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    2020,39(4):1-6                                                                                                                
    Abstract:
    178 recombinant inbred lines (F12) of crossing rice varieties Gang 46B with A232 were used to investigate the length,width and aspect ratio of flag leaves in Lingshui,Hainan province and Wuhan,Hubei Province. 14 QTLs in total including 5 flag leaf width QTLs,6 flag leaf length QTLs,and 3 flag leaf lengthto width ratio QTLs were detected,which were distributed on rice chromosomes 1,2,4,6,7,10 and 12. LOD values were ranged from 2.52 to 5.62. The contribution rate of a single QTL to phenotypic variation varied from 5.56% to 21.27%.
    2020,39(4):7-14                                                                                                                
    Abstract:
    The pot experiment was used to study the effects of salt stress on growth of Oceanrice 86 and absorption,transportation and distribution of mineral elements using Huanghuazhan as control. The results showed that salt stress inhibited the dry matter accumulation of rice plants. The salt tolerance threshold of Oceanrice 86 and Huanghuazhan was 8.72 g/kg and 6.35 g/kg,repectively. Compared with Huanghuazhan,salt tolerance of Oceanrice 86 was stronger. Under salt stress,Oceanrice 86 selectively absorbed Na + through the root system and regulated the distribution of Na+ at the organ level. Its leaf sheath accumulated more Na +,reducing the toxicity of Na+ to the leaves. The content of K + in Huanghuazhan leaves did not change significantly from that of the control,but the K + content in the leaf sheath and root system was 4.64 g/kg in the soil. The K+ content was greatly reduced by 53.8% and 70.0%,respectively. The K+ content in various organs of Oceanrice 86 gradually decreased with the increase of the degree of salt stress,and the decrease of K+ content in leaves was relatively low. The content of Ca2+ and Mg2+ in the leaf sheath of Huanghuazhan decreased significantly with the increase of salt stress,while Oceanrice 86 had no significant changes. Compared with Huanghuazhan,Oceanrice 86 had a strong ability to inhibit Na + and promote the upward transport of Ca2 + and Mg2 +.
    2020,39(4):15-21                                                                                                                
    Abstract:
    A surface enhanced Raman spectroscopy (SERS) technique based on functionalized Au@Ag nanorods (Au@Ag NRs) was established to quantitatively detect Hg2+ in aqueous solutions.In the presence of Hg2+,its coordination with 2,5 dimercapto 1,3,4-thiadiazole (DMCT) on the surface of Au@AgNRs caused the aggregation of SERS detection probes,resulting in a “hot spot” effect,leading to the SERS signal of DMCT increased at 1 360 cm-1.The increased SERS signal showed a good linear relationship with Hg2+ in the concentration range from 0.1 to 10 μg/L :Y=195.49384X+1676.23663(R2=0.991).The detection limit was as low as 17 ng/L,much lower than that of the Hg2+ content(1 μg/L) in drinking water specified by World Health Organization(WHO).The results of spiked recovery test carried out in the actual water sample showed that the spiked recoveries of Hg2+ were from 100.1% to 106.5%,and the relative standard deviations were from 1.23% to 7.99%.The Hg2+ sensing detection technique with accuracy,rapidity and high sensitivity based on SERS has an effective application for quantitatively detecting Hg2+ in real water.
    2020,39(4):22-28                                                                                                                
    Abstract:
    “Hot Green No. 2” pakchoi was pot-planted with five treatments including 0% C,1% C,2% C,4% C and normal application of potassium fertilizer to investigate the effects of biochar application on potassium content of different forms in red soil and the growth of pakchoi. Results showed that the effects of biochar on content of water-soluble potassium,exchangeable potassium and non-exchangeable potassium in red soil were increased by 12.6%-51.8%,13.3%-43.5% and 10.3%-26.1%,respectively,compared to the control. The effect of biochar on improving different forms of potassium between 4% C and normal potassium was the most similar. Biochar application increased soil pH value significantly by 0.06-0.25 units,as available phosphorus,available potassium and organic carbon in soil. Also the cation exchange capacity,exchangeable calcium and magnesium content increased significantly,while the exchangeable aluminum content decreased significantly with a decrease of 87%-98%. Biochar application could improve pakchoi growth performance as increasing the biomass,leaf number,plant height and fresh weight of pakchoi.
    2020,39(4):29-37                                                                                                                
    Abstract:
    This study investigated symbiotic function of purple acid phosphatase gene MtPAP3 in Medicago truncatula with MtPAP3Pro∶∶GUS histochemical location,over-expression and CRISPR/Cas9 gene knock-out. The results showed that MtPAP3 was mainly located in vascular bundle of roots and nodules,and meristem and infection zone of nodules. The transcription levels of MtPAP3 were enhanced in roots and nodules under Pi deficiency conditions. The numbers and nitrogenase activity of nodules were increased in transgenic overexpression plants. The knock-out of MtPAP3 significantly inhibited the development and nitrogenase activity of nodules. It is indicated that MtPAP3 involves in phosphorus metabolism and symbiotic nitrogen fixation in nodules under low phosphorus stress.
    2020,39(4):38-45                                                                                                                
    Abstract:
    Two phosphate solubilizing bacterial strains,PSB-1 and HZP1,were isolated form soybean nodules and rhizosphere soil. The ability of these two strains to produce IAA (indole-3-acetic acid IAA) and the ability to dissolve inorganic phosphorus were measured by Salkowski colorimetry and molybdenum antimony-phosphonium colorimetry. Soybean and Astragalus sinensis were co-inoculated. Results showed that both two phosphate solubilizing strain produced IAA. The legume growth-promoting effects of the phosphate solubilizing strains and rhizobium inoculum were investigated in unsterilized soil and soybean planting field. Inoculation with HZP1 or PSB-1 promoted the growth of Astragalus sinensis and soybean. Co-inoculation of phosphorus-solubilizing strains with rhizobium further increased the shoot biomass,fresh weight of nodules and the number of nodules of soybean and Astragalus sinensis. The results of field tests showed that inoculation with rhizobium or phosphate dissolving agents alone had a certain effect of increasing yield but double inoculation with rhizobium and phosphate dissolving bacteria did not increase the yield significantly.
    2020,39(4):46-56                                                                                                                
    Abstract:
    The dynamic changes of plant community structures at different restoration stages in the aerial-seeding region in Otindag Sandy Land were studied,aiming to understand the restoration characteristics and change rules of vegetation restoration. From 2013 to 2017,vegetation survey tests were conducted in 11 aerial seeding areas in the Otindag Sandy Land. Correspondence analysis,correlation analysis,and Mann-Kendall trend analysis were used to analyze stages of vegetation restoration in the aerial seeding area and to discuss the status and role of each functional plant in the community based on a functional perspective. The results showed that it was divided into three recovery stages across 19 years. Moreover,after aerial seeding,the degree of dependence among the following seven functional plants of rubs/subshrubs,perennial weeds,annual/biennial weeds,perennial leguminous forage,perennial gramineous forage and annual/biennial gramineous forage,was decreased gradually.Community stability was increased by the number of recovery years. Dominant function type of vegetation restoration was not consistent in different restoration stages,resulting in timing management could be employed at different stages. Consequently,the succession stage and overall development trend of plant community are more conducive to the recovery and reconstruction of the vegetations in degraded sandy land.
    2020,39(4):57-62                                                                                                                
    Abstract:
    Based on the tourist statistics data of the Taizishan Forest Park,the paper used the composition method of ecological footprint to calculate the tourism ecological footprint,tourism ecological carrying capacity and tourism sustainable development of the forest park. The results show that: the total tourist ecological footprint of the Taizishan National Forest Park in 2018 was 1 013.36 hm2,the total tourism ecological carrying capacity was 10 738.99 hm2,the total tourism ecological surplus was 9 725.63 hm2,the degree of tourism sustainable development was 0.09,which reflected that the tourism of the Taizishan National Forest Park is in an ideal state of ecological surplus and sustainable development. 
    2020,39(4):63-68                                                                                                                
    Abstract:
    Currently,litter size trait is an important indicator to measure sow fertility and play important roles in determining total income of pig farm in China. An accurate prediction of these traits in the early life of an animal will allow pig producers to adjust their management practices in order to cull bad sows early and improve the reproductive ability of core sows. However,there are many factors not only influence sow’s litter size trait,but also influence each other. Traditional prediction methods may not be powerful enough to capture complex interactions while avoiding overfitting. In this case,learning algorithms that can learn from current data to predict the animal’s future performance offers promise. In this study,firstly,the sow’s production data,including total number of piglets born (TNB),number born alive (NBA),number of healthy piglets(NHP),number of piglets aged 5 day (N5D) and number of piglets weight above 1 kg (NPWA1) were processed and described statistically. Then,the R-package Boruta was used to screen out important eigenvalues affecting the litter size traits of sows,such as breed,parity,mating season,delivery season,gestation period,interval birth and birth litter weight. Last,regression analysis was performed by traditional linear regression method and three different machine learning methods including decision tree (DT),K-nearest neighbor (KNN) and support vector machine (SVM). The evaluation index of model including R2 and MSE are obtained by ten flod cross validation. Additionally,modeling methods was assessed by these indexes and best model was screened scatter plot using a part of original data. The results showed that the R2 of all regression analysis methods in TNB,NBA,NHP,N5D NPWA1 was over 0.71 (0.71-0.88),which showed that the selection of characteristics is correct. The SVM model was not only significantly better than other machine learning methods (P<0.05),but also better than traditional regression method in predicting TNB,NBA,NHP,N5D and NPWA1. The SVM model of NPWA1 is the best in all models. Therefore,machine learning methods will become a new approach for pig producers to breed high-fecundity sows in the future.
    2020,39(4):69-76                                                                                                                
    Abstract:
    To investigate the expression of BMPR1A in various tissues during different physiological periods (follicular and luteal phases) and in ewes of different fecundity (monotocous and polytocous),and to analyze the association of its polymorphism with litter size in Small Tail Han (STH) sheep,qPCR was used to detect the expression of BMPR1A in 14 tissues in STH sheep,meanwhile,Sequenom MassARRAYSNP assay was applied to genotype three single nucleotide polymorphism sites (SNPs) of BMPR1A gene in different sheep breeds,and then the association between the BMPR1A polymorphism and litter size in STH sheep was analyzed. The results showed that the expression of BMPR1A in hypothalamus and ovary of polytocous ewes was higher than that of monotocous ewes,but did not reach a significant level (P>0.05). From genotyping,the genotype and allele frequencies of g.41128335A>T and g.41127600C>T loci of BMPR1A were significantly different (P<0.05) between polytocous and monotocous sheep breeds. The χ2 test indicated that the three SNPs were under Hardy-Weinberg equilibrium (P>0.05) in most of the sheep breeds. Association analysis showed that three loci of BMPR1A gene had no significant association with the litter size of different groups of STH sheep (P>0.05),and the litter size of mutation was higher than that of wild for g.41128335A>T and g.41127598A>G loci. Therefore,we concluded that there may be a certain positive correlation between the expression of BMPR1A gene and litter size in STH sheep,but the three SNPs had no significant association with the litter size of STH sheep,which indicated they may not be the key loci that affect the expression or function of BMPR1A. 
    2020,39(4):77-84                                                                                                                
    Abstract:
    Mycoplasma bovis is one of the serious pathogens causing bovine respiratory diseases. Meanwhile,M. bovis can cause a variety of clinical signs,including bronchopneumonia,mastitis,arthritis,genital tract inflammation,and tenosynovitis. Adhesion to airway epithelial cells is a key step for M. bovis colonization and invasion of cells. Adhesin is one of the main virulence factors of M. bovis. Research about attachment has become an important field of pathogenic mechanisms research of M. bovis. To further analyze the adhesion characteristics of the M. bovis VspX protein,experiments,including indirect immunofluorescence assay,adhesion assay of protein and mutant strain to embryonic bovine lung (EBL) cells,antibody inhibition adhesion detection,ELISA assay of protein and strains binding fibronectin (Fn),were carried out,to clarify the molecular mechanism of VspX protein adhesion. The results showed that the M. bovis VspX protein was located on the surface of the strain. The recombinant VspX protein (rVspX) was able to adhere to the embryonic bovine lung (EBL) cells. Compared with the M. bovis wild strain (M. bovis WT),the M. bovis VspX gene-deleted mutant strain (M. bovis ΔVspX) had a significantly decreased ability to adhere to EBL cells in vitro (P<0.05). The above results showed that the VspX protein was an adhesion-related protein. The anti-rVspX monoclonal antibody was able to inhibit the adhesion of M. bovis to EBL cells,which further confirmed the specificity of the adhesion. Also,the rVspX protein bound to Fn in a dose-dependent manner,and the M. bovis ΔVspX strain had a significantly lower adherence ability to Fn (P<0.05) than that of the M. bovis WT strain. These results further demonstrated the binding specificity of M. bovis VspX protein to Fn. And Fn was distributed on the surface of EBL cells. In summary,the study validated that M. bovis VspX protein was an adhesion-related protein with Fn binding properties,and the adhesion of VspX to EBL cells was mediated by the extracellular matrix component,Fn.
    2020,39(4):85-92                                                                                                                
    Abstract:
    Epidemic haemorrhagic disease virus (EHDV) is an arbovirus that seriously endangers ruminants. Currently,nine serotypes of EHDV have been discovered worldwide,and five of them are prevalent in China. Neutralization test is the gold standard for serotype identification of EHDV,which has the shortcomings of time-consuming,laborious and long experimental period. Therefore,establishing an accurate and rapid serotyping method for EHDV is of great significance for the prevention and control of this disease. In this study,the second gene segment (Seg-2),which determines the serotype of epizootic haemorrhagic disease virus (EHDV),was used as the target gene to establish a one-step RT-PCR method for serotype-specific detection of EHDV. The results of specificity test showed that the method could accurately identify different serotypes of EHDV,and had no cross-reaction with bluetongue virus,chuzan Virus and akabane virus. The results of sensitivity test showed that the detection limit of the EHDV nucleic acid for different serotypes could reach 102 copies. EHDV strains isolated from different times and different regions in China were identified by this one-step RT-PCR and the results showed that the 31 EHDV isolates belonged to five serotypes,inculding EHDV-1,-5,-6,-7 and -10. The results of the RT-PCR were completely consistent with the results of the serum neutralization test. The above results showed that the method established in this study had good specificity and high sensitivity,and could quickly and accurately identify the serotype of EHDV strains.
    2020,39(4):93-98                                                                                                                
    Abstract:
    After immunizing Bactrian camel with CRP as immunogen,the peripheral blood lymphocytes were isolated,the total RNA was extracted,and then the cDNA was obtained by reverse transcription. The target gene fragment was obtained by nested PCR and cloned on the arm of T7 vector of phage to construct the original phage library. After four rounds of biological panning,the phage library after panning was identified by Phage-ELISA. The recombinant plasmids of pET-28a and positive clones were constructed by BamH Ⅰ and HindⅢ double enzyme digestion and transformed into BL21 strain for low-temperature induction expression. The single domain antibody was purified by His-Ni affinity chromatography,and then the reactivity between the single domain antibody and CRP was identified by indirect ELISA. The results showed that the phage library with a capacity of 1.08×108 cfu was successfully constructed,and the gene insertion rate was 96.43% (27/28). Four positive clones were successfully constructed and expressed in BL21 cells. The molecular weight was about 22 ku. By ELISA,the four antibodies showed high affinity and specificity. The titer of V2 and V3 was 1∶3 200,which proved that the antibody could be applied to the development of practical detection methods.
    2020,39(4):99-104                                                                                                                
    Abstract:
    Recombinant expression vector of the Streptococcus agalactiae ATCC51487 gene was established by using PCR amplification,double digestion of EcoRⅠand XhoⅠ,and resistance screening,etc. Effects of induction temperature,concentration and time on the expression products were examined. The protein was purified by affinity chromatography and ion exchange chromatography,and the activity of SrtA was determined using energy transfer resonance. The results showed that after the srtAΔN82-pGEX- 6p - 1 vector was transformed into BL21 (DE3),a large amount of soluble protein were obtained by inducing at 1 mmol/L IPTG at 37℃ for 6 h. The purity of SrtA was higher than 85%. Moreover,the purified SrtA could significantly increase the fluorescence intensity when co-incubated with the substrate,indicating that the recombinant SrtA had good biological activity.
    2020,39(4):105-113                                                                                                                
    Abstract:
    With Penicillium digitatum DSM62840 as the object of research,the extraction conditions of related enzymes in the process of converting limonene to α-terpenol were optimized to obtain high activity. And limonene converting-enzyme was extracted by high pressure cell crushing method. Taking the limonene converting-enzyme activity as evaluation indicator,the response surface methodology was used to optimize the extraction technology based on single factor test. At the same time,the properties of limonene converting-enzyme were preliminarily studied. The results showed that the optimum conditions for extracting were as follows: disruption pressure of 100 MPa,crushing times of 6,and liquid-to material ratio of 15∶1 (mL/g). Under the conditions,the yield of α-terpenol was 855.75 mg/L,and the enzyme activity was 71.31 U. The optimum conversion time of limonene converting-enzyme was 4 h,and the highest enzyme activity was obtained in phosphate buffer. Limonene converting-enzyme might be cytochrome P450,and different metal ions have different effects on the enzyme: Fe2+ had slight inhibition on the enzyme,while Ca2+,Mg2+,Mn2+,Zn2+,Co2+,Ba2+,Na+,K+,Fe3+ and Ni2+ had different activation effects on the enzyme. SDS-PAGE analysis of the crude enzyme solution showed that the extraction effect could be better under the optimum conditions.
    2020,39(4):114-120                                                                                                                
    Abstract:
    The polypeptides were prepared from silver carp skin by the method of mixed enzymatic hydrolysis,and divided into SP1(>6 ku),SP2(3-6 ku) and SP3(<3 ku) by ultrafiltration. The antioxidant capacity in vitro of three polypeptides and the amino acid composition of SP1 and SP3 were analyzed. It was suggested that SP3 has the strongest antioxidant capacity in vitro. Subsequently,the antioxidant capacity in vivo of SP3 was measured. The results showed that the order of hydroxyl radical scavenging rate,superoxide anion radical scavenging rate and reducing ability in the three polypeptides was SP3>SP2>SP1,but there was no significant difference in chelating rate of copper ions. Analysis of amino acid composition showed that the percentage of hydrophobic amino acid in SP3 was significantly higher than SP1. Besides, compared with the injured group,SP3 group had higher indexes of liver and spleen. Furthermore,SP3 significantly increased the activities of SOD,GSH-Px and CAT and decreased the content of MDA in serum and liver. In conclusion,SP3 has better antioxidant activity than SP1 and SP2.
    2020,39(4):121-127                                                                                                                
    Abstract:
    Deep-frying is one of the traditional method of food processing with multiple advantages. However there are some safety hazard factors in deep-fired food which recently received many attentions. Advanced glycation end products (AGEs) is one of the main harmful compounds in deep-fried food which leads to human aging and insulin secretion defects. Nε-carboxymethyllysine (CML) and fluorescent AGEs are usually used as the marker of AGEs. Grass carp is the largest freshwater fish in China. A large number of grass carp is processed using deep-frying every year. Therefore it is necessary to study the level of CML and fluorescent AGEs in deep-fried grass carp and to find effective methods to reduce the content. The purpose of the study was to investigate the effects of frying time and batter on the content and distribution of AGEs in deep-fried fish nuggets and to develop processing method to reduce the safety concerns. In this study deep-fried fish nuggets (DFN) and breaded fish nuggets (BFN) were prepared using grass carp for 0,30,90,120,180,240 and 300 s. The AGEs content and physicochemical properties of the crust and internal of the fried fish were measured. The results showed that water loss oil absorption,Maillard reaction and oil oxidation mainly occurred on the fish crust during frying. Therefore the CML content in the fish crust of DFN and BFN was 5.6 and 6.4 times that of the interior,respectively. Extending frying time resulted in higher water loss and oil absorption in both the fish crust and interior while the malondialdehyde content firstly increased and then became stable. Extending frying time could also promote Maillard reaction in the fish crust and significantly increased the content of CML and fluorescent AGEs. Compared with DFN,the BFN crust had lower moisture content and higher fat content. The Maillard reaction and fluorescent AGEs content rapidly increased during the late frying period but the use of the batter prevented the protein from directly contacting the high-temperature oil and thus the CML and fluorescent AGEs content in BFN crust were significantly reduced by 34.6% and 20.8% compared with DFN at 300 s. The use of the batter also significantly reduced the CML content in the interior of fish but had no significant effect on the fluorescent AGEs content. In conclusion the use of the batter and reducing the frying time could reduce the AGEs content in the fish crust and interior.The study provided basic information for the development of the healthy aquatic food.
    2020,39(4):128-136                                                                                                                
    Abstract:
    To study the effects of micro-flowing water treatment on the crucian carp flesh quality,the main nutritional components,taste characteristics,odour characteristics,and volatile components of the pond-cultured crucian carp (Carassius auratus gibelio) flesh processed by the micro-flowing system were measured after different treatment durations (0-9 d).The results showed that the micro-flowing water treatment hardly influenced the moisture,crude protein and crude fat contents in cultured crucian carp flesh(P>0.05),whereas it had significant effects on the ash,muscle glycogen,total sugar content in fish flesh as well as on the taste,odour and sensory scores (P<0.05). With the extension of micro-flowing water treatment time,the glycogen and total sugar contents significantly decreased while the ash content significantly increased (P<0.05). According to the results of electronic tongue and electronic nose detection,the micro-flowing water treatment can significantly change the taste and odour characteristics of crucian carp flesh. As the micro-flowing water treatment time extended,the content of odour volatiles in the flesh of the crucian carp significantly decreased,and the representative flavor substance in the fish significantly increased. Meanwhile,the odour,taste,texture,and the sum scores of steamed fish were also greatly raised. The sensory score of the crucian carp flesh processed for 7 d was higher than that of samples processed for 0 d,1 d,3 d,and 5 d. However,there was no difference between the samples processed for 7 d and 9 d with micro-flowing water treatment. In summary,the short-time micro-flowing water treatment (≤7 d) hardly affected the crude protein and crude fat contents of crucian carp flesh,but it could remarkably improve the flesh quality of crucian carp with the most suitable treatment duration (7 d).
    2020,39(4):137-146                                                                                                                
    Abstract:
    Freezing is a common processing method used in the production of surimi. In order to prevent quality deterioration during freezing storage,commercial cryoprotectant (4% sucrose and 4% sorbitol) is added,which introduces excessive sweetness and calorie and limits partial consumers. With low sweetness,rich probiotic function and reasonable structure,inulin is a potential cryoprotectant. Therefore,it is essential to conduct a systematic research on the freezing resistance of inulin with different degree of polymerization for surimi. The purpose of the study was to investigate the effects of inulin with different degrees of polymerization on protein denaturation and quality deterioration of surimi,and to reveal the relationship between protein biochemical properties and gel properties. In this study,frozen silver carp surimi was prepared by adding short chain inulin (degree of polymerization 2-6),natural inulin (degree of polymerization 10-23) and long chain inulin (degree of polymerization 23-46). The protein biochemical and gel’s indicators were measured during frozen storage. Furthermore partial least squares regression analysis(PLSR) was performed to analyze the relationship between protein and gel’s indicators. Results showed that,all of the inulin had anti-freezing effect on surimi. Short chain inulin had the best effect among these,and could significantly inhibit the decrease of the salt-soluble protein content,Ca2+-ATPase activity,sulfhydryl content and the increase of surface hydrophobicity (P<0.05). Meanwhile,secondary structure,sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel properties (water holding capacity,gel strength and texture) of sample added with short chain inulin was the closest to those of fresh surimi. In addition,salt-soluble protein content,secondary structure,surface hydrophobicity and sulfhydryl content had sequentially decreased influence on gel qualities,which could be used as main indexes indirectly evaluating gel quality of frozen surimi. But Ca2+-ATPase activity exerted little influence. This study provided a reference for the freezing denaturation of surimi and the development of new cryoprotectant.
    2020,39(4):147-155                                                                                                                
    Abstract:
    Mechanized transplanting of rapeseed is an efficient planting mode. However,the complicated structure and instability of seedling detaching process affects the transplanting quality of rapeseed substrate seedling. An inclined detach device for rapeseed substrate seedling transplanter was developed to solve the problem that the seedling transplanting device of the traditional transplanting machine is easy to tip over during the transplanting of rapeseed. The structural composition and the seedling detach processes were analyzed. The key components were designed and the main structural parameters of the seedling detach device were determined. A mechanical model of seedlings in the transporting and separating stages of the seedling detach process was constructed to analyze the main factors affecting the stability of the seedlings. The results showed that the seedling block was stable during the transporting stage when the frictional characteristics of the seedlings were constant and the inclination angle of the belt was between 24.5° and 35.0°. The lager of the clamping force,the better of the separation effect in the separating stage. The optimized key parameters of the seedling detach device included 30° inclination angle of the belt,lager than 0.8 N clamping force(fj1),and 0.5-0.8 MPa air pressure of the cylinder(P). The results of bench experiment showed that the capsizes rate of seedlings block was 4.2% and the detaching rate was 92.5%,meeting the needs of seedling detaching of rapeseed substrate seedling. It will provide a reference for designing detach device of rapeseed substrate seedling transplanter
    2020,39(4):156-162                                                                                                                
    Abstract:
    A certain combine harvester cutting platform and grain allocation device was used to establish the geometric model based on Pro/E software and reasonably simplify by importing the model established into ADAMS. The virtual prototype model was obtained by adding constraints,loads and drives,and kinematics simulation was carried out on this basis. The range of the threshing device and other relevant parameters were obtained through the establishment of different drives and the simulation analyses of different working conditions of the threshing device. The results showed that only when the speed ratio was λ>1,the motion trajectory was cycloid,forming a closed buckle so that the spring teeth can push the crop stalk backwards. When the reel ratio of the reel is 1.55,it is closest to the best effect of the reel,which can meet the working requirements of normal work and avoid unnecessary falling loss. The maximum and minimum forward movement distances of the reel increase with the increase of pull-grain speed ratio. The forward movement range of the reel is 0.00-0.38 m.
    2020,39(4):163-168                                                                                                                
    Abstract:
    A kind of water chestnut (Eleocharis dulcis (Burm. f.) Trin. ) peeler using the combined cutting method of flat blade to remove top bud,inclined blade to remove bottom,and arc blade to remove lateral peel was designed to solve the problems of the irregular shape,large peeling loss and uncleanness of water chestnut. By measuring and modeling the shape parameters of water chestnut,the outer contour curve of water chestnut was fitted to determine the range of structural parameters of blades. Based on 3D printing technology,the single factor experiment was used to determine the effects of rotary speed,inclination angle and length of the inclined blade,and chord length of the arc blade on loss rate and removal rate of water chestnut. The structural parameters and motion parameters were optimized. The results showed that the removal rate and the loss rate of the peeler designed was 93% and 24.4% when the rotary speed was 40 r/min,the inclination angle and length of the inclined blade were 82° and 14 mm,and chord length of the arc blade was 22 mm(42.75 mm in diameter),significantly higher than that of manual peeling and mechanical friction peeling.
    2020,39(4):169-174                                                                                                                
    Abstract:
    Because of the existence of soil adhesion characteristics,it often causes soil to adhere to the surface of working parts,which increases the energy consumption of equipment and even prevents normal operation. With the improvement of modern agricultural mechanization and the increasing variety of soil-engaging components,researchers put forward higher requirements for designing and optimizing soil-engaging components. In this study,a paddy field soil adhesion measuring instrument was designed. The single factor experiment was carried out with normal pull-out velocity vn,tangential velocity vτ and paddy field soil spatial depth as influencing factors. The factors affecting the contact interface adhesion were preliminarily obtained. The results showed that the soil adhesion increased with the increase of normal drawing speed vn and tangential velocity vτ,and first increased and then decreased with the increase of spatial depth of paddy field soil.
    2020,39(4):175-181                                                                                                                
    Abstract:
    Dongfanghong-LX754 tractor and Huaifeng1LS-740 subsoiler were used to study the effects of different positions of farm tools on the vibration characteristics of tractor with suspended farm tools. CATIA software was used to establish simplified geometric model of tractor and farm tools. MATLAB was used to write random road surface file,which was imported into ADAMS to write tire property file and establish the mechanical system model of farm tool,tractor and road surface. Effects of the parameters of the suspension device on the vertical vibration acceleration of the driver,the pitch vibration angular acceleration at the seat installation and the vertical vibration acceleration of the tractor body were obtained by simulation. The results showed that when the angle between the inner lifting arm and the horizontal direction increased from 20° to 70°,the driver acceleration peak value reduced to 17.61 from 30.09 m/s2. The peak frequency of vertical vibration increased from 1.36 to 2.12 Hz. Seat installed in longitudinal vibration angular acceleration peak value reduced to 7.56 from 11.12 rad/s2. Tractor barycenter vertical vibration acceleration peak value reduced to 29.33 from 42.42 m/s2. It will provide an important reference for designing vibration damping system of tractor.
    2020,39(4):182-192                                                                                                                
    Abstract:
    The effects of different holding times on the biochar yield,composition,pH,electrical conductivity and pore structure of five kinds of straws including rice,wheat,corn,rape and cotton were investigated.Correlation between the physical and chemical properties of different biochars was analyzed.The results showed that effects of straw type and holding time on the physicochemical properties of biochar fertilizer were significant (P<0.05).The biochar yields and the carbon conversion efficiency of straws ranged from 41% to 61%,and 53% to 65%,respectively.With the increase of holding time,the biochar yields decreased,while the pyrolysis degree and the fixed carbon contents of biochars increased.The pH and electrical conductivity increased with the increase of holding time.The holding time was negatively correlated with carbon yield,H,O contents and volatile matter content of biochars,and positively correlated with fixed carbon content.The optimal holding time is 60-90 min,and the biochars obtained under this condition has a rich pore structure with smooth surface.The biochars with lower H/C and higher pH and electrical conductivity can be used as a good carbon-based fertilizer additive material.
    Display Method:
                                                                                                                   
    Abstract:
    Beta-D-xylosidase (BXL) is the key rate-limiting enzyme for the complete degradation of xylan, which is the main component of hemicellulose in the plant cell wall. In this study, 16 genes encoding putative BXL proteins were identified in Brassica juncea genome. Protein physicochemical properties, gene structure and conserved motifs, chromosomal distribution and gene expression during stem swelling of BjuBXL family genes were analyzed. The results showed that 16 BjuBXL genes were classified into seven categories and formed two subfamilies according to the phylogenetic tree analysis. Subfamily 1 included BjuBXL1~5 and Subfamily 2 included BjuBXL6 and BjuBXL7. BjuBXL1-1~1-4 were closely related to AtBXL1, which was involved in the Arabidopsis cell wall metabolism and plant development. Multiple alignments of the 16 BjuBXL protein sequences revealed that all of them contained the conserved WGR and KH motifs that are associated with substrate binding and conserved amino acids at two key active sites for xylose hydrolysis. Sixteen BjuBXL genes coded 769 to 984 amino acids, which corresponding 83.37 to 109.32 kD molecular weight protein. The grand average of hydropathicity (GRAVY) score of the 16 BjuBXL proteins was predicted from -0.273 to -0.049, indicating these proteins are hydrophilic. According to gene structure and conserved motifs analysis, subfamily 1 of BjuBXL contained 5~11 exons and subfamily 2 contained 3~5 exons, and all the BjuBXL proteins contain ten conserved motifs. Chromosomal distribution analyses showed that 7 BjuBXL genes were located in 5 chromosomes of A subgenomes and 8 BjuBXL genes are located in 4 chromosomes of B subgenomes. The expression patterns of 16 BjuBXL genes during stem swelling was obtained from the RNA-seq data, 9 BjuBXL genes showed noticeable expression changes during the stem swelling process, while other 7 BjuBXL genes were nearly not expressed. The expression of BjuBXL1-1 and BjuBXL 1-2 were found notably correlated with stem swelling. Furthermore, real-time PCR results revealed that the transcriptional levels of BjuBXL1-1and BjuBXL1-2 were up-regulated during stem swelling and were significantly higher in the inner pith (P2~P4) than in regions of the outer pith of swollen stem (P1). Our results suggest that BjuBXL1-1 and BjuBXL1-2 may play an essential role in the inner pith cell wall metabolism during stem swelling. This study laid a foundation for further investigations of the function of BXL family genes in B. juncea var. tumida.
                                                                                                                   
    Abstract:
    Water-soluble nanometer fluorescent carbon points were synthesized in one step by "microwave method", then the silicon dioxide was grafted on the surface of carbon points by “sol-gel” method through tetraethyl orthosilicate (TEOS) as the cross-linking agent and phenyl ether methyl cycloazole as the template molecule. The polymer C-dot@MIP with good application prospects in trace detection of pesticide residues was obtained after the template molecules were washed off. Experimental results showed that the minimum detection limit calculated by 3σ/K was 0.93 μg/mL, and the recoveries of blank and standard spiking sample were not exceeding 25 percent.
                                                                                                                   
    Abstract:
    The Millard reaction solution and fish bone powder prepared from processing by-product of Ictalurus Punctaus (the fish bone with meat) were added to the soybean sauce to develop the flavor sauce with high calcium content. The formula optimization of high calcium flavor sauce was realized through single factor and orthogonal experiments using sensory score as evaluation index. The results showed that the order of influencing the high calcium flavor sauce was the addition amount of soybean sauce > sugar > vegetable oil > Maillard reaction solution. The high calcium flavor sauce made according to this formula of 30.4% of soybean paste, 4.7% of sugar, 16.8% of vegetable oil, 6.8% of Maillard reaction solution was sweet in flavor and excellent in overall quality. The calcium content of flavor sauce was 353 mg/100g after addition of fish bone powder which according to the claim of high calcium food. The result of quality inspection showed that the flavor sauce produced under the process met the standard limit.
                                                                                                                   
    Abstract:
    In this paper, the method of extraction and transient transformation of oil palm leaf protoplasts was established. Protoplasts were isolated from leaves of oil palm by 30 g/L cellulase and 8 g/L macerozyme for 3.5 h, and collected by centrifugation at 2000 rpm/min for 5 min at 4°C. Moreover, the dual plasmid transient co-expression system was optimized using green fluorescent protein (GFP) and red fluorescent protein (RFP). The best transformation efficiency was the obtained when the plasmids were mixed with oil palm protoplasts with the mass ratio of 8: 1, heat shocked at 45 °C for 20 min after placed on ice for 30 min, and incubated at room temperature in the dark for 30 min with equal amount of PEG/Mg2+ (200 g/L PEG 4000 and 100 g/L MgCl2). Finally, the protoplast isolation and transient expression system provides a new method for the functional verification of the genes form oil palm.
                                                                                                                   
    Abstract:
    In order to explore the effects of different plant height, center of gravity height and basal stem traits on lodging resistance of rice, In this study, 533 core rice germplasms were used as experimental materials, and 10 traits were analyzed by correlation and path analysis under two cultivation modes of pot culture and field culture.The results show that the first internode wall thickness and basal stem breaking-resistant strength of the low-plant rice have synergy on the lodging index.The improvement of lodging resistance traits of low-plant rice should focus on the first internode stem thickness and wall thickness. The lodging of high-plant rice is more affected by plant height and height of centre of gravity and the improvement of lodging resistance should be concentrated in the second internode stem thickness.The improvement of lodging resistance of rice germplasm with different plant heights can be achieved by enhancing the bending strength of the base. This study would provide an important reference for the improvement of lodging resistance in different rice plants.
                                                                                                                   
    Abstract:
    A field experiment was conducted in 2011 to study the effects of phosphorus (P) fertilizer application on the phosphorus fractions and microbial diversity of rice - rape crop rotation. Two treatments, NK (-P) and NPK (+P), were selected for the experiment. The soil layer was divided into 0~10、10~20、20~30 and 30~40 cm for sampling and analysis. Soil available P, total P and organic P were determined by conventional analytical methods. Chemical continuous extraction method was used to determine the inorganic P fractions in the soil samples, and Illumina-miseqpe250 platform was used for high-throughput sequencing of surface soil (0~10 cm) microorganisms. The results showed that, compared with the CK (-P treatment), long-term application of P fertilizer (+P) could significantly increase the content of total P, inorganic P and available P in each soil layer, but the organic P content did not increase significantly. From the perspective of available P content in soil layer, P content in soil layer of 0~10 cm and 10~20 cm could be significantly increased by application of P fertilizer, but the effect on the bottom layer of 20~30 cm and 30~40 cm was not obvious. Compared with -P treatment, long-term application of P fertilizer reduced the Alpha of microbial community diversity and changed the structure of microbial community. At the level of phylum, the dominant bacteria were Chloroflexi, Acidobacteria and Proteobacteria. The relative abundance of Chloroflexi and Acidobacteria were increased, while that of Proteobacteria decreased. Ascomycota and Basidiomycota were the dominant phylum, the relative abundance of Ascomycota decreased and that of Basidiomycota increased. Compared with CK, although the application of P fertilizer caused a significant decrease in the number of bacteria and fungi in the layer soil in each taxa, the relative abundance of the dominant flora also decreased from the perspective of the genus level. The results of redundancy analysis showed that the content of Al-P and Fe-P was closely related to the abundance of various bacteria and fungi. It could be seen that long-term phosphorus deficiency would induce an increase in the number of microorganisms to activate soil nutrients, and a sufficient supply of phosphorus fertilizer would meet crop nutrient requirements and maintain the dynamic balance of soil microbial communities. Therefore, it is necessary to optimize the application of P fertilizer in the entire crop rotation system to promote the activation and release of soil phosphorus, thereby reducing the amount of P fertilizer and improving its recovery rate.
                                                                                                                   
    Abstract:
    Xanthomonas campestris belong to Gram-negative bacteria, which mainly harm cruciferous vegetables and economic forests such as walnuts and mangosteens, causing great economic losses to agricultural and forestry crops and seriously harming the healthy development of the agricultural and forestry industry. Secreted proteins play an important role in the pathogenic process of plant pathogenic fungi, bacteria, and oomycetes. There have been no reports on the physical and chemical properties and characteristics of secreted proteins of Xanthomonas. This study uses the secreted protein sequences of X. campestris B100, X. campestris pv. campestris str.8004, and X. campestris CN14 with the published genome-wide sequence as the basic data, and uses Protscale, SMART, TargetP 2.0 Server, and other organisms. Informatics analysis software analyzes the physicochemical properties, conserved domains, and transit peptides of the above-secreted proteins. The results show that there are no obvious rule between the theoretical isoelectric point of secreted proteins in X. campestris and the length of amino acids. The average 44.73% of the protein is Unstable protein, with an average of 83.21% of the total protein, the average hydrophilicity is less than 0, which is a hydrophilic protein. At the same time, 12 of the secreted proteins of each X. campestris have an obvious conserved domain, and all secreted The protein is localized at S (signal peptide), and the predicted probability distribution of the transit peptide is also relatively even. This study lays a solid theoretical foundation for the in-depth analysis of the function of X. campestris secreted proteins.
                                                                                                                   
    Abstract:
    The moisture content of citrus is one of the key factors affecting the subsequent storage and processing of citrus. In order to detect the moisture content of citrus, the visible/near infrared transmission spectroscopy was used to detect the moisture content of satsuma orange. Differential processing, multivariate scattering correction, standard normal variate,SG convolution smoothing and MinMaxScaler are used and compared. At the same time, the Competitive adaptive reweighted sampling algorithm was used to extract the characteristic wavelengths, and then the partial least squares regression model(PLS), BP neural network model and least squares support vector machine (LSSVM) model based on citrus moisture content were established. The results show that the LSSVM model with 359 wavelengths obtained by CARS screening using the SNV preprocessed spectrum is the best predictor. The correlation coefficient and root mean square error of the correction set are 0.9375 and 0.0086, respectively. The square root errors are 0.8316 and 0.0120, respectively. The results show that the visible/near infrared spectroscopy technique is feasible to detect the water content of satsuma orange.
                                                                                                                   
    Abstract:
    In order to explore the application technology of fertilizer and pesticide reduction, a two-factor and three-level experiment was designed to compare the effects of different fertilizer and pesticide reduction combinations on the occurrence and yield of major diseases and pests in rice. The results revealed that the reduction of fertilizer tended to reduce the incidence of disease and insects, whereas the reduction of pesticides gave rise to a tendency to increase the incidence of disease and insects. The occurrence of rice sheath blight, fourth generation rice planthopper, and rice leaf borer could be significantly affected by the reduction of fertilizer. By contrast, the occurrence of rice sheath blight, third - and fourth-generation rice planthopper, and rice leaf borer were significantly affected by the pesticide reduction. However, They both had no significant effect on the occurrence of rice blast, rice false smut, and rice borer. When the fertilizer reduction is approximately 30%, there is a significant effect on yield, leading to the harvest yield reduction of 10.29%. When the reduction of fertilizer is less than 20%, compared with the control treatment, the harvest yield of green additive alternative treatment and biological pesticide alternative treatment increased 0.38% and 2.49%, respectively. Biological pesticide and green additive alternative treatment can be used as technical measures for reducing the number of chemical pesticides.
                                                                                                                   
    Abstract:
    The concept of a modern vertical farm was proposed in 1999. Theoretically, it has many advantages over traditional soil-based agriculture. In order to analyze and summarize the development and research status of vertical farms during the past two decades, this article used “vertical farm” and related terms as key words to search literatures from three databases, including CNKI, SCOPUS and Web of Science (WoS). Bibliometrics quantitative analysis was conducted with 184 selected literatures. The research progress was compared in China and internationally. By sorting and categorizing the literature, the research hotspots of vertical farms, as well as their research methods, were summarized. Based on that, the technical and economic feasibility were further analyzed. The results reveal that during the last decade the research on the vertical farm has accelerated, but the overall number of documents is still small, and only 25 relevant documents have been found in the WoS core collection database which represent research of high quality. The starting time of research on vertical farms in China and globally is similar. However, after the introduction of the concept in China, the popularity has declined, accounting for a low proportion of publications in China's core journals (only 10.6%). While international research has maintained a continuous upward trend since 2008 and continues to accelerate. And Nearly a quarter of international researches come from WoS core collection database. Results also presents a research trend in interdisciplinary fields. The research hotspots are mainly in the three aspects: technology integration, economy and feasibility, and ecological and environmental benefits. Research methods cover experimental research, case studies, mathematical modeling analysis, and simulation software analysis. At present, the key technologies involved in vertical farms are basically mature and there are no major obstacles. The key factors restricting its development are the cost-effectiveness and the uncertainty of ecological and environmental impacts, which need to be studied timely. With the continuous improvement of technical level and the proper selection of development strategies, the development prospect of vertical farms is very optimistic.
                                                                                                                   
    Abstract:
    HP-PRRSV has caused great economic losses to pig industry in China. In order to study the changes of viremia in serum and body weight after HP-PRRSV infection,72 healthy piglets selected from a large white pigs and Tongcheng pigs crossed population were infected with HP-PRRSV. The clinical symptoms were observed,the blood samples were collected and weight was measured on 0 4, 7, 11, 14, 21, 28 and 35 day post infection(dpi),serum was separated and viremia was measured. The results showed that the growth rate of body weight was slow from 0 to 4dpi,the body weight increased negatively from 4 to 21dpi, the loss of weight reached the maximum from 7 to 11dpi,the body weight increased positively and the growth increased gradually 21 to 35dpi.Viremia increased from 0 to 4dpi, peaked on 4dpi and lasted until 7dpi ,viremia decreased to 6.62log10 copies/mL from 7dpi to 35dpi.Death occurred 7dpi, and the dead individuals were mainly concentrated on 7 to 14 dpi. The death peak appeared on the 10dpi, and the number of dead individual was basically stable 19dpi.According to the survival or not death on 14dpi, the pigs were divided into two groups: resistance and susceptibility,the viremia of resistance was significantly lower than susceptibility 4,7,11dpi(p<0.05),the weight gain of resistance was significantly higher than that of susceptibility at 4-7dpi,7-11dpi,11-14dpi(p< 0.05).The above results showed that the weight gain and viremia could be used as indicators to predict the resistance of PRRS.
                                                                                                                   
    Abstract:
    The object of experiment was to evaluate the feeding effects of golden needle mushroom barn by using the in vitro rumen fermentation to select the best feeding combination and further test it in the practice. Firstly, Firstly, we measured the nutrients compositions of golden needle mushroom barn and other roughages. Next, we designed six groups of mixture based on early study and applied in vitro rumen fermentation to measure pH, NH3 and dry matter degradation to select the best group of mixture. In the end, beef cattle feeding trial was conducted to test the best group and 16 healthy Simonthal hybrid cattle with similar bodyweight and age were selected. The cows were randomly assigned to two groups, control group and experimental group, 8 cows each group. The cows in control group were fed basal TMR and the cows in experimental group were fed basal TMR designed by best group. The trial included 10 days for adaption, 80 days for formal experiment. Blood collection and bodyweight were conducted at the beginning and end of trial to evaluate the effects on bodyweight gain, blood physiological parameters and serum biochemical index. Results showed that nutrient composition of golden needle mushroom barn was similar to straw and maize yellow storage; The best mixture group was maize green storage(50%)+golden needle mushroom barn(30%)+beef grain(10%)+ Bean curd residue (10%); The best group of mixture significantly increased bodyweight gain of beef cattle (P<0.01), reduced the feed cost and had no detrimental effects on blood physiological parameters and serum biochemical index. To sum up, golden needle mushroom barn can be used as roughage for beef cattles.
                                                                                                                   
    Abstract:
    The effects of four Culture medium on the symbiosis of different varieties of soybean and AM fungi (Rhizophagus irregularis) were studied by pot culture. The difference between black ink and trypan blue staining methods and the application of the magnified grid line and the five-class methods in mycorrhizal symbiosis structures detection were also compared in this research.The results show that vermiculite and soil (V: V = 4: 1) are more conducive to the infection of AM fungi with soybean. The arbuscular abundance, hypha density and vesicle abundance in this culture substrate are significant higher than others, so it can be used as the best culture substrates for soybean and AM fungi symbiosis. For large-scale mycorrhizal symbiosis structures detection, ink staining and the magnified grid line method are the best methods in currently.
                                                                                                                   
    Abstract:
    The kiwifruits soft rot is the most serious disease during the storage and transportation of kiwifruits, which causing great economic losses. In this study, the pathogenic fungus causing kiwifruit soft rots were isolated and identified by examining the morphological and microscopic characteristics, combined with the results of pathogenicity testing and ITS (internal transcribed spacer) sequencing, and the inhibitory effect of carvacrol on kiwifruits soft rot was further evaulated. Two species, Botryosphaeria dothidea and Phomopsis vaccinii, were identified as the main pathogens causing kiwifruit postharvest soft rots, the other three species followed by Botrytis cinerea, Fusarium proliferatum and Alternaria alternata. Carvacrol had significant antifungal activity against eight soft rot pathogens,especially for B. dothidea and Phomopsis sp.,which half effective concentration (EC50) were 12.57 and 9.09 μL / L, respectively. Simultaneously, carvacrol effectively reduced the incidence of soft rot in kiwifruit under simulatedsales environment, which was only 50.17% compared with the control group, and had no significant effect on fruit quality(P > 0.05). Therefore, carvacrol has great potential to control soft rot of postharvest kiwifruit.
                                                                                                                   
    Abstract:
    The popular used rice cultivar Guangliangyou 35 and conventional japonica rice cultivar Nipponbare were treated with combined application of three Zn levels and four N levels in field trials. We analyzed the shoot dry weight at different growth stages, the yield and its components at mature stage as well as the N and Zn concentrations, accumulations and distributions in different organs and tissues. Results showed that the combined application of N and Zn fertilizers had synergistic effect on both the rice biomass at the early growth stage and the yield production at the mature stage. The combined application of N and Zn fertilizers had significant synergistic effect on rice panicle numbers. The significantly increased panicle numbers determined the increased yield under the combined application of N and Zn fertilizers. The combined application of N and Zn fertilizers not only increased the concentrations of N and Zn in rice plant, but also promoted the N and Zn distribution to the productive organ (spikelet), which is one of the main physiological mechanisms of increased yield production under the combined application of N and Zn fertilizers.
                                                                                                                   
    Abstract:
    To provide more insight in the characteristics of the cutan in the S5 and its environmental significance, the mineralogy and geochemical composition of the cutan and matrix soil in the S5-1pedon at the Wugong section on the southern Chinese Loess Plateau (CLP) was investigated. The broad band between 400-800 cm-1 in the Raman spectrum of the dark cutan was attributed to the groups of Fe and Mn hydroxide/oxide. Enrichment of Mn and free iron (Fed) in the cutan verified the presence of Fe-Mn cutan in the S5-1 pedon which signified a periodic reduction under waterlogged conditions during the pedogenesis of S5-1 pedon on the southern CLP. The low permeability of S5-1 pedon as a result of lessivage of clay fraction characterized by high bulk density and low total porosity made the development of a seasonal perched water table possible. It provided favorable environmental conditions for the formation of Fe-Mn cutan. However, the low Mn/Fe ratio in the cutan suggested that the separation and accumulation of iron and manganese in the S5-1 pedon was not up to the level of typical Fe-Mn cutan from subtropical regions. Silicate minerals in the Fe-Mn cutan was was almost identical to the matrix soil. The difference of chemical weathering between the cutan and the matrix soil reflected by the Fed/Fet ratio was not epitomized by the mineralogical composition. While the S5-1 developed a subtropical climate prevailed on the southern CLP was further corroborated by the occurrence of Fe-Mn cutan.
                                                                                                                   
    Abstract:
    In order to evaluate the breeding effect of the hybrid combination of Barkshire and Etongliangtouwu, the carcass and meat quality traits were measured in 70 Bae hybrid pigs (Barkshire×Etongliangtouwu). The results showed the body weight of Bae hybrid pigs was (109.10 ± 11.01) kg, slaughter percentage was 74.28% ± 1.99%, eye muscle area was (31.40 ± 3.57) cm2, backfat thickness was (31.65 ± 5.66) mm, skin thickness is (3.32 ± 0.74) mm, flesh color score 1 is 3.80 ± 0.77, intramuscular fat content is 1.94%, and the drip loss at 48 hours after slaughter is 2.07%. Thirteen fatty acids were detected in the dorsal longest muscle, of which saturated fatty acid content was 31.92% ± 7.68%, unsaturated fatty acid content was 68.08% ± 7.68%, and inosine monophosphate content was detected in the longest muscle of the back was (3.71 ± 0.42) mg/g. Correlation analysis showed that the fat percentage of the Bae hybrid pigs was significantly positively correlated with the backfat thickness (P<0.01, r = 0.69). Intramuscular fat content was significantly negatively correlated with meat color score 1 (P<0.01, r= -0. 37). inosine monophosphate content was significantly positively correlated with carcass length (P<0.01, r = 0.4). The results of this study showed that the slaughter performance of Bae hybrid pigs is great, the backfat thickness and skin thickness are moderate, the muscle color is bright, the line is good in hydraulic power, and great cross use was obtained. Keywords: Bae hybrid pigs; carcass traits; meat quality traits; fatty acids; correlation analysis
                                                                                                                   
    Abstract:
    Tongcheng pig is the first batch of breeds to be listed on the national protection list of livestock and poultry breeds. It is a representative breed of "Huazhong Two-End-Black pig" and the meat of it tastes delicious, tender and succulent. At the same time, it is found that Tongcheng pig has special resistance to High pathogenic Porcine Reproductive and Respiratory Syndrome virus. In order to retain the advantages of disease resistance and meat quality , and improve the deficiency of slow growth and low lean ratio of Tongcheng pigs, Etong Two-end-black was cross bred by introducing lean meat varieties. To compare the differences between Etong Two-End-Black and Tongcheng pig in nutrition and flavor compounds, amino acids, fatty acids, inosine acids and thiamine in the longissimus dorsi muscle of 30 Etong Two-End-Black and 29 Tongcheng pig were measured. The results showed that there were various kinds of amino acids in the Tongcheng pig muscle, the total content of 16 kinds of amino acids was 19.42±1.31 g/100 g, the content of essential amino acid (EAA) was 8.47±0.98 g/100 g, and the content of fresh amino acid (FAA) was 6.80±0.46 g/100 g. Tongcheng pig was rich in fatty acids and had high nutritional flavor value, the content of saturated fatty acid was 43.04% ± 1.84%, the content of unsaturated fatty acid was 56.96% ± 1.84%, in which the content of monounsaturated fatty acid (MUFA) was 47.47% ± 2.63% and the content of polyunsaturated fatty acid (PUFA) was 9.50% ± 2.50%, and the content of linoleic acid was 8.93%±2.36%. The content of flavor compounds, thiamine was 0.23 ± 0.05 mg/100 g and inosinic acid was 3.23 ± 0.67 mg/g , which were the material basis of Tongcheng meat quality and taste. The content of PUFA (12.08% ± 4.72%), linoleic acid (11.36% ± 4.44%) and thiamine (0.23 ± 0.05 mg / 100 g) in Etong Two-End-Black were significantly or extremely significantly higher than those of Tongcheng, and the above other traits were not significantly different from Tongcheng pigs (P > 0.05). The above results showed that the pork of the two breeds had the characteristics of high nutritional value and unique flavor, Etong Two-End-black pig not only retain the nutritional and flavor of Tongcheng pig, but had higher contents of PUFA and thiamine, which is worthy of further development and utilization.
                                                                                                                   
    Abstract:
    To investigate the changes of hematological traits after infection with highly pathogenic porcine reproductive and respiratory syndrome virus, a total of 72 Large White×Tongcheng advanced generation inter-cross piglets of 5 weeks old ,infected with HP-PRRSV, were used for the artificial infected experiment. The WBC count, the lymphocyte percentage, the monocyte count and the granulocyte percentage were determined at 0,4,7,11,14,21,28,35 days post infection (DPI) ,then were correlated with viremia respectively. The results showed when compared to 0DPI, the WBC count, the lymphocyte percentage and the monocyte count were significantly reduced (P <0.01), and the granulocyte percentage was significantly increased (P <0.01) at both 4DPI and 7DPI, but there were no significant differences for the other DPI. Groups of piglets with PRRS-resistant and PRRS-susceptible were set on the basis of viremia and survive. It was detected that the lymphocyte and the granulocyte percentage were significantly different at 7DPI between groups. The lymphocyte percentage was significantly higher than PRRS-susceptible group(P <0.05), and the granulocyte percentage was significantly lower (P <0.05).For other DPI, as well as other hematological traits, there were no significant differences. Furthermore, the correlation analysis of hematological traits and viremia at all DPI in piglets revealed medium correlations between the hematological traits and viremia (P <0.01). Our current study provides basic data for further research on the changes of hematological traits after PRRSV infection and its relationship with viremia deeply.
                                                                                                                   
    Abstract:
    Tongcheng pig is an excellent representative of local pig breeds in China, it has the advantages of good motherhood, tolerance to roughage, and the meat is tender, juicy and delicious, but it also has the problems of slow growth, thick back fat and low lean meat rate. Therefore, in order to make use of the good meat quality of Tongcheng pig and improve its disadvantageous traits, the lean meat type large white pig was introduced to cultivate a new breed of Etong Two-End-Black. To evaluate the effect of new breeding in this study, the growth traits, carcass traits (carcass length, backfat thickness, eye muscle area, percentage of lean meat, etc.), meat quality traits (meat color, dripping loss, marbling and intramuscular fat content, etc.) and blood physiological and biochemical indexes were measured between Etong Two-End-Black and Tongcheng pigs. The results showed that the daily gain of the Etong Two-End-Black was (596.27 ± 90.24) g / d, which was significantly higher than that of Tongcheng pig ((513.28 ± 90.31) g / d (P < 0.01)). The lean meat percentage of Etong Two-End-Black was (49.56% ± 2.21%) ,which was significantly higher than that of Tongcheng pig (43.47% ± 1.39%, P < 0.01).The backfat thickness of Etong Two-End-Black was (34.73 ± 0.94) mm, which was significantly lower than that of Tongcheng pig((38.80 ± 0.96)mm(P<0.01)). Marbling score and intramuscular fat content of Tongcheng pigs were (3.47 ± 1.16) and (3.45% ± 1.11%) respectively. Except for intramuscular fat content(2.72%±0.87%)of Etong Two-End-Black decreasing, there was no significant difference in other meat quality traits between two breeds. In addition, only part of the blood physiological and biochemical indexes of the two breeds have significant differences. The results illustrated that Etong Two-End-Black has improved their growth and carcass traits while retaining the excellent meat quality traits of Tongcheng pigs. Therefore, the study can provide scientific basis for further popularization and utilization of Etong Two-End-Black.
                                                                                                                   
    Abstract:
    The pepper root system and soil samples were collected from the pepper planting area in Qimaba Township, Lvchun County, Honghe Prefecture, Yunnan Province. To investigate pepper phytophthora root rot and calculate its incidence and disease index, The spore density, richness, diversity index and mycorrhizal infection rate of arbuscular mycorrhizal fungi(AMF) in the rhizosphere and around roots of pepper were investigated by wet-screen precipitation method and Plant root staining. Then the final data were analyzed by SPSS software. The results showed that when the mycorrhizal infection rate was 62.5%, the spore density was also the highest, reaching 11.725 spores/ g, the incidence and disease index of pepper phytophthora root rot were the lowest (20% and 9, respectively). when mycorrhizal infection rate and spore density were the lowest 11% and 2.475 spores/ g, the incidence and disease index of pepper phytophthora root rot were the highest at 80% and 53.5, respectively. The results of the correlation analysis showed that the spore density, richness and mycorrhizal infection rate of the AMF were negatively correlated with the incidence and the disease index of pepper phytophthora root rot. That is, the higher the spore richness and spore density of AMF, the higher the mycorrhiza infection rate, the lower the incidence of pepper phytophthora root rot and the smaller the disease index. It follows that the existence of AMF in pepper root soil can enhance the disease resistance of pepper and reduce the occurrence of diseases.
                                                                                                                   
    Abstract:
    The purpose of this study was to explore the effect of PGF2α signal on the oocyte and early embryo in buffalo, the expression patterns of PTGFR in buffalo oocytes and early embryos development were determined by immunofluorescence and fluorescence quantification. Subsequently, the effects of AL-8810 on the maturation efficiency of oocytes and the efficiency of embryonic development in buffalo were studied by adding different concentrations of AL-8810 into the oocyte maturation medium and embryonic development medium. The results showed that PTGFR protein was widely distributed in buffalo oocytes and embryos, and the expression level of PTGFR gene was significantly higher in 4-16 cell stage than in unfertilized oocytes and morulae (P<0.01). AL-8810 had no significant differences effect on the nuclear maturation efficiency of buffalo oocytes (P>0.05), however, high concentration treatment group(1 600 nmol/L) significantly reduced the early apoptosis rate of buffalo oocytes (P<0.05). AL-8810 at the concentration of 100 and 800 nmol/L significantly improved embryonic development efficiency in 16 cell stage, and the morula formation rate was the highest in the 800 nmol/L group. The above results indicated that inhibition of prostaglandin PGF2α signal effectively improved in vitro maturation quality of oocytes and early embryos development potential in buffalo.
                                                                                                                   
    Abstract:
    Bi系光催化材料是近年来被广泛研究的一类新型光催化剂,具有独特的层状结构和合适的带隙,价导带位置可调,是一类性能优异、环境友好型、结构可调的光催化剂,在环境与能源领域具有广阔的应用前景。本文介绍了Bi系光催化材料的种类,系统综述了形貌调控、表面缺陷引入、晶面构建、表面等离子体修饰、元素掺杂、构建异质结等结构调控方法,分析了光催化性能增强作用机制,并重点总结了铋系光催化材料在水处理、空气净化、固氮、产氢等环境净化和能源转化领域的应用研究进展,最后讨论了该领域所面临的挑战,并对Bi系光催化材料未来的发展进行了展望。
                                                                                                                   
    Abstract:
    Frequent events of winter haze in China have caused various health issues in large populations. It is believed that the sulfate aerosol produced by a series of physical and chemical reactions of SO2 is an important culprit of haze generation, and the heterogeneous reactions of SO2 on mineral particles is particularly important. Therefore, clarifying the formation mechanism of sulfate on mineral particles is a key scientific problem to analyze the formation of haze. In this paper, the research progresses about the typical heterogeneous reactions of SO2 on various mineral particles were reviewed, the effects of multi-pollutant coexistence system, humidity and light on heterogeneous reactions of SO2 were discussed, the future work related to heterogeneous reactions was also proposed. This paper aims to gain a deep understanding of the mechanism of mineral particles promoting the formation of sulfate and attempts to provide theoretical support for effective haze control.
                                                                                                                   
    Abstract:
    Aiming at the working conditions of rice stubble with high stubble, heavy soil adhesion and large fluctuation of water content in the rice-rapeseed rotation area, combined with the agronomic requirements that surface flatting, seedbed crushing, straw returning to the field and water draining to the furrow for winter rapeseed direct-seeding, considering the production practice that the single function tillage machine is not conducive to scramble for farming time and will compacting soil as it repeatedly working in the fields, a kind of seedbed preoaration technology scheme of "left-turn disc plough group burying stubble, reverse rotary knife roll crushing soil, side mounted plough ditching furrow" was put forward, and a kind of driven disc ploughing and reverse rotary tilling integrated machine for rapeseed seedbed preparation was designed. The machine is mainly composed of driving disc plough group, reverse rotary blade roller, front ditch plough and rear ditch plough and soil-flated plate, which can realize the functions of surface flatting, seedbed crushing, straw burying and furrow ditching. The spatial layout design principle of each tillage component was analyzed, and the structure parameters and working parameters of drivin disc plough group and reverse rotary blade roller were determined. Field experiment showed that: The average values of tillage depth, furrow depth, furrow width, compartment flatness, the rate of soil pulverizing and straw burying in seedbed after preparation machine operation were 173.2mm, 190.2mm, 401.4mm, 11.6mm, 95.9% and 90.2% respectively; The average values of stability coefficient of tillage depth, furrow depth and furrow width were 85.6%, 86.7% and 84.6% respectively. And these can meet the agronomic requirements of seedbed preparation for rapeseed mechanized direct-seeding.
                                                                                                                   
    Abstract:
    Abstract:[Objectives] The content levels of heavy metals Cd, Hg, As, Pb, Cr, Cu, Ni and Zn in 208 surface soils in the study area were detected. The environmental baseline value of heavy metal elements and the accumulation of changes relative to background values were obtained in regional surface soil. Based on this, the disturbance degree of heavy metal elements in regional surface soil by human activities can be judged. [Methods] Standardized method and relative cumulative percentage statistical method were used to calculate the environmental baseline value and deviation of heavy metals in regional surface soil. The average environmental baseline values obtained by these two methods were taken as the environmental baseline values of heavy metals in the surface soil of the study area. [Results] The content levels of heavy metals Cd, Hg, As, Pb, Cr, Cu, Ni and Zn in the surface soil of the monitoring points in the study area were not exceed the risk screening values for soil contamination of agricultural land. The environmental baseline values of heavy metals Cd, Hg, As, Pb, Cr, Cu, Ni and Zn obtained by these two methods were 0.22 mg/kg, 0.09 mg/kg, 13.34 mg/kg, 30.7 mg/kg, 82.0 mg/kg, 29.7 mg/kg, 38.0 mg/kg and 89.1 mg/kg respectively. The relative deviation ranged from 0.5% to 12.0%. [Conclusions] The environmental quality was generally good of regional surface soil. Compared with the background value, the environmental baseline value increased in different degrees of heavy metals Cd、Hg、As、Pb、Cr、Cu、Ni、Zn in regional surface soil, but the change rate was less than 50%, and the increase was not significant. Among them, the cumulative index evaluation grade of Cd reached slight accumulation, while other heavy metals elements had no obvious accumulation. This shows that heavy metal elements in the surface soil of the study area have been disturbed by human factors to a certain extent, and the influence degree was slight.
                                                                                                                   
    Abstract:
    Reactive oxygen species (ROS) are a class of oxygen free radicals or non-radical derivatives of oxygen with oxidizing ability. Utilizing ROS to degrade environmental pollutants is one of the greenest and most effective chemical means for pollution control and environmental remediation. However, there are different types and various generating-routes of ROS, and the mechanisms of environmental pollutant degradation and removal are distinguishing. It is significant to further understand the production and action mechanism of different ROS in environmental pollutant degradation and transformation. This article reviews recent research progress on ROS (hydroxyl radical, superoxide anion, singlet oxygen and hydrogen peroxide) for environmental pollutants removal in recent years and introduces several common ROS and their generating pathways and detection methods. We also summarize the applications of ROS in air purification, organic wastewater treatment, bacterial inactivation and finally discuss the major problems about ROS for environmental pollutants degradation and prospect the application of ROS in pollution control and environmental remediation.
                                                                                                                   
    Abstract:
    In this experiment,artificially wounded yam tuber were cuerd with 1 mmol / L BABA with 1 mmol / L NaHCO3 at 35℃ for 7days. The occurrence and accumulation of lignin and suberin polyphenolics, the weight loss and lession diameter, phenolic metabolism and active oxygen metabolism related indexes at the cut sites of yam tuber, were measured to evaluate the effects of treatments .The results demonstrated treated by 1 mmol / L BABA with NaHCO3 could effectively reduce the decay of wounded yam tuber with lignin and suberin polyphenolics accumulation at the wounding sites through activation of the ROS and phenolic metabolism levels. It was suggested that the treatment can inhibit the infection of pathogens effectively during curing time,and advance the callus process in wound site.
                                                                                                                   
    Abstract:
    Eggs provide various of nutrients for human beings, such as proteins, lipids, and vitamins. Besides of the processing properties from egg white, bioactive peptides obtained by the enzymatic hydrolysis method have diversiform biological functions. In this paper, biological functions such as of anti-oxidation, prevention of cardiovascular diseases, promoting mineral absorption, anti-diabetes, and regulating intestinal health were summarized, and the structure-activity relationships of egg white peptides from duck egg and chicken egg were also reviewed. It was found that egg white-derived angiotensin-converting enzyme (ACE) inhibitory peptides could affect their ACE inhibitory activity when the C-terminal was proline, leucine, and the N-terminal was aromatic or alkaline amino acid. Hydrophobic amino acids in N-terminal, and aromatic amino acids in the primary structure of antioxidant peptides from egg white can greatly improve the antioxidant capacity of the peptides. Glutamic acid in the first C-terminal, and phosphorylation of serine in the sequence of egg white-derived calcium absorption peptides have important contributions to the calcium absorption. However, bioactive peptides obtained by hydrolysis were confirmed to have different bioactivities, low yield and significantly different structures, making it difficult to obtain universal structure-activity relationship conclusions. Thus, the purpose of this paper is to provide a basis for the high-valued utilization of egg white, and a certain application for the production of egg white bioactive peptides as nutritional supplements, functional nutritional health products and therapeutic drugs, as well as to put forward a new prospect for the research of bioactive peptides.
                                                                                                                   
    Abstract:
    Telomerase has the function of maintaining telomere length, and its catalytic subunit TERT (Telomerase Reverse Transcriptase) is tightly regulated in higher organisms such as mammals, and is usually not expressed in somatic cells. However, in lower eukaryotes such as invertebrates, TERT is often expressed in somatic cells, but the physiological function is not clear. In order to clarify the physiological function of TERT, the TERT gene of Lipaphis erysimi (Kaltenbach) was cloned and analyzed for its spatial and temporal expression. The results showed that the CDS region of the radish TERT gene was 2658 bp and capable of encoding 885 amino acids. Its secondary structure contained 41 α-helices and 60 coiled coils. Phylogenetic analysis indicated that the Lipaphis erysimi TERT gene has the closest relationship with Diuraphis noxia, and has high homology with Myzus persicae and Acyrthosiphon pisum, but has low homology with other insects. Real-time quantitative PCR showed that the TERT gene was expressed in all ages and tissues during the growth and development of Lipaphis erysimi,and the relative expression of adult TERT gene was higher than that of 1st, 2nd, 3rd and 4th nymphs. The expression of TERT gene in the abdomen of the Lipaphis erysimi was the highest, followed by the head, and the lowest in the chest, but lower than the expression of the whole worm. This study laid the foundation for further study of the physiological functions of TERT in insects.
                                                                                                                   
    Abstract:
    The yield of rice is closely related to the number of panicle of rice and the weight of panicle, and accurate prediction of rice yield can accelerate the breeding speed. In order to study the relationship between rice yield and plant phenotypic characteristics, this experiment took potted rice as the research object, using visible light images combined with image processing technology for feature extraction, and obtained 51 phenotypic traits of whole rice. Combined with deep learning technology, the Faster R-CNN convolutional neural network training model was used to detect the number of rice spikes. At the same time, the Rice-PanicleNet model was trained using the SegNet network framework to segment the rice spikes to obtain the binary image of the rice spikes. , Combined with image processing technology to extract 33 phenotypic feature data of the panicle. A total of 85 phenotypic features were extracted from the image. The artificial measurement data in the experiment included the fresh weight and dry weight of potted rice panicle. Normalize all the data to build a prediction model of fresh weight and dry weight of potted rice panicles. Finally, select the most according to the model's decision coefficient R2, average relative error (MAPE) and standard deviation of relative absolute value (SAPE) Excellent prediction model. The prediction results show that the panicle characteristics prediction effect is the best, and the decision coefficients R2 of the predicted value and the real value of the model with the best effect are 0.787±0.051 and 0.840±0.054, respectively. In this study, combined with deep learning, the number of panicle and panicle characteristics that are difficult to obtain automatically by traditional methods are extracted, which provides a new idea and method for rice panicle weight prediction, and further improves the accuracy of rice panicle weight prediction.
                                                                                                                   
    Abstract:
    Aiming at the disadvantages of the present traditional silage of green or semi-green corn stalk powder, the compactness of lapping and pressing is small, the degree of anaerobic is not enough, the ammoniation is not good, there are some rotten and deteriorated, and it is inconvenient to seal in the process of opening and using. The key part of the high compression ratio packer, compression devices is designed. The compression molding experiments of four times, five times and six times compression ratio were carried out for the key component compression device in advance. The optimal compression ratio of 1:6 was determined through orthogonal design and multi-level analysis. Based on the quality purpose of improving packaging forming rate, the compression box is used by two hydraulic cylinders to open and close the feeding movable cover plate, two main hydraulic cylinders to compress the pressure, one hydraulic cylinder to push out and the pressure maintaining box to complete the compression and pressure maintaining forming. According to the properties of material expansion and springbackdue to stress relaxation after compression,the design experiment was carried out.the length of the pressure maintaining box is 600mm, the width is 300mm and the height is 365mm. After design and inspection the internal effective working range of the compression device is 1800mm in length, 600mm in width and 365mm in height,and the volume compression reaches a high compression ratio of 1:6, the anaerobic conditions is improved, the degree of ammoniation is improved and the use is more convenient.
                                                                                                                   
    Abstract:
    Ammonia selective catalytic reduction of nitrogen oxides (NOx) technology with V2O5-WO3 (MoO3) / TiO2 as the core catalyst is currently widely used. But it has many problems such as narrow and high temperature window, easy to poison by alkali inactivation, vanadium"s biological toxicity and secondary pollution to the environment, which require researchers to develop new efficient and environmentally friendly catalyst systems. Due to its unique structure, perovskite materials have good mid-high temperature activity, excellent high temperature resistance, sintering resistance and environmental protection and harmless characteristics, which has attracted more and more concerns in the field of selective catalytic reduction of NOx. This paper summarized the research progress of perovskite NH3-SCR catalysts in recent years. The main types of perovskite catalysts, denitration activity, structure-activity relationship and reaction mechanism were comprehensively discussed. The future possible development direction of perovskite NH3-SCR catalysts are prospected.
                                                                                                                   
    Abstract:
    Biomass combustion product rice husk ash was selected as the carrier, and Ni-Mg/RHA catalyst was prepared by co-impregnation method. The catalytic performance of Ni-Mg/RHA for steam reforming of toluene was studied using toluene as a model compound of biomass tar. The effects of Ni and Mg loadings, reaction temperature and S/C ratio on toluene conversion and gas product composition were investigated in a fixed-bed reactor. The catalysts before and after reaction were characterized by XRD, BET and SEM.The experimental results show that RHA as a support of single metal Ni-based catalyst has a certain catalytic activity;The activity and resistance to carbon deposition of Ni/RHA catalyst were significantly improve by that formation of NiMgO solid solution active center after the loading of MgO, and the catalytic activity and the resistance to carbon deposition of Ni/RHA catalyst were optimal when the Mg loading amount was 6wt%, and the toluene conversion was as high as 98.6%;The optimum reaction temperature of 3Ni-6Mg/RHA is 700 ℃, S/C is 3, and the catalyst has good catalytic stability. The feasibility of using rice husk ash as the support of nickel-based catalyst in the presence of MgO was proved.
                                                                                                                   
    Abstract:
    In view of the complex production conditions of heavy soil compaction in the middle and lower reaches of the Yangtze River, large fluctuations in water content, and large remaining rice straw residues, and the production requirements of rapeseed cultivation for rapeseed cultivation, an imitation shoe-shaped ditching plough used in combination with a driven plough combined rotary tiller was developed. According to the principle of the guide curve of the plow body and the modeling analysis of the three-sided wedge, a smooth parabola is selected as the sliding cutting edge curve, and the sliding angle of the sliding cutting edge curve is determined to range from 25 ° to 65 °, and the plough body entry angle is 30°. The opening angle of the plow tip is 60 °. Through the dynamic analysis of the interaction between the shoe-like sharp-angle ditch plow and the soil, the length of the fender is 400mm, and the inclination of the wing is 40 °~79.2 °. Field tests have shown that a shoe-like sharp-angle ditching plough can produce a trapezoidal ditch with a ditch width of 200~400 mm and a ditch depth of 175~250 mm. The ditch width and ditch depth stability are both above 90%, and the ditch bottom is flat. The ditch shape is obvious, when the inclination of the wing is 46 °, the ditch depth is 183mm, and the working speed is 0.6m/s, which meets the agronomic requirements of rapeseed planting, and provides a reference for the equipment design of the furrow ditch for rapeseed bed preparation
                                                                                                                   
    Abstract:
    In order to solve the problem of severe vibration caused by fruit tea garden conveyer in practical use, a semi-active suspension system using CDC damper was designed, and the loading test was carried out by using fuzzy PID control method. According to the suspension system dynamics model, MATLAB was used to establish a Simulink model of fuzzy PID controller, which was analyzed and the parameters were adjusted, and the ideal simulation response results were obtained. Through the analysis, the performance of semi-active suspension system was improved by 10% ~ 20% compared with that of passive suspension system. Design of hardware part of the semi-active suspension system and loading test, the system of mechanical parts including the elastic element structure, shock absorber, steering mechanism, and the parts fitting the transformation, consider front axle layout space arrangement, the shock absorber system layout in the form of oblique arranged with the horizontal plane Angle of 30 °, elastic element for vertical layout, steering mechanism installed in the middle of the front axle position, to limit the movement before and after the front axle and constraint the trajectories of vertical direction. According to the design of fuzzy PID controller for the design of control circuit system, the semi-active suspension loading experiment was carried out, using vibration meter and vibration sensor system is built, the test vehicle in the process of driving seat position z axis vibration signal, respectively in speed and load conditions, through the semi-active suspension before and after loading, the results of test of conveyor with semi-active suspension vibration drop of about 50%, reached the design requirements of the semi-active suspension system.The vibration frequency concentration range of the vehicle body with semi-active suspension system is more than 8Hz, indicating that the driving comfort of the vehicle is better.
                                                                                                                   
    Abstract:
    Physical and mechanical characteristic parameters are indispensable in the design of potato minituber related mechanical equipment planter and classifier, developing of simulation technology the contact mechanics parameters are also. Aiming at these problems, "Daxiyang", "Zhongshu No. 5" and "Huashu No. 1" were taken as research objects. The Physical mechanics parameters and contact mechanics parameters were determined with the relevant parameters required for discrete element software EDEM in potato minituber research. The parameters measured in the above experiment were input into the EDEM for simulation to obtain the rolling friction coefficient between the potato minituber. the stacking angle was used as the response value, and the credibility of the simulation results was verified by raising a round pipe slowly. The results show that compared with the actual accumulation angle of the experiment, the simulation results of different varieties of potato minituber are less than 3%, and the results are reliable.
    Display Method:
    2015,34(4):108-113, DOI:
    [Abstract] (1524) [HTML] (0) [PDF 1.06 M] (8664)
    Abstract:
    In this study,we investigated the effect of bio-floating bed on growth and muscle quality of grass carp (Ctenopharyngodon idellus) and blunt snout bream(Megalobrama amblycephala) in ponds.Two modes of culture ponds were chosen:one equipped with bio-floating bed was the experimental pond,and the other without beds was the control pond.At the end of the experiment,we measured the growth parameters,the muscle conventional nutrients,water holding capacity (WHC),and texture characteristics using biochemical and physical methods.The results showed that the final weight of fish cultured in the experimental pond was higher than that in the control pond.The hepatic somatic index of grass carp (1.77%) in the experimental pond was significantly lower than that of the control (2.47%).The condition factors of grass carp and blunt snout bream (1.73 and 2.56,respectively) were significantly higher than those of the control (1.64 and 2.40,respectively).There was no significant difference in the eviscerated weight of both carp and bream between the experimental (91.06 and 88.28,respectively) and the control (89.22 and 88.49,respectively) ponds.The drop loss (14.49% and 10.69,respectively) and water loss rate (17.52% and 10.34%,respectively) of the experimental grass carp and blunt snout bream were significantly lower than those of the control.The cooked rate of the experimental fish was significantly higher than the control.The muscle crude fat content (1.89%) and crude protein content (14.60%) of grass carp in the experimental ponds were significantly higher than those of the control (1.54% and 13.46%),whereas muscle water content (81.68%) of the experimental fish was significantly lower than that (82.65%) of the control.There is no significant difference in muscle ash content between the two groups.Unlike grass carp,only muscle crude protein content (17.23%) of the experimental bream was significantly higher than that (15.90%) of the control.The muscular hardness,gumminess,and chewiness of the experimental carp (5 298.10 g,2 450.78 g and 770.78 g,respectively) were significantly higher than those of the control (3 226.79 g,1 881.43 g and 602.80 g,respectively).The resilience (0.31) and cohesion (0.48) of experimental carp were significantly lower than those (0.43 and 0.58,respectively) of the control.However,only the muscular springiness of the blunt snout bream in the experimental pond was significantly higher than that in the control pond.
    2015,34(4):120-124, DOI:
    [Abstract] (1860) [HTML] (0) [PDF 976.50 K] (6686)
    Abstract:
    Effects of soaking temperature,cultivation temperature and watering frequency on the growth characteristics and nutrition of mung bean sprout were investigated. Growth characteristics and nutrition of mung bean sprout were significantly affected by soaking temperature,cultivation temperature and watering frequency (P<0.05). When the bean was soaked at higher temperature (40℃),body weight of the cultivated mung bean sprout was heavier,hypocotyl was longer,contents of free amino acid (FAA),water soluble sugar (WSS) and γ-aminobutyric acid (GABA) were higher. The hypocotyl was longer while the diameter was smaller when the bean was cultivated in the relatively higher temperature (30-35℃). When the watering frequency decreased,weight,hypocotyl length and diameter decreased,WSS content decreased first and then increased,FAA content increased first and then decreased,GABA content was fluctuated. The optimal germination conditions of mung bean sprout were soaking bean at 40℃ for 5 h,with cultivation temperature of 25-30℃ and watering once per hour.
    2013,32(4):48-54, DOI: 1000-2421(2013)04-0048-07
    [Abstract] (1757) [HTML] (0) [PDF 1.58 M] (5295)
    Abstract:
    The spatial distribution of Valley County land use degree in 2009 was studied and the spatial autocorrelation of land use degree and its driving factors in different scales were analyzed.A spatial autoregressive model and geographically weighted regression model was established from the perspective of global local.The results showed that there was a certain spatial autocorrelation in land use degree and its driving factors with scale effect.Spatial regression model could estimate the overall parameter of various factors while geographically weighted regression model could give the local parameter of various factors.Scales of geographical weighted regression model could reflect the detailed geographical information to some extent.
    2015,34(1):128-135, DOI:
    [Abstract] (2013) [HTML] (0) [PDF 1.21 M] (4157)
    Abstract:
    In order to overcome the transition,field operation, and standardized batch production difficulties of the existing track cargo vehicle in mountainous orchard, as well as to raise the utilization rate, the mountain orchard detachable unidirectional traction double track cargo vehicle was developed. This paper introduced the whole machine structure, the wire rope diameter selection,the minimum track inclination,the maximum track distance,the minimum track turning radius and the working principle of the rope brake device. Load experiments were carried out to test the cargo′s synthetic track function. It is indicated by calculation that the wire rope diameter should be 7.7 mm,the minimum track inclination was 5.7°, the maximum track distance was 170 m, the minimum track horizontal turning radius was 7 m, and the minimum track vertical turning radius was 2 m. Load experiment results indicated that the cargo vehicle′s uplink average speed was 0.51 m/s, the downlink average speed was 0.54 m/s, the average energy consumption was 1.235 kW·h and the effective use degree was 100%. This cargo vehicle was suitable for fruit, pesticide, chemical fertilizer and other cargo transportation in the mountain orchard. Meanwhile, it can be applied to carry the spraying machine, the shave machine and other agricultural machines.
    2012,31(1):16-22, DOI: 1000-2421(2012)01-0016-07
    [Abstract] (2269) [HTML] (0) [PDF 1.07 M] (4089)
    Abstract:
    Nitrogen is one of essential nutrients for plant growth.Under the N deficiency at different time points,the dynamic changes of the expression of genes and activity of enzymes related to nitrogen assimilation in rice were investigated.The results showed that the concentrations of ammonium and nitrate significantly reduced under the N deficiency.Under the N deficiency for a short time,the expression level of genes including NR1, NR2, NiR2,GS2,Fd-GOGAT,GDH2,GDH3 in the shoots as well as NR1,NR2,GDH4 in the roots were up-regulated,and then their expression level decreased after a long time under the N deficiency.Along with the extension of time under the N deficiency,the GS,Fd-GOGAT activities in whole plants,NR activity in shoots and NADH-GOGAT activity in roots decreased while the NADPH-GDH activity in shoots increased.In roots the activities of NR,GDH increased at first and then decreased,while in shoots the NiR activity was just the opposite.Re-supplied N after 7 days of N deficiency,the transcriptional expression level and enzyme activities of NR,NiR,GS,GOGAT,GDH restored,and expression level of some genes increased as well.
    2013,32(5):124-133, DOI: 1000-2421(2013)05-0124-10
    [Abstract] (1369) [HTML] (0) [PDF 4.01 M] (3931)
    Abstract:
    Bacterial canker is a devastating disease of kiwifruit. In recent years,the disease is showing a tendency to outbreak in such countries as Italy and New Zealand,where kiwifruit is a major crop,and has the trends to further spread worldwide,which will be a serious threat to the development of the kiwifruit industry. Based on the latest research reports, this paper summarized the symptoms,pathogen identification,rapid detection methods,virulence differences,infected mechanism,epidemiology and control technology of the disease. Meanwhile,the future research prospect of kiwifruit bacterial canker was also discussed in order to reduce the loss and risk of the kiwifruit industry.
    2015,34(3):8-12, DOI:
    [Abstract] (1092) [HTML] (0) [PDF 3.41 M] (3713)
    Abstract:
    pCB302-3 is a plant mini-binary stable transformation vector.To investigate the transient expression of pCB302-3 vector in plant,GFP was inserted into pCB302-3 vector as a reporter gene,and various factors including density of Agrobacterium cell,supplementation of gene silencing suppression p19 and days post infiltration were optimized based on agroinfiltration method in Nicotiana benthamiana leaves.Results showed that high levels of GFP expression were observed in N.benthamiana leaves 3-5 d after infiltration by Agrobacterium cell suspension contained pCB302-3-GFP with an optical density (D600) of 0.8-1.0 co-infiltrated with p19 gene.
    2012,31(1):127-132, DOI: 1000-2421(2012)01-0127-06
    [Abstract] (1500) [HTML] (0) [PDF 930.13 K] (3632)
    Abstract:
    Post-harvest strawberries are susceptible to the decay of fruit and deterioration of quality due to pathogenic fungi infections,a main factor leading to economic losses for both growers and retailers.With the increase of strawberries planting in China,it is urgent to effectively reduce post-harvest rots of strawberry fruits.In this review,new management developments for controlling fungal diseases in post-harvest strawberry were summarized in terms of physical,chemical and biological approaches,which can help to extend the on-shelf time of strawberry fruits.
    2012,31(5):569-573, DOI: 1000-2421(2012)05-0569-05
    [Abstract] (1165) [HTML] (0) [PDF 912.59 K] (3436)
    Abstract:
    Hydroponic experiments of strawberry were conducted with three formulations of nutrient solution to select the best formulations for soilless cultivation of strawberry.Several main characteristics of growth including the fresh weight and dry weight of overground plant and root,the growth of crown,the photosynthetic and quality of strawberry,the diameter of staminate flower,the growth amass were investigated.The results showed that the effect of nutrient solution with the content of calcium nitrate tetrahydrate,potassium nitrate,ammonium dihydrogen phosphate,magnesium sulfate and ammonium nitrate at 295,303,62,246,0 mg/L on the growing status and fruit quality of strawberry are better than that of the other 2 treatments.This nutrient solution formula was the most propitious for the growth of ‘Jingyao’ strawberry and the enhancement of the fruit quality among the three different treatnments.That is,it facilitated the growth of strawberry in alimentation growth periods,and the leaves of ‘Jingyao’ strawberry was larger and thicker with a dark-green color,and the diameter of the pedicel was also larger. In addition,the nutrient solution formula was also conducive to the flowering promotion and the reproductive growth of strawberry,and resultes showed that the single fruit weight,yield and fruit quality is the best comparing to the other treatments.The results of this study provided academic and technological basis for establishing high yield and quality of strawberry in greenhouse substrate culture of irrigation and nitrogen application system. 
    2016,35(1):81-85, DOI:
    Abstract:
    Using Mesorhizobium sp.S-15 and Paenibacillus sp.S-17 as experimental strains.After cell disruption,NH4OAc extraction,H2O2 solution digestion or without any pre-treatment,K+ content in the fermentation broth of potassium solubilizing bacteria was determined with flame photometer.The efficiency of K solubilizing by potassium solubilizing bacteria in the culture medium was calculated.The results showed that the standard curves of the three kinds of K series of standard solutions were similar with the R2 values of 0.994 4,0.999 7 and 0.999 8,respectively.After digested by H2O2 solution,concentration of K+ was detected.The efficiency of two strains was 101.1% and 125.1%,significantly higher than that of other groups.The efficiency of potassium solubilizing detected after H2O2 digestion well reflected potassium solubilization of bacteria.
    2014,33(2):139-144, DOI: 1000-2421(2014)02-0139-06
    [Abstract] (1276) [HTML] (0) [PDF 968.56 K] (3245)
    Abstract:
    Algae are lower photosynthetic autotrophs which have close relationship with agricultural activities.With the deep understanding of physiological and ecological characteristics,algae have used more and more widelyin the practice of agricultural activities.This paper reviews the application of algaeas a resourcein agricultural activities including improvement of agricultural environment,utilized as food or food additives and health care products,as well as feed or bait.
    2014,33(01):12-17, DOI: 1000-2421(2014)01-0012-06
    [Abstract] (1495) [HTML] (0) [PDF 944.55 K] (3216)
    Abstract:
    Seventeen pairs of SSR primers with clear polymorphic bands were screened from 60 pairs of SSR locus covering 17 linkage groups of pear genetic map and amplified with 20 pear cultivars.136 polymorphic bands in total were obtained with 5~11 bands per primer locus (8.0 bands on average).The polymorphism information content (PIC) of the 17 SSR loci ranged from 0.614 to 0.848 with an average of 0.733.All pear cultivars studied could be identified with 38 different combinations of 2 markers each.Bands amplified by each marker were coded based on size of fragment and used as a molecular ID.
    2010,29(3):363-368, DOI: 1000-2421(2010)03-0363-06
    [Abstract] (2486) [HTML] (0) [PDF 11.41 M] (3206)
    Abstract:
    The index of heat injury and leaf anatomical structure under the scanning electron microscope of six Primula species were measured to study the responsive mechanism of Primula to the high temperature and to select the heat resistant Primula species.The results showed that Primula forrestii and P.malacoides franch had higher heat-resistance than that of P.obconica,P.veris,P.saxatilis,P.denticulatess.,P.sinodenticulata with lowest heat-resistance.Leaf anatomical structures of Primula associated with heat-resistance included leaf thickness,tightness of mesophyll cell arrangement,the number of open stomata,the number of epidermal hair and powders of leaves.
    2014,33(06), DOI:
    [Abstract] (752) [HTML] (0) [PDF 8.30 M] (3196)
    Abstract:
    The development of Golden Rice to date has taken longer than anticipated.It has been proven to have the potential to assist in the alleviation of an important public health problem,vitamin A deficiency,affecting millions.Complying with the highly precautionary,and now proven unnecessary,UN Cartagena Protocol for Biosafety has impeded scientific progress and scientific collaboration,particularly by delaying the selection of phenotypes grown in the open field.So far therefore,Golden Rice has not been able to assist in combatting vitamin A deficiency,identified by the UN as an important public health target for 25 years,and which continues to cause preventable deaths and blindness.However,the inventor’s original vision of the donation of the technology to assist the resource poor who want to benefit from it remains firm and achievable,subject to continuing philanthropic and public sector funding.
    2014,33(2):15-21, DOI: 1000-2421(2014)02-0015-07
    [Abstract] (1705) [HTML] (0) [PDF 980.62 K] (3181)
    Abstract:
    Teosinte is the ancestor of maize,and plays an important role in maize domestication process and gene cloning.Solexa RNA-Seq was used to de novo assembly and analyze the transcriptome of teosintes.40.6 GB raw data were produced,including 175 101 250 reads of 76 bp length.After quality control and de novo assembly,58 147 teosinte transcripts with an average length of 1 335 bp were obtained.After bioinformatically comparing,it was found that 94.3% of teosinte transcripts had good matching with B73 cDNAs,and that 84.1% of the transcript had good matching with rice,84.6% with sorghum and 83.9% with brachypodium at protein level.This research will provide a reference for subsequent studies on maize evolution and gene discovery.
    2014,33(2):96-102, DOI: 1000-2421(2014)02-0096-07
    Abstract:
    A 90-day study was conducted to investigate effects of dietary lipid levels on performance,fat deposition,activity and expression of lipoprotein lipase (LPL) in GIFT tilapia (Oreochromis niloticus) juvenile,and to explore the correlation between LPL gene expression and fat deposition.315 GIFT tilapia juveniles(average weight 2.63±0.16 g) were randomly divided into three groups with three replications,and fed with isonitrogenous diets with different lipid levels of 3.7% (low-lipid group),7.7%(middle-lipid group)and 16.6% (high-lipid group) by supplementing with 2%,6% and 15% fish oil as lipid source,respectively.The results showed:(1) the hepatosomatic index (HSI),viscerosomatic index (VSI) and lipid contents in liver and muscle increased with increasing dietary lipid level(P<0.05),but there was a trends for condition factor (CF) with first increased then decreased (P>0.05); (2)with increasing dietary lipid levels, the weight gain (WG) first increased, then decreased, and feed conversion ratio (FCR) decreased(P<0.05); (3)LPL gene was expressed in liver and muscle of GIFT tilapia,while the expression level in liver was significantly higher than that in muscle (P<0.05); (4) during the 48 h post-refeeding period,liver LPL activity in high-lipid group was significantly higher than that in low-lipid and middle-lipid group at 6 h,but significantly lower than that in low-lipid group at the 12 h,24 h and 48 h.There was a trend in low-lipid and middle-lipid group that liver LPL activity increased first and then decreased; (5) the expression of LPL was significantly higher in high-lipid group than that in low-lipid group (P<0.05); (6) there were a significant linear positive correlation between HSI,lipid contents in liver and muscle,and liver LPL expression in GIFT tilapia juvenile.The results indicated that LPL expression in GIFT tilapia was in a tissue specific pattern and liver was the main organ for secretion and expression of LPL; high dietary lipid level could inhibit growth of GIFT tilapia juvenile,decrease feed conversion ratio,induce the expression of LPL in liver,and promote fat deposition in liver and muscle; liver LPL expression was involved in fat deposition of GIFT tilapia juvenile.
    2015,34(3):134-141, DOI:
    [Abstract] (1152) [HTML] (0) [PDF 1.42 M] (3121)
    Abstract:
    Soil salinity is a major environmental constraint to agricultural productivity.It is a complex network for plant adaptation to salt stress,and it is still a great challenge to improve crop salt tolerance.Mechanisms of SOS signal transduction pathway on Na+ exclusion and compartmentation,the regulation of microRNA and transcription factors involved in salt stress were reviewed.It will provide a fundamental understanding and knowledge for studying salt resistance and breeding salt tolerance in plants.
    2010,29(6):798-804, DOI: 1000-2421(2010)06-0798-07
    Abstract:
    The cracking of fruit skin and the splitting of underlying flesh is a kind of fruit physiological disorder,which downgrades the fruit appearance quality and causes the infection of disease,thereby reducing the commercial value and resulting in serious economic loss.Herein recent studies on fruit cracking were reviewed,mainly focusing on the influence of phenotypic characteristics,genetic factor,physiological characters,mineral nutrients,environmental conditions,plant growth regulators and cultivation practices.The prospect of research was discussed.
    2011,30(2):249-259, DOI: 1000-2421(2011)02-0249-11
    [Abstract] (1052) [HTML] (0) [PDF 1.05 M] (3040)
    Abstract:
    Chloroplast transformation in plants has many advantages over nuclear transformation.Proteins in chloroplasts can be expressed at high levels with proper folding and disulfide bonds as the cells of higher plants contain a large number of chloroplast genomes.Multiple genes can be co-expressed in chloroplast genomes.Furthermore,chloroplast genes are inherited in a strictly maternal fashion in most angiosperm plant species,and this minimizes the possibility of out-crossing transgenes to related weeds or species.In addition,gene silencing,position effects and random integration have not been reported in chloroplast transformation.Although chloroplast transformation is very attractive,this technology is not as widely used as nuclear transformation.It has been mostly focused on 16 plants species,especially tobacco in which many proteins has been expressed including vaccines and antibodies.In this review we briefly summarize the rationales,methodologies,applications,bottlenecks and prospects of this promising genetic engineering technology for chloroplasts.
    2011,30(5):613-617, DOI: 1000-2421(2011)05-0613-05
    [Abstract] (1130) [HTML] (0) [PDF 914.54 K] (3018)
    Abstract:
    Pot experiment was conducted to study the effects of spraying different micronutrients and amino acids into the surface of leaves on yield and quality of Chinese cabbage (Brassica rapa L.).The results showed that methionine,zinc,molybdenum,boron and glycine could increase yield of Chinese cabbage.The treatments of spraying methionine,zinc and molybdenum increased yield of Chinese cabbage significantly.All treatments could reduce the nitrate content of Chinese cabbage with the highest decrease of 35.0% compared with the control.Molybdenum,boron,zinc and methionine might reduce nitrate content of Chinese cabbage significantly.Experiment also indicated that glycine,proline and selenium could both increase the contents of vitamin C,soluble sugar and soluble protein of Chinese cabbage.Therefore,spraying micronutrient or amino acids into the surface of leaves is a good application for increasing yield,reducing nitrate content and improving quality of Chinese cabbage.

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