Leaf area index （LAI） is used for crop growth monitoring in agronomic research, and is promising to diagnose the nitrogen （N） status of crops. This study was conducted to develop appropriate LAI-based N diagnostic...Leaf area index （LAI） is used for crop growth monitoring in agronomic research, and is promising to diagnose the nitrogen （N） status of crops. This study was conducted to develop appropriate LAI-based N diagnostic models in irrigated lowland rice. Four field experiments were carried out in Jiangsu Province of East China from 2009 to 2014. Different N application rates and plant densities were used to generate contrasting conditions of N availability or population densities in rice. LAI was determined by LI-3000, and estimated indirectly by LAI-2000 during vegetative growth period. Group and individual plant characters （e.g., tiller number （TN） and plant height （H）） were investigated simultaneously. Two N indicators of plant N accumulation （NA） and N nutrition index （NNI） were measured as well. A calibration equation （LAI=1.7787LAI2o00-0.8816, R2=0.870＂） was developed for LAI-2000. The linear regression analysis showed a significant relationship between NA and actual LAI （R2=0.863^＊＊）. For the NNI, the relative LAI （R2=0.808-） was a relatively unbiased variable in the regression than the LAI （R^2=0.33^＊＊）. The results were used to formulate two LAI-based N diagnostic models for irrigated lowland rice （NA=29.778LAI-5.9397; NNI=0.7705RLAI＋0.2764）. Finally, a simple LAI deterministic model was developed to estimate the actual LAI using the characters of TN and H （LAI=-0.3375（THxHx0.01）2＋3.665（TH×H×0.01）-1.8249, R2=0.875＊＊）. With these models, the N status of rice can be diagnosed conveniently in the field.展开更多
The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and th...The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.展开更多
Tomatoes, peppers and eggplants＇ seedings were used as experiment materials to study the leaf development mechanism of solanaceous vegetable crops by using blot observation method. Results showed that an increasing t...Tomatoes, peppers and eggplants＇ seedings were used as experiment materials to study the leaf development mechanism of solanaceous vegetable crops by using blot observation method. Results showed that an increasing trend was presented at the density of cells and stomata in upper and lower epidermis, but a declined trend was presented at the cells＇ diameters and the size of stomata with the joint position rising. At the same joint position, no matter in adaxial side or abaxial side, there were some differences among cells diameters, size of stomata, density of cells and stomata.展开更多
Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions ...Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).展开更多
The leaf-vein drip irrigation emitter is a new type of drip emitter based on a bionic structure able to support shunting,sharp turns,and increased dissipation.In the present work,the results of twenty-five tests execu...The leaf-vein drip irrigation emitter is a new type of drip emitter based on a bionic structure able to support shunting,sharp turns,and increased dissipation.In the present work,the results of twenty-five tests executed in the framework of an orthogonal design strategy are presented in order to clarify the influence of the geometrical parameters of the flow channel on the hydraulic characteristics of such emitter.The corresponding flow index and head loss coefficient are determined through numerical simulations and model testing.The results show that the flow index of the flow channel is 0.4970∼0.5461,which corresponds to good hydraulic performances.The head loss coefficient of the flow channel is 572.74∼3933.05,which in turn indicates a good energy dissipation effect.The order of influence of the leaf vein flow channel parameters on the flow index can be represented in a synthetic way as a>b>c>d>e,where(a)is the width of the inlet,(b)is the horizontal distance of the front water inlet,(c)is the vertical distance of the inner edge of the front end,(d)is the horizontal distance of the rear water outlet and(e)is the vertical distance of the outer edge of the front end.The flow index increases with d,decreases with a,first decreases,and then increases with b,and first increases and then decreases with the increase of c and e.The coefficient(R^(2))of the fitted model related to geometric parameters and flow index is 0.9986-0.9999.The relative errors among experimental testing,simulation calculation and predictive estimates are shown to be less than 5%.展开更多
Duyun Maojian tea is a famous tea in China.In this study,the specific-locus amplified fragment(SLAF)sequencing method was used to analyze the population structure and conduct a genome-wide association study(GWAS)of 2 ...Duyun Maojian tea is a famous tea in China.In this study,the specific-locus amplified fragment(SLAF)sequencing method was used to analyze the population structure and conduct a genome-wide association study(GWAS)of 2 leaf traits of 123 tea plants in Qiannan,China.A total of 462,019 SLAF tags and 11,362,041 single-nucleotide polymorphism(SNP)loci were obtained.The results of phylogenetic tree analysis,cluster analysis,and principal component analysis showed that 123 tea germplasms were clustered into three groups,and the heterozygosity rates for Groups I,II,and II were 0.206,0.224,and 0.34,respectively.Generally,tea germplasms in a production area are clustered in a group,indicating that tea germplasms in different production areas have certain genetic diversity.The traditional Duyun Maojian tea core production areas,TS and DC-SJ,are clustered into Group I and Group II respectively,while the ZY production area is relatively independent in Group III.Furthermore,based on GWAS analysis,11 candidate genes related to leaf apex and 7 candidate genes related to leaf shape were obtained.This study clarified the genetic relationship among eight Duyun Maojian tea production areas and obtained candidate genes related to leaf apex and leaf shape development.The results showed that population structure and candidate genes are an effective basis for the breeding of Duyun Maojian tea germplasm.展开更多
基金supported by the Special Program for Agriculture Science and Technology from the Ministry of Agriculture of China (201303109)the National Key Research & Development Program of China (2016YFD0300604+3 种基金 2016YFD0200602)the Fundamental Research Funds for the Central Universities,China (262201602)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China (PAPD)the 111 Project of China (B16026)
文摘Leaf area index （LAI） is used for crop growth monitoring in agronomic research, and is promising to diagnose the nitrogen （N） status of crops. This study was conducted to develop appropriate LAI-based N diagnostic models in irrigated lowland rice. Four field experiments were carried out in Jiangsu Province of East China from 2009 to 2014. Different N application rates and plant densities were used to generate contrasting conditions of N availability or population densities in rice. LAI was determined by LI-3000, and estimated indirectly by LAI-2000 during vegetative growth period. Group and individual plant characters （e.g., tiller number （TN） and plant height （H）） were investigated simultaneously. Two N indicators of plant N accumulation （NA） and N nutrition index （NNI） were measured as well. A calibration equation （LAI=1.7787LAI2o00-0.8816, R2=0.870＂） was developed for LAI-2000. The linear regression analysis showed a significant relationship between NA and actual LAI （R2=0.863^＊＊）. For the NNI, the relative LAI （R2=0.808-） was a relatively unbiased variable in the regression than the LAI （R^2=0.33^＊＊）. The results were used to formulate two LAI-based N diagnostic models for irrigated lowland rice （NA=29.778LAI-5.9397; NNI=0.7705RLAI＋0.2764）. Finally, a simple LAI deterministic model was developed to estimate the actual LAI using the characters of TN and H （LAI=-0.3375（THxHx0.01）2＋3.665（TH×H×0.01）-1.8249, R2=0.875＊＊）. With these models, the N status of rice can be diagnosed conveniently in the field.
基金This project is supported by National Natural Science Foundation of China (No.50275089)
文摘The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.
基金Supported by Natural Science Foundation of Heilongjiang Province (C2005-32)China Doctoral Science Foundation (LRB04-217)Scientific Research Initiation Fund of Northeast Agricultural University
文摘Tomatoes, peppers and eggplants＇ seedings were used as experiment materials to study the leaf development mechanism of solanaceous vegetable crops by using blot observation method. Results showed that an increasing trend was presented at the density of cells and stomata in upper and lower epidermis, but a declined trend was presented at the cells＇ diameters and the size of stomata with the joint position rising. At the same joint position, no matter in adaxial side or abaxial side, there were some differences among cells diameters, size of stomata, density of cells and stomata.
基金funded by the National Natural Science Foundation of China(41971038U20A2085+3 种基金32171559U21A2005)the Fundamental Research Funds of CAF(CAFYBB2020QB004CAFYBB2021ZW002)。
文摘Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).
基金supported by the Basic Scientific Research Fund of Heilongjiang Provincial Universities(2021-KYYWF-0050).
文摘The leaf-vein drip irrigation emitter is a new type of drip emitter based on a bionic structure able to support shunting,sharp turns,and increased dissipation.In the present work,the results of twenty-five tests executed in the framework of an orthogonal design strategy are presented in order to clarify the influence of the geometrical parameters of the flow channel on the hydraulic characteristics of such emitter.The corresponding flow index and head loss coefficient are determined through numerical simulations and model testing.The results show that the flow index of the flow channel is 0.4970∼0.5461,which corresponds to good hydraulic performances.The head loss coefficient of the flow channel is 572.74∼3933.05,which in turn indicates a good energy dissipation effect.The order of influence of the leaf vein flow channel parameters on the flow index can be represented in a synthetic way as a>b>c>d>e,where(a)is the width of the inlet,(b)is the horizontal distance of the front water inlet,(c)is the vertical distance of the inner edge of the front end,(d)is the horizontal distance of the rear water outlet and(e)is the vertical distance of the outer edge of the front end.The flow index increases with d,decreases with a,first decreases,and then increases with b,and first increases and then decreases with the increase of c and e.The coefficient(R^(2))of the fitted model related to geometric parameters and flow index is 0.9986-0.9999.The relative errors among experimental testing,simulation calculation and predictive estimates are shown to be less than 5%.
基金This work was supported by the Science and Technology Foundation of Guizhou Province[20181044]the Construction Program of Biology First-Class Disciplining Guizhou(GNYL[2017]009)the Young Scholars and Technology Talents Development Project of Guizhou Education Department KY(2018)124,and the Independent Subject Grant Open Project of the Key Laboratory of Mountain Plant Resources Conservation and Plantation Innovation of the Ministry of Education(Guizhou University).
文摘Duyun Maojian tea is a famous tea in China.In this study,the specific-locus amplified fragment(SLAF)sequencing method was used to analyze the population structure and conduct a genome-wide association study(GWAS)of 2 leaf traits of 123 tea plants in Qiannan,China.A total of 462,019 SLAF tags and 11,362,041 single-nucleotide polymorphism(SNP)loci were obtained.The results of phylogenetic tree analysis,cluster analysis,and principal component analysis showed that 123 tea germplasms were clustered into three groups,and the heterozygosity rates for Groups I,II,and II were 0.206,0.224,and 0.34,respectively.Generally,tea germplasms in a production area are clustered in a group,indicating that tea germplasms in different production areas have certain genetic diversity.The traditional Duyun Maojian tea core production areas,TS and DC-SJ,are clustered into Group I and Group II respectively,while the ZY production area is relatively independent in Group III.Furthermore,based on GWAS analysis,11 candidate genes related to leaf apex and 7 candidate genes related to leaf shape were obtained.This study clarified the genetic relationship among eight Duyun Maojian tea production areas and obtained candidate genes related to leaf apex and leaf shape development.The results showed that population structure and candidate genes are an effective basis for the breeding of Duyun Maojian tea germplasm.
