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- Abstract：To explore the climate suitability for naked oat cultivation in China, the MaxEnt model was used to analyze the climatic factors and to divide the potential suitable area based on the multi-year average data of 707 standard meteorological stations from 1991 to 2017 combined with the geographical distribution information of naked oat. Among 16 potential climatic factors affecting the growth, development and yield formation of naked oat, four major climatic factors affecting the distribution of naked oat were annual precipitation, annual average minimum temperature, duration days of ≥30 ℃ and annual range of air temperature. The optimum thresholds of dominant climatic factors for naked oat are 302. 7-462. 8 mm of annual precipitation, -3. 5-1. 0 ℃ of annual average minimum temperature, 2. 3-21. 1 d of duration days of ≥30 ℃ and 29. 2-37. 4 ℃ of the annual range of air temperature, respectively. The result showed that the area of the high suitable, suitable, less suitable and unsuitable areas for naked oat are 386. 37×103, 780. 72×103, 2 593. 53×103 and 5 894. 10×103 km2, respectively, accounting for 4. 00%, 8. 09%, 26. 86% and 61. 05% of the total land area of China. The optimum and suitable areas for naked oat planting are mainly distributed in North China and Northwest China, including central Inner Mongolia; the north of Hebei and Shanxi Province; the southern part of Ningxia Hui Autonomous Region and Gansu Province; Qinghai Province except its west part; Shannan region of Tibet Autonomous Region; and sporadic distribution in western Xinjiang Uygur Autonomous Region. The suitable area in the western part of Northeast China is vast, and there is a high potential for large-scale cultivation of naked oat.12|11|13<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the method of breeding soybean hybrids with strong restorer and fertility stability, fourteen representative materials including six three-line soybean hybrid combinations(two male sterile lines, two maintainer lines and four restorer lines)were used to analyze the fertility related indexes of hybrid soybean and its parents under short light(SL)and normal light(NL)at seedling stage. The results showed that the fertility of male sterile lines, maintainer lines and restorer lines was highly stable, and not affected by SL treatment at seedling stage. The fertility of different hybrids showed significant differences. The fertility of four hybrid combinations with ‘SXTH 3', ‘SXTH 5' and ‘SXTH 21' restorer lines was greatly affected by SL treatment at seedling stage. After SL treatment, the plants almost did not pod and showed sterility. The fertility of hybrid combinations was unstable, and ‘SXTH 3', ‘SXTH 5' and ‘SXTH 21' were weak restorer lines. The fertility of two hybrid combinations prepared with ‘SXTH 40' restorer line was less affected by SL treatment at seedling stage. After SL treatment, the plants could still set pod normally, which was fertile. The fertility of hybrid combinations was stable, and ‘SXTH 40' was a strong restorer line. The pollen fertility rate was significantly positively correlated with pod number per plant and seed number per plant. In conclusion, the combination of short light treatment at seedling stage and detection of pollen fertility rate is conducive to breeding strong restorer lines and stable fertility soybean hybrid combinations.Keywords：hybrid soybean;short light;fertility;pollen fertility rate;agronomic trait2|10|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：The aim of this study was to explore the physiological characteristic of root and grain yield of rice under different long-term fertilizer regime in the double-cropping rice system. The superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), nitrate reductase and glutamine synthetase activity of rice root, dry matter accumulation of rice plant, and grain yield of rice were investigated from 2018 to 2019 based on long-term fertilizer field experiment. The experiment were included four different fertilizer treatments: Without fertilizer input as control(CK), chemical fertilizer alone(MF), rice straw returning and chemical fertilizer(RF), and 30% organic fertilizer and 70% chemical fertilizer(OM). The results showed that compared with MF and CK treatments the activity of SOD, POD and CAT of rice root were increased in RF and OM treatments at main different growth stages of early rice and late rice. Meanwhile, compared with MF and CK treatments, the malondialdehyde(MDA)and proline(Pro)contents of rice root were decreased with RF and OM treatments at main different growth stages of early rice and late rice. The nitrate reductase and glutamine synthetase activity of rice root and root activity with different fertilizer treatments were decreased in the order of OM>RF>MF>CK at main different growth stages of early rice, and RF>OM>MF>CK at main different growth stages of late rice, respectively. The dry weights of rice root and shoot with OM treatment were significantly higher than that of MF and CK treatments. The grain yield of early rice with OM and RF treatments were higher than that of MF and CK treatments and the grain yield of late rice with RF and OM treatments were higher than that of MF and CK treatments, respectively. In 2018 and 2019, the grain yield of early rice were increased by 944. 8-1 143. 2 and 435. 9-516. 1 kg/hm2 with OM and RF treatments compared with MF treatment, respectively. The grain yield of late rice were increased by 386. 2-387. 4 and 119. 8-123. 7 kg/hm2 with RF and OM treatments in 2018 and 2019, compared with MF treatment, respectively. In conclusion, the long-term combined application of organic manure and rice straw returning with chemical fertilizer practice was an effective way to improve protective enzyme activity of rice root and grain yield of rice in double-cropping rice system of Hunan Province.Keywords：fertilizer regime;rice;root;dry matter;protective enzyme;rice yield4|12|6<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To precisely analyze the yield and current comprehensive utilization of crop straws in China, the straw yields of cereals, beans, potatoes, cotton and other crops in 31 provinces(autonomous regions and cites)from 2009 to 2018 were estimated by combining straw coefficient based on China Statistical Yearbook on 2019 released by the National Bureau of Statistics of China. The results showed that the total straw yield of China was increased by 126. 73 million tons from 2009 to 2018 with an annual growth rate of 2. 01%. Among those crop straws, corn straw had the most significant contribution. In 2018, the overall distribution of straw production in China showed a trend of higher in the eastern and northern provinces and lower in the western and southern provinces. Specifically, the crop straw yield was higher in Henan, Shandong, Heilongjiang, Guangxi, Jiangsu and Anhui provinces, while it was lower in Beijing, Shanghai, Tianjin, Zhejiang, Hainan Province, Tibet Autonomous Region, Qinghai Province and Ningxia Hui Autonomous Region. The overall distribution of arable straw yields is distributed in three steps, and the high yield areas concentrated in the third step. Therefore, the yield of China's crop straws is huge, it needs to increase research and development of “five key” technologies(straw fertilizer, straw feed, straw fuel, straw matrix and straw materials)to improve the comprehensive utilization efficiency.Keywords：straw yield;straw fuel;straw fertilizer;straw feed;straw building materials88|38|58<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To study the impact of climate change on the cultivation region of high-quality wheat in Henan Province, the historical climate data of 113 meteorological stations from 1971 to 2000 and simulation data(1971—2050)based on regional climate model under RCP4. 5 and RCP8. 5 emission scenarios were used. Eight factors were selected to determine the regionalization index of high-quality wheat in Henan Province. The eight factors were precipitation during the whole growth period, degree days when daily mean temperature ≥0 ℃ during the growth period, incident solar energy flux from March to April, rain days of March and April, precipitation of May, mean diurnal temperature range of May, days of daily maximum temperature≥32 ℃ of May and incident solar energy flux of May. Combined with the longitude, latitude and DEM information of stations, 1 km grid data of each climate element was calculated by using the inverse gradient distance method. The scoring method was then used to determine the planting area and area ratio of different types of high-quality wheat in 2030, 2040 and 2050 under the scenarios of RCP4. 5 and RCP8. 5 in Henan Province. The results showed that: 1)On the condition that the existing cropping system and variety attributes remain unchanged, the proportion of suitable area for high-quality strong gluten wheat in Henan Province will gradually decrease from 37. 2% in the base period(1971-2000)to less than 13. 0% in 2050, under the two scenarios of RCP4. 5 and RCP8. 5; 2)The proportion of suitable area of medium gluten wheat will maintain at 16. 8%~22. 9%; 3)The proportion of suitable area of weak gluten wheat will increase form 6. 1% to 11. 6%~12. 4%. In the future, the influence of climate change on cultivation region of high-quality wheat in Henan Province can be adapted by adjusting the sowing date and enhancing the high temperature resistance of wheat varieties.Keywords：high-quality wheat;climate change;agro-climate resources;Henan Province8|12|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Aiming to solve the problem that the wheat scab meteorological grade forecast model in the agrometeorological service of Anhui Province was not accurate enough, this study established a meteorological grade forecast model with comprehensive precipitation index which was based on the number of rainy days and precipitation, through the methods of linear correlation and regression analysis, using the historical data including percentage of diseased panicles of wheat scab, phenology data and meteorological data during corresponding period on Chuzhou, Lujiang, Chizhou and Xuancheng in south central of Anhui Province. And the model was tested by fitting and prediction. The results showed that the key period of wheat scab was from the 5th day before the initial heading stage to the 25th day after that for Chuzhou, and for Lujiang was, from the 8th day before that to the 20th day after that, and for Chizhou was from the 7th day before that to the 24th day after that, and the last for Xuancheng was from the 4th day before that to the 24th day after that. Fitting test and prediction test were carried out for the established regional meteorological grade forecast model of wheat scab. The results indicated that the fitting accuracy of Chuzhou, Lujiang, Chizhou and Xuancheng were 86. 8%, 87. 6%, 85. 6% and 88. 3% respectively, while the prediction accuracy of them were 92. 0%, 70. 0%, 88. 0% and 84. 0% respectively. Therefore the regional forecast model established for wheat scab meteorological grade could be used for the agrometeorological service in south and south central Anhui Province.Keywords：wheat scab;meteorological grade;forecast;precipitation;Anhui Province4|12|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To solve the problem of temperature error caused by the simple substitution of July/January for the hottest/coldest duration in agricultural regionalization, a more accurate statistical method of temperature in the hottest/coldest month was explored. The daily temperature data of Yinchuan ground meteorological station in Ningxia Province were taken as the research object, and 31 days was set as the month-long period. This study adopted agricultural meteorological statistics method to analyze the annual change of the start and end date and temperature of the hottest/coldest month-long period. The results showed that: 1)the hottest/coldest month occurred mostly in July/January and the average temperature of the hottest/coldest temperature occurred in July/January as well. The hottest periods occurred during mid-June to late August, and the coldest months occurred during early December to mid-February. 2)From 1951 to 2019, the hottest month-long period's maximum temperature was 2. 0 ℃ higher than the maximum temperature in July and 0. 5 ℃ higher on average. The coldest month-long period's lowest temperature was 4. 6 ℃ lower than the lowest temperature in January and was 1. 1 ℃ lower on average. 3)By using the 30-year standard of WMO climate normals, with four standard periods during 1951 to 2010, the dates of the hottest/coldest month-long periods were relatively consistent, the average temperature was rising, and the coldest month-long period's average temperature was increasing at almost 3 times that of the hottest month-long period. 4)The hottest average temperature prediction reached 92. 1% accuracy and the coldest average temperature prediction had 55. 3% accuracy. Therefore, this method in the study can accurately predict the average temperature of the hottest month-long period but still needs to be improved to predict the lowest average temperature of the coldest month-long period.Keywords：hottest month duration;coldest month duration;moving average;average dates of the hottest month duration;average dates of the coldest month duration8|9|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To improve the traits of transgenic plants through efficient herbicide-resistant genes, a Gram-stain-negative bacterial strain MST-5, which was highly resistant to mesotrione, was isolated from herbicide contaminated soil. 16S rRNA gene sequence analysis showed that strain MST-5 belongs to the genus Stenotrophomonas sp. Subsequently, Sthppd, encoding a 4-hydroxyphenylpyruvate dioxygenase StHPPD, was cloned from MST-5. Its length was 1 071 bp, encoding 356 amino-acid residues. The sequence identity between StHPPD and other HPPDs was only 47%-51%. The purified StHPPD displayed high resistance to HPPD inhibitor herbicides. The IC50 values of mesotrione, topramezone and diketonitrile against StHPPD were 15. 5, 10. 8, 28. 2 μmol/L, respectively. The optimum temperature and optimum pH of StHPPD were 30 ℃ and 7. 0, respectively. The enzymatic activity of StHPPD was severely inhibited by most metal ion and some chemical additives, while was not affected by Fe3+, Mg2+ and Urea. In conclusion, Sthppd showed high resistance to hervicide and it was suggested that Sthppd might have a potential value in transgenic engineering of mesotrione-resistant crops.Keywords：mesotrione;HPPD;resistant strain;gene cloning;herbicide resistance4|11|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：The aim of this study was to explore the effects of nitrogen mass concentration on dry matter and nutrient uptake of potted chrysanthemum, and find a scientific fertilization scheme. Taking ‘Dong Li Qiu Xin' as the test object and perlite as the cultivation medium, an experiment was conducted with different nitrogen mass concentrations(40, 120, 180, 240 and 350 mg/L). Dry matter mass, nutrient content, N accumulation, N uptake efficiency, etc. were analyzed. The results showed that: At 240 mg/L nitrogen mass concentration, ‘Dong Li Qiu Xin' grew better, and the dry matter mass of flower, leaf, and whole plant were the largest, and there were no significantly differences compared with 180 mg/L nitrogen mass concentration. The root-shoot ratio decreased with the increase of nitrogen mass concentration. The N content and accumulation rate of each organ was the largest at 350 mg/L. The P content of flower was the largest at 240 mg/L. The K content of flower, leaf, and stem were the largest at 40 mg/L. N uptake efficiency and partial factor productivity decreased with the increase of nitrogen mass concentration. In summary, 180-240 mg/L nitrogen mass concentration, and the corresponding nitrogen application rate of 270-360 mg/plant can be used as the reference of nitrogen application rate for this variety.Keywords：nitrogen mass concentration;potted chrysanthemum;dry matter;N,P and K nutrients3|11|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to provide theoretical basis for molecular marker assisted breeding of Phalaenopsis, SNP loci related to yellow and white ground color of Phalaenopsis flower were screened and verified in different germplasm resources. A population was constructed through the cross of Phalaenopsis Frigdaas Oxford(♀)×Phalaenopsis Join Angel(♂). A total of 33 yellow-ground-color hybrids with 5 different color patterns and the only 2 evenly yellow individuals were selected as the yellow group, another 35 white-ground-color hybrids with the same color patterns were selected as the white group, and their DNA were pooled to construct two bulked DNA pools according to the ground color. Specific-locus amplified fragment sequencing(SLAF-seq)combined with bulked segregant analysis(BSA)was used to identify candidate DNA markers closely linked to the flower ground color. A total of 164 874 SLAF tags including 21 031 polymorphic SLAF tags and having a polymorphism rate of 12. 76%, were procured from the parents and two progeny pools. The average sequence depths of SLAF markers were 42-fold in parents and 46-fold in each progeny pool. Twenty seven single-nucleotide polymorphism(SNP)loci were obtained from 15 related SLAF markers associated with the flower ground color with SNP index of >0. 745 5. SNP locus validation was performed using SNaPshot sequencing method in the parents, 11 hybrids and another 4 Phalenopsis. The two SNP locus by using the primers Marker35886 and Marker70907 were consistent with the SNP locus in the related SLAF-seq. The accuracy rates of the genotypes consistent with the flower ground color were 66. 67% and 73. 33%, respectively, the accuracy rate of combined reached 93. 33%. In conclusion, the two SNP loci can be used as effective molecular marker sites for early selection in Phalaenopsis breeding.Keywords：Phalaenopsis;flower ground color;SLAF-BSA;SNP3|10|4<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the effect of LED pulsed light on the chlorophyll fluorescence characteristics of crops, glass lettuce was taken as the research object. A total of 14 different frequencies(1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1 024, 2 048, 4 096 and 8 192 Hz)were designed and 5 duty ratios(20%, 40%, 60%, 80% and 100%)combined pulsed light. The chlorophyll fluorescence parameters of lettuce leaves under different pulsed light treatment with dual-channel PAM-100 fluorometer were measured. The results showed that: Photosystem II(PSII)biggest quantum efficiency Fv/Fm under the low frequency(<256 Hz)and low duty ratio(≤60%)processed, actual photochemical quantum yield ФPSII and photochemical quenching qP were all significantly lower than under continuous light. The non photochemical quenching NPQ and PSII regulatory quantum yield of energy dissipation ФNPQ wwere significantly higher than that of continuous light treatment; The quantum yield of non-regulatory energy dissipation ФNO treated with low duty ratio below 2 Hz significantly was higher than that of continuous light; There was no significant difference in fluorescence parameters between treatment of continuous light and treatment of 256 Hz or below in the high duty ratio and 256 Hz or above. In summary, the pulsed light with low frequency and low duty ratio could reduce the photosynthetic activity of lettuce leaves, and low duty ratio of 2 Hz could lead to PSII damage. The PSII activity, photosynthetic electron transfer and energy distribution of lettuce leaves were not affected by the pulsed light treatment with high frequency and low frequency high duty ratio compared with continuous light. This research can provide theoretical support for the research and development of LED energy saving supplementary light lamp.Keywords：lettuce;pulsed light;chlorophyll fluorescence;frequency;duty ratio6|11|4<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：The purpose of this study was to understand the virulence of Mycobacterium bovis(M. bovis) in Xinjiang. A total of 29 virulence genes of 66 clinical isolates of M. bovis were detected by polymerase chain reaction assay(PCR). After Sanger sequencing, the sequences were compared with M. bovis AF2122/97, M. bovis C68004 and M. bovis N. The effects of gene mutations on protein function and structure were analyzed. The results showed that: 1)The isolates tested in this study possessed virulence gene sequences, which shared high similarity to those in highly virulent M. bovis strain N. Among the 29 virulence genes detected, more than 50% of the clinical isolated strains had 25 genes that were consistent with M. bovis N. 2)The PROVEAN score of Mb2958, Mb2982C and Mb1553C gene mutations in clinical isolates were lower than -2. 5, which might change the catalytic activity of the enzyme encoded, thus affected the biosynthesis of cell wall lipids. 3)Mutations of Mb0607, Mb0609, Mb0606, Mb2979C and Mb1214 genes cause the secondary structural changes of mammalian cell entry protein, methyltransferase and acyltransferase proteins, which might affect the intracellular survival of M. bovis. In summary, the mutations of 8 virulence genes might play an important role in the virulence changes of epidemic strains in Xinjiang. This study provides a preliminary reference for further research of molecular characteristics of M. bovis and provides a solid basis for further evolutionary analysis of M. bovis.Keywords：Mycobacterium bovis;virulence genes;clinical isolates;gene mutation1|9|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to analyze the expression of macrophage migration inhibitory factor(MIF)in different diameters follicles of healthy pigs, 90 ovaries of healthy sows were collected. The concentration of MIF in follicular fluid of different diameters were detected by ELISA. The expression of MIF mRNA and protein in granulosa cells were detected by quantitative real-time PCR and Western blot, and the distribution of MIF in granulosa cells was assayed by immunofluorescence. The results showed that: 1)The concentration in medium follicles(diameter 3-4 mm)fluid(54. 17±7. 86 ng/mL)was significantly higher than that in large follicles(diameter>6 mm, 32. 29±1. 47 ng/mL)and small follicles(diameter 1-2 mm, 38. 89±0. 98 ng/mL)(P<0. 05); 2)The expression of MIF mRNA and protein in granulosa cells of medium diameter follicles was also significantly higher than that in large follicles and small follicles(P<0. 05); 3)MIF was also expressed in the nucleus and cytoplasm of granulosa cells with different diameters, but mostly concentrated in the cytoplasm. In summary, with the development of porcine follicles, the expression of MIF was the highest in medium-sized follicles(diameter 3-4 mm). This study provides new clues for follicular development and ovulation.Keywords：macrophage migration inhibitory factor;follicular development;granulosa cells0|9|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
Effects of dietary complex probiotics on growth performance, fecal microbiota and metabolite of pigs
Abstract：The study aimed to explore the effects of six probiotic combinations from the digestive tract of Diqing Tibetan pigs on the growth performance, fecal mocrobial diversity and matabolites of pigs. Fecal samples were collected from 12 pigs(n=12, 6 pigs in each group). The diversity of fecal microbiota was analysised by high-throughput sequencing, the different metabolites were analysised by untargeted metabolomics. The results were as follows: 1)There was no significant difference between the two groups. 2)The ACE index and Chao1 index of alpha diversity index in test group was significantly higher than that in the control group(P<0. 05). 3)The dominant flora analysis showed that the relative abundance of Bacteroidetes was extremely increased at the phylum level(P<0. 01). At the genus level, the relative abundance of Rikenellaceae_RC9_gut-group(P<0. 01)in test group was extremely higher than that in control group(P<0. 01). 4)The result of multi-level species difference discriminant analysis showed that the relative abundance of fecal flora in the two groups was significantly different(P<0. 05). A total of sixteen biomarkers were obtained when the LDA value was higher than 2. 0(6 biomarkers in test group and 10 biomarkers in control group). The largest LDA value of bacteria in control group and test group were Lachnospiraceae_AC2044_group and Ruminococcaceae_UCG_014, respectively. 5)The partial least squares discrimination analysis showed that there was significant different in the two groups(P<0. 05). The metabolite analysis showed that the content of the((±)-Equol(P<0. 05)and neoacrimarine K(P<0. 01))were significantly up-regulated in test group with dietary complex probiotics. In conclusion, the addition of complex probiotics can enrich the abundance of intestinal floras, improve the relative abundance of the disease-resistant bacteria(Rikenellaceae_RC9_gut-group and Ruminococcaceae_UCG_014), increase the content of disease-resistant metabolites((±)-Equol(P<0. 05))and fungus-resistant metabolites(Neoacrimarine K(P<0. 01)), which has the potential probiotic function.Keywords：pig;complex probiotics;fecal microbiota;metabolite13|17|4<HTML><L-PDF> <Meta-XML>Updated：2023-12-22- Abstract：To investigate the effects of wheat bran feruloylated oligosaccharides(FOs)on the antioxidant capacity in rat liver, forty healthy weaned rats were randomly assigned to five groups, including control(normal saline), positive control(w(Vc)=100 mg/kg), low-dose(w(FOs)=20 mg/kg), medium-dose(w(Fos)=40 mg/kg), and high-dose(w(FOs)=80 mg/kg)FOs groups. The experiment duration was 21 d. The normal saline, Vc and FOs were given by gavage every day. At the end of the experiment, the liver tissues were collected to measure antioxidant related indexes by ELISA. The mRNA expression of antioxidant related genes and the protein expression of Nrf2 were determined using RT-PCR and Western Blot, respectively. The results showed that: 1)With the increase of FOs dosage, the SOD and GSH-Px activities, GCLC, NQO1, CAT, SOD, GSH-Px and Nrf2 mRNA expression level were increased quadratically, the protein expression level of Nrf2 was increased linearly(P<0. 05), whereas 8-OHdG concentrations was decreased linearly and quadratically(P<0. 01). 2)Compared with Vc, low-dose group had greater CAT mRNA expression level(P<0. 05), and lower GSH-Px activity and 8-OHdG concentrations(P<0. 01); medium-dose group had greater GCLC, NQO1, CAT, SOD, GSH-Px and Nrf2 mRNA expression level(P<0. 05), and lower T-AOC, CAT activity and 8-OHdG concentrations(P<0. 05)); high-dose group had lower GSH-Px activity and 8-OHdG concentrations(P<0. 05). In conclusion, FOs could increase antioxidant enzymes activity, decrease DNA oxidative damage, and increase mRNA expression level of Nrf2 and downstream antioxidant genes. The suitable dietary supplemental level of FOs is 40 mg/kg BW.Keywords：feruloylated oligosaccharide(FOs);rat;liver;antioxidant capacity2|8|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To explore the biological features of Staphylococcal superantigen-like proteins(SSLs)related to complement system, the recombinant protein SSL7 was expressed by prokaryotic expression system and the biological characteristics of SSL7 associated with complement system were studied by complement killing test, Western blot, and Pull-down analyse. The results showed that: 1)The recombinant SSL7 could be expressed soluble in E. coli competent cell BL21(DE3)in a large amount with a size of about 25 ku; 2)SSL7 blocked the complement killing effect of fresh rabbit serum on E. coli DH5α; 3)SSL7 inhibited the formation of membrane attack complex(MAC). Fresh rabbit serum lost the ability to form MAC deposition on the surface of S. aureus NCTC 8325; 4)SSL7 intercepted the activation of complement system via capturing complement C5 in human normal serum. In a nutshell, SSL7 is capable to block the cascade reaction by specifically binding complement C5, evade the host immune response to achieve the purpose of pathogenicity, which lays the foundation for further exploring the infection mechanism of SSL7 and revealing the function of SSLs.Keywords：Staphylococcus aureus;SSL7;complement system11|10|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Aiming at the low accuracy of the hanging cup transplanting machine's feeding mechanism, seedling throwing tests were conducted on the hanging cup transplanting test device. A high-speed camera was used to film the movement track of the plug seedlings from the feeding mechanism to the planter. Image post-processing technology was used to analyze the influence of plug seedling weight, the height of plug seedling and feeding cup speed on the throwing movement of plug seedlings. The orthogonal experiment was conducted and response surface analysis was used to determine the optimal combination of seedling parameters that affect the seedlings' accuracy rate. The results showed that: 1)The height, weight and feeding speed of the plug seedlings affected the seedlings' posture and trajectory, which significantly affected the horizontal displacement. According to the statistical analysis, the plug seedlings' horizontal displacement area was ［30, 50］ mm. The horizontal displacement of the seedlings' falling port of the feeding mechanism relative to the planting point was 32. 1 mm≤L≤42. 8 mm; 2)The primary and secondary factors affecting the feeding mechanism's accuracy were the seedling's height, the weight of the seedling and the feeding cup speed. When the feeding cup speed was 0. 184 m/s, the weight of seedling was(20±4)g, and the height of seedling was(130±10)mm, the accuracy of seedling feeding reached 99%. This research provided references for the design of the hanging cup transplanting machine.Keywords：feeding mechanism;throwing motion;planting device;high speed photography;horizontal displacement0|9|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：At present, the harvest of winter bamboo shoots in China can only rely on traditional manual work, and there is no suitable detection equipment. According to the principle that the difference in dielectric properties between winter bamboo shoots and soil under the action of high-frequency electromagnetic waves results in significantly different reflection coefficients, a winter bamboo shoot detector is designed based on the microwave reflection method. The detector transmits and receives electromagnetic wave signals to the soil through two patch antennas. It constructs an echo sequence detection model based on a conventional neural network used to classify the echo signals received by the designed winter bamboo shoot detector and uses the echo signal's electromagnetic waves. The attenuation intensity judges whether there are winter bamboo shoots in the soil. The results show that the echo sequence detection model proposed in this study uses the winter bamboo shoot detector's echo signal to judge the presence of winter bamboo shoots in the soil with an accuracy rate of 79. 08%, missed alarm rate is 21. 47%. The false alarm rate is at 20. 37%. Compared with the SVM and the spectral threshold method, the performance of the echo sequence detection model is the best in accuracy, false alarm rate, and missed alarm rate of winter bamboo shoots detection. The detector can predict underground winter bamboo shoots' location and improve winter bamboo shoots' harvesting efficiency.Keywords：winter bamboo shoots detector;dielectric constant;microwave reflection method;convolutional neural network(CNN)6|10|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to solve the problems such as unreasonable structure of grabbing planks, low production efficiency and poor quality of bedding material existing in the process of drum fermentation, this study combined a field test with discrete element simulation to explore the particle movement during the process of using the solid cow manure to produce the bedding in the composting-drum. The retention time and the mixing state of solid cow manure in the rotating drum were simulated with two sets of helix arranged and the angle between the plate and the central axis of the roller 0°, two sets of helix with an angel of 45°, and four sets of helices with an angle of 45°, respectively. The results showed that: 1)The particle movement modelling established by EDEM could describe the movement of the solids manure in the drum-composting process properly. 2)The scheme where the structure of four three-dimensional spirals with welding angle 45o showed the best performance, with the conveying rate being 1. 7×10-4m/s and the fermentation time being 16. 2 h, which could achieve a high quality of production efficiency. In conclusion, the structure of the grabbing planks which were arranged in four sets of helices with an angle of 45° towards the central axle was optimal among the three structures. This study provides a theoretical basis for structural optimization, quality and production efficiency improvement of the solid manure producing by composting-drum in large-scale dairy farms.Keywords：recycled manure solids as bedding;rotating drum;discrete element method;grabbing planks;structural optimization0|9|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to study the blockage effect of pig under different air velocities and orientations, a semi-empirical correlation of cylinders for validation and OpenFOAM are used to simulate the blockage of a pig model in virtual wind tunnel. A simplified pig model is built to study the blockage effect of a single pig under different air velocities(0. 2, 0. 5, 1. 0, 1. 5, 2. 0, 2. 5 m/s)and orientations(Airflow angle between the main axis of the pig and the airflow, 0°, 15°, …, 180°). The results show that: 1)Simulation in proper grids can both ensure the accurate calculation and reduce the computational load. 2)The geometry difference can not be ignored between pig model and cylinder model that has the same volume as pig model, and the cylinder cannot characterize the law of air resistance coefficient(R2=0. 603 3). 3)The orientations between pig and airflow can be divided into three ranges of 0°-45°and 135°-180°, 45°-75° and 105°-135°, 75°-105°, which represent the small, medium and large air resistance, respectively. This study clarifies the blockage effect of the drag coefficient of a single pig under different airflow velocities and different angles of airflow and promotes the application of OpenFOAM in agricultural engineering.Keywords：OpenFOAM;air distribution;ventilation;airflow5|12|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Under the background of economic transformation, it is of great significance to explore land urbanization and its influencing factors. This study measures the level of urban land urbanization in the Yangtze River Economic Belt from 2009 to 2018, and analyzes the impact of economic globalization, marketization and decentralization on the level of urban land urbanization in the context of economic transformation. The results show that the land urbanization level of the Yangtze River Economic Belt shows a rising trend, but there are significant regional differences from 2009 to 2018. The spatial distribution of the land urbanization level shows the clustering feature of high northeast to low southwest, and the hot areas with land urbanization level have significant spatial polarization. The results of regression analyses show that with China's economic transformation, globalization, marketization, decentralization and other factors have significantly affected the land urbanization level of the Yangtze River Economic Belt. In addition, the urban population density, economic development level, industrial structure, and fixed asset investment have all affected the urban land urbanization of the Yangtze River Economic Belt. However, various factors under the economic globalization have different effects on the land urbanization in different regions of the Yangtze River Economic Belt.Keywords：economic transformation;land urbanization;influencing factor;Yangtze River Economic Belt3|10|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：For supporting the digital precise management of circulating land spatial information, this study took Guanyintan town in Hunan province as an example and based on the land ownership data and the land transfer data, firstly, from an economic perspective, using land Gini coefficient to determine whether the land transfer area and spatial distribution were reasonable. Secondly, based on the land rent theory and man-land relationship theory, the relationship between the land transfer price and its related population was studied in spatial. Using the spatial autocorrelation analysis method to explore the spatial relationship between the land transfer price, the number of migrant workers and the location of the land transfer. The study area was in the hills. The results show that, in 2015, only 9. 03% of the contracted land was transferred. The transferred land showed a trend of expansion in the east and north, and sporadic distribution in the west. The Gini coefficients of the transferred land area and its spatial structure were 0. 557 and 0. 555, respectively, indicating that the transferred land area and spatial structure were unreasonable and require human management and control. The rural households with 3. 89% involved in the land circulation, and migrant workers mainly aged in 19-40 years old. After land transferred, the spatial relationship of migrant workers numbers had no significant positive correlation in the whole study area, and the local gathered in some villages of north with “High-High” state, and in some villages of middle-east with “Low-Low” state. The land transfer price has a positive correlation in the whole study area. The local spatial agglomeration of land transfer prices was reflected in the number of migrant workers of the transferred land and different land transfer times. The research results showed that the agricultural land right confirmation result data can support the land transfer information management. The transfer price was the embodiment of differential rent, and the labor of different age groups on the transferred land was also the result of the interaction and coordination of the man-land relationship. The study provides references to develop appropriate scale operation of the land, optimize the allocation of agricultural land resources, improve the utilization rate of labor force and provide a reference for the realization of precise management of agricultural land.Keywords：land circulation;right to rural land management registration;land Gini coefficient;spatial autocorrelation;land price;population2|9|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the impacts of service outsourcing and contract selection on the technical efficiency of wheat production, based on the survey data of 3 305 farmers in Henan Province, Cobb-Douglas production function is used to measure the technical efficiency of wheat production in Henan Province from the perspective of service outsourcing. Tobit model is adopted for empirical research. The results show that: 1)The average technical efficiency of wheat production in Henan sample farmers is 0. 7, the output elasticity of land is the largest, and the output elasticity of labor is the smallest; 2)The higher the degree of service outsourcing, the higher the technical efficiency of wheat production; 3)Service outsourcing Informal contracts such as empty contracts and oral contracts by farmers can improve their production technical efficiency more than written contracts. The distance between farmers and service providers has a significant impact on the efficiency of wheat production technology. Therefore, to encourage farmers' participation in service outsourcing, promote agricultural service organizations to improve service quality, and achieve large-scale services through vertical cooperation. At present, the contractual production should not be forced to improve technical efficiency of agricultural production at present.Keywords：Cobb-Douglas production function;Tobit model;service outsourcing;contract selection;technical efficiency of production2|9|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：This study aimed to clarify the food consumption categories and find out the evolution characteristics. Based on the data of 13 kinds of food consumption in the food balance sheets of the Food and Agriculture Organization of the United Nations from 1991 to 1995 and 2015 to 2017, five factors and seven consumption categories were obtained using factor and cluster analysis. The changes of different categories and influencing factors of food consumption were also analyzed. The results showed typical regional characteristics, and reflected the differences in economic development among various countries. Over the past 20 years, the per capital consumption of rice, poultry and sugar had generally increased for all categories. For the categories at the food and clothing stage or well-off stage, the changes of food consumption mainly came from the increase of vegetable food such as grain, vegetable and fruit. While the categories of the richest stage reduced the consumption of potato, red meat, fruit, vegetable oil and animal fat. Initial consumption had negative impact on the growth of per capita consumption, while economic growth and domestic production generally showed a positive impact. Economic growth had a strong impact on the consumption of milk, sugar, fruits, vegetables, and domestic output had a greater impact on the consumption of fresh products such as fruits, vegetables, meat and aquatic products. The impact of urbanization, aging and tariff changes on different food consumption varied greatly. Urbanization might drive the consumption of high-calorie foods such as vegetable oil and animal fat, and reduce the consumption of high-protein foods such as eggs, milk, meat and vegetables. Aging might cause the consumption of sugar, vegetable oil and animal fat reduced, and drive the consumption of eggs, red meat and other food growth.Keywords：food consumption;food balance sheets;factor analysis;cluster analysis1|10|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the implementation path of the current whole-process networked food traceability with multi-agent participation and multi-supply chain cooperation, research on food quality traceability from the perspective of multi-functional open food supply and demand network are carried out, and an innovative traceability model of the food supply and demand network enabled by blockchain is put forward. Based on the discussion of the network structure collaboration and system function collaboration mechanism between blockchain and food supply and demand network, this study constructs an overall framework of the traceability model of food supply and demand network enabled by blockchain, and takes processed food as an example to illustrate the specific operation of the model. The results show that blockchain provide strong technical support and implementation support for the implementation of the food supply and demand network traceability system. The mode constructed in this study is more in line with the current situation of food complex network traceability, which greatly solves the problems of centralized control, incomplete information and low credibility of food traceability, deepens the awareness of multi-agent and multi supply chain cooperation, and provides a model reference for the development of food traceability.Keywords：food quality traceability model;blockchain technology;food supply and demand network1|9|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to obtain a better understanding of demand preference for imported sheep meat products among Chinese consumers, based on monthly import data from 2010 to 2019, a source and attribute differentiated Rotterdam model is employed to estimate demand for imported sheep meat products in China. Product aggregation tests indicate, that in Chinese sheep meat import market, relatively independent preferences exist between sheep meat products from different sources, between bone-in versus boneless cuts, and between chilled versus frozen cuts, implicating products should be disaggregated by source and attribute and included in one system for analysis. Empirical analysis suggests that if the expenditures for sheep meat imports in China continue to soar in the future, the structure of sheep meat imports among different sources and product attributes will continue to change. Chilled bone-in sheep meat imported from New Zealand would have the greatest growth potential. Substitutions between different categories of sheep meat products are weak, indicating that the diversified trade strategies should be formulated and it is necessary to adjust and optimize the structure of sheep meat imports and exports according to corresponding demand preferences.Keywords：sheep meat imports;differentiated import demand;Rotterdam model;product attribute;restriction test0|9|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：As a unique development issue in our country, the problem of left-behind children in rural areas has long attracted attentions from the academic circles and public. However, the existing research on the development of left-behind rural children mainly focuses on the short-term impact, and it is relatively rare to investigate the impact of left-behind experience on the long-term development of rural children. In fact, left behind not only has a short-term impact on childhood, but also has a long-term impact on the development in their adulthood. The latter is closely related to the quality of individual life and employment, and the country's social and economic development. Based on this, this study first reviews the basic logic of left-behind experience and the development of rural children, and then systematically combs the research progress of the long-term effects of left-behind experience on academic achievement, mental health, employment quality, and subjective well-being. On this basis, this study points out the possible deficiencies of the existing research in outcome variables, time dimensions, and group differences. It is believed that in the future, relevant research needs to include urban left-behind children, expand childhood experiences, and focus on the shift of children's migration policies. In the context of promoting new urbanization and rural revitalization. This study provides references for resolving the long-term development of left-behind children and promoting the accumulation of human capital of rural left-behind children.Keywords：children;rural areas;left-behind experience;migrant workers6|11|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
