The acoustic emission(AE)method is commonly used to measure in-situ stress,while the Kaiser efect(KE)is usually afected by the stress history and specimen direction.In this study,three types of rocks were tested under...The acoustic emission(AE)method is commonly used to measure in-situ stress,while the Kaiser efect(KE)is usually afected by the stress history and specimen direction.In this study,three types of rocks were tested under uniaxial defection loading at various defection angles.Both the KE and the incomplete erasion phenomenon(IEP)were investigated,and the obtained in-situ stress using the AE method was compared with that obtained using the stress relief method.The results demonstrate that both the KE and the IEP exhibit directional independence.The rock type signifcantly afects the critical angle(θ),with marble showing a higher value(15°)compared to granite(10°)and red sandstone(5°).This is attributed to the initiation and development of interface cracks or crystal interfaces in mineral grains.The similar in-situ stress measured by the AE and stress relief methods suggests that small-angle defection coring is applicable in engineering.This study provides a reference for in-situ stress measurement using the AE method.展开更多
In deep underground engineering,understanding of time-related stress memory properties is critical to evaluate the in situ stress conditions of a rock mass.In this study,the time-sensitivity mechanism of the rock stre...In deep underground engineering,understanding of time-related stress memory properties is critical to evaluate the in situ stress conditions of a rock mass.In this study,the time-sensitivity mechanism of the rock stress memory properties under tensile stress was investigated.It was found that the material property(Poisson’s ratio)and crack angle were the controlling factors of the Kaiser effect(KE)under tensile stress.In particular,the time-sensitivity of the stress memory properties was closely related to the crack growth path.When the failure of the rock specimen was dominated by tensile microcracks and the crack development direction was deflected by up to 30°in the successive loading process,the stress memory capacity was likely to be time-independent for a sandstone specimen.The distribution of the Felicity ratio in a Brazilian test was more discrete than that in a three-point bending test It also showed that the changes in the crack path,rather than the time interval between successive loading cycles,led to inaccuracy of the detected KE.This study provides insights into stress memory-related issues under uniaxial or more complex stress conditions and thus facilitates development of methods for testing in situ mechanical behaviors of rocks with acoustic emission(AE)technology.展开更多
Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approa...Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.展开更多
Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,esp...Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.展开更多
Industrialization and the rapid growth of economies have caused severe environmental pollution,which might impact the survival of sensitive species.In this study,we investigated the defense responses of two common mos...Industrialization and the rapid growth of economies have caused severe environmental pollution,which might impact the survival of sensitive species.In this study,we investigated the defense responses of two common mosses with varying anti-haze capacities,Hypnum callichroum and Homomallium incurvatum,in response to simulated haze pollution.Photoprotection and antioxidant mechanisms of both mosses were measured immediately after the first exposure to the haze treatment,followed by the initial recovery stage and again after exposure to secondary stress and secondary recovery.Haze exposure caused severe oxidative stress and photodamage in both H.callichroum and H.incurvatum.Metabolic processes such as photorespiration,the ascorbate-glutathione cycle and secondary metabolism-which play roles in defense responses-were significantly activated in both moss species after haze treatment.During the recovery following haze stress,H.callichroum exhibited a significant stress memory response,as evidenced by the greater accumulation of several memory substances,including xanthophylls and phenolic acids.However,H.incurvatum did not exhibit a strong stress memory response,which might explain its relatively inferior anti-haze capacity in the natural environment.展开更多
The effect of deformation on recovery stress of Ni144.7Ti46.3Nb9 alloy has been studjed using tensile test at various temperatures and TEM observation. It ls shown that the recovery stress increases with jncreasing to...The effect of deformation on recovery stress of Ni144.7Ti46.3Nb9 alloy has been studjed using tensile test at various temperatures and TEM observation. It ls shown that the recovery stress increases with jncreasing total strain ET and reaches a maximum value (max) as ET= 9% but the maximum recov erV strain of the alloy is only about 4.6%. This is different from that of Ti-Ni binary alloy in which is obtained usually at maximum recovery strain and the reason of the difference is dis Cussed. Deformation temperature Td has a little effect on recovery stress when Td is less than Ms However, recovery stress decreases sharply when Td is higher than M, and lowers approximately down to zero near Msσ展开更多
Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trai...Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trait for adapting to an everchanging environment,and root pruning is an artificial technique for regenerating the root system.In the present study,we investigated whether root pruning in soybean can effectively alleviate the inhibitory effects of anaerobic stress.Soybean plants were affected by anaerobic stress at the germination,vegetative stage 1(V1),and reproductive stage 1(R1)stages,and then the plants were treated with root pruning just after the stress treatment.Soybean plants at the germination stage were treated with root cap and tip removals after hypoxia(N_(2)treatment).Root cap removal was more effective in suppressing the inhibitory effects of hypoxia than root tip removal(5 mm from the tip).The shoot dry weights of the soybean plants with and without root cap removal after hypoxia were 51.2 and 73.8%of the control,respectively,while the root dry weights of plants with and without root cap removal after hypoxia were 43.2 and 62.8%of the control,respectively.As root cap removal effectively enhanced soybean growth after anaerobic stress,the root cap may be the candidate tissue for the stress memory mechanism.When soybean plants at the V1 stage of growth were affected by anaerobic stress,the branch number,pod weight in the main stem,root length,and root surface area of the soybean plants treated with anaerobic stress at the R1 stage significantly decreased compared with those of the control.In contrast,root pruning(2 mm from the tip)immediately after the stress treatment enhanced root growth,branch number,and pod weight.The branch number,pod weight,root length,and root surface area of the plants treated with root pruning were 1.13,1.14,1.12,and 1.13 times higher than those of plants treated with anaerobic stress.Plasmolysis was observed in the root meristem,columella,and cortical cells in soybean roots subjected to anaerobic conditions.However,damage was not observed in the newly emerged roots after root pruning in plants treated with anaerobic stress.These results suggested that root pruning is effective in enhancing soybean growth after anaerobic stress.This effectiveness may be due to the regeneration and elongation of healthy lateral roots during the recovery period.When soybean plants were affected by anaerobic stress at the R1 stage,root pruning just after the stress treatment was ineffective.Thus,suppressing the growth reduction due to anaerobic stress at reproductive stages using only root pruning may be difficult.展开更多
In order to explore the quantitative method of metal magnetic memory testing（MMMT） and clarify the relationship between Hp（y）, the normal component of spontaneous stray field, and applied stress or residual stress...In order to explore the quantitative method of metal magnetic memory testing（MMMT） and clarify the relationship between Hp（y）, the normal component of spontaneous stray field, and applied stress or residual stress, the static tensile tests of 0.45%C steel sheet specimens are carried out on a servo hydraulic MTS810 machine. Hp（y） values are measured during the test process by an EMS-2003 metal magnetic memory diagnostic apparatus and a non-magnetic electric control displacement instrument. Residual stresses of some points on the surface of a specimen are measured by a Stress Tech X-Stress 3000 X-ray diffraction instrument. The results show that the same variation rules of Hp（y） value versus applied tensile stress are presented under the different conditions of load-on and load-off. However, the same rule does not exist between the Hp（y） value and residual stress. The variation of Hp（y） value reflects the history of applied tensile stress.展开更多
Intergenerational inheritance of stress memory plays a crucial role in plant adaptation to environmental changes,particularly in the context of spaceflight,where plants may serve as a food source for humans on long-du...Intergenerational inheritance of stress memory plays a crucial role in plant adaptation to environmental changes,particularly in the context of spaceflight,where plants may serve as a food source for humans on long-duration missions.However,the intergenerational genetic effects of spaceflight-induced stress memory in plants remain unclear.In this study,we assessed the cross-generational genetic effects of spaceflight stress memory using the rice mutant B10,identified during the SJ-10 return satellite mission.Our results showed that the oxidative stress effects induced by spaceflight persisted until the M5 generation in rice.We found that the rice genome remained unstable post-spaceflight,leading to alterations in genome methylation levels.Additionally,we observed significant changes in the methylation levels of transposons,suggesting their involvement in the intergenerational inheritance of spaceflight-induced stress memory.Furthermore,we identified thousands of differentially expressed genes(DEGs)and differentially alternatively spliced(DAS)genes induced by spaceflight stress memory across multiple rice generations.Notably,differentially methylated cytosines were more abundant in non-expressed genes than in DEGs or DAS genes.A substantial number of DEGs and DASs related to oxidative stress were identified,primarily involved in the generation and scavenging of reactive oxygen species.This study also presented report on the response of alternative splicing events in rice to spaceflight stress.Moreover,our findings revealed that genome methylation was associated with gene expression but not with DAS.In conclusion,our study provides comprehensive insights into the intergenerational inheritance of spaceflight-induced stress in rice and may contribute to uncovering novel mechanisms of oxidative stress-induced genomic instability and epigenetic regulation in plant stress inheritance.展开更多
Anticipated more frequent extreme events due to changes in global climatic variability requires adaptation of crop species to multi-occurrence abiotic stresses hereby sustaining the food security. Priming, by pre-expo...Anticipated more frequent extreme events due to changes in global climatic variability requires adaptation of crop species to multi-occurrence abiotic stresses hereby sustaining the food security. Priming, by pre-exposure of plants to an eliciting factor, enables plants to be more tolerant to later biotic or abiotic stress events. Priming induced “stress memory” exists in both present generation and the offspring. Thus, priming is suggested to be a promising strategy for plants to cope with the abiotic stresses under global change scenarios. In this review, the underlying physiological and molecular mechanisms of priming induced enhancement of stress tolerance to the major abiotic stresses of drought and waterlogging, and high and low temperature in crop plants were discussed, and the potential to utilize the priming effect for sustaining crop productivity in future climates was also suggested.展开更多
Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known...Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known, recent discoveries reveal that epigenetic processes are an integral part of ABA-regulated processes. Epigenetic mechanisms, namely, histone modifications and cytosine DNA methylation-induced modification of genome give rise to epigenomes, which add diversity and complexity to the genome of organisms. Histone monoubiquitination appears to regulate ABA levels in developing seeds through histone H2B monoubiquitination. ABA and H2B ubiquitination dependent chromatin remodeling regulate seed dormancy. Transcription factor networks necessary for seed maturation are repressed by histone deacetylases （HDACs）-dependent and PICKLE chromatin remodeling complexes （CRCs）, whereas ABA induces the expression of these genes directly or through repression of HDACs. Abiotic stress-induced ABA regulates stomatal response and stress- responsive gene expression through HDACs and HOS15-dependent histone deacetylation, as well as through the ATP- dependent SWITCH/SUCROSE NONFERMENTING CRC. ABA also probably regulates the abiotic stress response through DNA methylation and short interfering RNA pathways. Further studies on ABA-regulated epigenome will be of immense use to understand the plant development, stress adaptation and stress memory.展开更多
Objective To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats.Methods One hundred and eight male Wistar rats...Objective To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats.Methods One hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n = 42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 μA with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n = 33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n =33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze.Results The stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10. 4±2. 3, P<0. 05) and increases in resistance to capture (scale: 2. 85±0. 56, P < 0. 01 ). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29±7) seconds after 15 trials in the water maze, P<0. 05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze.Conclusions Following repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.展开更多
Plants exhibit remarkable abilities to learn,communicate,memorize,and develop stimulus-dependent decision-making circuits.Unlike animals,plant memory is uniquely rooted in cellular,molecular,and biochemical networks,l...Plants exhibit remarkable abilities to learn,communicate,memorize,and develop stimulus-dependent decision-making circuits.Unlike animals,plant memory is uniquely rooted in cellular,molecular,and biochemical networks,lacking specialized organs for these functions.Consequently,plants can effectively learn and respond to diverse challenges,becoming used to recurring signals.Artificial intelligence(AI)and machine learning(ML)represent the new frontiers of biological sciences,offering the potential to predict crop behavior under environmental stresses associated with climate change.Epigenetic mechanisms,serving as the foundational blueprints of plant memory,are crucial in regulating plant adaptation to envi-ronmental stimuli.They achieve this adaptation by modulating chromatin structure and acces-sibility,which contribute to gene expression regulation and allow plants to adapt dynam-ically to changing environmental conditions.In this review,we describe novel methods and approaches in AI and ML to elucidate how plant memory occurs in response to environmental stimuli and priming mechanisms.Furthermore,we explore innovative strategies exploiting transgenerational memory for plant breeding to develop crops resilient to multiple stresses.In this context,AI and ML can aid in integrating and analyzing epigenetic data of plant stress responses to optimize the training of the pa-rental plants.展开更多
Plants have evolved efficient mechanisms for adapting to temperature fluctuations,known as heat stress response and heat stress memory.Although the transcriptional regulatory network of plant heat stress response has ...Plants have evolved efficient mechanisms for adapting to temperature fluctuations,known as heat stress response and heat stress memory.Although the transcriptional regulatory network of plant heat stress response has been established,little is known about the genome-wide transcriptional changes occurring within the first several minutes after heat shock.Here,we investigated the nascent RNA and mature messenger RNA(mRNA)from plant leaf tissues exposed to 5 min of heat shock treatment using global run-on sequencing and RNA sequencing methods.Only a small group of genes were up-or downregulated at both the nascent RNA and mRNA levels.Primed plants that were already exposed to mild heat stress exhibited a more drastic alteration at multiple transcriptional steps than naive plants that had not experienced heat stress.Upon heat shock,we also observed the following:(i)engaged RNA polymerase Ⅱ accumulated downstream of transcription start sites;(ii)5′pausing release was a ratelimiting step for the induction of some heat shock protein genes;(iii)numerous genes switched transcription modes;(iv)pervasive read-through was induced at terminators;and(v)heat stress memory occurs at multiple steps of the transcription cycle,such as at Pol Ⅱ recruitment,5′pausing,elongation,and termination.展开更多
基金the National Science Foundation of China(52074352)the Natural Science Foundation of Hunan Province,China(2023JJ30680)。
文摘The acoustic emission(AE)method is commonly used to measure in-situ stress,while the Kaiser efect(KE)is usually afected by the stress history and specimen direction.In this study,three types of rocks were tested under uniaxial defection loading at various defection angles.Both the KE and the incomplete erasion phenomenon(IEP)were investigated,and the obtained in-situ stress using the AE method was compared with that obtained using the stress relief method.The results demonstrate that both the KE and the IEP exhibit directional independence.The rock type signifcantly afects the critical angle(θ),with marble showing a higher value(15°)compared to granite(10°)and red sandstone(5°).This is attributed to the initiation and development of interface cracks or crystal interfaces in mineral grains.The similar in-situ stress measured by the AE and stress relief methods suggests that small-angle defection coring is applicable in engineering.This study provides a reference for in-situ stress measurement using the AE method.
基金funded by the National Natural Science Foundation of China(Grant No.51779021)Chongqing Natural Science Foundation(Grant No.cstc2019jcyj-msxm2176)Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN201800745).
文摘In deep underground engineering,understanding of time-related stress memory properties is critical to evaluate the in situ stress conditions of a rock mass.In this study,the time-sensitivity mechanism of the rock stress memory properties under tensile stress was investigated.It was found that the material property(Poisson’s ratio)and crack angle were the controlling factors of the Kaiser effect(KE)under tensile stress.In particular,the time-sensitivity of the stress memory properties was closely related to the crack growth path.When the failure of the rock specimen was dominated by tensile microcracks and the crack development direction was deflected by up to 30°in the successive loading process,the stress memory capacity was likely to be time-independent for a sandstone specimen.The distribution of the Felicity ratio in a Brazilian test was more discrete than that in a three-point bending test It also showed that the changes in the crack path,rather than the time interval between successive loading cycles,led to inaccuracy of the detected KE.This study provides insights into stress memory-related issues under uniaxial or more complex stress conditions and thus facilitates development of methods for testing in situ mechanical behaviors of rocks with acoustic emission(AE)technology.
基金This work was financially supported by the National Natural Science Foundation of China(No.61965012)Project of Yunnan Provincial Natural Science Foundation(Nos.202001AS070008,202101AT070126)+3 种基金Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(No.YNWRQNBJ-2018-295)the Excellent Youth Project of Yunnan Province Applied Basic Research Project(No.2019FI001)Rare and Precious Metal Materials Genome Engineering Project of Yunnan Province(No.202002AB080001)Sichuan Natural Science Foundation(No.2022JDJQ0030).
文摘Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.
基金supported by the National Natural Science Foundation of China(Grant No.32061143012 to A.Z.,32101352 to X.H.).
文摘Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.
基金supported by the National Science for Youth Foundation(No.31500404)China Postdoctoral Science Foundation(No.2015M571155)Science and Technology Project of Hebei Education Department(No.QN2019194).
文摘Industrialization and the rapid growth of economies have caused severe environmental pollution,which might impact the survival of sensitive species.In this study,we investigated the defense responses of two common mosses with varying anti-haze capacities,Hypnum callichroum and Homomallium incurvatum,in response to simulated haze pollution.Photoprotection and antioxidant mechanisms of both mosses were measured immediately after the first exposure to the haze treatment,followed by the initial recovery stage and again after exposure to secondary stress and secondary recovery.Haze exposure caused severe oxidative stress and photodamage in both H.callichroum and H.incurvatum.Metabolic processes such as photorespiration,the ascorbate-glutathione cycle and secondary metabolism-which play roles in defense responses-were significantly activated in both moss species after haze treatment.During the recovery following haze stress,H.callichroum exhibited a significant stress memory response,as evidenced by the greater accumulation of several memory substances,including xanthophylls and phenolic acids.However,H.incurvatum did not exhibit a strong stress memory response,which might explain its relatively inferior anti-haze capacity in the natural environment.
文摘The effect of deformation on recovery stress of Ni144.7Ti46.3Nb9 alloy has been studjed using tensile test at various temperatures and TEM observation. It ls shown that the recovery stress increases with jncreasing total strain ET and reaches a maximum value (max) as ET= 9% but the maximum recov erV strain of the alloy is only about 4.6%. This is different from that of Ti-Ni binary alloy in which is obtained usually at maximum recovery strain and the reason of the difference is dis Cussed. Deformation temperature Td has a little effect on recovery stress when Td is less than Ms However, recovery stress decreases sharply when Td is higher than M, and lowers approximately down to zero near Msσ
基金supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI(JP20K06003 to M.I.)。
文摘Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trait for adapting to an everchanging environment,and root pruning is an artificial technique for regenerating the root system.In the present study,we investigated whether root pruning in soybean can effectively alleviate the inhibitory effects of anaerobic stress.Soybean plants were affected by anaerobic stress at the germination,vegetative stage 1(V1),and reproductive stage 1(R1)stages,and then the plants were treated with root pruning just after the stress treatment.Soybean plants at the germination stage were treated with root cap and tip removals after hypoxia(N_(2)treatment).Root cap removal was more effective in suppressing the inhibitory effects of hypoxia than root tip removal(5 mm from the tip).The shoot dry weights of the soybean plants with and without root cap removal after hypoxia were 51.2 and 73.8%of the control,respectively,while the root dry weights of plants with and without root cap removal after hypoxia were 43.2 and 62.8%of the control,respectively.As root cap removal effectively enhanced soybean growth after anaerobic stress,the root cap may be the candidate tissue for the stress memory mechanism.When soybean plants at the V1 stage of growth were affected by anaerobic stress,the branch number,pod weight in the main stem,root length,and root surface area of the soybean plants treated with anaerobic stress at the R1 stage significantly decreased compared with those of the control.In contrast,root pruning(2 mm from the tip)immediately after the stress treatment enhanced root growth,branch number,and pod weight.The branch number,pod weight,root length,and root surface area of the plants treated with root pruning were 1.13,1.14,1.12,and 1.13 times higher than those of plants treated with anaerobic stress.Plasmolysis was observed in the root meristem,columella,and cortical cells in soybean roots subjected to anaerobic conditions.However,damage was not observed in the newly emerged roots after root pruning in plants treated with anaerobic stress.These results suggested that root pruning is effective in enhancing soybean growth after anaerobic stress.This effectiveness may be due to the regeneration and elongation of healthy lateral roots during the recovery period.When soybean plants were affected by anaerobic stress at the R1 stage,root pruning just after the stress treatment was ineffective.Thus,suppressing the growth reduction due to anaerobic stress at reproductive stages using only root pruning may be difficult.
基金This project is supported by National Natural Science Foundation of China (No.50235030,No.50505052).
文摘In order to explore the quantitative method of metal magnetic memory testing（MMMT） and clarify the relationship between Hp（y）, the normal component of spontaneous stray field, and applied stress or residual stress, the static tensile tests of 0.45%C steel sheet specimens are carried out on a servo hydraulic MTS810 machine. Hp（y） values are measured during the test process by an EMS-2003 metal magnetic memory diagnostic apparatus and a non-magnetic electric control displacement instrument. Residual stresses of some points on the surface of a specimen are measured by a Stress Tech X-Stress 3000 X-ray diffraction instrument. The results show that the same variation rules of Hp（y） value versus applied tensile stress are presented under the different conditions of load-on and load-off. However, the same rule does not exist between the Hp（y） value and residual stress. The variation of Hp（y） value reflects the history of applied tensile stress.
基金supported by the Natural Science Foundation of Chongqing,China(Grant No.CSTB2024NSCQ-MSX0462)the Postdoctoral Fellowship Program of CPSF,China(Grant No.GZC20242211)+1 种基金the Heilongjiang Touyan Team,China(Grant No.HITTY-20190034)the Project of the Aerospace Science and Technology Collaborative Innovation Center,China(Grant No.BSAUEA5740600223).
文摘Intergenerational inheritance of stress memory plays a crucial role in plant adaptation to environmental changes,particularly in the context of spaceflight,where plants may serve as a food source for humans on long-duration missions.However,the intergenerational genetic effects of spaceflight-induced stress memory in plants remain unclear.In this study,we assessed the cross-generational genetic effects of spaceflight stress memory using the rice mutant B10,identified during the SJ-10 return satellite mission.Our results showed that the oxidative stress effects induced by spaceflight persisted until the M5 generation in rice.We found that the rice genome remained unstable post-spaceflight,leading to alterations in genome methylation levels.Additionally,we observed significant changes in the methylation levels of transposons,suggesting their involvement in the intergenerational inheritance of spaceflight-induced stress memory.Furthermore,we identified thousands of differentially expressed genes(DEGs)and differentially alternatively spliced(DAS)genes induced by spaceflight stress memory across multiple rice generations.Notably,differentially methylated cytosines were more abundant in non-expressed genes than in DEGs or DAS genes.A substantial number of DEGs and DASs related to oxidative stress were identified,primarily involved in the generation and scavenging of reactive oxygen species.This study also presented report on the response of alternative splicing events in rice to spaceflight stress.Moreover,our findings revealed that genome methylation was associated with gene expression but not with DAS.In conclusion,our study provides comprehensive insights into the intergenerational inheritance of spaceflight-induced stress in rice and may contribute to uncovering novel mechanisms of oxidative stress-induced genomic instability and epigenetic regulation in plant stress inheritance.
基金supported by the National Key Research andDevelopment Program of China (2016YFD0300107)the National Natural Science Foundation of China (31325020, 31401326, 31471445, 31771693)+3 种基金the earmarked fund for China Agriculture Research System (CARS-03)the Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, Chinathe Fundamental Research Funds for the Central Universities, China (KJQN201505)the Jiangsu Collaborative Innovation Center for Modern Crop Production, China (JCIC-MCP)
文摘Anticipated more frequent extreme events due to changes in global climatic variability requires adaptation of crop species to multi-occurrence abiotic stresses hereby sustaining the food security. Priming, by pre-exposure of plants to an eliciting factor, enables plants to be more tolerant to later biotic or abiotic stress events. Priming induced “stress memory” exists in both present generation and the offspring. Thus, priming is suggested to be a promising strategy for plants to cope with the abiotic stresses under global change scenarios. In this review, the underlying physiological and molecular mechanisms of priming induced enhancement of stress tolerance to the major abiotic stresses of drought and waterlogging, and high and low temperature in crop plants were discussed, and the potential to utilize the priming effect for sustaining crop productivity in future climates was also suggested.
基金SERC Fact Track Scheme for Young Scientist, DST, Govt.of India, New Delhi to V. Chinnusamythe State Key Basic Researchand Development Plan of China (2003CB114300)the National Natural Science Foundation of China (30421002 and 30670182) to Z. Gong.
文摘Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known, recent discoveries reveal that epigenetic processes are an integral part of ABA-regulated processes. Epigenetic mechanisms, namely, histone modifications and cytosine DNA methylation-induced modification of genome give rise to epigenomes, which add diversity and complexity to the genome of organisms. Histone monoubiquitination appears to regulate ABA levels in developing seeds through histone H2B monoubiquitination. ABA and H2B ubiquitination dependent chromatin remodeling regulate seed dormancy. Transcription factor networks necessary for seed maturation are repressed by histone deacetylases （HDACs）-dependent and PICKLE chromatin remodeling complexes （CRCs）, whereas ABA induces the expression of these genes directly or through repression of HDACs. Abiotic stress-induced ABA regulates stomatal response and stress- responsive gene expression through HDACs and HOS15-dependent histone deacetylation, as well as through the ATP- dependent SWITCH/SUCROSE NONFERMENTING CRC. ABA also probably regulates the abiotic stress response through DNA methylation and short interfering RNA pathways. Further studies on ABA-regulated epigenome will be of immense use to understand the plant development, stress adaptation and stress memory.
基金This study was supported by grants from the National Natural Science Foundation of China (No. 39870284) and the Tenth Five-Year Plan for Medical Projects of PLA (No. 01L028).
文摘Objective To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats.Methods One hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n = 42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 μA with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n = 33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n =33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze.Results The stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10. 4±2. 3, P<0. 05) and increases in resistance to capture (scale: 2. 85±0. 56, P < 0. 01 ). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29±7) seconds after 15 trials in the water maze, P<0. 05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze.Conclusions Following repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.
基金Project No. TKP2021-EGA-20 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-EGA funding schemein receipt of a Postdoctoral grant in the frame of the TEPIMEPORY project (Plant Science Project, University of Bordeaux)a Postdoctoral grant of the PRIMA (Partnership for Research and Innovation in the Mediterranean Area) program supported by the European Union in the frame of PROSIT (Plant microbiomes in sustainable viticulture. Grant number 1565)
文摘Plants exhibit remarkable abilities to learn,communicate,memorize,and develop stimulus-dependent decision-making circuits.Unlike animals,plant memory is uniquely rooted in cellular,molecular,and biochemical networks,lacking specialized organs for these functions.Consequently,plants can effectively learn and respond to diverse challenges,becoming used to recurring signals.Artificial intelligence(AI)and machine learning(ML)represent the new frontiers of biological sciences,offering the potential to predict crop behavior under environmental stresses associated with climate change.Epigenetic mechanisms,serving as the foundational blueprints of plant memory,are crucial in regulating plant adaptation to envi-ronmental stimuli.They achieve this adaptation by modulating chromatin structure and acces-sibility,which contribute to gene expression regulation and allow plants to adapt dynam-ically to changing environmental conditions.In this review,we describe novel methods and approaches in AI and ML to elucidate how plant memory occurs in response to environmental stimuli and priming mechanisms.Furthermore,we explore innovative strategies exploiting transgenerational memory for plant breeding to develop crops resilient to multiple stresses.In this context,AI and ML can aid in integrating and analyzing epigenetic data of plant stress responses to optimize the training of the pa-rental plants.
基金supported by the National Natural Science Foundation of China(31900463 to M.L.and 31871289,31471165 to Z.D.)。
文摘Plants have evolved efficient mechanisms for adapting to temperature fluctuations,known as heat stress response and heat stress memory.Although the transcriptional regulatory network of plant heat stress response has been established,little is known about the genome-wide transcriptional changes occurring within the first several minutes after heat shock.Here,we investigated the nascent RNA and mature messenger RNA(mRNA)from plant leaf tissues exposed to 5 min of heat shock treatment using global run-on sequencing and RNA sequencing methods.Only a small group of genes were up-or downregulated at both the nascent RNA and mRNA levels.Primed plants that were already exposed to mild heat stress exhibited a more drastic alteration at multiple transcriptional steps than naive plants that had not experienced heat stress.Upon heat shock,we also observed the following:(i)engaged RNA polymerase Ⅱ accumulated downstream of transcription start sites;(ii)5′pausing release was a ratelimiting step for the induction of some heat shock protein genes;(iii)numerous genes switched transcription modes;(iv)pervasive read-through was induced at terminators;and(v)heat stress memory occurs at multiple steps of the transcription cycle,such as at Pol Ⅱ recruitment,5′pausing,elongation,and termination.
