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- Abstract：Selectable marker genes have been extraordinarily useful in genetic transformation of plants.Currently,the most frequently used selectable marker genes are antibiotic or herbicide resistance genes,which are being increasingly concerned on the safety issues of transgenic plants.In this paper,methods and applications for the cultivation of marker-free transgenic plants were reviewed,including co-transformation,site-specific recombination,transposable system,homologous recombination and multi-auto transformation system.The "pros" and "cons" of these approaches were also discussed with a view to promote the industrialization process of transgenic plants.Keywords：transgenic plants;selectable marker genes;co-transformation;site-specific recombination;transposition5|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Despite the various technologies in place for GMC test,a robostic method is highly demanded.The technology described here represents a breakthrough development in that direction.Aimming to nos/plamid gene of four GMCs(RRS,Bt11,GA21,NK603),by combining the multiple PCR with pyrosequencing,we developed a rapid assay for genotyping nos/plamid that relies on the identification of a single,type-specific ‘sentinel’ base.The prototype assay was developed to recognize the four GMCs and was capable of recognizing simultaneously multiple GMCs infections.The studies established a rapid,reliable and cost-effective assay.Keywords：GMCs;multiple PCR;pyrosequencing;Special-Base;nos/plamid5|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Establishment of high efficiency Agrobacterium-mediated transgenic techniques has greatly accelerated the widespread application of transgene in rice.It was very important to improve the salt-tolerance.In this study,the ORF of vacuolar Na+/H+ antiporter gene was transferred into nipponbare via Agrobacterium-madiated method.The transformed plants were verified by PCR,over expression of AlNHX in rice conferred high salt tolerance to the transgenic plants.The transgenic plants could survive in the medium containing up to 200 mmol/L NaCl for 15 days,while the wild-type plants failed to grow higher than 150 mmol/L NaCl.3|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Lipid transfer proteins(LTPs) have the ability to transfer phospholipids between donor and acceptor on the membrane of advanced plants.LTPs are important in the membrane forming in cells and related to the resistance to the extremely environment.In order to investigate the function of LTP(blt14.2)in the hulless barley,the cDNA encoding blt14.2 was cloned from "KunLun12" by RT-PCR.The full length of cDNA is 470 bp encoding a protein with 82 amino acids.It was a stable protein with the molecular weight of 7 709.8,theoretical pI 6.52,and coefficient of instability 27.36.LTPs have two transmembrane domains,within the position of 1-19 aa (from inside to outside) and 57-76 aa (from outside to inside).The protein is a small and highly hydrophilic protein with the average hydrophilicity of 0.522.The sequence is very similar to the gene from barley (Hordeum vulgare L.) with the homology of 98.9%.Result from the Real-time PCR showed that the expression level of blt14.2 were increased to 8.3,13.6 and 14.6 times comapred with control respectively,after the plant under 4 ℃,for 12,24 and 48 h.The results proved the expression of blt14.2 gene changed remarkably under different time of cold stress,and played a role on cold tolerance of hulless barley.Keywords：hulless barley;blt14.2;gene;clone;gene expression2|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The study for developing a high-yield model of hybrid wheat was carried out by using the principle of agricultural ecology and the qualified design of three factor square saturated D,in which the factors of sowing date (x1),sowing quantity (x2) and amount of fertilizer application (x3) were taken as the adjusting factors,and the yield per hectare (y) as target function,through which a mathematical model for high yield cultivation of hybrid wheat was obtained.The result indicated that under the condition of experiment design the factors affecting hybrid wheat yield were in sequence of amount of fertilizer application x3,sowing quantity x2,and sowing date x1;when the target yield was from 7 500~9 000 kg/hm2,the optimum formula of hybrid wheat was as follows:fertilizer application x3 of 208.24~301.88 kg/hm2(m(N):m(P2O5)=1:1),sowing quantity x2 of 218 2.8~301 2.9×104 seed/hm2 and sowing date x1 from 4 to 19 October.Keywords：hybrid wheat;yield;mathematical model;agronomic form2|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to investigate the results of UV-B radiation on the accumulation of proteins in wheat seeding leaves,the cultivar LiaoDa 1 was subjected to UV-B radiation stress.Compared with control samples,the UV-B radiation stressed samples accumulated significantly higher amounts of protein.These proteins were separated by two-dimensional electrophoresis (2-DE),visualized by silver staining and analyzed by Image Master.It revealed 15 differentially expressed polypeptides,6 of which were successful identified by MALDI-TOF,including a Rubisco large subunit,an ATP synthase CF1 alpha chain,proteins involved in protein translation and transportation.These results might provide information for further UV-B radiation stress study in wheat.Keywords：wheat;seeding leaf;UV-B radiation;proteome;2-DE1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Enhancing the drought tolerance of rice variety is an important technology and strategy to food safety of China.Improvement and innovation of rice drought tolerance index is the key to improve drought tolerance rice variety and breeding technology.In this research,different rice varieties were used to identify physiological traits associated with drought tolerance.The major traits were leaf water pressure potential,leaf midrib coarse,mesophyll thickness and relative water content,the difference between typical rice and the other rice type under drought environment.Difference between two treatments of drought and flooded was studied.Correlation between tested traits and yield drought resistant index,booting stage biomass drought resistant index,harvest stage biomass drought resistant index was analysed.The result showed that leaf water pressure potential,leaf midrib coarse,mesophyll thickness and relative water content could be used as index for drought tolerance identification in rice,though this method could miss some drought tolerant materials.The leaf water pressure potential,mesophyll thickness were correlated with dry matter production and accumulation,and consequently with the final yield.Therefore,the leaf water pressure potential,leaf midrib coarse was recommended as main index,complemented with other index in rice breeding for drought tolerance.Keywords：rice;drought tolerance;physiological index;breeding4|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analyze the cause of yield gap and the yield gap limiting factors of winter wheat,and then to explore scientific measures to narrow the yield gap,this research studied the yield gap of wheat between different farmlands by household survey and participatory evaluation.The results showed that the yield difference between different farmlands was obvious,the gap between high yield farmland and low yield farmland was 3 375 kg/hm2,and the gap between high yield farmland and average yield farmland was 1 754 kg/hm2,and it is clear that there’s large room for the low and medium yield farmlands to improve yield.The impact of yield gap limiting factors was described by analyzing the factors surveyed.Soil fertility,fertilizer input,tillage,irrigation,pest and disease control were the major limiting factors for the yield gap between different farmlands.As far as the composition of production input of winter wheat was concered,fertilizer inputs accounted for the largest proportion,and fertilizer inputs between different incomes showed a significant difference,but the mechanical,pesticides,seeds and irrigation have little difference.Once the input exceeded a threshold,the profit would show diminishing returns to input.For example the biggest benefit cost ratio was 4.02 when the input was 4 102.5 yuan/hm2.Strengthening the balanced fertilization and improving the use of cultivation were the important way to narrow the yield gap at farmland scale.Keywords：wheat;yield gap;yield limiting factors;Wuqiao4|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This study determined the carbon input,carbon output and its efficiency for the main cropping systems in Beijing with the input-output method.The results showed that emissions from the fertilizers and electricity accounted for 70%~90% of the total emissions.Of which,the vegetable crops had higher carbon input than other crops,and the vegetables with facility system heightened its carbon input by 80.4%,92.0%,94.3% compared with wheat-maize system,spring maize monoculture system,peanut monoculture system,respectively.And there were no significant differences among these three traditional systems.As for the advanced field management and higher resource utilization rate,the spring maize was the most carbon efficienct crop with a carbon efficiency of 4.59;and the spring maize monoculture system heightened its carbon efficiency by 30.8%,8.31%,and 96.8% compared with wheat-maize pattern,peanut monoculture pattern,facilities vegetables pattern,respectively.The spring maize in Beijing could low carbon emissions from farming system.Keywords：crop;cropping system;input-output;carbon efficiency0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This paper is on the effect of fertilization on the water consumption and use efficiency for potato from the experiments of farmland in WuChuan County,Inner Mongolia,so as to provide a scientific basis for sustainable development and eco-regional agricultural building.It is shown that with the increase of fertilizer,water consumption increased,But it decreased when the fertilizer reached to a certain degree.In rainy years,production and water consumption were high,but in dry years they were low.The relationship between potato yield and water consumption is logarithmic.Considering the production and water use efficiency,in rainy years,the middle-fertilizer treatment is appropriate and low fertilizer in dry years and low or middle fertilizer in normal years.It indicates that agricultural production should be based on different levels of precipitation.So from moderate fertilization on potato fields,it would ensure production and section water conservation.Keywords：potato;dry land;fertility levels;water consumption;water use efficiency2|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The effects of water stress (the relative water contents were 80%,60% and 40% respectively) on growth and biomass quality of switchgrass (Panicum virgatum L.) were studied using three cultivars,namely Alamo,Cave-in-Rock and Bay Canada,in pots with soil from marginal land of sand with gravel in greenhouse.It showed that all the plant height,tiller number and biomass accumulation were decreased with the increase of the intensity of water stress;whereas the root/shoot ratio was increased.The net photosynthetic rate,stomatal conductance,intercellular CO2 concentration and transpiration rate were lowered significantly under water stress.Water stress reduced significantly the concentrations of cellulose and hemicellulose and the gross caloric values;while increased the lignin concentration.Three cultivas showed different responses to water stress.When concerned growth,net photosynthetic rate,water use efficiency and dry biomass accumulation in this experiment,Alamo was better than Bay Canada and Cave-in-Rock.Keywords：switchgrass;water stress;marginal land;biomass1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To fasten energy conversion of lignocellulosic biomass,we used the switchgrass as the substrate to screen the microbial community which could produce hydrolysis enzymes.By the continuous enrichment,a community was obtained.The characteristics to produce enzymes and microbial diversity of the community were mainly investigated.During the fourteen-day liquid cultivation the dry weight loss drastically occurred at the first four days and amounted to 70% of the total loss.14 days after liquid cultivation,the degradation rate of the cellulose and hemicellulose amounted to 50% and 60%,respectively,and higher CMCase and xylanase activity were both detected in the liquid cultivation system.The highest values for the CMCase activity and xylanase activity during the cultivation reached 0.21 and 3.75 IU,respectively.The investigations on the enzyme characteristics indicated that the optimal pH for CMCase was 5.0 and that for xylanase was 6.0.The optimal reaction temperature of CMCase and xylanase was 60 ℃.The results from the cloning libraries showed that the relative species of most bacteria was Achromobacter xylosoxidans and the relative species of most fungi was Fusarium sporotrichioides.Keywords：switchgrass;microbial community;cellulase;xylanase;clone library0|5|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：It is very important to discriminate wheat stripe rust and wheat leaf rust quickly and accurately for forecast and integrated management of the diseases.In this study, a new method based on supporting vector machine (SVM) and multiple feature parameters of their images was proposed for recognition of two kinds of wheat rusts.Sub-images of visual symptoms were acquired using image cutting.The image de-noising was performed with median filtering.The diseased region was then segmented by K_means clustering algorithm.Fifty feature parameters from shape-related,color-related and texture-related features were extracted as inputs of the SVMs to identify the best classification model.The results showed that,using the SVMs with radial basis function (RBF) kernel based on the selected twenty-six features,the recognition rates of wheat stripe rust and wheat leaf rust were both 96.67% for the training sets,and 100% for the tested sets,It was thus evident that RBF kernel function was the most suitable method for image recognition of these two kinds of wheat rusts.The image recognition method based on SVM and multiple features could successfully discriminate wheat stripe rust from wheat leaf rust.Keywords：wheat stripe rust;wheat leaf rust;support vector machine;image recognition;feature extraction;kernel function10|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Both rootstock SH40,Malus micromalus and scion-rootstock combinations Fuji/SH40/Malus micromalus,Fuji/Malus micromalus were used as the materials in this experiment,Both IAA and ABA were measured by HPLC in the bark of different materials.qRT-PCR (quantitative realtime PCR) were also used to search for the difference of expression of pin1 gene.Our aim was to explore the relationship between the content of hormone,the expression of pin1 gene and the possible dwarfing factors of SH40 as the interstock of apple.The results showed that the ratio of ABA/IAA was remarkable higher in the dwarf trees than the vigorous controls.In graft combination Fuji/SH40/Malus micromalus,the content of IAA in the bark of the interstock was much lower than the scion,which might be due to the significant lower expression of IAA-transporting protein gene pin1 in the bark of the interstock.Keywords：apple;rootstock;SH40;dwarfing;IAA;ABA;pin1;gene0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In this paper,‘Red coral’ peach was used for detecting the effects of DA-6 on net photosynthesis,activities of Rubisco and FBPase and fruit quality in greenhouse.The results indicated that 20 mg/L DA-6 significantly increased net photosynthesis rate(Pn) stomatal conductance (Gs) transpiration rate(Tr) chlorophyll contents and the activities of Rubisco and FBPase.Both Pn and Gs increased by 25.38%and 12.85% at most respectively.The ratio of soluble solid content to titrable acid increased by almost 8.68.Our results may imply that DA-6 regulates the activity of net photosynthesis rate through stomatal limitation and activity of enzymes related to photosynthesis,and improves fruit quality by either increasing the single fruit weight and content of soluble solid, or decreasing the content of titratable acid.Keywords：DA-6;greenhouse;peach;photosynthesis;fruit quality1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to improve the detection reliability,grapevine leaves with typical leafroll symptom originated from Huailai region in Hebei and Xingcheng region in Liaoning Province were detected for GLRaV-1 by RT-PCR.The complete sequences of coat protein (CP) gene of GLRaV-1-HB and GLRaV-1-LN isolates were amplified.Sequence comparisons revealed that GLRaV-1-HB and GLRaV-1-LN shared 90.7% and 93.8% identities at nucleotide and amino acid levels,respectively. In contrast with the reported 3 foreign isolates,the identities of nucleotide sequence and deduced amino acid sequence ranged from 90.0% to 96.0% and 92.9% to 97.5%,respectively.The phylogenetic tree from alignments of CP nucleotide sequences of 5 GLRaV-1 isolates revealed the existence of three well-defined clusters.GLRaV-1-HB showed a close relationship with Isolate PS from Brazil (GLRaV-1-PS,GenBank accession number GQ332536.1),while GLRaV-1-LN and Isolate IR-S7 from Iran(GLRaV-1-IR-S7,FJ952151.2)clustered together.An Australia Isolate(GLRaV-1-AUS,AF195822.1)was grouped into a cluster alone.Keywords：grapevine leafroll disease;RT-PCR;phylogenetic tree0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Sequence analysis technology of mitochondrion DNA,a 690 bp COⅠ gene,was used in this study.By sequencing and the haplotype network evolution of the COⅠ gene from a total of 10 geographic populations with 122 COⅠ gene sequences from Xiamen,Danzhou,Panzhihua,Zhaoqing,Simao,and Shanghai Baoshan,Jiading,Pudong,Qingpu,Songjiang,the population genetic structure and expansion trend were analysed.The results showed that Bactrocera dorsalis(Hendel) populations of Songjiang mainly was spread from Simao Yunnan,the other some populations from Zhaoqing Guangdong and Jiading Shanghai populations.In addition, some Bactrocera dorsalis(Hendel) were from the population which were earlier than those of Simao,Yunnan and Danzhou Hainan.Qingpu population mainly was from Simao,Yunnan populations,some from Xiamen,Fujian,and Jiading,Shanghai populations.Baoshan population of Bactrocera dorsalis(Hendel) was also mainly from Simao,Yunnan populations, others from Songjiang,Shanghai and Zhaoqing Guangdong.Jiading populations of Bactrocera dorsalis (Hendel) were mainly from Simao,Yunnan populations,but another part from Baoshan Shanghai.Pudong population was mainly from Simao,Yunnan and Jiading Shanghai populations.Keywords：Bactrocera dorsalis;mitochondrial DNA;COⅠ genes;population genetics0|5|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A southern root-knot nematode resistant inbred line 09C649 was crossed with a susceptible line 09C108.The F2 segregating population was obtained.Disease investigation and heredity analysis revealed that the resistance to southern root-knot nematode in 09C649 was controlled by a dominant gene,tentatively named as Me8.Two hundreds and thirty six pairs of SSR markers,1 pair of SCAR marker,1 pair of SSCP marker,8 pairs of EST-SSR markers and 2 pairs of COSII markers were used to map Me8.It was located on the chromosome 9 of pepper.The four molecular markers SSCP_B322,COS710,SCAR_315 and COS970,were the nearest markers away from Me8 with genetic distances of 0,0.1,1.3 and 3.3 cM respectively.Southern root-knot nematode resistance genes N,Me1,Me3 and Me7 were also located in this genomic region.These markers could thus be used in marker-assisted selection for all the southern root-knot nematode resistance genes that were found currently.The SCAR_315 was used in marker-assisted selection of 37 pepper lines.And the molecular identification was well in agreement with the southern root-knot nematode resistance tests.Keywords：pepper;southern root-knot nematode;gene mapping;marker-assisted selection(MAS)1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the effects of Amino acids supplementation on performance,free amino acid concentrations, plasma uric acid,and cecal microbial flora of laying hens in low-protein feed,225 20-weeks Highland Brown laying hens were devided into 5 groups with 3 replications.The control group were fed with CP13% basal corn-bean diet without amino acids supplement (group Ⅰ),while the experimental groups were fed with amino acid supplement (methionine,lysine,and threonine) at 100%(group Ⅱ),110% (group Ⅲ),120%(group Ⅳ) and 130%(group Ⅴ) of their requirements.The experiment lasted 40 weeks.The results showed that:the average egg production rate of group Ⅲ is 87.8%,which is 5.1% (P<0.05)、1.7%、3.2% (P<0.05)、and 11.7%(P<0.05) higher than the groups Ⅱ、Ⅳ、Ⅴ in average, respectively.The egg weight of the three experimental groups was significant better than the cntrol group (P<0.05).There is no significant difference in plasma amino acid levels among the groups (P>0.05);while the plasma uric acid and urea nitrogen levels were the highest in group Ⅴ,and lowest in group Ⅲ(P<0.05).The similarities of the bacteria samples of cecal mixture of the experimental groups are all higher than Group Ⅰ and the differences of the fingerprint average stripes among the experimental groups are quite evident (P<0.05).The addition of amino acid made Group Ⅳ and Group Ⅲ rich in bacteria varieties and had great effects on cecal microflora of the laying hens.By cloning and sequencing specific bands from cecum segments of the laying hens,it was revealed that Lactobacillus johnsonii,Clostridium sp.,Pediococcus acidilactici,and unculturable bacteria abound in the cecum parts of hens in groups Ⅲ and Ⅳ.This indicated that Lactobacillus,Clostridium,and Prevost are superior bacteria in the cecal sections of the laying hens.The results showed,amino acids supplement significantly improved the performance of layers hen in low protein fodder for the groups Ⅲ and Ⅳ,while lactobacillus, spindle of bacteria and Mr Wolfowitz in cecum improved their production performance.Keywords：laying hen;low-protein dietbreeding;amino acids;cecum bacterial flora3|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This study is to establish and apply quantitative methods for detecting the mRNA expression of porcine proinflammatory cytokine.In order to study the pathogenesis of encephalomyocarditis virus(EMCV) in molecular level,a recombinant plasmid containing the fragment of target gene,i.e.porcine IL-1β,IL-6 and TNF-α genes and housekeeping gene β-actin,were constructed as standard control.Thereafter,one multiplex real-time RT-PCR assay based on TaqMan probe for detection of IL-1β/β-actin,IL-6/β-actin,TNF-α/β-actin genes was established.The correlation coefficient of the standard curves was over 0.998;The detection limit reached 10 copies/μL of initial templates;The fluorescent signals could only be detected by the reaction with cDNA,specific primer and probe for each cytokine;The coefficient of variation was less than 2 percent for both intra- and inter-assay.The established assays were successfully used to detect IL-1β,IL-6 and TNF-α mRNA expression levels in heart tissue from piglets experimentally infected with porcine EMCV GXLC strain.The multiplex TaqMan real-time RT-PCR could be used as an effective tool for detection and quantification of these proinflammatory cytokines with high sensitivity,specificity and reproducibility.Keywords：porcine;proinflammatory cytokine;encephalomyocarditis virus(EMCV);multiplex real-time RT-PCR;TaqMan probe2|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the sensentivity of Ornithobacterim thinotracheale (ORT) on different medicines,six isolates were used after confirmed by Gram-stain,biochemical test and PCR methods,where five samples were isolated from the lungs with the severe pneumonia in broilers in Beijing,Hebei,Inner Mongolia,Jilin and Shandong province,and one was obtained from the broiler breeder’s egg yolk in Liaoning.Subsequently,the typical pneumonia were replicated with the characterization of the airsaccitis in 21-day SPF chickens post infection intraperioneally with the Shandong isolate.Additionally,half lethal dose (LD50) was determined to be 1.43×108cfu/mL in SPF chickens.Furthermore,minimum inhibition concentrations (MIC) of nine isolates were determined post incubation with the different antibiotics,including 6 isolated strains and 3 reference strains.Nine ORT strains were more sensitive to moxifloxacin gatifloxacin,and ciproxacin and the average MIC arranged from 0.49 to 31.25 μg/mL.Although doxycycline was widely used against avian respiratory disease,the MIC was found to be diversity arranged from 1.90 to 125 μg/mL.As for the MIC of rifampcin,7 ORT strains was found to be sensitive and the MIC values arranged from 3.91 to 15.6 μg/mL except for the Beijing isolate and Jilin strain.Furthermore,9 isolates were not sensitive to the drugs like florfenicol,tetracycline,aureomycin,sulfamonomethoxine sodium,fosfomycin sodium and cefotaxime sodium,the MIC values was higher than 1 000.0 μg/mL.Keywords：chicken;Ornithobacterium rhinotracheale;isolation;identification;minimum inhibition concentration1|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The effect of freshness on change ratio of impedance (Q value) of bighead carp stored at temperature of 3 ℃ was investigated.The indexes of freshness,K value,total volatile basic nitrogen (w(TVB-N)) and total aerobic count,as well as sensory assessment were determined based on the investigations.The correlation models were developed via analyzing the correlation between the freshness indexes and sensory assessment.The results indicated that the sensory assessment has exceeded the acceptable limit with the score of 14 on the twelfth day,while the K value,w(TVB-N) and total aerobic count increased to 74.1%,16.1 mg/100g and 1.30×105 CFU/g,respectively,and the Q value declined to 12.7%.The correlation coefficients are 0.993,0.971,0.977 and 0.981,respectively,indicating significant linear relations (P<0.01) between the Q value and the K value,w(TVB-N),total aerobic count and sensory scores.Therefore,one can use Q value as a fast nondestructive method to estimate the freshness of bighead carp fillets under 3 ℃ storage.Keywords：bighead carp;chilling storage;freshness;impedance change ratio;correlation2|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：An air-suction roller rice precision direct seed-metering device was designed to solve the existing problem in seed-metering,such as poor adaptability,high rate of seed injury and low seed-metering rate.The conditions of seeds sucking were analyzed and the influencing parameters of performance were obtained.The experimental studies showed that the designed seed-metering device could meet the requirements of rice precision seeding and low rate of bud injury,and a positive correlation relationship was observed between the diameter of the sucking pinhole and suction performance.The diameter of the sucking pinhole should be greater than 0.60 mm.The main factors that affect suction performance were the diameter of the sucking pinhole,the degree of vacuum and roller speed respectively.The rate of qualified sowing is 98% when the diameter of the sucking needle was 1.55 mm,the degree of vacuum was 0.035 MPa and the roller speed was 50 r/min respectively.Keywords：rice;air-suction roller;precision direct seed-metering device;mechanical design;sucking condition4|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Employing realizable k-ε turbulence model,emitters of three different jagged channels were numerically investigated,in which the wall roughness elements were simulated by adopting porous medium model so as to describe geometric model of micro-channels based on Fluent.The testing result of Micro-PIV proves the reliability of the approach,which also can be applied to numerical computations of emitters of three different structure jags.According to the numerical simulation,anti-clogging and hydraulic property were analyzed.In the analysis of anti-clogging,it was found that impurity sediment was seldom to happen because of the high speed mainstream,next to which there were recirculation zones at the swerving inside of all the three channels;it was also not liable to happen at the cusp of the jags because of the turbulence;while it only exited s at the jag cusp and the left side of the flat-jagged channel.By comparing the pressure drops and flow pattern index in emitters of three different jagged channels,the hydraulic property is analyzed,which proves the advantage of cusp jag emitters to control steady outflow.Keywords：emitter;property;jagged micro-channel;numerical simulation;Micro-PIV;porous medium1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Starch nanoparticles were prepared by water-in-oil (W/O) miniemulsion-crosslinking method assisted by high-pressure homogenization.The preparation of W/O miniemulsion was study and the results indicated that coarse emulsion of spherical shape with good dispersibility could be prepared at 84:16 mass ratio of Span-80 to Tween-80 and 6:100 mass ratio of NaCl to H2O.The Z-average diameter and polydispersity index (PDI) of W/O miniemulsion changed slightly when the mass-to-volume ratio of compound emulsifier to cyclohexane ranged from 0.04 to 0.08 g/mL,but declined gradually along with the increase in the homogenization pressure.With the increase in homogenization cycle,the Z-average diameter and PDI decreased gradually in the beginning and tended to be stable after 5 cycles.It is demonstrated that starch nanoparticles of 50-100 nm can be successfully synthesized in W/O miniemulsion using epichlorohydrin as crosslinking agents.Keywords：starch;nanoparticle;high-pressure homogenization;miniemulsion;crosslinking1|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：LiDAR data processing is an urgent problem to be solved in LiDAR technique application area.The LiDAR data processing module on OpenGL was developed in this study,and the key techniques include LiDAR data reading methods of LAS format,presentation of LiDAR points and improved hierarchical moving curved fitting filtering method of LiDAR points.The LiDAR points filtering experiment was done to validate the LiDAR data processing module,and the filtered results were used to confirm the efficiency of this module in presenting and editing LiDAR points.Keywords：OpenGL;LiDAR;LAS format;coordinate transformation;data filtering3|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this paper is to quantitatively evaluate the man-land relationship of Quzhou county,calculate the realistic potential of land consolidation of rural residential area and analyze the influence of man-land relationship on the transformation from theoretical potential to realistic potential at a village.The used methods included statistical analysis,hierarchy analysis and modified coefficient on limited conditions.The results showed that the poor man-land relation existed mainly in the area around the town and both side of main road due to booming economy and expansive land requirement.The relation was harmonious in 77.14% of the researched area.Only about 26.99% of the potential could become realistic through land consolidation in this typical agricultural county of the Plain of Yellow,Huai and Hai Rivers.Our results can provide with a new scale and thinking for the research of land consolidation, and also have a sort of directive meaning for confirming the time and spatial sequence of land consolidation of rural residential area.Keywords：man-land relation;rural residential area;land consolidation;realistic potential;Quzhou County1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：By engaging the methods of questionnaire survey,the field observation and in-depth interview,this paper made the empirical research on the rice farmers in Hubei province.Based on existing research results,we established a binary logit model to analyze the factors that influence the framers’ choices of new technology from four aspects,namely farmer’s personal characteristics,family characteristics,production characteristics and external environment features.The results indicated that the key factors that influence farmers’ adoption of the new rice variety mainly depend on the cost and expected return of the new technology,and farmer’s personal characteristics,family characteristic such as the age,education level,income and health condition have remarkable effect on the choice of a new technology,the planting area also has significant impact on technological choice.Keywords：rice;farmers;new varieties;technological choice;influencing factors3|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The application of cultivation technology on the edible fungus has a significant impact on farmers to improve their competitiveness as well as to increase incomes.According to some related scientific researches,this thesis,with the aid of some scientific data from the national industrial technology system of the edible fungus,has analyzed the difference between the improved technology and the production-process technology with the adoption of Logistic model,discussing about how these two technology have affected the farmers as well as the similarities and dissimilarities of the factors in using these two technologies.In the respect of features of planting edible fungus,farmers’ recognition level and technology attribute,the article analyzes some possible reasons,and gives a reasonable explanation for farmers’ cognitive illusion of two technologies’ cost.Keywords：fungus-planting farmer;improved technology;cultivation technology;logistic model3|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：What kind of influence that provision of rural public goods financing through market participants in rural areas on the welfare of farmers?What is the influence mechanism of it?This paper on the Background of the abolition of agricultural tax in China,through the construction of production and consume model,analysis the mechanism and effects of rural public goods to farmers’ income and utility separately.By using 400 households survey data of five counties in Shaanxi province,empirical analysis find that provision of public goods financing through market sources have a significant positive effect on household’s income.So the paper suggested the central government to increase public investment in rural areas,while the township government should create more channels help the provision of rural public goods financing through market participants,thus achieve more investors involving in the supply of public goods in rural areas.Keywords：rural;rural public goods;household income;financing through market sources;influence mechanisms5|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
