Temperature is a key factor governing the growth and development,distribution,and seasonal behavior of plants.The entireplant life cycle is affected by environmental temperatures.Plants grow rapidly and exhibit specif...Temperature is a key factor governing the growth and development,distribution,and seasonal behavior of plants.The entireplant life cycle is affected by environmental temperatures.Plants grow rapidly and exhibit specific changes in morphology under mild average temperature conditions,a response termed thermomorphogenesis.When exposed to chilling or moist chilling low temperatures,flowering or seed germination is accelerated in some plant species;these processes are known as vernalization and cold stratification,respectively.Interestingly,once many temperate plants are exposed to chilling temperatures for some time,they can acquire the ability to resist freezing stress,a process termed cold acclimation.In the face of global climate change,heat stress has emerged as a frequent challenge,which adversely affects plant growth and development.In this review,we summarize and discuss recent progress in dissecting them olecular mechanism sregulating plant thermomorphogenesis,vernalization,and responses to extreme temperatures.We also discuss the remaining issues that are crucial for understanding the interactions between plants and temperature.展开更多
A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolutio...A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolution surface observations, sounding data, and radar measurements. New convective ceils are continuously initiated along a mesoscale boundary at the surface, leading to formation and maintenance of the quasi-linear-shaped MCS from about 2000 BT 19 to 1200 BT 20 May. The boundary is originally formed between a cold dome generated by previous convection and southwesterly flow from the ocean carrying higher equivalent potential temperature （θe） air. The boundary is subsequently maintained and reinforced by the contrast between the MCS-generated cold outflow and the oceanic higher-θe air. The cold outflow is weak （wind speed ≤ 5 m s-1）, which is attributable to the characteristic environmental conditions, i.e., high humidity in the lower troposphere and weak horizontal winds in the middle and lower troposphere. The low speed of the cold outflow is comparable to that of the near surface southerly flow from the ocean, resulting in very slow southward movement of the boundary. The boundary features temperature contrasts of 2-3℃ and is roughly 500-m deep. Despite its shallowness, the boundary appears to exert a profound influence on continuous convection initiation because of the very low level of free convection and small convection inhibition of the near surface oceanic air, building several parallel rainbands （of about 50-kin length） that move slowly eastward along the MCS and produce about 80% of the total rainfall. Another MCS moves into the area from the northwest and merges with the local MCS at about 1200 BT. The cold outflow subsequently strengthens and the boundary moves more rapidly toward the southeast, leading to end of the event in 3 h.展开更多
Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding c...Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding climate-resilient crops. In this review,we summarize recent progress on understanding plant drought, salt, and cold stress responses, with a focus on signal perception and transduction by different protein kinases, especially sucrose nonfermenting1(SNF1)-related protein kinases(Sn RKs),mitogen-activated protein kinase(MAPK) cascades,calcium-dependent protein kinases(CDPKs/CPKs),and receptor-like kinases(RLKs). We also discuss future challenges in these research fields.展开更多
Cold temperatures, a major abiotic stress, threaten the growth and development of plants, worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated m...Cold temperatures, a major abiotic stress, threaten the growth and development of plants, worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated mechanisms to acclimate to cold periods, increasing their ability to tolerate freezing stress. Over the last decade, significant progress has been made in determining the molecular mechanisms underpinning cold acclimation, including following the identification of several pivotal components, including candidates for cold sensors, protein kinases, and transcription factors. With these developments, we have a better understanding of the CBF-dependent cold-signaling pathway. In this review, we summarize recent progress made in elucidating the cold-signaling pathways, especially the C-repeat binding factor-dependent pathway, and describe the regulatory function of the crucial components of plant cold signaling. We also discuss the unsolved questions that should be the focus of future work.展开更多
High-performance metal additive manufacturing （AM） has been extensively investigated in recent years because of its unique advantages over traditional manufacturing processes. AM has been applied to form complex com...High-performance metal additive manufacturing （AM） has been extensively investigated in recent years because of its unique advantages over traditional manufacturing processes. AM has been applied to form complex components of Ti, Fe or Ni alloys. However, for other nonferrous alloys such as AI alloys, Mg alloys and Cu alloys, AM may not be appropriate because of its melting nature during processing by laser, electron beam, and/or arc. Cold spraying （CS） has been widely accepted as a promising solid-state coating technique in last decade for its mass production of high-quality metals and alloys, and/or metal matrix composites coatings. It is now recognized as a useful and powerful tool for AM, but the related research work has just started. This review summarized the literature on the state-of-the-art and problems for CS as an AM and repairing technique.展开更多
Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil...Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. The interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun Mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. The results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. The alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. Those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 28.11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively serious degradation. Furthermore, from the angl展开更多
Endoscopic polypectomy and endoscopic mucosal resection(EMR) are the established treatment standards for colorectal polyps. Current research aims at the reduction of both complication and recurrence rates as well as o...Endoscopic polypectomy and endoscopic mucosal resection(EMR) are the established treatment standards for colorectal polyps. Current research aims at the reduction of both complication and recurrence rates as well as on shortening procedure times. Cold snare resection is the emerging standard for the treatment of smaller(< 5 mm) polyps and is possibly also suitable for the removal of noncancerous polyps up to 9 mm. The method avoids thermal damage, has reduced procedure times and probably also a lower risk for delayed bleeding. On the other end of the treatment spectrum, endoscopic submucosal dissection(ESD)offers en bloc resection of larger flat or sessile lesions. The technique has obvious advantages in the treatment of high-grade dysplasia and early cancer. Due to its minimal recurrence rate, it may also be an alternative to fractionated EMR of larger flat or sessile lesions. However, ESD is technically demanding and burdened by longer procedure times and higher costs. It should therefore be restricted to lesions suspicious for high-grade dysplasia or early invasive cancer.The latest addition to endoscopic resection techniques is endoscopic fullthickness resection with specifically developed devices for flexible endoscopy.This method is very useful for the treatment of smaller difficult-to-resect lesions,e.g., recurrence with scar formation after previous endoscopic resections.展开更多
As one kind of key anti-fatigue manufacture approaches with simplicity and effectiveness, the hole cold expansion technology satisfies the increasing needs for light weight and durability of aircraft structures.It can...As one kind of key anti-fatigue manufacture approaches with simplicity and effectiveness, the hole cold expansion technology satisfies the increasing needs for light weight and durability of aircraft structures.It can improve the fatigue life by several times at no additional weight conditions.The hole cold expansion technology has been widely used in manufacturing and repairing of both fighters and commercial aircraft, and has become a research hotspot in the strengthening technology.In recent years, hole cold expansion process methods, residual stress around expanded holes, the behavior of fatigue crack initiation and propagation, and fatigue lives after cold expansion are researched extensively through lots of experiments and finite element simulations.A review on the hole cold expansion technology research status in the last twenty years is presented in this paper.Via the analysis of the current characteristics and defects of the hole cold expansion technology, combined with the actual needs in design and manufacture of new-generation aircraft, development trends and novel research directions are presented for realizing precise and high-efficiency anti-fatigue manufacture.展开更多
The transcription factors DREB1s/CBFs play important roles in the regulation of plant resistance to environmental stresses and are quite useful for generating transgenic plants tolerant to these stresses. In the prese...The transcription factors DREB1s/CBFs play important roles in the regulation of plant resistance to environmental stresses and are quite useful for generating transgenic plants tolerant to these stresses. In the present work, a cDNA encoding DREB1/CBF-like protein (GhDREB1L) from cotton was isolated, and its sequence features, DNA binding preference, and expression patterns of the transcripts were also characterized. GhDREB1L contained one conserved AP2/ERF domain and its amino acid sequence was similar to the DREB1/CBF group of the DREB family from other plants. The DNA-binding domain of GhDREB1L was successfully expressed as a fusion protein in Escherichia coli BL21 (DE3) and purified by Ni-NTA affinity chromatography. Electrophoretic mobility shift assay revealed that the purified GhDREB1L fusion protein had a specific binding activity with the previously characterized DRE ele-ment (core sequence, ACCGAC) and also with the DRE-like sequence (core sequence, GCCGAC) in the promoter of the dehydration-responsive late embryogenesis-abundant gene LEA D113. Semi-quantita- tive RT-PCR showed that GhDREB1L was induced in the cotton cotyledons by low temperature, as well as drought and NaCl treatments. These results suggested that the novel cotton GhDREB1L might play an important role in response to low temperature as well as drought and high salinity through binding to the DRE cis-element.展开更多
Summer rainfall is vital for crops in Northeast China. In this study, we investigated large-scale circulation anomalies related to monthly summer rainfall in Northeast China using European Center for Medium-Range Weat...Summer rainfall is vital for crops in Northeast China. In this study, we investigated large-scale circulation anomalies related to monthly summer rainfall in Northeast China using European Center for Medium-Range Weather Forecast ERA-40 reanalysis data and monthly rainfall data from 79 stations in Northeast China. The results show that the interannual variation in rainfall over Northeast China is mainly dominated by a cold vortex in early summer (May-June) and by the East Asian summer monsoon in late summer (July-August). In early summer, corresponding to increased rainfall in Northeast China, an anomalous cyclonic anomaly tilted westward with height appears to the northwest and cold vortices occur frequently. In late summer, the rainfall anomaly is mainly controlled by a northward shift of the local East Asian jet stream in the upper troposphere and the northwest extension of the western Pacific subtropical high (WPSH) in the lower troposphere. The enhanced southwesterly anomaly in the west of the WPSH transports more moisture into Northeast China and results in more rainfall. In addition, compared with that in July, the rainfall in Northeast China in August is also influenced by a mid- and high-latitude blocking high over Northeast Asia.展开更多
The possible physiological mechanism of enhancement of cold tolerance by salicylic acid (SA) in banana seedlings ( Musa acuminata cv. Williams 8188) was explored. Measurements of leakage electrolyte after 2 d of re...The possible physiological mechanism of enhancement of cold tolerance by salicylic acid (SA) in banana seedlings ( Musa acuminata cv. Williams 8188) was explored. Measurements of leakage electrolyte after 2 d of recovery at 30/22 ℃ (day/night) following 3 d of cold stress at 7 ℃ showed that pretreatment with hydroponic solution containing SA 0.3-0.9 mmol/L as foliar spray under normal growth conditions (30/22 ℃) could significantly enhance cold tolerance of banana plants. The highest enhancing effect of SA occurred at 0.5 mmol/L and it showed the lowest leakage rate of electrolyte or smaller leaf wilting area after 2 d of recovery at normal temperature from 3 d of 7 ℃ or 5 ℃ cold stress. Higher concentrations (≥2.5 mmol/L) of SA, however, caused more electrolyte leakage, indicating that they aggravated chilling damage. Enhanced cold tolerance by SA could be related to H 2O 2 metabolism. Compared with water_treated seedlings (control), SA 0.5 mmol/L treatment inhibited activities of catalase (CAT) and ascorbate peroxidase (APX), increased peroxidase (POX) activity, but did not affect the activity of superoxide dismutase (SOD) under normal growth conditions, and these changes might lead to an accumulation of H 2O 2, whereas SA pretreatment enhanced the activities of CAT and APX, and reduced the increase in productions of H 2O 2 and thiobarbituric acid_reaction substances (TBARS) during subsequent 7 ℃ cold stress and recovery periods. Exogenous H 2O 2 treatments (1.5 -2.5 mmol/L) also increased cold tolerance of banana seedlings. Furthermore, pretreatment of banana seedlings with dimethylthiourea (a trap for H 2O 2) significantly inhibited cold tolerance induced by SA. These results suggested that endogenous H 2O 2 may be required for SA_enhanced cold tolerance. The significance of the interaction of SA, H 2O 2 and H 2O 2_metabolizing enzymes during cold stress has been discussed.展开更多
基金This work was supported by grants from the Ministry of Agriculture of China for Transgenic Research(2016ZX08009003-002)the National Natural Science Foundation of China(31920103002,31921001)the Beijing Outstanding University Discipline Program.
文摘Temperature is a key factor governing the growth and development,distribution,and seasonal behavior of plants.The entireplant life cycle is affected by environmental temperatures.Plants grow rapidly and exhibit specific changes in morphology under mild average temperature conditions,a response termed thermomorphogenesis.When exposed to chilling or moist chilling low temperatures,flowering or seed germination is accelerated in some plant species;these processes are known as vernalization and cold stratification,respectively.Interestingly,once many temperate plants are exposed to chilling temperatures for some time,they can acquire the ability to resist freezing stress,a process termed cold acclimation.In the face of global climate change,heat stress has emerged as a frequent challenge,which adversely affects plant growth and development.In this review,we summarize and discuss recent progress in dissecting them olecular mechanism sregulating plant thermomorphogenesis,vernalization,and responses to extreme temperatures.We also discuss the remaining issues that are crucial for understanding the interactions between plants and temperature.
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund(GYHY201406013 and GYHY201406003)National Natural Science Foundation of China(91437104)National(Key)Basic Research and Development(973)Program of China(2012CB417202)
文摘A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolution surface observations, sounding data, and radar measurements. New convective ceils are continuously initiated along a mesoscale boundary at the surface, leading to formation and maintenance of the quasi-linear-shaped MCS from about 2000 BT 19 to 1200 BT 20 May. The boundary is originally formed between a cold dome generated by previous convection and southwesterly flow from the ocean carrying higher equivalent potential temperature （θe） air. The boundary is subsequently maintained and reinforced by the contrast between the MCS-generated cold outflow and the oceanic higher-θe air. The cold outflow is weak （wind speed ≤ 5 m s-1）, which is attributable to the characteristic environmental conditions, i.e., high humidity in the lower troposphere and weak horizontal winds in the middle and lower troposphere. The low speed of the cold outflow is comparable to that of the near surface southerly flow from the ocean, resulting in very slow southward movement of the boundary. The boundary features temperature contrasts of 2-3℃ and is roughly 500-m deep. Despite its shallowness, the boundary appears to exert a profound influence on continuous convection initiation because of the very low level of free convection and small convection inhibition of the near surface oceanic air, building several parallel rainbands （of about 50-kin length） that move slowly eastward along the MCS and produce about 80% of the total rainfall. Another MCS moves into the area from the northwest and merges with the local MCS at about 1200 BT. The cold outflow subsequently strengthens and the boundary moves more rapidly toward the southeast, leading to end of the event in 3 h.
基金supported by grants from the Natural National Science Foundation of China (31730007 and 31921001)the Beijing Outstanding University Discipline Program。
文摘Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding climate-resilient crops. In this review,we summarize recent progress on understanding plant drought, salt, and cold stress responses, with a focus on signal perception and transduction by different protein kinases, especially sucrose nonfermenting1(SNF1)-related protein kinases(Sn RKs),mitogen-activated protein kinase(MAPK) cascades,calcium-dependent protein kinases(CDPKs/CPKs),and receptor-like kinases(RLKs). We also discuss future challenges in these research fields.
基金supported by grants from the National Natural Science Foundation of China(31730011 and 31700214)
文摘Cold temperatures, a major abiotic stress, threaten the growth and development of plants, worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated mechanisms to acclimate to cold periods, increasing their ability to tolerate freezing stress. Over the last decade, significant progress has been made in determining the molecular mechanisms underpinning cold acclimation, including following the identification of several pivotal components, including candidates for cold sensors, protein kinases, and transcription factors. With these developments, we have a better understanding of the CBF-dependent cold-signaling pathway. In this review, we summarize recent progress made in elucidating the cold-signaling pathways, especially the C-repeat binding factor-dependent pathway, and describe the regulatory function of the crucial components of plant cold signaling. We also discuss the unsolved questions that should be the focus of future work.
基金the financial support from the National Key Research and Development Program of China (2016YFB0701203)the National Natural Science Foundation of China (51574196)+1 种基金the fund of SAST (SAST2016043)the 111 Project (B08040)
文摘High-performance metal additive manufacturing （AM） has been extensively investigated in recent years because of its unique advantages over traditional manufacturing processes. AM has been applied to form complex components of Ti, Fe or Ni alloys. However, for other nonferrous alloys such as AI alloys, Mg alloys and Cu alloys, AM may not be appropriate because of its melting nature during processing by laser, electron beam, and/or arc. Cold spraying （CS） has been widely accepted as a promising solid-state coating technique in last decade for its mass production of high-quality metals and alloys, and/or metal matrix composites coatings. It is now recognized as a useful and powerful tool for AM, but the related research work has just started. This review summarized the literature on the state-of-the-art and problems for CS as an AM and repairing technique.
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.30270255 and No.90511003)the"Hundred Talents"Project of the Chinese Academy of Sciences under the leadership of Wang Genxuthe State Key Project(973)(Grant No.2003CB415201).
文摘Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. The interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun Mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. The results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. The alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. Those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 28.11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively serious degradation. Furthermore, from the angl
文摘Endoscopic polypectomy and endoscopic mucosal resection(EMR) are the established treatment standards for colorectal polyps. Current research aims at the reduction of both complication and recurrence rates as well as on shortening procedure times. Cold snare resection is the emerging standard for the treatment of smaller(< 5 mm) polyps and is possibly also suitable for the removal of noncancerous polyps up to 9 mm. The method avoids thermal damage, has reduced procedure times and probably also a lower risk for delayed bleeding. On the other end of the treatment spectrum, endoscopic submucosal dissection(ESD)offers en bloc resection of larger flat or sessile lesions. The technique has obvious advantages in the treatment of high-grade dysplasia and early cancer. Due to its minimal recurrence rate, it may also be an alternative to fractionated EMR of larger flat or sessile lesions. However, ESD is technically demanding and burdened by longer procedure times and higher costs. It should therefore be restricted to lesions suspicious for high-grade dysplasia or early invasive cancer.The latest addition to endoscopic resection techniques is endoscopic fullthickness resection with specifically developed devices for flexible endoscopy.This method is very useful for the treatment of smaller difficult-to-resect lesions,e.g., recurrence with scar formation after previous endoscopic resections.
基金the Fund of National Engineering and Research Center for Commercial Aircraft Manufacturing of China (No.SAMC12-JS-15-021)the Funding of Jiangsu Innovation Program for Graduate Education of China (No.CXLX12_0137)the Fundamental Research Funds for the Central Universities of China
文摘As one kind of key anti-fatigue manufacture approaches with simplicity and effectiveness, the hole cold expansion technology satisfies the increasing needs for light weight and durability of aircraft structures.It can improve the fatigue life by several times at no additional weight conditions.The hole cold expansion technology has been widely used in manufacturing and repairing of both fighters and commercial aircraft, and has become a research hotspot in the strengthening technology.In recent years, hole cold expansion process methods, residual stress around expanded holes, the behavior of fatigue crack initiation and propagation, and fatigue lives after cold expansion are researched extensively through lots of experiments and finite element simulations.A review on the hole cold expansion technology research status in the last twenty years is presented in this paper.Via the analysis of the current characteristics and defects of the hole cold expansion technology, combined with the actual needs in design and manufacture of new-generation aircraft, development trends and novel research directions are presented for realizing precise and high-efficiency anti-fatigue manufacture.
基金the State Key Basic Research and Development Plan of China (Grant No. 2004CB117303),the Hi-Tech Research and Development Program of China (Grant Nos.2004AA222100, 2002AA212051 and 2002AA207006),the National Natural Science Foundation of China (Grant Nos. 30170080 and 39770078)
文摘The transcription factors DREB1s/CBFs play important roles in the regulation of plant resistance to environmental stresses and are quite useful for generating transgenic plants tolerant to these stresses. In the present work, a cDNA encoding DREB1/CBF-like protein (GhDREB1L) from cotton was isolated, and its sequence features, DNA binding preference, and expression patterns of the transcripts were also characterized. GhDREB1L contained one conserved AP2/ERF domain and its amino acid sequence was similar to the DREB1/CBF group of the DREB family from other plants. The DNA-binding domain of GhDREB1L was successfully expressed as a fusion protein in Escherichia coli BL21 (DE3) and purified by Ni-NTA affinity chromatography. Electrophoretic mobility shift assay revealed that the purified GhDREB1L fusion protein had a specific binding activity with the previously characterized DRE ele-ment (core sequence, ACCGAC) and also with the DRE-like sequence (core sequence, GCCGAC) in the promoter of the dehydration-responsive late embryogenesis-abundant gene LEA D113. Semi-quantita- tive RT-PCR showed that GhDREB1L was induced in the cotton cotyledons by low temperature, as well as drought and NaCl treatments. These results suggested that the novel cotton GhDREB1L might play an important role in response to low temperature as well as drought and high salinity through binding to the DRE cis-element.
基金supported by National Technology Support Project (Grant Nos. 2009BAC51B04, 2007BAC29B01)Key Knowledge Innovation Programs of the Chinese Academy of Sciences (Grant No. KZCX2-YW-220)+1 种基金National Natural Science Foundation of China (Grant Nos. 40575047 and 40705036)the New Technology Projects of China Meteorological Administration (Grant No. CMATG2009MS01)
文摘Summer rainfall is vital for crops in Northeast China. In this study, we investigated large-scale circulation anomalies related to monthly summer rainfall in Northeast China using European Center for Medium-Range Weather Forecast ERA-40 reanalysis data and monthly rainfall data from 79 stations in Northeast China. The results show that the interannual variation in rainfall over Northeast China is mainly dominated by a cold vortex in early summer (May-June) and by the East Asian summer monsoon in late summer (July-August). In early summer, corresponding to increased rainfall in Northeast China, an anomalous cyclonic anomaly tilted westward with height appears to the northwest and cold vortices occur frequently. In late summer, the rainfall anomaly is mainly controlled by a northward shift of the local East Asian jet stream in the upper troposphere and the northwest extension of the western Pacific subtropical high (WPSH) in the lower troposphere. The enhanced southwesterly anomaly in the west of the WPSH transports more moisture into Northeast China and results in more rainfall. In addition, compared with that in July, the rainfall in Northeast China in August is also influenced by a mid- and high-latitude blocking high over Northeast Asia.
文摘The possible physiological mechanism of enhancement of cold tolerance by salicylic acid (SA) in banana seedlings ( Musa acuminata cv. Williams 8188) was explored. Measurements of leakage electrolyte after 2 d of recovery at 30/22 ℃ (day/night) following 3 d of cold stress at 7 ℃ showed that pretreatment with hydroponic solution containing SA 0.3-0.9 mmol/L as foliar spray under normal growth conditions (30/22 ℃) could significantly enhance cold tolerance of banana plants. The highest enhancing effect of SA occurred at 0.5 mmol/L and it showed the lowest leakage rate of electrolyte or smaller leaf wilting area after 2 d of recovery at normal temperature from 3 d of 7 ℃ or 5 ℃ cold stress. Higher concentrations (≥2.5 mmol/L) of SA, however, caused more electrolyte leakage, indicating that they aggravated chilling damage. Enhanced cold tolerance by SA could be related to H 2O 2 metabolism. Compared with water_treated seedlings (control), SA 0.5 mmol/L treatment inhibited activities of catalase (CAT) and ascorbate peroxidase (APX), increased peroxidase (POX) activity, but did not affect the activity of superoxide dismutase (SOD) under normal growth conditions, and these changes might lead to an accumulation of H 2O 2, whereas SA pretreatment enhanced the activities of CAT and APX, and reduced the increase in productions of H 2O 2 and thiobarbituric acid_reaction substances (TBARS) during subsequent 7 ℃ cold stress and recovery periods. Exogenous H 2O 2 treatments (1.5 -2.5 mmol/L) also increased cold tolerance of banana seedlings. Furthermore, pretreatment of banana seedlings with dimethylthiourea (a trap for H 2O 2) significantly inhibited cold tolerance induced by SA. These results suggested that endogenous H 2O 2 may be required for SA_enhanced cold tolerance. The significance of the interaction of SA, H 2O 2 and H 2O 2_metabolizing enzymes during cold stress has been discussed.
