Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone ...Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone transport and rice growth and development remains unknown.In this study,we described OsNPF3.1 as an essential nitrate and phytohormone transporter gene for rice tillering and nitrogen utilization efficiency(NUtE).OsNPF3.1 possesses four major haplotypes of its promoter sequence in 517 cultivars,and its expression is positively associated with tiller number.Its expression was higher in the basal part,culm,and leaf blade than in other parts of the plant,and was strongly induced by nitrate,abscisic acid(ABA)and gibberellin 3(GA_3)in the root and shoot of rice.Electrophysiological experiments demonstrated that OsNPF3.1 is a pH-dependent low-affinity nitrate transporter,with rice protoplast uptake assays showing it to be an ABA and GA_3 transporter.OsNPF3.1 overexpression significantly promoted ABA accumulation in the roots and GA accumulation in the basal part of the plant which inhibited axillary bud outgrowth and rice tillering,especially at high nitrate concentrations.The NUtE of OsNPF3.1-overexpressing plants was enhanced under low and medium nitrate concentrations,whereas the NUtE of OsNPF3.1 clustered regularly interspaced short palindromic repeats(CRISPR)plants was increased under high nitrate concentrations.The results indicate that OsNPF3.1 transports nitrate and phytohormones in different rice tissues under different nitrate concentrations.The altered OsNPF3.1 expression improves NUtE in the OsNPF3.1-overexpressing and CRISPR lines at low and high nitrate concentrations,respectively.展开更多
Strengthening limonitic nickel laterite sintering and reducing CO_(2) emission were performed by the application of multiforce fields including external thermodynamic and pressure fields.Sinter pot tests of limonitic ...Strengthening limonitic nickel laterite sintering and reducing CO_(2) emission were performed by the application of multiforce fields including external thermodynamic and pressure fields.Sinter pot tests of limonitic nickel laterite were carried out,and the relevant industrial production was briefed.The chemistry and mineralogy of product sinter and the thermodynamic and kinetic conditions during sintering were analyzed to reveal the relevant mechanism.The results indicate that sintering performance of limonitic nickel laterite in the new sintering process with multi-force fields is significantly improved with tumble index and productivity increased by 24.11%and 18.56%,respectively,and solid fuel rate reduced by 23.21%,compared with those in traditional sintering process.In this case,greenhouse and pollutant gas emissions are greatly reduced,and metallurgical performances of product sinter are excellent.The industrial production has been successfully conducted,indicating a bright application prospect.Mechanism analysis shows that the great improvement of thermodynamic and kinetic conditions during sintering and the densification of loose sinter can be achieved via the application of multi-force fields.Sinter microstructure is transformed from large thin-wall pores to small thin-wall pores or medium thick-wall pores with the dramatic reduction of sinter porosity and more formation of silico-ferrite of calcium and alumina(SFCA).Meanwhile,the homogenization of mineral compositions is achieved,and much denser interlocking texture between hercynite and SFCA is formed.The application of multi-force fields contributes to the substantial improvement of sintering performance of limonitic nickel laterite and CO_(2) emission reduction.展开更多
Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops.Maize(Zea mays) is one of the most widely distributed crops worldwide.In China,althoug...Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops.Maize(Zea mays) is one of the most widely distributed crops worldwide.In China,although maize consumes a large amount of K fertilizer,the K uptake/utilization efficiency(KUE)of maize cultivars is relatively low.Elucidation of KUE mechanisms and development of maize cultivars with higher KUE are needed.Maize KUE is determined by K+uptake,transport,and remobilization,which depend on a variety of K+channels and transporters.We review basic information about K+channels and transporters in maize,their functions and regulation,and the roles of K+in nitrogen transport,sugar transport,and salt tolerance.We discuss challenges and prospects for maize KUE improvement.展开更多
Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to in...Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.展开更多
Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 pub...Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.展开更多
Electrical discharge milling(ED-milling) can be a good choice for titanium alloys machining and it was proven that its machining efficiency can be improved to compete with mechanical cutting. In order to improve energ...Electrical discharge milling(ED-milling) can be a good choice for titanium alloys machining and it was proven that its machining efficiency can be improved to compete with mechanical cutting. In order to improve energy utilization efficiency of ED-milling process, unstable arc discharge and stable arc discharge combined with normal discharge were implemented for material removal by adjusting servo control strategy. The influence of electrode rotating speed and dielectric flushing pressure on machining performance was investigated by experiments. It was found that the rotating of electrode could move the position of discharge plasma channel, and high pressure flushing could wash melted debris out the discharge gap effectively. Both electrode rotating motion and high pressure flushing are contributed to the improvement of machining efficiency.展开更多
This paper proposes cooperative adaptive control schemes for a train platoon to improve efficient utility and guarantee string stability. The control schemes are developed based on a bidirectional strategy, i.e., the ...This paper proposes cooperative adaptive control schemes for a train platoon to improve efficient utility and guarantee string stability. The control schemes are developed based on a bidirectional strategy, i.e., the information of proximal(preceding and following) trains is used in the controller design. Based on available proximal information(prox-info) of location, speed, and acceleration, a direct adaptive control is designed to maintain the tracking interval at the minimum safe distance. Based on available prox-info of location, an observer-based adaptive control is designed to achieve the same target, which alleviates the requirements of equipped sensors to measure prox-info of speed and acceleration. The developed schemes are capable of on-line estimating of the unknown system parameters and stabilizing the closed-loop system, the string stability of train platoon is guaranteed on the basis of Lyapunov stability theorem. Numerical simulation results are presented to verify the effectiveness of the proposed control laws.展开更多
Water shortage is increasingly an important factor limiting the sustainable development of global economy, posing a hugethreat to social security and human existence. Water usage in agriculture accounts for about 70% ...Water shortage is increasingly an important factor limiting the sustainable development of global economy, posing a hugethreat to social security and human existence. Water usage in agriculture accounts for about 70% of total water consumptionin the world, and rice cultivation is in turn the largest water user, which accounts for about 50% of total water usage inagriculture. Therefore, it is quite important to improve water utilization efficiency to reduce water consumption in rice.Water stress causes severe inhibition of plant growth and development as well as yield reduction, however the extent ofinhibition or reduction varies greatly with the growth stages, duration and severity of stress, and plant genotypes. In rice,drought resistance and water utilization efficiency might be improved by developing stress resistant cultivars and conductingproper agronomic practices. It is hence imperative to determine the suitable criteria in morphological and physiologicaltraits for drought resistance and water utilization efficiency in conventional breeding of rice. At present, leaf rolling, leafwater potential and carbon isotope discrimination are commonly used criteria for the evaluation and identification ofgermplasm with high drought resistance or water utilization efficiency. With rapid development of molecular biology,marker-assisted selection has been used in rice breeding against water stress. In this review, therefore, the agronomicaspect of water saving techniques such as selection of suitable rice cultivars, planting pattern, mulching, deficit irrigationand alternative drying and moist irrigation are discussed and effective approaches are also recommended.展开更多
China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency i...China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.展开更多
Four rainwater diversion patterns including undisturbed soil ditch (T1), slope compaction (T2), asbestos sheet covering after compac- tion (T3) and plastic film covering after compaction (T4) were set in cornf...Four rainwater diversion patterns including undisturbed soil ditch (T1), slope compaction (T2), asbestos sheet covering after compac- tion (T3) and plastic film covering after compaction (T4) were set in cornfield in arid areas of Yunnan Province, and effects of various patterns on rainwater collection efficiency, water utilization efficiency and corn yield were studied. The results shows that rainwater collection efficiency, water utilization efficiency and corn yield of the four diversion patterns presented the same trend, namely T4 〉T3 〉T2 〉T1. Overall, rainwater collection efficiencies of the four diversion patterns ranged from 41.7% to 58.7% ; compared with T1, water utilization efficiencies of T2 ,T3 and T4 increased by 34.9%, 53.5% and 92.5%, and maize yields of them improved by 1 767.0, 1 981.5 and 2 385.0 kg/hm2.展开更多
[Objectives]To systematically study the effects of different nitrogen levels on the growth and nitrogen utilization of sugarcane in Guangxi.[Methods]Through field experiment and indoor analysis,different nitrogen appl...[Objectives]To systematically study the effects of different nitrogen levels on the growth and nitrogen utilization of sugarcane in Guangxi.[Methods]Through field experiment and indoor analysis,different nitrogen application levels were set up to determine soil nitrogen content and sugarcane nitrogen content.The effects of different nitrogen levels on sugarcane yield,agronomic characters and nitrogen utilization were studied.[Results]The effect of nitrogen application rate on sugarcane yield showed a quadratic curve,and nitrogen application could significantly increase sugarcane yield,and the sugarcane yield reached the maximum when the nitrogen application rate reached 714 kg/ha.[Conclusions]With the increase of nitrogen application rate,sugarcane yield increased,but when it exceeded a certain range,the sugarcane yield decreased significantly.展开更多
Organic phosphorus(P) is an important component of the soil P pool, and it has been proven to be a potential source of P for plants. The phosphorus utilization efficiency(PUE) and PUE related traits(tiller number...Organic phosphorus(P) is an important component of the soil P pool, and it has been proven to be a potential source of P for plants. The phosphorus utilization efficiency(PUE) and PUE related traits(tiller number(TN), shoot dry weight(DW), and root dry weight) under different phytate-P conditions(low phytate-P, 0.05 mmol L^-1 and normal phytate-P, 0.5 mmol L^-1) were investigated using a population consisting of 128 recombinant inbred lines(RILs) at the vegetative stage in barley. The population was derived from a cross between a P-inefficient genotype(Baudin) and a P-efficient genotype(CN4027, a Hordeum spontaneum accession). A major locus(designated Qpue.sau-3 H) conferring PUE was detected in shoots and roots from the RIL population. The quantitative trait locus(QTL) was mapped on chromosome 3 H and the allele from CN4027 confers high PUE. This locus explained up to 30.3 and 28.4% of the phenotypic variance in shoots under low and normal phytate-P conditions, respectively. It also explains 28.3 and 30.7% of the phenotypic variation in root under the low and normal phytate-P conditions, respectively. Results from this study also showed that TN was not correlated with PUE, and a QTL controlling TN was detected on chromosome 5 H. However, dry weight(DW) was significantly and positively correlated with PUE, and a QTL controlling DW was detected near the Qpue.sau-3 H locus. Based on a covariance analysis, existing data indicated that, although DW may affect PUE, different genes at this locus are likely involved in controlling these two traits.展开更多
China is short of potassium resources, it only produces about 30 t of potash fertilizers per year. While China used about 650 t of potash fertilizer in 2000 by importing more than 95% of its potash fertilizers from Ca...China is short of potassium resources, it only produces about 30 t of potash fertilizers per year. While China used about 650 t of potash fertilizer in 2000 by importing more than 95% of its potash fertilizers from Canada or Europe. So, using varieties with high K utilization efficiency was very important.展开更多
In this study, four phosphorus-inefficient soybean genotypes (1903, 1305, D17 and D18) and four phosphorus-efficient soybean genotypes (D31, D34, D37 and D38 ) were selected as experimental materials for soil cult...In this study, four phosphorus-inefficient soybean genotypes (1903, 1305, D17 and D18) and four phosphorus-efficient soybean genotypes (D31, D34, D37 and D38 ) were selected as experimental materials for soil culture experiment under high and low phosphorus treatments, to investigate the grain yield, phosphorus content, phosphorus uptake and the relationship between phosphorus utilization efficiency and phosphorus efficiency of soybean genotypes with different phos- phorus efficiency in mature period. According to the experimental results, under low phosphorus treatment, four phosphorus-efficient soybean genotypes exhibited significantly high phosphorus uptake in mature period, especially for D31 and D37; however, three phosphorus-efficient genotypes showed no advantages in adapta- bility of phosphorus utilization efficiency, while only I)31 exhibited high phosphorus utilization and absorption capacity. Correlation analysis and path analysis showed that phosphorus deficiency of soybean was mainly detemained by phosphorus absorption capacity, and phosphorus deficiency under (-P) treatment was sig- nificandy higher than ( + P) treatment. Phosphorus uptake and phosphorus utilization efficiency posed great direct effects on phosphorus efficiency, and phosphorus uptake exhibited a greater contribution ; in addition, these two factors both posed small indirect effects. In mature period at reproductive growth stage, phosphorus absorption efficiency (phosphorus uptake) was the main variation source of phosphorus efficiency of various soybean genotypes in mature period. Therefore, strong phosphorus uptake and accumulation capacity of phosphorus-efficient soybean genotypes in mature period is an important nutrition foundation for the information of high grain yield.展开更多
On Nov.4th, AQSIQ (General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China), SAC (Standardization Administration of China), National Audit Office of China (CNAO), an...On Nov.4th, AQSIQ (General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China), SAC (Standardization Administration of China), National Audit Office of China (CNAO), and National Ministry of Finance of China jointly held the conference press on the national standard of Information Technology-Data Interface of Accounting Software (GB/T 19581-2004) in Beijing. The standard was approved and issued on Sept. 20, 2004 by AQSIQ and SAC, and it would come into effect all over the whole nation from January 1st, 2005.展开更多
In this study,a model of combined cooling,heating and power system with municipal solid waste(MSW)and liquefied natural gas(LNG)as energy sources was proposed and developed based on the energy demand of a large commun...In this study,a model of combined cooling,heating and power system with municipal solid waste(MSW)and liquefied natural gas(LNG)as energy sources was proposed and developed based on the energy demand of a large community,andMSW was classified and utilized.The systemoperated by determining power by heating load,and measures were taken to reduce operating costs by purchasing and selling LNG,natural gas(NG),cooling,heating,and power.Based on this system model,three operation strategies were proposed based on whether MSW was classified and the length of kitchen waste fermentation time,and each strategy was simulated hourly throughout the year.The results showed that the strategy of MSW classified and centralized fermentation of kitchen waste in summer(i.e.,strategy 3)required the least total amount of LNG for the whole year,which was 47701.77 t.In terms of total annual cost expenditure,strategy 3 had the best overall economy,with the lowest total annual expenditure of 2.7730×108 RMB at LNG and NG unit prices of 4 and 4.2 RMB/kg,respectively.The lower heating value of biogas produced by fermentation of kitchen waste from MSW being classified was higher than that of MSW before being classified,so the average annual thermal economy of the operating strategy of MSW being classified was better than that of MSW not being classified.Among the strategies in which MSW was classified and utilized,strategy 3 could better meet the load demand of users in the corresponding season,and thus this strategy had better thermal economy than the strategy of year-round fermentation of kitchen waste(i.e.,strategy 2).The hourly analysis data showed that the net electrical efficiency of the system varies in the same trend as the cooling,heating and power loads in all seasons,while the relationship between the energy utilization efficiency and load varied from season to season.This study can provide guidance for the practical application of MSW being classified in the system.展开更多
The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE an...The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE and promote local economic growth and conservation of water.This study uses 19 provinces and regions along the Yangtze River’s mainstream from 2009 to 2019 as its research objects and uses a Vector Auto Regression(VAR)model to quantitatively evaluate the spatiotemporal evolution of the coupling coordination degree(CCD)between the two subsystems of WUE and STI.The findings show that:(1)Both the WUE and STI in the Yangtze River Basin showed an upward trend during the study period,but the STI effectively lagged behind the WUE;(2)The CCD of the two subsystems generally showed an upward trend,and the CCD of each province was improved to varying degrees,but the majority of regions did not develop a high-quality coordination stage;(3)The CCD of the two systems displayed apparent positive spatial autocorrelation in the spatial correlation pattern,and there were only two types:high-high(H-H)urbanization areas and low-low(L-L)urbanization areas;(4)The STI showed no obvious response to the impact of the WUE,while the WUE responded greatly to the STI,and both of them were highly dependent on themselves.Optimizing their interaction mechanisms should be the primary focus of high-quality development in the basin of the Yangtze River in the future.These results give the government an empirical basis to enhance the WUE and promote regional sustainable development.展开更多
Quantitative information on the fate and efficiency of nitrogen (N) fertilizer applied to coarse textured calcareous soils in arid farming systems is scarce but, as systems intensify, is essential to support sustain...Quantitative information on the fate and efficiency of nitrogen (N) fertilizer applied to coarse textured calcareous soils in arid farming systems is scarce but, as systems intensify, is essential to support sustainable ag- ronomic management decisions. A mesh house study was undertaken to trace the fate of N fertilizer applied to cotton (Gossypium hirsutum L. cv., Huiyuan701) growing on a reconstructed profile (0-100 cm) of a calcareous (〉15% CaCQ) sandy loam soil. Two irrigation methods (drip irrigation, DI; and furrow irrigation, FI) and four N ap- plication rates (0, 240, 360 and 480 kg/hm2, abbreviated as No, N240, N360, and N480, respectively) were applied. 15N-labelled urea fertilizer was applied in a split application. DI enhanced the biomass of whole plant and all parts of the plant, except for root; more fertilizer N was taken up and mostly stored in vegetative parts; N utilization efficiency (NUE) was significantly greater than in FI. N utilization efficiency (NUE) decreased from 52.59% in N240 to 36.44% in N480. N residue in soil and plant N uptake increased with increased N dosage, but recovery rate decreased consis- tently both in DI and Fl. Plant N uptake and soil N residue were greater in DI than in FI. N residue mainly stayed within 0-40 cm depth in DI but within 40-80 cm depth in Ft. FI showed 17.89% of N leached out, but no N leaching occurred in DI. N recovery rate in the soil-plant system was 75.82% in DI, which was markedly greater than the 55.97% in FI. DI exhibited greater NUE, greater residual N in the soil profile and therefore greater N recovery rate than in FI; also, N distribution in soil profile shallowed in DI, resulting in a reduced risk of N leaching compared to FI; and enhanced shoot growth and reduced root growth in DI is beneficial for more economic yield formation. Com- pared to furrow irrigation, drip irrigation is an irrigation method where N movement favors the prevention of N from being lost in the plant-soil system and benefits a more efficient use of N.展开更多
In order to establish methods for indentification and screening of rice genotypes with high nitrogen (N) efficiency, N absorption efficiency (NAE), N utilization efficiency (NUE) and N harvest index (NHI) in t...In order to establish methods for indentification and screening of rice genotypes with high nitrogen (N) efficiency, N absorption efficiency (NAE), N utilization efficiency (NUE) and N harvest index (NHI) in ten rice genotypes were investgated at the elongation, booting, heading and maturity stages under six N levels in a pot experiment with soil-sand mixtures at various ratios. NAE in various rice genotypes firstly increased, peaked under a medium nitrogen rate of 0.177 g/kg and then decreased, but NUE and NHI always decreased with increasing nitrogen levels. NAE in various rice genotypes ever increased with growing process and NUE indicated a descending tendency of elongation stage〉heading stage〉maturity stage〉booting stage. N level influenced rice NAE, NUE and NHI most, followed by genotype, and the both effects were significant at 0.01 level. In addition, the interaction effects of genotype and nitrogen level on rice NAE and NUE were significant at 0.01 level, but not significant on rice NHI. Because the maximum differences of NAE and NUE were found at the elongation stage, it was thought to be the most suitable stage for identification and screening these two paremeters. Therefore, the optimum conditions for identification and screening of rice NAE, NUE and NHI in a pot experiment were the nitrogen rate of 0.157 g/kg at the elongation stage, low nitrogen at the elongation stage, and the nitrogen rate of 0.277 g/kg at the maturity stage, respectively.展开更多
As a specific type of acid phosphatses, phytases play diverse roles in plants by catalazing the degradation of phytic acid and its derivatives. In this study, a rice phytase gene referred to OsPHY1 has been functional...As a specific type of acid phosphatses, phytases play diverse roles in plants by catalazing the degradation of phytic acid and its derivatives. In this study, a rice phytase gene referred to OsPHY1 has been functionally characterized. OsPHY1 contains a 1 620 bp of open reading frame, encoding a 539-aa polypeptide. A conserve domain metallophosphatase (MPP) (MPP_PAPs), generally harbored in phytase and purple acid phosphatases (PAP), was identified in OsPHY1 (residue 194-398). Phylogenetic analysis revealed that OsPHY1 shares high similarities with phytase genes and PAP-type genes that derived from diverse plant species. The OsPHY1 transcripts were detected to be abundant in germinating seeds, suggesting that this gene plays potential roles on degradation of seed phytic acid and its derivatives during the germination process. Biochemical analysis confirmed that OsPHY1 possesses strong catalytic activities on phytic acid-Na2, with optimal temperature of 57°C and suitable pH of 3.5. Based on transgene analysis, the putative role of OsPHY1 in plants on utilization of phytate was assessed. Under the condition that phytic acid-Na2 was used as sole P source, the OsPHY1-overexpressing tobacco plants behaved higher phytase activities, higher concentrations of Pi, more accumulative amount of total phosphorus, and much more improved growth traits than those of the control plants. Therefore, OsPHY1 is acted as an important component on degradation of the phytins during the seed germination process in rice. Also, OsPHY1 has a potential use on generation of elite crop germplasms with improved use efficiencies on phytate and its derivatives.展开更多
基金supported by the the Guizhou Provincial Excellent Young Talents Project of Science and Technology,China(YQK(2023)002)the Guizhou Provincial Science and Technology Projects,China((2022)Key 008)+2 种基金the Guizhou Provincial Science and Technology Support Plan,China((2022)Key 026)the Key Laboratory of Molecular Breeding for Grain and Oil Crops in Guizhou Province,China((2023)008)the Key Laboratory of Functional Agriculture of Guizhou Provincial Higher Education Institutions,China((2023)007)。
文摘Low-affinity nitrate transporter genes have been identified in subfamilies 4-8 of the rice nitrate transporter 1(NRT1)/peptide transporter family(NPF),but the OsNPF3 subfamily responsible for nitrate and phytohormone transport and rice growth and development remains unknown.In this study,we described OsNPF3.1 as an essential nitrate and phytohormone transporter gene for rice tillering and nitrogen utilization efficiency(NUtE).OsNPF3.1 possesses four major haplotypes of its promoter sequence in 517 cultivars,and its expression is positively associated with tiller number.Its expression was higher in the basal part,culm,and leaf blade than in other parts of the plant,and was strongly induced by nitrate,abscisic acid(ABA)and gibberellin 3(GA_3)in the root and shoot of rice.Electrophysiological experiments demonstrated that OsNPF3.1 is a pH-dependent low-affinity nitrate transporter,with rice protoplast uptake assays showing it to be an ABA and GA_3 transporter.OsNPF3.1 overexpression significantly promoted ABA accumulation in the roots and GA accumulation in the basal part of the plant which inhibited axillary bud outgrowth and rice tillering,especially at high nitrate concentrations.The NUtE of OsNPF3.1-overexpressing plants was enhanced under low and medium nitrate concentrations,whereas the NUtE of OsNPF3.1 clustered regularly interspaced short palindromic repeats(CRISPR)plants was increased under high nitrate concentrations.The results indicate that OsNPF3.1 transports nitrate and phytohormones in different rice tissues under different nitrate concentrations.The altered OsNPF3.1 expression improves NUtE in the OsNPF3.1-overexpressing and CRISPR lines at low and high nitrate concentrations,respectively.
基金supports from the Youth Natural Science Foundation of China(No.51904347)Major Project of Master Alloy Manufacture for Heat Resistant Stainless Steel Production(No.AA18242003)funded by the Provincial Government of Guangxi Zhuang Autonomous District are sincerely acknowledged.
文摘Strengthening limonitic nickel laterite sintering and reducing CO_(2) emission were performed by the application of multiforce fields including external thermodynamic and pressure fields.Sinter pot tests of limonitic nickel laterite were carried out,and the relevant industrial production was briefed.The chemistry and mineralogy of product sinter and the thermodynamic and kinetic conditions during sintering were analyzed to reveal the relevant mechanism.The results indicate that sintering performance of limonitic nickel laterite in the new sintering process with multi-force fields is significantly improved with tumble index and productivity increased by 24.11%and 18.56%,respectively,and solid fuel rate reduced by 23.21%,compared with those in traditional sintering process.In this case,greenhouse and pollutant gas emissions are greatly reduced,and metallurgical performances of product sinter are excellent.The industrial production has been successfully conducted,indicating a bright application prospect.Mechanism analysis shows that the great improvement of thermodynamic and kinetic conditions during sintering and the densification of loose sinter can be achieved via the application of multi-force fields.Sinter microstructure is transformed from large thin-wall pores to small thin-wall pores or medium thick-wall pores with the dramatic reduction of sinter porosity and more formation of silico-ferrite of calcium and alumina(SFCA).Meanwhile,the homogenization of mineral compositions is achieved,and much denser interlocking texture between hercynite and SFCA is formed.The application of multi-force fields contributes to the substantial improvement of sintering performance of limonitic nickel laterite and CO_(2) emission reduction.
基金supported by the National Key Research and Development Program of China (2021YFF1000500)National Natural Science Foundation of China (32025004, 32161133014, and31921001)Beijing Outstanding University Discipline Program。
文摘Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops.Maize(Zea mays) is one of the most widely distributed crops worldwide.In China,although maize consumes a large amount of K fertilizer,the K uptake/utilization efficiency(KUE)of maize cultivars is relatively low.Elucidation of KUE mechanisms and development of maize cultivars with higher KUE are needed.Maize KUE is determined by K+uptake,transport,and remobilization,which depend on a variety of K+channels and transporters.We review basic information about K+channels and transporters in maize,their functions and regulation,and the roles of K+in nitrogen transport,sugar transport,and salt tolerance.We discuss challenges and prospects for maize KUE improvement.
基金the Key Program for International S&T Cooperation Projects of China(2022YFE0130100)Central Public-interest Scientific Institution Basal Research Fund of Chinese Academy of Agricultural Sciences(Y2022GH12).
文摘Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.
基金supported by the National Key Research and Development Program of China(2016YFD0300100)the Innovation Program of Chinese Academy of Agricultural Sciencesthe Elite Youth Program of the Chinese Academy of Agricultural Science。
文摘Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.
基金Project(MSV-2013-09)supported by State Key Laboratory of Mechanical System and Vibration,China
文摘Electrical discharge milling(ED-milling) can be a good choice for titanium alloys machining and it was proven that its machining efficiency can be improved to compete with mechanical cutting. In order to improve energy utilization efficiency of ED-milling process, unstable arc discharge and stable arc discharge combined with normal discharge were implemented for material removal by adjusting servo control strategy. The influence of electrode rotating speed and dielectric flushing pressure on machining performance was investigated by experiments. It was found that the rotating of electrode could move the position of discharge plasma channel, and high pressure flushing could wash melted debris out the discharge gap effectively. Both electrode rotating motion and high pressure flushing are contributed to the improvement of machining efficiency.
基金Project supported by the Beijing Jiaotong University Research Program,China(Grant No.RCS2014ZT18)the Fundamental Research Funds for Central Universities,China(Grant No.2015JBZ007)the National Natural Science Foundation of China(Grant Nos.61233001,61322307,and 61304196)
文摘This paper proposes cooperative adaptive control schemes for a train platoon to improve efficient utility and guarantee string stability. The control schemes are developed based on a bidirectional strategy, i.e., the information of proximal(preceding and following) trains is used in the controller design. Based on available proximal information(prox-info) of location, speed, and acceleration, a direct adaptive control is designed to maintain the tracking interval at the minimum safe distance. Based on available prox-info of location, an observer-based adaptive control is designed to achieve the same target, which alleviates the requirements of equipped sensors to measure prox-info of speed and acceleration. The developed schemes are capable of on-line estimating of the unknown system parameters and stabilizing the closed-loop system, the string stability of train platoon is guaranteed on the basis of Lyapunov stability theorem. Numerical simulation results are presented to verify the effectiveness of the proposed control laws.
文摘Water shortage is increasingly an important factor limiting the sustainable development of global economy, posing a hugethreat to social security and human existence. Water usage in agriculture accounts for about 70% of total water consumptionin the world, and rice cultivation is in turn the largest water user, which accounts for about 50% of total water usage inagriculture. Therefore, it is quite important to improve water utilization efficiency to reduce water consumption in rice.Water stress causes severe inhibition of plant growth and development as well as yield reduction, however the extent ofinhibition or reduction varies greatly with the growth stages, duration and severity of stress, and plant genotypes. In rice,drought resistance and water utilization efficiency might be improved by developing stress resistant cultivars and conductingproper agronomic practices. It is hence imperative to determine the suitable criteria in morphological and physiologicaltraits for drought resistance and water utilization efficiency in conventional breeding of rice. At present, leaf rolling, leafwater potential and carbon isotope discrimination are commonly used criteria for the evaluation and identification ofgermplasm with high drought resistance or water utilization efficiency. With rapid development of molecular biology,marker-assisted selection has been used in rice breeding against water stress. In this review, therefore, the agronomicaspect of water saving techniques such as selection of suitable rice cultivars, planting pattern, mulching, deficit irrigationand alternative drying and moist irrigation are discussed and effective approaches are also recommended.
文摘China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.
基金Supported by the National Key Technology R&D Program(2012BAD40B02)
文摘Four rainwater diversion patterns including undisturbed soil ditch (T1), slope compaction (T2), asbestos sheet covering after compac- tion (T3) and plastic film covering after compaction (T4) were set in cornfield in arid areas of Yunnan Province, and effects of various patterns on rainwater collection efficiency, water utilization efficiency and corn yield were studied. The results shows that rainwater collection efficiency, water utilization efficiency and corn yield of the four diversion patterns presented the same trend, namely T4 〉T3 〉T2 〉T1. Overall, rainwater collection efficiencies of the four diversion patterns ranged from 41.7% to 58.7% ; compared with T1, water utilization efficiencies of T2 ,T3 and T4 increased by 34.9%, 53.5% and 92.5%, and maize yields of them improved by 1 767.0, 1 981.5 and 2 385.0 kg/hm2.
基金Guangxi Key R&D Program(GuiKe AB18221027)Guangxi Natural Science Foundation(2018GXNSFAA281027)Basic Scientific Research Program of Guangxi Academy of Agricultural Sciences(2020YM110,2021YT036).
文摘[Objectives]To systematically study the effects of different nitrogen levels on the growth and nitrogen utilization of sugarcane in Guangxi.[Methods]Through field experiment and indoor analysis,different nitrogen application levels were set up to determine soil nitrogen content and sugarcane nitrogen content.The effects of different nitrogen levels on sugarcane yield,agronomic characters and nitrogen utilization were studied.[Results]The effect of nitrogen application rate on sugarcane yield showed a quadratic curve,and nitrogen application could significantly increase sugarcane yield,and the sugarcane yield reached the maximum when the nitrogen application rate reached 714 kg/ha.[Conclusions]With the increase of nitrogen application rate,sugarcane yield increased,but when it exceeded a certain range,the sugarcane yield decreased significantly.
基金supported by the National Natural Science Foundation of China (31401377)the Science and Technology Project of Sichuan Province, China (2017JY0126)the Key Project of Education Department of Sichuan Province, China (14ZA0002)
文摘Organic phosphorus(P) is an important component of the soil P pool, and it has been proven to be a potential source of P for plants. The phosphorus utilization efficiency(PUE) and PUE related traits(tiller number(TN), shoot dry weight(DW), and root dry weight) under different phytate-P conditions(low phytate-P, 0.05 mmol L^-1 and normal phytate-P, 0.5 mmol L^-1) were investigated using a population consisting of 128 recombinant inbred lines(RILs) at the vegetative stage in barley. The population was derived from a cross between a P-inefficient genotype(Baudin) and a P-efficient genotype(CN4027, a Hordeum spontaneum accession). A major locus(designated Qpue.sau-3 H) conferring PUE was detected in shoots and roots from the RIL population. The quantitative trait locus(QTL) was mapped on chromosome 3 H and the allele from CN4027 confers high PUE. This locus explained up to 30.3 and 28.4% of the phenotypic variance in shoots under low and normal phytate-P conditions, respectively. It also explains 28.3 and 30.7% of the phenotypic variation in root under the low and normal phytate-P conditions, respectively. Results from this study also showed that TN was not correlated with PUE, and a QTL controlling TN was detected on chromosome 5 H. However, dry weight(DW) was significantly and positively correlated with PUE, and a QTL controlling DW was detected near the Qpue.sau-3 H locus. Based on a covariance analysis, existing data indicated that, although DW may affect PUE, different genes at this locus are likely involved in controlling these two traits.
文摘China is short of potassium resources, it only produces about 30 t of potash fertilizers per year. While China used about 650 t of potash fertilizer in 2000 by importing more than 95% of its potash fertilizers from Canada or Europe. So, using varieties with high K utilization efficiency was very important.
基金Supported by Doctoral Scientific Research Start-up Project of Mudanjiang Normal University(MSB200912)Provincial Key Pre-research Project of Mudanjiang Normal University(SY2014010)Teaching Reform Project of Mudanjiang Normal University(2013JGZX0074)
文摘In this study, four phosphorus-inefficient soybean genotypes (1903, 1305, D17 and D18) and four phosphorus-efficient soybean genotypes (D31, D34, D37 and D38 ) were selected as experimental materials for soil culture experiment under high and low phosphorus treatments, to investigate the grain yield, phosphorus content, phosphorus uptake and the relationship between phosphorus utilization efficiency and phosphorus efficiency of soybean genotypes with different phos- phorus efficiency in mature period. According to the experimental results, under low phosphorus treatment, four phosphorus-efficient soybean genotypes exhibited significantly high phosphorus uptake in mature period, especially for D31 and D37; however, three phosphorus-efficient genotypes showed no advantages in adapta- bility of phosphorus utilization efficiency, while only I)31 exhibited high phosphorus utilization and absorption capacity. Correlation analysis and path analysis showed that phosphorus deficiency of soybean was mainly detemained by phosphorus absorption capacity, and phosphorus deficiency under (-P) treatment was sig- nificandy higher than ( + P) treatment. Phosphorus uptake and phosphorus utilization efficiency posed great direct effects on phosphorus efficiency, and phosphorus uptake exhibited a greater contribution ; in addition, these two factors both posed small indirect effects. In mature period at reproductive growth stage, phosphorus absorption efficiency (phosphorus uptake) was the main variation source of phosphorus efficiency of various soybean genotypes in mature period. Therefore, strong phosphorus uptake and accumulation capacity of phosphorus-efficient soybean genotypes in mature period is an important nutrition foundation for the information of high grain yield.
文摘On Nov.4th, AQSIQ (General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China), SAC (Standardization Administration of China), National Audit Office of China (CNAO), and National Ministry of Finance of China jointly held the conference press on the national standard of Information Technology-Data Interface of Accounting Software (GB/T 19581-2004) in Beijing. The standard was approved and issued on Sept. 20, 2004 by AQSIQ and SAC, and it would come into effect all over the whole nation from January 1st, 2005.
基金support provided by the Nature Science Foundation of Shandong Province(ZR201709180049)the Shandong Key Research and Development Program(2019GSF109023).
文摘In this study,a model of combined cooling,heating and power system with municipal solid waste(MSW)and liquefied natural gas(LNG)as energy sources was proposed and developed based on the energy demand of a large community,andMSW was classified and utilized.The systemoperated by determining power by heating load,and measures were taken to reduce operating costs by purchasing and selling LNG,natural gas(NG),cooling,heating,and power.Based on this system model,three operation strategies were proposed based on whether MSW was classified and the length of kitchen waste fermentation time,and each strategy was simulated hourly throughout the year.The results showed that the strategy of MSW classified and centralized fermentation of kitchen waste in summer(i.e.,strategy 3)required the least total amount of LNG for the whole year,which was 47701.77 t.In terms of total annual cost expenditure,strategy 3 had the best overall economy,with the lowest total annual expenditure of 2.7730×108 RMB at LNG and NG unit prices of 4 and 4.2 RMB/kg,respectively.The lower heating value of biogas produced by fermentation of kitchen waste from MSW being classified was higher than that of MSW before being classified,so the average annual thermal economy of the operating strategy of MSW being classified was better than that of MSW not being classified.Among the strategies in which MSW was classified and utilized,strategy 3 could better meet the load demand of users in the corresponding season,and thus this strategy had better thermal economy than the strategy of year-round fermentation of kitchen waste(i.e.,strategy 2).The hourly analysis data showed that the net electrical efficiency of the system varies in the same trend as the cooling,heating and power loads in all seasons,while the relationship between the energy utilization efficiency and load varied from season to season.This study can provide guidance for the practical application of MSW being classified in the system.
基金funded by the Humanities and Social Science Research Project of Chongqing Education Commission(23SKJD111)Science and Technology Research Project of Chongqing Education Commission(KJQN202101122 and KJQN201904002)+6 种基金Project of Chongqing Higher Education Association(CQGJ21B057)Chongqing Graduate Education Teaching Reform Research Project(yjg223121)Chongqing Higher Education Teaching Reform Research Project(233337)Higher Education Research Project,Chongqing University of Technology(2022ZD01)Annual project of the“14th Five-Year Plan”for National Business Education in 2022(SKKT-22015)Party Building and Ideological and Political Project,Chongqing University of Technology(2022DJ307)Chongqing University of Technology Undergraduate Education and Teaching Reform Research Project(2021YB21).
文摘The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE and promote local economic growth and conservation of water.This study uses 19 provinces and regions along the Yangtze River’s mainstream from 2009 to 2019 as its research objects and uses a Vector Auto Regression(VAR)model to quantitatively evaluate the spatiotemporal evolution of the coupling coordination degree(CCD)between the two subsystems of WUE and STI.The findings show that:(1)Both the WUE and STI in the Yangtze River Basin showed an upward trend during the study period,but the STI effectively lagged behind the WUE;(2)The CCD of the two subsystems generally showed an upward trend,and the CCD of each province was improved to varying degrees,but the majority of regions did not develop a high-quality coordination stage;(3)The CCD of the two systems displayed apparent positive spatial autocorrelation in the spatial correlation pattern,and there were only two types:high-high(H-H)urbanization areas and low-low(L-L)urbanization areas;(4)The STI showed no obvious response to the impact of the WUE,while the WUE responded greatly to the STI,and both of them were highly dependent on themselves.Optimizing their interaction mechanisms should be the primary focus of high-quality development in the basin of the Yangtze River in the future.These results give the government an empirical basis to enhance the WUE and promote regional sustainable development.
基金financed by the Special Fund for Agro-scientific Research in the Public Interest (201103003)the National Natural Science Foundation of China (31060276)the National High Technology Research and Development Program of China (2011AA100508)
文摘Quantitative information on the fate and efficiency of nitrogen (N) fertilizer applied to coarse textured calcareous soils in arid farming systems is scarce but, as systems intensify, is essential to support sustainable ag- ronomic management decisions. A mesh house study was undertaken to trace the fate of N fertilizer applied to cotton (Gossypium hirsutum L. cv., Huiyuan701) growing on a reconstructed profile (0-100 cm) of a calcareous (〉15% CaCQ) sandy loam soil. Two irrigation methods (drip irrigation, DI; and furrow irrigation, FI) and four N ap- plication rates (0, 240, 360 and 480 kg/hm2, abbreviated as No, N240, N360, and N480, respectively) were applied. 15N-labelled urea fertilizer was applied in a split application. DI enhanced the biomass of whole plant and all parts of the plant, except for root; more fertilizer N was taken up and mostly stored in vegetative parts; N utilization efficiency (NUE) was significantly greater than in FI. N utilization efficiency (NUE) decreased from 52.59% in N240 to 36.44% in N480. N residue in soil and plant N uptake increased with increased N dosage, but recovery rate decreased consis- tently both in DI and Fl. Plant N uptake and soil N residue were greater in DI than in FI. N residue mainly stayed within 0-40 cm depth in DI but within 40-80 cm depth in Ft. FI showed 17.89% of N leached out, but no N leaching occurred in DI. N recovery rate in the soil-plant system was 75.82% in DI, which was markedly greater than the 55.97% in FI. DI exhibited greater NUE, greater residual N in the soil profile and therefore greater N recovery rate than in FI; also, N distribution in soil profile shallowed in DI, resulting in a reduced risk of N leaching compared to FI; and enhanced shoot growth and reduced root growth in DI is beneficial for more economic yield formation. Com- pared to furrow irrigation, drip irrigation is an irrigation method where N movement favors the prevention of N from being lost in the plant-soil system and benefits a more efficient use of N.
基金supported by the National High-Tech Research&Development program(Grant No.2003AA206030)the National Natural Science Foundation of China(Grant No.30030090)
文摘In order to establish methods for indentification and screening of rice genotypes with high nitrogen (N) efficiency, N absorption efficiency (NAE), N utilization efficiency (NUE) and N harvest index (NHI) in ten rice genotypes were investgated at the elongation, booting, heading and maturity stages under six N levels in a pot experiment with soil-sand mixtures at various ratios. NAE in various rice genotypes firstly increased, peaked under a medium nitrogen rate of 0.177 g/kg and then decreased, but NUE and NHI always decreased with increasing nitrogen levels. NAE in various rice genotypes ever increased with growing process and NUE indicated a descending tendency of elongation stage〉heading stage〉maturity stage〉booting stage. N level influenced rice NAE, NUE and NHI most, followed by genotype, and the both effects were significant at 0.01 level. In addition, the interaction effects of genotype and nitrogen level on rice NAE and NUE were significant at 0.01 level, but not significant on rice NHI. Because the maximum differences of NAE and NUE were found at the elongation stage, it was thought to be the most suitable stage for identification and screening these two paremeters. Therefore, the optimum conditions for identification and screening of rice NAE, NUE and NHI in a pot experiment were the nitrogen rate of 0.157 g/kg at the elongation stage, low nitrogen at the elongation stage, and the nitrogen rate of 0.277 g/kg at the maturity stage, respectively.
基金supported by the National Natural Science Foundation of China (30871466)and the Key Laboratory of Crop Growth Regulation of Hebei Province, China
文摘As a specific type of acid phosphatses, phytases play diverse roles in plants by catalazing the degradation of phytic acid and its derivatives. In this study, a rice phytase gene referred to OsPHY1 has been functionally characterized. OsPHY1 contains a 1 620 bp of open reading frame, encoding a 539-aa polypeptide. A conserve domain metallophosphatase (MPP) (MPP_PAPs), generally harbored in phytase and purple acid phosphatases (PAP), was identified in OsPHY1 (residue 194-398). Phylogenetic analysis revealed that OsPHY1 shares high similarities with phytase genes and PAP-type genes that derived from diverse plant species. The OsPHY1 transcripts were detected to be abundant in germinating seeds, suggesting that this gene plays potential roles on degradation of seed phytic acid and its derivatives during the germination process. Biochemical analysis confirmed that OsPHY1 possesses strong catalytic activities on phytic acid-Na2, with optimal temperature of 57°C and suitable pH of 3.5. Based on transgene analysis, the putative role of OsPHY1 in plants on utilization of phytate was assessed. Under the condition that phytic acid-Na2 was used as sole P source, the OsPHY1-overexpressing tobacco plants behaved higher phytase activities, higher concentrations of Pi, more accumulative amount of total phosphorus, and much more improved growth traits than those of the control plants. Therefore, OsPHY1 is acted as an important component on degradation of the phytins during the seed germination process in rice. Also, OsPHY1 has a potential use on generation of elite crop germplasms with improved use efficiencies on phytate and its derivatives.