Archive

25 August 2019, Volume 31 Issue 8 Previous Issue    Next Issue
---
Crop Science
Animal Science
Horticultural Science
Plant Protection
Environmental Science
Biosystems Engineering
Agricultural Economy and Development


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Crop Science

Select

Research on development of high quality rice industry in Tianjin based on SWOT analysis: Taking "Xiaozhan" rice as an example BING Jingjing, GAO Hongmei 2019, 31(8):  1217-1223.  DOI: 10.3969/j.issn.1004-1524.2019.08.01 Abstract ( 693 )   HTML ( 1074266374 )   PDF (1175KB) ( 1958 )   The present study analyzed the development and advantages and disadvantages of Tianjin "Xiaozhan" rice industry, and pointed out the opportunities and threats based on SWOT analysis. It was found that "Xiaozhan" rice was restricted by natural environment, irregular management entities, competition from other brands, and homogenization of commodities. Therefore, it was proposed that the "Xiaozhan" rice should be promoted with good taste and salt tolerance, and the cultures of "Xiaozhan" rice cultivation should be explored, so as to drive the sustainable development of Tianjin’s "Xiaozhan" rice industry. References | Related Articles | Metrics

Select

Cloning and sequence analysis of StBSKs gene of Solanum tuberosum MA Jie, ZHENG Hao, ZHOU Ping, CHEN Chunyan, WU Rui, MA Wei, SONG Lei, SUN Bo 2019, 31(8):  1224-1230.  DOI: 10.3969/j.issn.1004-1524.2019.08.02 Abstract ( 746 )   HTML ( 1 )   PDF (2296KB) ( 1618 )   Brassinolide (BR) is a kind of plant hormone that participates in the regulation of plant growth and environmental resistance. Brassinolide signal kinase (BSKs) is an important signal transduction kinase in BR signaling pathway. Solanum tuberosum used as material and specific primers were designed by homologous sequence retrieval. Seven genes of the StBSK gene family were cloned by RT-PCR technology, and respectively named StBSK1, StBSK2, StBSK3, StBSK4, StBSK5, StBSK6 and StBSK7. Total length of coding sequences were 1 497, 1 479, 1 464, 1 461, 1 476, 1 476 and 1 476 bp that encoded 498, 492, 487, 486, 491, 491 and 491 amino acid protein, respectively. Bioinformatics analysis showed that the isoelectric points of StBSKs protein were weakly acidic between 5.14 and 6.37, and these seven proteins had no transmembrane domain and signal peptide. Amino acid sequence alignment revealed that the amino acid sequences of StBSKs protein were different in N-terminal. Phylogenetic tree analysis showed that StBSKs protein was more closely related to the same species. The results of this study enriched the knowledge of the StBSKs gene and laid a foundation for further study on StBSKs gene function in Solanum tuberosum. References | Related Articles | Metrics

Animal Science

Select

Genetic diversity analysis of Psoroptes ovis var. cuniculi by full-length of mitochondrial ATP6 gene in China YIN Xiaoxiao, LI Yanfang, GU Jiang, LIAO Yan, XIE Yue, YANG Guangyou, GU Xiaobin 2019, 31(8):  1231-1238.  DOI: 10.3969/j.issn.1004-1524.2019.08.03 Abstract ( 857 )   HTML ( 0 )   PDF (1299KB) ( 1717 )   To explore the genetic variation and genetic taxonomy of Psoroptes ovis var. cuniculi in China, the complete sequence of mitochondrial ATP6 gene of P. ovis var. cuniculi isolated from 5 geographical regions (Huabei, Huadong, Huazhong, Xibei, and Xinan) were amplified by PCR sequencing techniques, and evaluated the genetic diversity and population structure of P. ovis var. cuniculi population. Eighty-eight sequences of mitochondrial ATP6 were obtained which were 672 bp, including 41 haplotypes. The whole population of P.ovis var. cuniculi in China showed high genetic diversity (π=0.014 94) and haplotype diversity (Hd=0.925 81), and the genetic variation within the population held the dominant positon(97.92%). The genetic differentiation index among the five populations was low (Fst=0.02081), and there was no obvious differentiation and frequent gene exchange (Nm=11.763 5). In P. ovis var. cuniculi population, the average values of Tajima’s D and Fu’s Fs were positive (Tajima’s D=0.937 98, Fu’s Fs=0.522 06) and there was no significant differentiation(P>0.05). The mismatch distribution curve showed multiple peaks, indicating that the population of P. ovis var. cuniculi was relatively stable in the evolutionary process and had no population expansion events. From NJ phylogenetic tree and haplotype network map, it can be seen that there was no genetic structure based on rabbit breed, temperature zone or geographical distribution. The results revealed that there was high level of genetic diversity, little population genetic differentiation, but population structure has not formed according to rabbit breed, temperature zone or geographical distribution. References | Related Articles | Metrics

Select

Preliminary study on hemolytic ascites disease of Pelteobagrus fulvidraco YANG Yibin, AI Xiaohui, SONG Yi, DONG Jing, XU Ning, JIANG Lan 2019, 31(8):  1239-1248.  DOI: 10.3969/j.issn.1004-1524.2019.08.04 Abstract ( 551 )   HTML ( 3 )   PDF (2420KB) ( 1617 )   Bacterial strain HS01 was isolated from diseased Pelteobagrus fulvidraco suffered from serious hemolytic ascites, and it was identified as Aeromonas hydrophila based on biochemical reaction characters and 16S rRNA and gyrB gene sequence analyses. Artificial affected fish by intraperitoneal HS01-injection showed the same clinic signs as the diseased fish in ponds. Therefore, the isolated A.hydrophila was proved as the main pathogen, and its LD50 to tilapia was determined as 2.51×105 CFU·g-1 using the probabilistic graphical method. The antibiotic sensitivity test showed that the isolated was very sensitive to cefotaximee, cefotaxime, netilmicin, florfenicol, etc., less sensitive to cefadroxil, streptomycin1, neomycin, kanamycin, etc., and not sensitive to amoxicillin, penicillin, tobramycin, erythrocin. This study provided a theoretical basis for the prevention and control of the hemorrhagic disease caused by A.hydrophila in Pelteobagrus fulvidraco. References | Related Articles | Metrics

Select

Whole-genome sequencing and antibiotic resistance study of a multi-drug resistant Escherichia coli isolated from chicken CHANG Jiang, LUO Yi, TANG Biao, ZHANG Ling, DAI Xianjun, QIU Hanqi, YANG Hua, XIA Xiaodong 2019, 31(8):  1249-1256.  DOI: 10.3969/j.issn.1004-1524.2019.08.05 Abstract ( 753 )   HTML ( 513 )   PDF (1176KB) ( 1684 )   An Escherichia coli called ECCNB12-2 isolated from chicken in Ningbo city was studied. The MICs to antibiotic were determined using mircrobroth dilution assay. The results indicated that ECCNB12-2 showed resistance to 10 kinds of antibiotics including ampicillin, gentamicin, spectinomycin, tetracycline, florfenicol, sulfisoxazole, trimethoprim/sulfamethoxazole, ceftiofur, enrofloxacin and ofloxacin. Whole genome sequencing of strain ECCNB12-2 with the third generation of high-throughput sequencing technology was performed. The prediction of acquired antimicrobial resistance genes, virulence factors and mobile genetic elements was carried out based on the whole-genome sequence. The whole genome size of strain ECCNB12-2 was 5 539 489 bp with GC content of 50.37%. At the same time, four plasmids were carried, which had the size of 147 451 bp (pTB-nb1), 139 752 bp (pTB-nb2), 82 252 bp (pTB-nb3) and 253 793 bp (pTB-nb4), respectively. A total of 40 acquired antimicrobial resistance genes were detected on the chromosome, pTB-nb1 and pTB-nb4. And 12 virulence factors were found on the whole-genome sequence. The prediction results of mobile genetic elements showed that the pTB-nb4 had high potential for self-transferability. The study indicated that the ECCNB12-2 isolated from chicken was a multi-drug resistant strain which had a serious risk. It also reflected the severity of antibiotic resistance in commercial chickens. These results provided basic information for risk assessment of antibiotic resistance of foodborne bacterial. References | Related Articles | Metrics

Select

Genetic diversity analysis and RAPD identification of three successive generations of meio-gynogenetic population in Megalobrama amblycephala TANG Shoujie, BI Xiang, ZHANG Feiming, ZHANG Youliang 2019, 31(8):  1257-1271.  DOI: 10.3969/j.issn.1004-1524.2019.08.06 Abstract ( 755 )   HTML ( 2 )   PDF (2053KB) ( 1664 )   To assess the genetic diversity and genetic homozygosity of the three generations of meiotic gynogenetic populations of blunt snout bream (Megalobrama amblycephala), and to find a stable molecular genetic marker that distinguishes different breeding populations of M. amblycephala(Pujiang No.1 genetically selected strains F9, three consecutive generations of meiotic gynogenetic populations), genetic diversity and genetic structure of meiotic gynogenetic populations meio-G1 (the first generation), meio-G2 (the second generation), meio-G3 (the third generation) and the control group (Pujiang No.1 genetically selected strains F9) of M. amblycephala was analysed using thirty-nine RAPD markers in this study. Several stable RAPD markers for distinguishing different breeding populations were obtained. And the efficiency to pure gene for successive artificial meiotic gynogenesis in M.amblycephala was assessed. The results showed that: the number of loci detected in the control group, meio-G1, meio-G2 and meio-G3 were 213, 202, 200 and 190, respectively. The percentage of polymorphic loci detected in the control group, meio-G1, meio-G2 and meio-G3 were 36.15%, 35.64%, 27.00% and 26.84%, respectively. Shannon's information index estimated within the control group, meio-G1, meio-G2 and meio-G3 were 0.207 9, 0.185 7, 0.146 1 and 0.138 3, respectively. The genetic diversity of meio-G1, meio-G2 and meio-G3 were much lower than that in the control group.The genetic diversity of three consecutive generations of meiotic gynogenetic populations decreased with the increasing of gynogenetic generations. Genetic identity between individuals within each population ranged from 0.828 5 to 0.906 0. The genetic identity between individuals within populations of meio-G1, meio-G2 and meio-G3 were much higher than that in the control group. The genetic identity between individuals within three consecutive generations of meiotic gynogenetic populations increased with the increasing of gynogenetic generations. Genetic differentiation index (pairwise FST values) between four populations ranged from 0.269 2 to 0.419 5. And the probabilities of the permutation test of genetic differentiation between four populations ranged from 0.000 0 to 0.009 0, indicating extremely significant genetic differentiation between four populations. Five primers (S3, S40, S58, S71 and S75) were observed to produce specific bands for discriminating different populations. Of these primers, four primers (S3, S40, S58 and S75) could be used as molecular markers for distinguish between meio-G3 and the other three populations (F9, meio-G1 and meio-G2). Primer S3 has the highest reliability for population identification. Only one primer (S71) could be used as molecular markers for distinguish between meio-G2 and the other three populations (F9, meio-G1 and meio-G3).The results of this study indicated that the continuous generations of artificial meiosis gynogenesis had affected the breeding populations of M. amblycephala in the following two aspects: on one hand, the genetic diversity significantly reduced with the increasing of gynogenetic generations. On the other hand, the genetic purity increased significantly with the increasing of gynogenetic generations. Continuous multi-generation meiotic gynogenesis could significantly accelerate the homozygous rate of the gene, and the meio-G3 population was already a high-purity line with high genetic consistency. References | Related Articles | Metrics

Select

Prokaryotic expression and polyclonal antibody preparation of Hsc70 in Nile tilapia PAN Chuanyan, LIN Yong, FENG Pengfei, ZHANG Yongde, LUO Honglin 2019, 31(8):  1272-1279.  DOI: 10.3969/j.issn.1004-1524.2019.08.07 Abstract ( 557 )   HTML ( 0 )   PDF (2666KB) ( 1591 )   To express Hsc70 (heat shock cognate 70) of Nile tilapia via a prokaryotic expression system, the recombinant protein was purified and polyclonal antibody was prepared. Bioinformatics analysis of Hsc70 was analyzed, primers were designed, and then Hsc70 gene was amplified. A prokaryotic expression vector of Hsc70 was constructed and the Hsc70 recombinant protein was induced by IPTG.The recombinant protein was identified by SDS-PAGE and purified with a Ni-NTA. To obtain the polyclonal antibody, the purified Hsc70 recombinant protein was used to immunize Japanese white rabbits, the titer was determined by ELISA, and the specificity was analyzed by Western blot. The Hsc70 recombinant protein was mainly obtained from the inclusion body with a molecular weight of 75 ku. After the purified recombinant protein was immunized with Japanese white rabbits, the rabbit anti-Hsc70 polyclonal antibody was successfully obtained, whose titer was 1∶2 048 000 and the specificity was good. Hsc70 of Nile Tilapia expressed successfully in E. coli B21, and the recombinant protein and polyclonal antibody obtained in this study provided a molecular tool for further study the function of Hsc70. References | Related Articles | Metrics

Select

SNP site screening and bioinformatics analysis of TLR2 gene in Datong yak PENG Shuai, CHEN Lang, ZHENG Tianyu, LU Huining, ZHANG Li, LIU Lixia 2019, 31(8):  1280-1285.  DOI: 10.3969/j.issn.1004-1524.2019.08.08 Abstract ( 514 )   HTML ( 0 )   PDF (2358KB) ( 1580 )   The SNP sites of the coding region of TLR2 gene in Datong yak was screened by DNA mixed pool amplification and direct sequencing, and the allele frequency of each SNP site was estimated, and the effect of mutation to TLR2 mRNA and protein structure was predicted by the bioinformatics software. The results showed that there were two SNP sites in the coding region of Datong yak TLR2 gene, G677A and G1587A respectively, of which G677A was missense mutation, resulting in the transformation of cysteine (Cys) to tyrosine (Tyr). The results of bioinformatics analysis showed that both G677A and G1587A sites reduced the stability of the secondary structure of the RNA, and the secondary and tertiary structure of the protein also changed. References | Related Articles | Metrics

Horticultural Science

Select

Alleviating effect of exogenous nitric oxide donor sodium nitroprusside on tomato seedlings under salt stress SUN Dezhi, YANG Hengshan, ZHANG Qingguo, FAN Fu, Suyale qiqige, PENG Jing, HAN Xiaori 2019, 31(8):  1286-1294.  DOI: 10.3969/j.issn.1004-1524.2019.08.09 Abstract ( 750 )   HTML ( 4 )   PDF (1348KB) ( 1765 )   In order to clarify the alleviating effects of exogenous nitric oxide (NO) on tomato seedlings under salt stress, using tomato variety Qinfengbaoguan as research object, and sodium nitroprusside (SNP) as donor of NO, the effects of different SNP concentration (50, 100, 200, 400, 800 μmol·L-1) on the growth, photosynthetic pigment contents, gas exchange and chlorophyll fluorescence parameters, membrane peroxidation and antioxidase activity under stress of 100 mmol·L-1 NaCl were studied in this paper. The results showed that, under salt stress, the growth inhibition of tomato seedlings treated with different concentrations of SNP could be effectively alleviated. At the same time, chlorophyll content, photosynthetic rate (Pn), stomatal conductance (Gs), maximal fluorescence (Fm), PSⅡ maximal photochemistry efficiency (Fv/Fm), practical photochemical efficiency (ΦPSⅡ) and photochemical fluorescence quenching coefficient (qP) of leaves increased significantly, while original fluorescence (Fo) and non-photochemical quenching coefficient (qN) decreased significantly, and when the SNP concentration was 100 μmol·L-1, the variation range of each index reached the maximum. The activity of catalase (CAT) in tomato leaves was not significantly changed under salt stress, and the activity of superoxide dismutase (SOD) and peroxidase (POD) were significantly increased. Except that the activity of POD was inhibited by 400 and 800 μmol·L-1 SNP treatment, the SNP treatment at all concentrations could promote the increase of the above three enzyme activities, and significantly reduced the malondialdehyde content and electrolyte leakage rate in leaves, with the most significant change at 100 μmol·L-1. These results suggested that exogenous NO donor SNP alleviated the oxidative damage caused by salt stress by enhancing the photosynthetic ability of seedling leaves, and thus improved the salt tolerance of tomato plants. References | Related Articles | Metrics

Select

DNA barcoding identification and phylogenetic relationship in Cymbidium based on ITS2 sequences WU Weifeng, CHEN Xiaochou, CHEN Faxing, CHEN Chun, ZHANG Yizhi 2019, 31(8):  1295-1304.  DOI: 10.3969/j.issn.1004-1524.2019.08.10 Abstract ( 607 )   HTML ( 0 )   PDF (1615KB) ( 1565 )   Many types of Cymbidium have high ornamental and economic value and occupy important position in the orchid industry. However, due to the complex evolution and genetic history of Cymbidium, there have been problems in identification and there are many taxonomic disputes. In recent years, the rapid development of DNA barcoding technology has provided new ideas for taxonomy and molecular identification. In this study, 12 native samples of Cymbidium and 250 Orchidaceae ITS2 sequences downloaded from GenBank (81 of which belong to the genus Cymbidium) were used to evaluate the feasibility of ITS2 sequence for molecular identification of Cymbidium by BLAST1, genetic variation, and phylogenetic tree-construction methods, and based on the results of phylogenetic tree-construction, explored the phylogenetic relationship of the genus Cymbidium. The results of BLAST1 showed that ITS2 sequence could accurately identify the genus and subgenus of 12 native Cymbidium samples, and the success rate of identification was 100%. It also had good identification ability at the section level, the success rate was 92%. But at the species level, identification ability was poor, and the identification success rate was only 17%. The genetic variation analysis of the reference library (250 ITS2 sequences of Orchidaceae downloaded from GenBank) showed that the Cymbidium ITS2 sequences had high genetic diversity (variation rate was 74.9%), and could be better distinguished at the genus and subgenus levels, but the level of species under the section or section were poor due to the large overlap between intra-and inter-section variation, intra-and inter-species variation. According to the analysis of phylogenetic tree, ITS2 sequence could clearly distinguished subgenus Jensoa, Cymbidium and Cyperorchis. The relationship between the subgenus Jensoa and Cymbidium was relatively close, and they were both far from the subgenus Cyperorchis. At the same time, it was also found that Cymbidium tortisepalum and C. goeringii were close in the phylogenetic tree. This result supported the division of the 3 subgenus of Du Puy & Cribb, and suggested that C. tortisepalum might be a variety or variety from C. goeringii(bootsrap value was 69%). In summary, ITS2 sequences had certain application value in the molecular identification of Cymbidium, and could be used as an auxiliary sequence for the DNA barcoding identification of Cymbidium. References | Related Articles | Metrics

Select

Characteristics of wild habitat and ecological niche of Passiflora edulis in karst peak cluster depression DONG Wanpeng, LI Anding, ZHANG Jianli, LONG Xiuqin 2019, 31(8):  1305-1311.  DOI: 10.3969/j.issn.1004-1524.2019.08.11 Abstract ( 441 )   HTML ( 1 )   PDF (1097KB) ( 1355 )   This paper studied wild habitat characteristics and ecological characteristics of associated species of Passiflora edulis in karst peaks and valleys in Guizhou. The results showed that the habitat of Passiflora edulis in karst peak-cluster depression was complex and varied, semi-continuous soil and sporadic, rocky desert. The slope of rocky desertification was steep and the soil layer was thin, the erosion of soil by rain leaded to serious loss of organic matter, serious erosion, high bulk density of soil and poor soil structure. The branches of Passiflora edulis sprout among rocks mostly. In that area, the other dominant species included Lonicera japonica, Broussonetia papyrifera, Rubus biflorus, Toona sinensis and Alangium chinense. The important values of Broussonetia papyrifera and Rubus biflorus were 60.54% and 51.64%. The top seven niche widths were Passiflora edulis, Rubus biflorus, Broussonetia papyrifera, Alangium chinense, Toona sinensis, Lonicera japonica and Smilax china Linn. The niche overlap values of Passiflora edulis and companion species were 0.023-0.088 (Lih) and the reverse were 0.014-0.075 (Lhi). Vines were abundant in the survey area, mainly shrub and vine. There was no obvious niche overlap among 20 dominant species, and there were significant differences in resource utilization among different populations, and the trend of resource sharing among populations was not prominent. The results showed that Passiflora edulis community was unstable. Passiflora edulis had significant bidirectional niche overlap with Broussonetia papyrifera, Rubus biflorus, Toona sinensis and Alangium chinense. Passiflora edulis and its associated species could coexist mutually, adapt to the environment, grow rapidly, and produce high biomass. In the future, Passiflora edulis resources could be reasonably exploited and utilized to promote the development of local industries. References | Related Articles | Metrics

Select

Screening of internal reference gene of Agaricus bisporus ZHAO Jianxia, SHEN Yingyue, FENG Weilin, JIN Qunli, SONG Tingting, FAN Lijun, CAI Weiming 2019, 31(8):  1312-1320.  DOI: 10.3969/j.issn.1004-1524.2019.08.12 Abstract ( 464 )   HTML ( 3 )   PDF (1676KB) ( 1514 )   According to specific experimental materials and conditions, the selection of appropriate internal reference genes in RT-qPCR analysis was crucial for accurate correction of target genes expression. In present study, eight internal genes were used to analyze expression stability between five development stages, three different tissues or organs, four different temperature by GeNorm, NormFiner softwares and Δ Ct methed. The results showed that the optimal internal reference genes of Agaricus bisporus at different developmental stages, in different tissues and at different temperatures were 40s+actin+Eif5 combination, Eif5+ubiquitin+PRL14 combination and EF1+ubiquitin+RPL14 combination, respectively. This study had important practical value for the quantitative expression analysis of key genes related with developmet and temperatural response in Agaricus bisporus. References | Related Articles | Metrics

Select

Comparison of morphology, anatomical structure and karyotype between two Talinum crassifolium (Jacq.) Gaertn. species YAN Wenyi, XIE Yongdong, YANG Luxi, CHEN Yan, WANG Haixia, SUN Bo, HE Zhongqun 2019, 31(8):  1321-1330.  DOI: 10.3969/j.issn.1004-1524.2019.08.13 Abstract ( 577 )   HTML ( 0 )   PDF (8248KB) ( 1540 )   Two species of Talinum crassifolium (Jacq.) Gaertn. were used in this experiment, morphological structure and karyotype differences between the two species of T. crassifolium(Jacq.) Gaertn. were observed and analyzed by paraffin sectioning combined with fluorescence microscopy and root tip squash method,it provided theoretical reference for the identification of T. crassifolium (Jacq.) Gaertn. The results indicated that plant height, stem diameter, leaf thickness, leaf area and flower diameter in species 2 were significantly greater than those in species 1, but there was no significant differences in flower color and thousand kernel weight between the two species. In microstructure, the number of stomata per unit area in upper epidermis of species 1 was significantly less than that of species 2, while the number of stomata per unit area in lower epidermis was significantly greater than that of species 2; The style morphology of the two species of T. crassifolium (Jacq.) Gaertn. were both three-petal feather; The stem cross section of species 1 was nearly round, and that of species 2 was irregular. In species 1, the chromosome number was 2n=2x=40, the karyotype formula was 2n=2x=38m+2M, the relative length of chromosomes was 8L+14M2+12M1+6S, the karyotype category belonged to type 1B, the coefficient of karyotype asymmetry was 54.50%; In species 2, the chromosome number was 2n=2x=24, the karyotype formula was 2n=2x=18m+6sm, the relative length of chromosomes was 6L+4M2+8M1+6S, the karyotype category belonged to type 2B, the coefficient of karyotype asymmetry was 59.37%. The number of stomata per unit area of upper and lower epidermis, stem cross section shape and karyotype of two species were significantly different, it could be used as reference indexes to identify T. crassifolium (Jacq.) Gaertn. species. References | Related Articles | Metrics

Plant Protection

Select

Prediction of potential distribution of Phenacocccus solani in China by BIOCLIM model HUANG Fang, ZHANG Wenjun, ZHANG Jiancheng, WU Zhiyi 2019, 31(8):  1331-1336.  DOI: 10.3969/j.issn.1004-1524.2019.08.14 Abstract ( 501 )   HTML ( 3 )   PDF (1942KB) ( 1384 )   The potential geographic distribution of Phenacoccus solani in China was predicted in BIOCLIM mode and the prediction was evaluated by ROC. The results showed that the prediction should be reliable, and P. solani could colonize in most parts of China. The high probable occurrence areas covered Huanghuai region, Jianghuai region and the lower-middle reaches of Yangtze-river basin, including provinces of Hainan, Guizhou, Sichuan, Guangxi, Guangdong, Hunan, Hubei, Henan, Hebei, Anhui, Jiangxi, Fujian, Zhejiang. Other probable occurrence areas involved southwest, northwest and northeast of China, including Yunnan, Xinjiang, Tibet, Gansu, Ningxia, Inner Mongolia, Shaanxi, Liaoning. References | Related Articles | Metrics

Select

Identification of tobacco anthracnose and isolation of antagonistic Streptomyces LI Jiye, WANG Jingjing, YANG Lu, PENG Lijuan 2019, 31(8):  1337-1344.  DOI: 10.3969/j.issn.1004-1524.2019.08.15 Abstract ( 569 )   HTML ( 1 )   PDF (5790KB) ( 1636 )   A strain of tobacco anthracnose pathogen was isolated from Guizhou Province. In order to clarify the taxonomic status in the genus of Colletotrichum and investigate the suitable Streptomyces biocontrol strain, morphology and polygenic phylogenetic analysis were performed. The biological characteristics were studied and antagonistic Streptomyces were isolated. Results showed that the pathogen was identified as Colletotrichum orbiculare. The best carbon source and nitrogen source for growth was starch and peptone, but it couldn't use oxamic acid. The optimum temperature for growth was 25 ℃. Illumination and pH had little effect on colony diameter. Two strains of Streptomyces F18 and F35 with good antagonistic effects were isolated and preliminarily identified as Streptomyces albolongus and Streptomyces plumbiresistens. References | Related Articles | Metrics

Select

Observations on infection of Nilaparvata lugens (Stål) by Metarhizium flavoviride ZHANG Juefeng, CHEN Jianming, LI Fang, ZHONG Haiying, WU Hong 2019, 31(8):  1345-1352.  DOI: 10.3969/j.issn.1004-1524.2019.08.16 Abstract ( 420 )   HTML ( 2 )   PDF (5306KB) ( 1616 )   In the present study, the process of Metarhizium flavoviride conidia infecting Nilaparvata lugens(Stål) and its eggs was observed by using a scanning electron microscope (SEM) and semithin section, and the effects of M. flavoviride on hatching rate and adult and nymph development duration were also detected. The results showed that M. flavoviride invaded the internode membranes on cuticle preferentially, form appressoriums, the appressorium germinated and formed an invading mycelia to invade the host's blood cavity. Mycelia multiplied rapidly using host's nutrition and accumulated in the abdomen, which caused the death of the host. M. flavoviride sprayed on rice plants could not infect N. lugens eggs produced in the leaf sheath, but could colonize and reproduce on eggs in vitro. The hatching rate of N. lugens infected by M. flavoviride was in the range of 61.10%-72.67% mostly, and the prolongation of treatment time did not decrease the hatching rate of N. lugens. There was no significant difference in duration of nymphs and adults among different treatments. Therefore, M. flavoviride could infect cuticle and eggs of N. lugens, yet the process took a long time and was susceptible to external factors. Thus, rational strategy of using M. flavoviride as a control agent against N. lugens should take external factors well into account. References | Related Articles | Metrics

Environmental Science

Select

Distribution of soil aggregate and organic carbon under different land use types in Linzhi, Tibet LIAN Yuzhen, LIU Heman, CAO Lihua, HAN Xiaohao, MA Heping 2019, 31(8):  1353-1360.  DOI: 10.3969/j.issn.1004-1524.2019.08.17 Abstract ( 528 )   HTML ( 2 )   PDF (1100KB) ( 1579 )   In order to reveal the impact of land use types on soil aggregates and soil organic carbon in Linzhi, farm land (FL), vegetable greenhouse (VG), abandoned land (AL), grass land (GL) and secondary forestland (SF) of Bayi Town were selected as the research objects, dry sieving method was introduced to classify soil aggregates, and the aggregates as well as the content and distribution of soil organic carbon and labile organic carbon were explored. It was shown that soil aggregate with the size ≥2 mm constituted the majority at 0-20 cm, and its content was higher in GL and AL than that of VG and FL, indicating that the soil structure of natural ecosystem was better than agriculture land (FL and VG). The content of organic carbon and labile organic carbon in soil aggregate was higher in 0-10 cm layer than that in 10-20 cm layer, and was higher in macroaggregate (≥0.25 mm) than that in microaggregate (<0.25 mm). The aggregate with size ≥2 mm showed the highest contribution rate to organic carbon and labile organic carbon in soil aggregate, and possessed strong capacity of carbon sink. The soil structure of natural ecosystems was good, and the reclamation of GL and SF would lead to deterioration of soil structure. Protective farming measures or reducing artificial interruption to forest lands and grass lands should be carried out, to enhance the stability of soil organic carbon storage, and ensure its role as soil carbon sink. References | Related Articles | Metrics

Select

Variations of cotton rhizosphere microbial community in different growth stages LIU Shanshan, WEI Xin, SHENG Furui, QIAO Qinghua 2019, 31(8):  1361-1371.  DOI: 10.3969/j.issn.1004-1524.2019.08.18 Abstract ( 489 )   HTML ( 0 )   PDF (1782KB) ( 1544 )   To understand the cotton rhizosphere bacterial and fungal community structure during different growth stages, 16S and ITS regions of soil DNAs sampled from the rhizosphere and corresponding control soil of upland and island cotton were sequenced and analyzed. The results indicated that species richness of bacteria and fungi in rhizosphere of different growth stages were significantly (P<0.05) lower than that of control soil, and the species richness in rhizosphere were the highest in the budding stage. Evolutionary distance between the microbiome leading to the difference between seedling stage and budding stage was farther than that between budding stage and flowering stage. Cluster analysis showed that dominate phyla of cotton rhizosphere bacterial community were Proteobacteria, Acidobacteria, Firmicutes, Cyanobacteria, Actinobacteria, Planctomycetes, Bacteroidetes and Verrucomicrobia, and dominate phyla of cotton rhizosphere fungal community were Ascomycota, Basidiomycota and Zygomycota. Moreover, the cotton rhizosphere bacterial and fungal genus with higher or lower relative abundance compared with control soil varied in different growth stages, and the quantity of genus with significantly (P<0.05) higher relative abundance was the highest in budding stage. References | Related Articles | Metrics

Biosystems Engineering

Select

Nondestructive recognition of surface defect on kiwifruits using hyperspectral imaging technology MENG Qinglong, ZHANG Yan, SHANG Jing 2019, 31(8):  1372-1378.  DOI: 10.3969/j.issn.1004-1524.2019.08.19 Abstract ( 509 )   HTML ( 2 )   PDF (1696KB) ( 1559 )   In order to explore a rapid and nondestructive recognition method to identify kiwifruits with surface defect, the hyperspectral imaging system was used to collect the hyperspectral image of Guichang kiwifruits with no defect and surface defect. After the minimum noise fraction transform (MNF), threshold segmentation and mathematical morphology, the recognition algorithm for kiwifruits with surface defect was proposed and then applied in 60 intact kiwifruits and 60 kiwifruits with surface defect. The results showed that the noise of the hyperspectral image of kiwifruits could be effectively removed by MNF transform. And the intact kiwifruits and kiwifruits with surface defect had obvious reflectance value between 700-810 nm and 810-1 000 nm. The spectral reflectance between 0.30-0.56 at 785.98 nm and the spectral reflectance between 0.54-0.73 at 982.59 nm were both selected as the threshold conditions to distinguish the region of normal and surface defect on kiwifruits. The correct identification rates for the intact kiwifruits and kiwifruits with surface defect reached 98.3% and 95.0%, respectively, which indicated that the hyperspectral imaging technology could be effective for identifying kiwifruits with surface defect. References | Related Articles | Metrics

Select

Experiment of sucking performance of inside-filling pneumatic type precision hill-drop drilling seed-metering device for rice ZHANG Shun, YANG Jitao, LI Yong, LIAO Juan, LI Zhaodong, ZHU Dequan 2019, 31(8):  1379-1387.  DOI: 10.3969/j.issn.1004-1524.2019.08.20 Abstract ( 515 )   HTML ( 0 )   PDF (2007KB) ( 1321 )   In order to meet the direct seeding requirement of 2-4 seeds per hill for hybrid rice, an unique inside-filling pneumatic type precision hill-drop drilling seed-metering device was designed with multi-suction holes-socket structure. The structural parameters of the sucking cylinder were analyzed and designed in this paper. The hybrid rice seed Zhongnong2008 was selected as experimental material, and the effects of the three main impact factors (cylinder rotational speed, vacuum degree and seed-inlet height) on miss-sucking index, qualified index and multi-sucking index were studied by orthogonal experimental design, and the seed sucking adaptability tests of hybrid rice varieties with different sizes were carried out. The results showed that the orders of factors affecting the seed sucking performance of the metering device were different according to different evaluation indexes, and the optimal working parameter combination was cylinder rotational speed of 17.14 r·min-1, vacuum degree of 1.1 kPa and seed-inlet height of 25 mm. Under this working parameter combination, the miss-sucking index, qualified index and multi-sucking index were 1.0%, 92.4%, and 6.6%, respectively. The seed sucking adaptability tests were carried out under the same working conditions with three different sized hybrid rice seeds (short size Tesan'ai No. 2, medium size Gangyou898 and long size Fengliangyou3948), respectively. All the miss-sucking and multi-sucking indexes were less than 2.4% and 7.8%, respectively, and all the qualified indexes were higher than 91.2%. Experiment results indicated that the multi-suction holes-socket structure of the seed-metering device had good adaptability to different hybrid rice varieties, and the seed-sucking performance could meet the agronomic requirements of precision hill-drop drilling for hybrid rice. References | Related Articles | Metrics

Agricultural Economy and Development

Select

Analysis into development of pastoral complex based on dissipative structure theory HE Lan, ZHOU Guohua 2019, 31(8):  1388-1398.  DOI: 10.3969/j.issn.1004-1524.2019.08.21 Abstract ( 389 )   HTML ( 1 )   PDF (1316KB) ( 1403 )   Pastoral complex (PC) is one of important ways to pursue the rural vitalization in China. Based on dissipative structure theory, by using inductive method and comprehensive analysis method, the present study examined problems in PC construction and proposed corresponding countermeasures and suggestions according to the data of 19 national PC pilot projects. It was shown that PC had basic features of dissipative structures. The over-tourism development, destruction of ecological environment, lack of cultural creativity, unclear policies, and dispersion power of stakeholders were the main factors affecting PC. The key to the development of PC was to adopt the strategy of "controlling the internal entropy and increasing negentropy". Specifically, the increase of internal entropy should be controlled from three aspects of ensuring the development of high-quality agriculture, protecting ecological environment and culture, and negative entropy flow should be input in five aspects of matching supply with demand of industrial development, increasing budgetary input in technology, deepening cultural creativity, expanding support for policy and establishing a benefit sharing mechanism. References | Related Articles | Metrics