This study aimed to explore and improve the different economic values of Pinus koraiensis(Siebold and Zucc.)by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P.koraiensis ha...This study aimed to explore and improve the different economic values of Pinus koraiensis(Siebold and Zucc.)by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P.koraiensis half-sib families.Growth traits assessed included height,diameter at breast height,volume,degree of stem straight-ness,stem form,and branch number per node,while wood properties assessed included density,fiber length and width,fiber length to width ratio,and cellulose,hemicel-lulose,holocellulose,lignin,and ash contents.Except for degree of stem straightness and branch number per node,all other traits exhibited highly significant variations(P<0.01)among families.The coefficients of variation ranged from 5.3(stem form)to 66.7%(ash content),whereas,the herit-ability ranged from 0.136(degree of stem straightness)to 0.962(ash content).Significant correlations were observed among growth traits and wood physicochemical properties.Principal component analysis identified four distinct groups representing growth traits,wood chemical and physical properties,and stem form traits.Multi-trait comprehensive evaluation identified three groups of elite families based on breeding objectives,including rapid growth,improved timber production for building and furniture materials,and pulpwood production.These specific families should be used to establish new plantations.展开更多
Laboratory visual detection on the hydrate accumulation process provides an effective and low-cost method to uncover hydrate accumulation mechanisms in nature.However,the spatial hydrate distribution and its dynamic e...Laboratory visual detection on the hydrate accumulation process provides an effective and low-cost method to uncover hydrate accumulation mechanisms in nature.However,the spatial hydrate distribution and its dynamic evolutionary behaviors are still not fully understood due to the lack of methods and experimental systems.Toward this goal,we built a two-dimensional electrical resistivity tomography(ERT)apparatus capable of measuring spatial and temporal characteristics of hydrate-bearing porous media.Beach sand(0.05–0.85 mm)was used to form artificial methane hydrate-bearing sediment.The experiments were conducted at 1°C under excess water conditions and the ERT data were acquired and analyzed.This study demonstrates the utility of the ERT method for hydrate mapping in laboratory-scale.The results indicate that the average electrical conductivity decreases nonlinearly with the formation of the hydrate.At some special time-intervals,the average conductivity fluctuates within a certain scope.The plane conductivity fields evolve heterogeneously and the local preferential hydrate-forming positions alternate throughout the experimental duration.We speculate that the combination of hydrate formation itself and salt-removal effect plays a dominant role in the spatial and temporal hydrate distribution,as well as geophysical parameters changing behaviors during hydrate accumulation.展开更多
The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in th...The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China's first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitation projects.展开更多
High-temperature(HT)stress causes male sterility in crops,thus decreasing yields.To explore the possible contribution of histone modifications to male fertility under HT conditions,we defined the histone methylation l...High-temperature(HT)stress causes male sterility in crops,thus decreasing yields.To explore the possible contribution of histone modifications to male fertility under HT conditions,we defined the histone methylation landscape for the marks histone H3 lysine 27 trimethylation(H3K27me3)and histone H3 lysine 4 trimethylation(H3K4me3)by chromatin immunoprecipitation sequencing(ChIP-seq)in two differing upland cotton(Gossypium hirsutum)varieties.We observed a global disruption in H3K4me3 and H3K27me3 modifications,especially H3K27me3,in cotton anthers subjected to HT.HT affected the bivalent H3K4me3–H3K27me3 modification more than either monovalent modification.We determined that removal of H3K27me3 at the promoters of jasmonate-related genes increased their expression,maintaining male fertility under HT in the HT-tolerant variety at the anther dehiscence stage.Modulating jasmonate homeostasis or signaling resulted in an anther indehiscence phenotype under HT.Chemical suppression of H3K27me3 deposition increased jasmonic acid contents and maintained male fertility under HT.In summary,our study provides new insights into the regulation of male fertility by histone modifications under HT and suggests a potential strategy for improving cotton HT tolerance.展开更多
To further understand the characteristics of clay and sand production(hereafter collectively referred to as sand production)and to provide optimization designs of sand control schemes are critical for gas production f...To further understand the characteristics of clay and sand production(hereafter collectively referred to as sand production)and to provide optimization designs of sand control schemes are critical for gas production from clayey silt natural gas hydrate reservoirs in the South China Sea.Thus,gas-water-sand production behavoirs and coupling reservoir subsidence characteristics before,during,and after hydrate dissociation of the clayey silt hydrate reservoirs with different clay contents(5%,10%,15%,20%,25%,and 30%)have been studied through a self-developed experimental system.The results show that with the increase of clay content,the total mass of sand production first increases and then decreases,and it reaches maximum when the clayey content is 20%.The sand production is the lowest before hydrate dissociation and increases significantly during hydrate dissociation,which mainly occurs in the high-speed gas and water production stage at the beginning of hydrate dissociation.After hydrate dissociation,the sand production decreases significantly.During the whole depressurization process,the clay and free sand particles generally move to the sand outlet due to the fluid driving force and overlying stress extrusion.However,for conditions of high clay contents,those particles fail to pass through the sand control screen and gradually accumulate and block the screen by forming a mud cake,which greatly reduce the permeability of the screen and limite sand production as well as gas and water production.Our research lays a foundation for sand production prediction and sand control scheme selection during gas recovery from clayey silty hydrate reservoirs that greatly need to consider a balance between sand control and gas productivity.展开更多
Birch(Betula platyphylla Suk.),distributed in Eurasia,North America,and Australia,is a kind of cold-resistant,fast-growing,and vital pulpwood tree species.It is also one of the most important ecological restoration tr...Birch(Betula platyphylla Suk.),distributed in Eurasia,North America,and Australia,is a kind of cold-resistant,fast-growing,and vital pulpwood tree species.It is also one of the most important ecological restoration tree species with high values of economic benefits in Northeast China.To improve the genetic gain and expand the economic benefit of B.platyphylla,many genetic improvements have been carried out.In China,B.platyphylla is widely distributed and varied,and there are many varieties with excellent genetic characteristics.In this paper,the genetic improvement of B.platyphylla was reviewed,and the previous research results were discussed from two aspects:conventional breeding and molecular breeding.Some problems and corresponding solutions in the genetic improvement were put forward to provide ideas for B.platyphylla breeding in the future.展开更多
Lycium exsertum A. Gray is a wild species of wolfberry, which is mainly distributed in the desert area of Arizona, USA. It was introduced from the United States in 2016. The plant grows vigorously, and its morphologic...Lycium exsertum A. Gray is a wild species of wolfberry, which is mainly distributed in the desert area of Arizona, USA. It was introduced from the United States in 2016. The plant grows vigorously, and its morphological characteristics are different from those of domestic Lycium. The introduction of this material can enrich the domestic Lycium germplasm resources, and it can also be applied in the creation of anti-root rot Lycium germplasm materials and the study on reproductive evolution of Lycium species.展开更多
The double-recessive genic male-sterile(ms)line ms5 ms6 has been used to develop cotton(Gossypium hirsutum)hybrids for many years,but its molecular-genetic basis has remained unclear.Here,we identified the Ms5 and Ms6...The double-recessive genic male-sterile(ms)line ms5 ms6 has been used to develop cotton(Gossypium hirsutum)hybrids for many years,but its molecular-genetic basis has remained unclear.Here,we identified the Ms5 and Ms6 loci through map-based cloning and confirmed their function in male sterility through CRISPR/Cas9 gene editing.Ms5 and Ms6 are highly expressed in stages 7–9 anthers and encode the cytochrome P450 mono-oxygenases CYP703A2-A and CYP703A2-D.The ms5 mutant carries a single-nucleotide C-to-T nonsense mutation leading to premature chain termination at amino acid 312(GhCYP703A2-A^(312aa)),and ms6 carries three nonsynonymous substitutions(D98E,E168K,and G198R)and a synonymous mutation(L11L).Enzyme assays showed that GhCYP703A2 proteins hydroxylate fatty acids,and the ms5(GhCYP703A2-A^(312aa))and ms6(GhCYP703A2-D^(D98E,E168K,G198R))mutant proteins have decreased enzyme activities.Biochemical and lipidomic analyses showed that in ms5 ms6 plants,C12–C18 free fatty acid and phospholipid levels are significantly elevated in stages 7–9 anthers,while stages 8–10 anthers lack sporopollenin fluorescence around the pollen,causing microspore degradation and male sterility.Overall,our characterization uncovered functions of GhCYP703A2 in sporopollenin formation and fertility,providing guidance for creating male-sterile lines to facilitate hybrid cotton production and therefore exploit heterosis for improvement of cotton.展开更多
Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway...Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands,while the effect of defoliation timing has not been unexplored.The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem.Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments:early defoliation,peak defoliation,late defoliation and non-defoliation.We measured plant nitrogen(N)and phosphorus(P)resorption at species and community levels,and quantified plant N and P fluxes in resorption,litter return and hay output.Plant production in the mowing system was assessed by hay production and quality.Important Findings Peak and late defoliation,but not early defoliation,reduced plant community N and P resorption proficiency;and late defoliation reduced N resorption efficiency but not P resorption efficiency.Peak and late defoliation,but not early defoliation,reduced plant nutrient resorption flux and litter nutrient return flux.Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption.Peak defoliation had the highest hay production and quality,while early defoliation had the lowest.Our results provide new insights into the nutrient cycling in mowing grassland,and imply that the mowing timing can be used as a tool to mediate the balanee between conservation and production of steppes,and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.展开更多
The control of large edge localized modes(ELMs) is a critical issue for the successful operation of future burning plasma devices,such as the international thermonuclear experimental reactor(ITER) and China fusion eng...The control of large edge localized modes(ELMs) is a critical issue for the successful operation of future burning plasma devices,such as the international thermonuclear experimental reactor(ITER) and China fusion engineering test reactor(CFETR). In this paper, we present a new active and effective means of ELM suppression using ion cyclotron resonant heating(ICRH) on the experimental advanced superconducting tokamak(EAST). We obtained the key role of the external E × B velocity shear near the pedestal top and the scrape-off-layer(SOL) induced by the RF sheath potential of ICRH in ELM suppression. The experimental results showed a positive correlation between the RF sheath and the E × B shear rate in SOL. BOUT++ simulations indicate that increased E × B velocity shear rates in the pedestal and SOL regions promote ELM suppression;thereby, supporting the experimental observations on EAST. These findings suggest a new simple approach to access the ELM suppressed regimes in plasma with low torque input as ITER baseline discharges.展开更多
The 440 t/h circulating fluidized bed boiler was numerically simulated by the Computational Particle Fluid Dynamics(CPFD)method.The combustion characteristics of circulating fluidized bed boiler and the effect of seco...The 440 t/h circulating fluidized bed boiler was numerically simulated by the Computational Particle Fluid Dynamics(CPFD)method.The combustion characteristics of circulating fluidized bed boiler and the effect of secondary air on NO emission were investigated.The full-scale three-dimensional model of a 440 t/h circulating fluidized bed boiler was established.The rationality of the grid was validated by the experimental data of material layer resistance.The accuracy of the simulation was validated by measuring the temperature of each measuring point in the dense phase area.The combustion conditions in the furnace under different setting modes were simulated.The effects of secondary air rates on NO formation in fluidized bed were predicted.The results show that when the secondary air rate increases to 27%,the proper secondary air rate has a positive effect on the inhibition of NO generation,and the proper strengthening of the central air supply will improve the permeability of the secondary air and make the combustion more uniform and stable.When the secondary air rate increases to 33%,excessive improvement of air classification and central air distribution will affect the stability of circulating fluidized bed operation.Therefore,air classification and strengthening of central air supply can be used together to inhibit the generation of NO.展开更多
This paper presents an improved method for imaging in turbid water by using the individual strengths of the quadrature lock-in discrimination(QLD)method and the retinex method.At first,the high-speed QLD is performed ...This paper presents an improved method for imaging in turbid water by using the individual strengths of the quadrature lock-in discrimination(QLD)method and the retinex method.At first,the high-speed QLD is performed on images,aiming at capturing the ballistic photons.Then,we perform the retinex image enhancement on the QLD-processed images to enhance the contrast of the image.Next,the effect of uneven illumination is suppressed by using the bilateral gamma function for adaptive illumination correction.The experimental results depict that the proposed approach achieves better enhancement than the existing approaches,even in a high-turbidity environment.展开更多
Atmospheric particulate matter with diameter<2.5μm now makes up much of the air pollution in China,but it is the ultrafine particles(UFPs)with diameter<90 nm that are of particular interest.This is because UFPs...Atmospheric particulate matter with diameter<2.5μm now makes up much of the air pollution in China,but it is the ultrafine particles(UFPs)with diameter<90 nm that are of particular interest.This is because UFPs are strongly linked with human health for two reasons:they contain a variety of hazardous substances and they can deeply penetrate human respiratory systems.Therefore,scanning electron microscopy combined with X-ray dispersive energy spectrometry was used to characterize the morphology and surface texture,as well as the elemental composition of 60 UFPs.The UFPs was generated in a sewage sludge-incineration power plant in Zhejiang Province.This was done to determine the microstructure of the ultrafine particles and to follow the evolution of particle surface elemental composition with increasing particle size.Then,a comparison of the characteristic time for nucleation,condensation and coagulation was done to estimate the dominant mechanism.The results show that the UFPs have generally irregular shapes(cotton-like,irregular balls,sheets,etc.)and that they usually aggregate to form a mass.With increase in the size of a UFP,the mass fraction of the elements presents clearly changed:Na,K and Fe gradually decreased;while Ca,Si and Al,as well as the heavy metals Cu,Zn and Ni increased.Characteristic time estimation is a convenient and effective tool for identifying the predominant mechanisms during combustion.In this study,calculations of characteristic time were used to reveal a mechanism of vaporization,nucleation,condensation and coagulation,which drives the formation and growth of ultrafine particles.展开更多
基金This work was fi nancially supported by the fundamental Research Funds for the Central Universities(2572020DR01)HeilongjiangTouyan Innovation team program(Tree Genetics and Breeding Innovation Team).
文摘This study aimed to explore and improve the different economic values of Pinus koraiensis(Siebold and Zucc.)by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P.koraiensis half-sib families.Growth traits assessed included height,diameter at breast height,volume,degree of stem straight-ness,stem form,and branch number per node,while wood properties assessed included density,fiber length and width,fiber length to width ratio,and cellulose,hemicel-lulose,holocellulose,lignin,and ash contents.Except for degree of stem straightness and branch number per node,all other traits exhibited highly significant variations(P<0.01)among families.The coefficients of variation ranged from 5.3(stem form)to 66.7%(ash content),whereas,the herit-ability ranged from 0.136(degree of stem straightness)to 0.962(ash content).Significant correlations were observed among growth traits and wood physicochemical properties.Principal component analysis identified four distinct groups representing growth traits,wood chemical and physical properties,and stem form traits.Multi-trait comprehensive evaluation identified three groups of elite families based on breeding objectives,including rapid growth,improved timber production for building and furniture materials,and pulpwood production.These specific families should be used to establish new plantations.
基金The Taishan Scholar Special Experts Project of Shandong Province under contract No.ts201712079the National Natural Science Foundation of China under contract No.41976074the National Key Research and Development Program of China under contract No.2018YFE0126400。
文摘Laboratory visual detection on the hydrate accumulation process provides an effective and low-cost method to uncover hydrate accumulation mechanisms in nature.However,the spatial hydrate distribution and its dynamic evolutionary behaviors are still not fully understood due to the lack of methods and experimental systems.Toward this goal,we built a two-dimensional electrical resistivity tomography(ERT)apparatus capable of measuring spatial and temporal characteristics of hydrate-bearing porous media.Beach sand(0.05–0.85 mm)was used to form artificial methane hydrate-bearing sediment.The experiments were conducted at 1°C under excess water conditions and the ERT data were acquired and analyzed.This study demonstrates the utility of the ERT method for hydrate mapping in laboratory-scale.The results indicate that the average electrical conductivity decreases nonlinearly with the formation of the hydrate.At some special time-intervals,the average conductivity fluctuates within a certain scope.The plane conductivity fields evolve heterogeneously and the local preferential hydrate-forming positions alternate throughout the experimental duration.We speculate that the combination of hydrate formation itself and salt-removal effect plays a dominant role in the spatial and temporal hydrate distribution,as well as geophysical parameters changing behaviors during hydrate accumulation.
基金The National Natural Science Foundation of China under contract No.41606078the Taishan Scholar Special Experts Project under contract No.ts201712079+1 种基金the National Key Research and Development Plan under contract No.2017YFC0307600the Open Fund of Qingdao National Laboratory for Marine Science and Technology of China under contract Nos QNLM2016ORP0203 and QNLM2016ORP0207
文摘The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China's first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitation projects.
基金supported by the Major Project of Hubei Hongshan Laboratory(2022hszd004)the National Cotton Production System,Ministry of Agriculture and Rural Affairs of China(CARS-15-04)+1 种基金the National Key R&D Program of China(2022YFF1003502)the National Natural Science Foundation of China(32072024).
文摘High-temperature(HT)stress causes male sterility in crops,thus decreasing yields.To explore the possible contribution of histone modifications to male fertility under HT conditions,we defined the histone methylation landscape for the marks histone H3 lysine 27 trimethylation(H3K27me3)and histone H3 lysine 4 trimethylation(H3K4me3)by chromatin immunoprecipitation sequencing(ChIP-seq)in two differing upland cotton(Gossypium hirsutum)varieties.We observed a global disruption in H3K4me3 and H3K27me3 modifications,especially H3K27me3,in cotton anthers subjected to HT.HT affected the bivalent H3K4me3–H3K27me3 modification more than either monovalent modification.We determined that removal of H3K27me3 at the promoters of jasmonate-related genes increased their expression,maintaining male fertility under HT in the HT-tolerant variety at the anther dehiscence stage.Modulating jasmonate homeostasis or signaling resulted in an anther indehiscence phenotype under HT.Chemical suppression of H3K27me3 deposition increased jasmonic acid contents and maintained male fertility under HT.In summary,our study provides new insights into the regulation of male fertility by histone modifications under HT and suggests a potential strategy for improving cotton HT tolerance.
基金National Key Research and Development Program of China(2018YFE0126400)China Geological Survey Project(DD20190232)+1 种基金Qingdao National Laboratory for Marine Science and Technology Open Fund(QNLM2016ORP0203)Department of Natural Resources of Guangdong Province Project(GDNRC[2020]-047).
文摘To further understand the characteristics of clay and sand production(hereafter collectively referred to as sand production)and to provide optimization designs of sand control schemes are critical for gas production from clayey silt natural gas hydrate reservoirs in the South China Sea.Thus,gas-water-sand production behavoirs and coupling reservoir subsidence characteristics before,during,and after hydrate dissociation of the clayey silt hydrate reservoirs with different clay contents(5%,10%,15%,20%,25%,and 30%)have been studied through a self-developed experimental system.The results show that with the increase of clay content,the total mass of sand production first increases and then decreases,and it reaches maximum when the clayey content is 20%.The sand production is the lowest before hydrate dissociation and increases significantly during hydrate dissociation,which mainly occurs in the high-speed gas and water production stage at the beginning of hydrate dissociation.After hydrate dissociation,the sand production decreases significantly.During the whole depressurization process,the clay and free sand particles generally move to the sand outlet due to the fluid driving force and overlying stress extrusion.However,for conditions of high clay contents,those particles fail to pass through the sand control screen and gradually accumulate and block the screen by forming a mud cake,which greatly reduce the permeability of the screen and limite sand production as well as gas and water production.Our research lays a foundation for sand production prediction and sand control scheme selection during gas recovery from clayey silty hydrate reservoirs that greatly need to consider a balance between sand control and gas productivity.
基金the Scientific Research Start-Up Funds of Jilin Agricultural University(No.2021002)。
文摘Birch(Betula platyphylla Suk.),distributed in Eurasia,North America,and Australia,is a kind of cold-resistant,fast-growing,and vital pulpwood tree species.It is also one of the most important ecological restoration tree species with high values of economic benefits in Northeast China.To improve the genetic gain and expand the economic benefit of B.platyphylla,many genetic improvements have been carried out.In China,B.platyphylla is widely distributed and varied,and there are many varieties with excellent genetic characteristics.In this paper,the genetic improvement of B.platyphylla was reviewed,and the previous research results were discussed from two aspects:conventional breeding and molecular breeding.Some problems and corresponding solutions in the genetic improvement were put forward to provide ideas for B.platyphylla breeding in the future.
基金Supported by Ningxia Hui Autonomous Region Key Research and Development Plan(2019BFG02026)Wolfberry Breeding Program of Ningxia Hui Autonomous Region(2013NYYZ0102)Scientific and Technological Innovation Guiding Project of Ningxia Academy of Agriculture and Forestry Sciences(NKYJ-17-13,NKYG-19-06)
文摘Lycium exsertum A. Gray is a wild species of wolfberry, which is mainly distributed in the desert area of Arizona, USA. It was introduced from the United States in 2016. The plant grows vigorously, and its morphological characteristics are different from those of domestic Lycium. The introduction of this material can enrich the domestic Lycium germplasm resources, and it can also be applied in the creation of anti-root rot Lycium germplasm materials and the study on reproductive evolution of Lycium species.
基金supported by funding from the National Key Research and Development Program of China(2016YFD0101402)the National Natural Science Foundation of China(32072024)the Fundamental Research Funds for the Central Universities(2021ZKPY019)。
文摘The double-recessive genic male-sterile(ms)line ms5 ms6 has been used to develop cotton(Gossypium hirsutum)hybrids for many years,but its molecular-genetic basis has remained unclear.Here,we identified the Ms5 and Ms6 loci through map-based cloning and confirmed their function in male sterility through CRISPR/Cas9 gene editing.Ms5 and Ms6 are highly expressed in stages 7–9 anthers and encode the cytochrome P450 mono-oxygenases CYP703A2-A and CYP703A2-D.The ms5 mutant carries a single-nucleotide C-to-T nonsense mutation leading to premature chain termination at amino acid 312(GhCYP703A2-A^(312aa)),and ms6 carries three nonsynonymous substitutions(D98E,E168K,and G198R)and a synonymous mutation(L11L).Enzyme assays showed that GhCYP703A2 proteins hydroxylate fatty acids,and the ms5(GhCYP703A2-A^(312aa))and ms6(GhCYP703A2-D^(D98E,E168K,G198R))mutant proteins have decreased enzyme activities.Biochemical and lipidomic analyses showed that in ms5 ms6 plants,C12–C18 free fatty acid and phospholipid levels are significantly elevated in stages 7–9 anthers,while stages 8–10 anthers lack sporopollenin fluorescence around the pollen,causing microspore degradation and male sterility.Overall,our characterization uncovered functions of GhCYP703A2 in sporopollenin formation and fertility,providing guidance for creating male-sterile lines to facilitate hybrid cotton production and therefore exploit heterosis for improvement of cotton.
基金supported by the Ministry of Science and Technology of China(2015BAC02B04,2016YFC0500508)the Departmeni of Science and Technology of Inner Mongolia Autonomous Region of China(201503001,2019ZD007)the National Natural Science Foundation of China(32071564).
文摘Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands,while the effect of defoliation timing has not been unexplored.The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem.Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments:early defoliation,peak defoliation,late defoliation and non-defoliation.We measured plant nitrogen(N)and phosphorus(P)resorption at species and community levels,and quantified plant N and P fluxes in resorption,litter return and hay output.Plant production in the mowing system was assessed by hay production and quality.Important Findings Peak and late defoliation,but not early defoliation,reduced plant community N and P resorption proficiency;and late defoliation reduced N resorption efficiency but not P resorption efficiency.Peak and late defoliation,but not early defoliation,reduced plant nutrient resorption flux and litter nutrient return flux.Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption.Peak defoliation had the highest hay production and quality,while early defoliation had the lowest.Our results provide new insights into the nutrient cycling in mowing grassland,and imply that the mowing timing can be used as a tool to mediate the balanee between conservation and production of steppes,and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.
基金supported by the National Key Research and Development Program(Grant Nos.2016YFA0400600,and 2016YFA0400601)the National MCF Energy R&D Program(Grant No.2018YFE0311200)+1 种基金the National Natural Science Foundation of China(Grant Nos.11975265,and U1967206)the Comprehensive Research Facility for Fusion Technology Program of China(Grant No.2018-000052-73-01-001228)。
文摘The control of large edge localized modes(ELMs) is a critical issue for the successful operation of future burning plasma devices,such as the international thermonuclear experimental reactor(ITER) and China fusion engineering test reactor(CFETR). In this paper, we present a new active and effective means of ELM suppression using ion cyclotron resonant heating(ICRH) on the experimental advanced superconducting tokamak(EAST). We obtained the key role of the external E × B velocity shear near the pedestal top and the scrape-off-layer(SOL) induced by the RF sheath potential of ICRH in ELM suppression. The experimental results showed a positive correlation between the RF sheath and the E × B shear rate in SOL. BOUT++ simulations indicate that increased E × B velocity shear rates in the pedestal and SOL regions promote ELM suppression;thereby, supporting the experimental observations on EAST. These findings suggest a new simple approach to access the ELM suppressed regimes in plasma with low torque input as ITER baseline discharges.
基金This study was supported by the Jilin City Science and Technology Innovation Development Program(grant No.20210103091).
文摘The 440 t/h circulating fluidized bed boiler was numerically simulated by the Computational Particle Fluid Dynamics(CPFD)method.The combustion characteristics of circulating fluidized bed boiler and the effect of secondary air on NO emission were investigated.The full-scale three-dimensional model of a 440 t/h circulating fluidized bed boiler was established.The rationality of the grid was validated by the experimental data of material layer resistance.The accuracy of the simulation was validated by measuring the temperature of each measuring point in the dense phase area.The combustion conditions in the furnace under different setting modes were simulated.The effects of secondary air rates on NO formation in fluidized bed were predicted.The results show that when the secondary air rate increases to 27%,the proper secondary air rate has a positive effect on the inhibition of NO generation,and the proper strengthening of the central air supply will improve the permeability of the secondary air and make the combustion more uniform and stable.When the secondary air rate increases to 33%,excessive improvement of air classification and central air distribution will affect the stability of circulating fluidized bed operation.Therefore,air classification and strengthening of central air supply can be used together to inhibit the generation of NO.
基金supported by the National Natural Science Foundation of China(32071564)the Natural Science Foundation of Inner Mongolia Autonomous Region(2019ZD007).
基金supported in part by the National Key Research and Development Program of China(Nos.2022YFC2808200 and 2022YFB2903403)the National Natural Science Foundation of China(NSFC)(No.61971378)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22030208).
文摘This paper presents an improved method for imaging in turbid water by using the individual strengths of the quadrature lock-in discrimination(QLD)method and the retinex method.At first,the high-speed QLD is performed on images,aiming at capturing the ballistic photons.Then,we perform the retinex image enhancement on the QLD-processed images to enhance the contrast of the image.Next,the effect of uneven illumination is suppressed by using the bilateral gamma function for adaptive illumination correction.The experimental results depict that the proposed approach achieves better enhancement than the existing approaches,even in a high-turbidity environment.
基金supported by the National Natural Science Foundation of China(32071564)the Department of Science and Technology of Inner Mongolia Autonomous Region of China(2019ZD007 and 2022LHQN03001)the Open Project of Collaborative Innovation Center for Grassland Ecological Security,Ministry of Education of China.Conflict of interest statement.
基金the National Natural Science Foundation of China in the form of a research grant(No.51576134)the National Key R&D Program of China(2017YFC0703100).
文摘Atmospheric particulate matter with diameter<2.5μm now makes up much of the air pollution in China,but it is the ultrafine particles(UFPs)with diameter<90 nm that are of particular interest.This is because UFPs are strongly linked with human health for two reasons:they contain a variety of hazardous substances and they can deeply penetrate human respiratory systems.Therefore,scanning electron microscopy combined with X-ray dispersive energy spectrometry was used to characterize the morphology and surface texture,as well as the elemental composition of 60 UFPs.The UFPs was generated in a sewage sludge-incineration power plant in Zhejiang Province.This was done to determine the microstructure of the ultrafine particles and to follow the evolution of particle surface elemental composition with increasing particle size.Then,a comparison of the characteristic time for nucleation,condensation and coagulation was done to estimate the dominant mechanism.The results show that the UFPs have generally irregular shapes(cotton-like,irregular balls,sheets,etc.)and that they usually aggregate to form a mass.With increase in the size of a UFP,the mass fraction of the elements presents clearly changed:Na,K and Fe gradually decreased;while Ca,Si and Al,as well as the heavy metals Cu,Zn and Ni increased.Characteristic time estimation is a convenient and effective tool for identifying the predominant mechanisms during combustion.In this study,calculations of characteristic time were used to reveal a mechanism of vaporization,nucleation,condensation and coagulation,which drives the formation and growth of ultrafine particles.
