
[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 ty...[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.展开更多
Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With th...Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves:convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.展开更多
High temperature stress(HTS) on spring maize(Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain(NCP).Subsoiling(SS) and ridge tillage(R) were intr...High temperature stress(HTS) on spring maize(Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain(NCP).Subsoiling(SS) and ridge tillage(R) were introduced to enhance the ability of spring maize to resist HTS during the filling stage.The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County,Hebei Province,China.Compared with rotary tillage(RT),the net photosynthetic rate,stomatal conductance,transpiration rate,and chlorophyll relative content(SPAD) of maize leaves was increased by 40.0,42.6,12.8,and 29.7% under SS,and increased by 20.4,20.0,5.4,and 14.2% under R,repectively.However,the treatments reduce the intercellular CO 2 concentration under HTS.The SS and R treatments increased the relative water content(RWC) by 11.9 and 6.2%,and the water use efficiency(WUE) by 24.3 and 14.3%,respectively,compared with RT.The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile,whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment.Compared with 2011,the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012,whereas the plant yield decreased by 2.5,8.5 and 10.9%,the net photosynthetic rate reduced by 7.5,10.5 and 18.0%,the RWC reduced by 3.9,5.6 and 6.2%,and the WUE at leaf level reduced by 1.8,5.2 and 13.1% in the SS,R and RT treatments,respectively.Both the root length density and the soil moisture also decreased at different levels.The yield,photosynthetic rate,plant water status,root length density,and soil moisture under the SS and R treatments declined less than that under the RT treatment.The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage,and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status,photosynthesis and grain filling.The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP.展开更多
Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to dec...Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grain- filling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6-34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.展开更多
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 lea...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.展开更多
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 clim...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.展开更多
The shrinkage behavior of high performance cement concrete made from Portland cement, ultra fine granulated blast furnace slag and pulverized fly ash with addition of superplasticizer at different temperatures from am...The shrinkage behavior of high performance cement concrete made from Portland cement, ultra fine granulated blast furnace slag and pulverized fly ash with addition of superplasticizer at different temperatures from ambient temperature to 120 ℃ under different seuliug conditions was investigated by means of length change measurement on cylindrical concrete specimens along with curing age. Results show that drying shrinkage deformations of titled concrete specimens increased rapidly as the curing temperature rose. The development of dryiing shrinkage deformatian can be efficiently controlled with the aid of aluminum tape sealing as compared with the unsealed specimens, especially when the curing temperature is below 60℃ , although it will increase dramatically when the curing temperature is elevated to above 90%" . Polymer coating on concrete specimens showed a similar effect on the control of drying shrinkage as the sealing operation with aluminum tape.展开更多
High temperature stress (HT) is efficient in breaking endo-dormancy of perennial trees. The effects of HT (50°C) on the respiration of dormant nectarine (Prunus persica var. nectariana cv. Shuguang) vegetat...High temperature stress (HT) is efficient in breaking endo-dormancy of perennial trees. The effects of HT (50°C) on the respiration of dormant nectarine (Prunus persica var. nectariana cv. Shuguang) vegetative buds were evaluated in the research. We found that bud respiration was transiently inhibited by HT and the pentose phosphate pathway (PPP) and the cytochrome C pathway (CYT) were significantly affected. On the substrate level, PPP was activated in the HT-treated buds compared with the control group. However, the activation did mot occur until hours after HT treatment. The tricarboxylic acid cycle (TCA) in both the HT-treated buds and in the control group proceeded at a low level most of the time compared with total respiration. On the electron transfer level, CYT was transiently inhibited by HT but became significantly active in the later stage. CYT operation in the control group exhibited an attenuation process. The alternative pathway (ALT) fluctuated both in the HT-treated samples and in the control. The results suggest that the temporary CYT inhibition and the following PPP activation may be involved in HT-induced bud dormancy release and budburst mechanisms.展开更多
Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resi...Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resistance. The results showed that under 40C(day/night), Ca2+ immersion pretreatment enabled the eggplant seedlings to keep relatively higheractivities of superoxide dismutase(SOD) and peroxidase(POD), reduced the production rate ofsuperoxide anion O2_ and the content of malondialdehyde(MDA), alleviated the damage of reducedglutathione(GSH) and the accumulation of proline (Pro), whereas calmodulin antagonist TFP andW7 immersion pretreatments could lead to more rapid loss of SOD and POD activities, increasethe contents of MDA, Pro and production rate of O2_, aggravate the damage of GSH. Under the samestress condition, heat-resistant variety Nongyouqie was less injured compared to the heat-sensitive variety Erminqie. These data indicated that Ca2+-CaM signal transduction systemmight regulate the heat resistance of eggplant seedlings by controlling the activity of someantioxidant enzymes and the contents of antioxidant substance.展开更多
The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on co...The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings (chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81) under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.展开更多
A study on the autogenous shrinkage (AS) of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity (ARH), two fac...A study on the autogenous shrinkage (AS) of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity (ARH), two factors that have been shown to have occasional influence on this process in previous studies, were introduced into this study. According to these concepts, a program for simulation of the temperature field, humidity field, and stress field based on the equivalent age method and a fully automatic aggregate modeling tool were used. With the help of these programs, the study of a small concrete specimen provided some useful conclusions: the aggregate and the matrix show distinct distribution properties in the temperature field, humidity field, and stress field; the aggregate-matrix interface has a high possibility of becoming the location of the initial cracking caused by AS of concrete; the distribution of random aggregates is extremely important for mesoscopical analysis; and the temperature history is the main factor affecting the AS of concrete. On the whole, inherent mechanisms and cracking mechanisms of AS of concrete can be explained more reasonably and realistically only by considering the different characteristics of material phases and the effects of temperature and humidity.展开更多
The growth and development of rice are closely related with temperature. In order to clarify the mechanism of high temperature resistance in riee, in this study, using high temperature-resistant Indian rice cultivar N...The growth and development of rice are closely related with temperature. In order to clarify the mechanism of high temperature resistance in riee, in this study, using high temperature-resistant Indian rice cultivar N22 as the experimental material, Osa-rniR159c, Osa-miR159d, Osa-miR159f, Osa-miR164d, Osa- rrdR529b and Osa-miR166h-3p obtained by high-throughput sequencing as target genes, the expression patterns of these genes in young panicles of rice under high temperature stress were analyzed by RNA-tailing and primer-extension RT-PCR, which provided theoretical basis for breeding high temperature-resistant rice eultivars.展开更多
In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam e...In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam especially morphology of gamma ' phase and boride was observed and the strength of brazing seam was measured in this process. The results show that heat treatment can enhance high-temperature stress rupture strength by improving the microstructure of brazing seam. The strength of brazing seam after solution heat treatment decreases in comparison with that only after diffusion treatment while aging treatment after solution heat treatment increases the strength of brazing seam.展开更多
[ Objective] This study aimed to investigate the effects of heat shock factor AtHsfAla on Caspase-3 activity in Arabidopsis thaliana under high tempera-ture stress, thus revealing the relationship between heat shoc...[ Objective] This study aimed to investigate the effects of heat shock factor AtHsfAla on Caspase-3 activity in Arabidopsis thaliana under high tempera-ture stress, thus revealing the relationship between heat shock factor AtHsfAl a and programmed cell death in A. thaliana. [ Method ] Different genotypes of A. thaliana (AtHsfAla-silenced transgenic and wild-type) seedlings were treated at 42 ℃. According to the fragmentation level of fluorogenic substrate Ac-DEVD- pNA, Caspase-3 activity was determined by spectrophotometry. [ Result] After high temperature treatment, Caspase-3 activity in A. thaliana was enhanced signifi-cantly. Caspase-3 activity in AtHsfAla-si/enced transgenic A. thaliana was higher than that in wild-type A. thaliana, which indicated that AtHsfAla could inhibit Caspase-3 activity in A. thaliana under high temperature stress. [ Conclusion] Under high temperature stress, heat shock factor AtHsfAla might exert inhibitory effects on programmed cell death by reducing Caspase-3 activity. This study provided the basis for clarifying the mechanism of stress resistance in plants.展开更多
M202, IR50 and advanced backcross (BC4F6) lines carrying the cold tolerance QTLs qCTS4 and qCTS12 were evaluated using three low temperature stress assays (constant, intermittent and constant with recovery period)...M202, IR50 and advanced backcross (BC4F6) lines carrying the cold tolerance QTLs qCTS4 and qCTS12 were evaluated using three low temperature stress assays (constant, intermittent and constant with recovery period). Under constant stress, two BC4F6 lines (MIb 4853-9 and MIb 6885-2) exhibited differences in seedling growth and accumulation of stress-related compounds although both carry the two QTLs in the IRS0 background. Differences between these lines were also observed in the constant with recovery period assay, although both of them performed comparably under intermittent stress, MIb 6885-2 performed more similarly to M202 in the constant and constant with recovery period assays, suggesting that this line contains an introgressed region(s) not present in MIb 4853-9. The three assays were also applied to assess variations in cold tolerance in a set of diverse germplasms. Performance metrics and visual ratings were comparable for evaluating tolerance to constant stress. However, differences in response to intermittent stress were more evident from growth and total chlorophyll measurements than from visual ratings. With regard to the constant with recovery period assay, about 15% of the germplasm accessions did not recover. However, some lines which exhibited chilling injuries of comparable severity were able to overcome them. This recovery phenotype may improve rice performance in the field and warrant further investigation.展开更多
Many proteins require assistance from molecular chaperones at various stages to attain correctly folded states and functional conformations during protein synthesis. In this study, the gene encoding T-complex polypept...Many proteins require assistance from molecular chaperones at various stages to attain correctly folded states and functional conformations during protein synthesis. In this study, the gene encoding T-complex polypeptide 1(TCP-1), which belongs to the heat shock protein 60(HSP60) family, was isolated and characterized from the rice stem borer, Chilo suppressalis, by RACE and q PCR, respectively. The full-length c DNA of Tcp-1 was 2 144 bp and encoded a 1 635-bp ORF; the deduced translational product contained 545 amino acids with 5′-and 3′-UTRs and an isoelectric point of 5.29. Cluster analysis confirmed that the deduced amino acid sequence shared high identity(60–99%) with TCP-1 from other insects. To investigate Tcp-1 expression in response to abiotic stress, q PCR was used to analyze expression levels of Tcp-1 m RNA in C. suppressalis larvae exposed to temperatures ranging from –11 to 43°C. With respect to heat shock, Tcp-1 expression was higher than the control after a 2-h exposure to 30 and 36°C and declined at 39 and 43°C. Difference in Tcp-1 expression was observed at temperatures ranging from –11 to 27°C. q PCR analyses revealed that Tcp-1 expression was the highest in hindgut tissue as compared to heads, epidermis, fat body, foregut, midgut, and malpighian tubules. Our results indicated that Tcp-1 expression was differentially expressed in C. suppressalis tissues, and was impacted by temperature stress.展开更多
基金supported by China Agriculture Research System of MOF and MARA (Grant No.CARS-27)the Fundamental Research Funds for the Central Universities (Grant No.2452020033)Shaanxi Engineering Research Center of Apple。
文摘Apples are one of the most important economic crops worldwide.Because of global warming and an aggravation of environmental,abnormally high temperatures occur frequently in fruit-growing season and seriously affect normal fruit growth and reduce fruit quality and yield.We took five-year-old Ruixue’(Qinfu 1×Pink Lady;CNA20151469.1) fruits as test materials,and the ambient temperature during fruit development was monitored.The results showed that during the fruit-growing season,especially during the rapid growth stage (July to August),the maximum daily temperature exceeded 30℃ and lasted for more than 40 days.To determine the effects of high temperature stress on the apple fruit resistance,we treated expanding,veraison,and maturity-period fruits at different temperatures.It was found that the fruits of the expanding period showed strong resistance to high temperature stress,whereas during veraison and maturity,fruit resistance to high temperature stress decreased,and the fruit peel browning phenotype appeared.Meanwhile,the content of malonaldehyde (MDA),hydrogen peroxide (H_(2)O_(2)),and superoxide anion (O._(2)^(-)) in the peel gradually increased with increasing temperature.The content of total phenols,flavanol,and flavonoids in the peel decreased substantially at 45℃.Moreover,it was found that polyphenol oxidase gene (MdPPO1) was most sensitive to high temperature stress in apple.Furthermore,transient and stable MdPPO1 overexpression significantly promoted peel browning.The transgenic materials were more sensitive to high temperatures,and browning was more severe compared to non-genetically modified organism (WT).Stable MdPPO1 knockout calli obtained via clustered regularly interspersed short palindromic repeats (CRISPR/Cas9) gene knockout technology reduced the browning phenotype,and the resultant fruits were not sensitive to the effects of high temperature stress.Thus,MdPPO1 expression may be a key factor of high temperature-related changes observed in the browning phenotype that provides a scientific theoretical basis for the selection of high temperature-resistant varieties and apple cultivation and management in the future.
基金Supported by Zhejiang Basic Public Welfare Research Program Project(LGN21C020006)Key Research and Development Project of Zhejiang Province(2021C02057)+1 种基金Zhejiang Major Science and Technology Project of Agricultural New Variety(Upland Food)Breeding(2021C02064)Key Research and Development Project of Zhejiang Province(2022C04024).
文摘[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.
基金supported by the following grants:the National Key R&D Program of China(2019YFD1000500)the National Natural Science Foundations of Shandong Province(ZR2020MC138)the Agricultural Variety Improvement Project of Shandong Province(2020LZGC007).
文摘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.
基金Supported by Science and Technology Research Project of Henan Provincial Science and Technology Department(222102110448)Key Scientific Research Projects of Colleges and Universities in Henan Province(21B210007)Open Research Project of Guangxi Sugarcane Genetic Improvement Key Laboratory(19-185-24-K-01-01).
文摘[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.
基金National Key R&D Plan Project(No.2021YFC3090102)。
文摘Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves:convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.
基金supported by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD16B15)
文摘High temperature stress(HTS) on spring maize(Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain(NCP).Subsoiling(SS) and ridge tillage(R) were introduced to enhance the ability of spring maize to resist HTS during the filling stage.The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County,Hebei Province,China.Compared with rotary tillage(RT),the net photosynthetic rate,stomatal conductance,transpiration rate,and chlorophyll relative content(SPAD) of maize leaves was increased by 40.0,42.6,12.8,and 29.7% under SS,and increased by 20.4,20.0,5.4,and 14.2% under R,repectively.However,the treatments reduce the intercellular CO 2 concentration under HTS.The SS and R treatments increased the relative water content(RWC) by 11.9 and 6.2%,and the water use efficiency(WUE) by 24.3 and 14.3%,respectively,compared with RT.The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile,whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment.Compared with 2011,the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012,whereas the plant yield decreased by 2.5,8.5 and 10.9%,the net photosynthetic rate reduced by 7.5,10.5 and 18.0%,the RWC reduced by 3.9,5.6 and 6.2%,and the WUE at leaf level reduced by 1.8,5.2 and 13.1% in the SS,R and RT treatments,respectively.Both the root length density and the soil moisture also decreased at different levels.The yield,photosynthetic rate,plant water status,root length density,and soil moisture under the SS and R treatments declined less than that under the RT treatment.The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage,and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status,photosynthesis and grain filling.The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP.
基金supported by the National Basic Research Program of China (2010CB951302-2)the National Natural Science Foundation of China (51109214 and 31101074)
文摘Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grain- filling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6-34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.
基金supported by a grant from the National Natural Science Foundation of China (30571271)
文摘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.
基金Supported by the China Postdoctoral Science Foundation(2012M510839)Doctoral Fund of Ministry of Education of China(20122103120011)+2 种基金the National Natural Science Initial Foundation of Shenyang Agricultural University,China(20112013)the Postdoctoral Science Foundation of Shenyang Agricultural University,China(105110)the Peanut Nutrition and Fertilizer Program for China Agriculture Research System,China(CARS-14)
文摘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.
基金supported by the National Natural Science Foundation of China (Grant Nos. 30971745 and 30900874)the Natural Science Foundation of Hunan Province, China (Grant No. 08JJ1003)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20070537006)the Scientific Research Fund of Hunan Provincial Education Department, China (Grant No. 06B042)
文摘The shrinkage behavior of high performance cement concrete made from Portland cement, ultra fine granulated blast furnace slag and pulverized fly ash with addition of superplasticizer at different temperatures from ambient temperature to 120 ℃ under different seuliug conditions was investigated by means of length change measurement on cylindrical concrete specimens along with curing age. Results show that drying shrinkage deformations of titled concrete specimens increased rapidly as the curing temperature rose. The development of dryiing shrinkage deformatian can be efficiently controlled with the aid of aluminum tape sealing as compared with the unsealed specimens, especially when the curing temperature is below 60℃ , although it will increase dramatically when the curing temperature is elevated to above 90%" . Polymer coating on concrete specimens showed a similar effect on the control of drying shrinkage as the sealing operation with aluminum tape.
基金supported by the the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2011BAD12B02)
文摘High temperature stress (HT) is efficient in breaking endo-dormancy of perennial trees. The effects of HT (50°C) on the respiration of dormant nectarine (Prunus persica var. nectariana cv. Shuguang) vegetative buds were evaluated in the research. We found that bud respiration was transiently inhibited by HT and the pentose phosphate pathway (PPP) and the cytochrome C pathway (CYT) were significantly affected. On the substrate level, PPP was activated in the HT-treated buds compared with the control group. However, the activation did mot occur until hours after HT treatment. The tricarboxylic acid cycle (TCA) in both the HT-treated buds and in the control group proceeded at a low level most of the time compared with total respiration. On the electron transfer level, CYT was transiently inhibited by HT but became significantly active in the later stage. CYT operation in the control group exhibited an attenuation process. The alternative pathway (ALT) fluctuated both in the HT-treated samples and in the control. The results suggest that the temporary CYT inhibition and the following PPP activation may be involved in HT-induced bud dormancy release and budburst mechanisms.
文摘Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resistance. The results showed that under 40C(day/night), Ca2+ immersion pretreatment enabled the eggplant seedlings to keep relatively higheractivities of superoxide dismutase(SOD) and peroxidase(POD), reduced the production rate ofsuperoxide anion O2_ and the content of malondialdehyde(MDA), alleviated the damage of reducedglutathione(GSH) and the accumulation of proline (Pro), whereas calmodulin antagonist TFP andW7 immersion pretreatments could lead to more rapid loss of SOD and POD activities, increasethe contents of MDA, Pro and production rate of O2_, aggravate the damage of GSH. Under the samestress condition, heat-resistant variety Nongyouqie was less injured compared to the heat-sensitive variety Erminqie. These data indicated that Ca2+-CaM signal transduction systemmight regulate the heat resistance of eggplant seedlings by controlling the activity of someantioxidant enzymes and the contents of antioxidant substance.
基金Supported by the Special Agricultural Project of Agricultural Department (200903003)the Agricultural Modernization Project in the Science and Technology Development Plan of Jilin Province (2009-2010) the High-yield Project of Science and Technology Department (2011BAD16B10)
文摘The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings (chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81) under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.
基金supported by the Key Program of the National Natural Science Foundation of China (Grant No. 50539010)the National Natural Science Foundation of China (Grant No. 50779010)
文摘A study on the autogenous shrinkage (AS) of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity (ARH), two factors that have been shown to have occasional influence on this process in previous studies, were introduced into this study. According to these concepts, a program for simulation of the temperature field, humidity field, and stress field based on the equivalent age method and a fully automatic aggregate modeling tool were used. With the help of these programs, the study of a small concrete specimen provided some useful conclusions: the aggregate and the matrix show distinct distribution properties in the temperature field, humidity field, and stress field; the aggregate-matrix interface has a high possibility of becoming the location of the initial cracking caused by AS of concrete; the distribution of random aggregates is extremely important for mesoscopical analysis; and the temperature history is the main factor affecting the AS of concrete. On the whole, inherent mechanisms and cracking mechanisms of AS of concrete can be explained more reasonably and realistically only by considering the different characteristics of material phases and the effects of temperature and humidity.
基金Supported by Science and Technology Support Project of 12thFive-Year Plan(2012BAD14B13)Dachuang Fund of Anhui Agricultural University(XJDC2014260)
文摘The growth and development of rice are closely related with temperature. In order to clarify the mechanism of high temperature resistance in riee, in this study, using high temperature-resistant Indian rice cultivar N22 as the experimental material, Osa-rniR159c, Osa-miR159d, Osa-miR159f, Osa-miR164d, Osa- rrdR529b and Osa-miR166h-3p obtained by high-throughput sequencing as target genes, the expression patterns of these genes in young panicles of rice under high temperature stress were analyzed by RNA-tailing and primer-extension RT-PCR, which provided theoretical basis for breeding high temperature-resistant rice eultivars.
文摘In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam especially morphology of gamma ' phase and boride was observed and the strength of brazing seam was measured in this process. The results show that heat treatment can enhance high-temperature stress rupture strength by improving the microstructure of brazing seam. The strength of brazing seam after solution heat treatment decreases in comparison with that only after diffusion treatment while aging treatment after solution heat treatment increases the strength of brazing seam.
基金Supported by National Natural Science Foundation of China(31260061,31060039)Project of Key Laboratory of Special Biological Resource Development and Utilization of Universities in Yunnan Province(GXZD201601)+1 种基金Key Discipline Construction Project of Kunming UniversityNational College Students' Innovation Project of China
文摘[ Objective] This study aimed to investigate the effects of heat shock factor AtHsfAla on Caspase-3 activity in Arabidopsis thaliana under high tempera-ture stress, thus revealing the relationship between heat shock factor AtHsfAl a and programmed cell death in A. thaliana. [ Method ] Different genotypes of A. thaliana (AtHsfAla-silenced transgenic and wild-type) seedlings were treated at 42 ℃. According to the fragmentation level of fluorogenic substrate Ac-DEVD- pNA, Caspase-3 activity was determined by spectrophotometry. [ Result] After high temperature treatment, Caspase-3 activity in A. thaliana was enhanced signifi-cantly. Caspase-3 activity in AtHsfAla-si/enced transgenic A. thaliana was higher than that in wild-type A. thaliana, which indicated that AtHsfAla could inhibit Caspase-3 activity in A. thaliana under high temperature stress. [ Conclusion] Under high temperature stress, heat shock factor AtHsfAla might exert inhibitory effects on programmed cell death by reducing Caspase-3 activity. This study provided the basis for clarifying the mechanism of stress resistance in plants.
文摘M202, IR50 and advanced backcross (BC4F6) lines carrying the cold tolerance QTLs qCTS4 and qCTS12 were evaluated using three low temperature stress assays (constant, intermittent and constant with recovery period). Under constant stress, two BC4F6 lines (MIb 4853-9 and MIb 6885-2) exhibited differences in seedling growth and accumulation of stress-related compounds although both carry the two QTLs in the IRS0 background. Differences between these lines were also observed in the constant with recovery period assay, although both of them performed comparably under intermittent stress, MIb 6885-2 performed more similarly to M202 in the constant and constant with recovery period assays, suggesting that this line contains an introgressed region(s) not present in MIb 4853-9. The three assays were also applied to assess variations in cold tolerance in a set of diverse germplasms. Performance metrics and visual ratings were comparable for evaluating tolerance to constant stress. However, differences in response to intermittent stress were more evident from growth and total chlorophyll measurements than from visual ratings. With regard to the constant with recovery period assay, about 15% of the germplasm accessions did not recover. However, some lines which exhibited chilling injuries of comparable severity were able to overcome them. This recovery phenotype may improve rice performance in the field and warrant further investigation.
基金funded by the National Natural Science Foundation of China (31401733)the Incubation Study Project of Science and Technology of Fuyang Normal University, China (2014KJFH02)
文摘Many proteins require assistance from molecular chaperones at various stages to attain correctly folded states and functional conformations during protein synthesis. In this study, the gene encoding T-complex polypeptide 1(TCP-1), which belongs to the heat shock protein 60(HSP60) family, was isolated and characterized from the rice stem borer, Chilo suppressalis, by RACE and q PCR, respectively. The full-length c DNA of Tcp-1 was 2 144 bp and encoded a 1 635-bp ORF; the deduced translational product contained 545 amino acids with 5′-and 3′-UTRs and an isoelectric point of 5.29. Cluster analysis confirmed that the deduced amino acid sequence shared high identity(60–99%) with TCP-1 from other insects. To investigate Tcp-1 expression in response to abiotic stress, q PCR was used to analyze expression levels of Tcp-1 m RNA in C. suppressalis larvae exposed to temperatures ranging from –11 to 43°C. With respect to heat shock, Tcp-1 expression was higher than the control after a 2-h exposure to 30 and 36°C and declined at 39 and 43°C. Difference in Tcp-1 expression was observed at temperatures ranging from –11 to 27°C. q PCR analyses revealed that Tcp-1 expression was the highest in hindgut tissue as compared to heads, epidermis, fat body, foregut, midgut, and malpighian tubules. Our results indicated that Tcp-1 expression was differentially expressed in C. suppressalis tissues, and was impacted by temperature stress.