Archive

25 July 2020, Volume 32 Issue 7 Previous Issue    Next Issue
---
Crop Science
Animal Science
Horticultural Science
Environmental Science
Foods Science
Biosystems Engineering
Agricultural Economy and Development
Review


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Crop Science

Select

Physiological response and salt tolerance mechanism of cotton seedlings to salt stress SHI Jing, LIU Dongyang, ZHANG Fenghua 2020, 32(7):  1141-1148.  DOI: 10.3969/j.issn.1004-1524.2020.07.01 Abstract ( 1985 )   HTML ( 268437727 )   PDF (958KB) ( 2107 )   To study the physiological response characteristics of cotton seedlings with different salt tolerance under salt stress, the salt-tolerant variety Zhong 9806 and salt-sensitive variety Zhong S9612 were used as test materials, four different concentrations (0, 100, 150, 200 mmol·L-1) of NaCl were set to simulate different conditions of salt stress by hydroponic method. The results showed that with the increase of salt concentration, soluble sugar content of each cotton variety increased, and the antioxidant enzyme activity increased first and then decreased. Under salt treatment, the soluble protein and proline content of salt-tolerant cultivar increased more than those of salt-sensitive cultivar; Under S1 treatment (100 mmol·L-1 NaCl), the accumulation of malondialdehyde content was lower in salt-sensitive cultivar, but under S2 and S3 treatments (150, 200 mmol·L-1 NaCl), the increase of malondialdehyde content of salt-tolerant cultivar (5.35%-6.83%) was lower than those of salt-sensitive cultivar (36.93%-77.34%), and the activities of superoxide dismutase and peroxidase increased greatly. Under low salt concentration stress, the above-ground part of the salt-sensitive cultivar could maintain less Na+, and under high salt concentration stress, the increase of Na+ in the root of salt-tolerant variety was less than that of the salt-sensitive cultivar, and K+, K+/Na+ in the stems were relatively high. In summary, it had been shown that under salt stress, salt-tolerant cultivars of cotton could increase the content of osmoregulation substance, increase the activity of antioxidant enzymes to relieve membrane lipid peroxidation, and maintain a higher K+/Na+ ratio, thereby improving salt tolerance of seedlings. References | Related Articles | Metrics

Animal Science

Select

Cloning and bioinformatic analysis of rpoE gene of Streptococcus suis DU Yanbin, ZHANG Gangchen, WANG Yuxin, LIU Baobao, GONG Shenglong, DONG Xiao, WANG Yang 2020, 32(7):  1149-1154.  DOI: 10.3969/j.issn.1004-1524.2020.07.02 Abstract ( 730 )   HTML ( 3 )   PDF (2910KB) ( 1828 )   This study aimed to clone the rpoE gene of Streptococcus suis and to analyze the function and related biological characteristics of the rpoE gene encoding protein of Streptococcus suis by bioinformatic software. The rpoE gene was amplified from Streptococcus suis and sequenced; the physicochemical properties and antigenic epitopes of the protein encoded by the gene were predicted by bioinformatic software. The results showed that the rpoE gene of Streptococcus suis was 582 bp in length, encoding a hydrophilic cytoplasmic protein rich in glutamic acid, aspartic acid and serine. Besides, the secondary structure analysis showed that the main structural components of RpoE protein were α-helix and random coil, accounting for 52.3% and 36.3%, respectively. The comprehensive analysis indicates that there are 5 dominant epitopes on RpoE protein. References | Related Articles | Metrics

Select

Functional analysis of EEF1D mutation site in dairy cow milk fat traits candidate gene JIANG Qiufei, CAI Zhengyun, HUANG Zengwen, FENG Xiaofang, ZHANG Juan, GU Yaling 2020, 32(7):  1155-1159.  DOI: 10.3969/j.issn.1004-1524.2020.07.03 Abstract ( 550 )   HTML ( 2 )   PDF (788KB) ( 1601 )   Increasing milk fat content and improving milk quality have become one of the key research directions in the dairy industry. In the previous study, the G/A mutation in the 5'-untranslated region (5'-UTR) of EEF1D gene was significantly correlated with the milk fat percentage. In order to further analyze the functional site of the candidate gene EEF1D, the EEF1D gene mutant and wild-type fragments were obtained by artificial synthesis, and functional verification experiments were carried out at the cellular level. This study found that the G/A mutation of the 5'-UTR of the EEF1D gene caused a 33 bp shift in the Sp3 transcription initiation site, and the activity of the mutant was about three times that of the wild type. These findings indicated that this mutation can alter the transcription initiation site of the transcription factor, thereby up-regulating the expression of EEF1D. References | Related Articles | Metrics

Select

Study on mRNA expression pattern of IGF-1R gene in chicken skeletal muscles during early development SHENG Zhongwei, JI Gaige, LIU Yifan, JU Xiaojun, SHAN Yanju, ZOU Jianmin, ZHANG Ming, TU Yunjie, SHU Jingting 2020, 32(7):  1160-1165.  DOI: 10.3969/j.issn.1004-1524.2020.07.04 Abstract ( 757 )   HTML ( 2 )   PDF (575KB) ( 1678 )   In the present study, the Huashan and Qingyuan partridge chickens differing in growth rates were used as experimental materials,fluorescent real-time quantitative PCR (RT-PCR) was used to detect the mRNA expression pattern of IGF1R gene in pectoral and leg muscle of chickens on the embryonic days of 9, 12, 16, 21 and 7 days post-hatching. The results showed that pectoral muscle weight significantly decreased in the two breeds at the embryonic days 21, but leg muscle weigh significantly increased as time going. IGF1R mRNA expression tendency of pectoral muscle in Huashan partridge chickens were from the high to the low: the embryonic days 9 was an expression peak, and then the expression level significantly decreased and kept a low level and down-regulated in 7 days post-hatching again. IGF1R mRNA expression of pectoral muscle in Qingyuan partridge chickens were a wavy trend: the expression levels of IGF1R gene on pectorals at 9 and 16 embryo age were higher, others were significant down-regulated. In leg muscle, the expression levels of IGF1R gene were significant down-regulated after 16 embryo age in Huashan partridge chicken; the expression levels of IGF1R gene in Qingyuan partridge chickens were decreased gradually and there were significant differences among groups(P<0.05). The expression level of IGF1R gene in pectoral and leg muscles were significantly different between varieties at different time(P<0.05). The expression level of IGF1R gene were significantly correlated with the weight of pectoral and leg muscles, respectively (P<0.01). The above results were preliminarily revealed the development changes and difference of IGF1R gene expression in pectoral and leg muscles during early development of different breeds, provide basic data for further study on regulation mechanism of chicken muscle development. References | Related Articles | Metrics

Select

Comparative analysis of nutritional components in the muscle of hybrid F1, F2 of (Culter alburnus)(♀)×(Megalobrama amblycephala)(♂) and its parents JIANG Wenping, JIA Yongyi, LIU Shili, CHENG Shun, CHI Meili, ZHENG Jianbo, LI Fei, GU Zhimin 2020, 32(7):  1166-1175.  DOI: 10.3969/j.issn.1004-1524.2020.07.05 Abstract ( 651 )   HTML ( 8 )   PDF (822KB) ( 1841 )   In this study, the nutritional components of the back muscles of topmouth culter (Culter alburnus) (Abbr. CA), blunt nose bream (Megalobrama amblycephala) (Abbr. MA), hybrid of (female C. alburnus) × (male M. amblycephala ) (Abbr. HF1) and self-crossing of hybrid of (female C. alburnus) × (male M. amblycephala) (Abbr. HF2) were analyzed, and their nutritional quality were also evaluated and compared. Results showed that moisture contents were significantly lower in HF1 and HF2 than that in MA (P<0.05), while their crude protein contents were significantly higher (P<0.05), and crude fat content in HF1 was significantly higher when compared with that in HF2 and MA (P<0.05). Eighteen kinds of amino acids were found in muscles from four kinds of fish with all of them higher in HF2 than HF1 and their parents, including the total amino acids (TAA), essential amino acids (EAA), delicious amino acids (DAA), ∑EAA/∑TAA, ∑EAA/∑NEAA, amino acids score (AAS), chemical score (CS) and essential amino acid index (EAAI) to some degree (specific). More than twenty kinds of fatty acids were found in muscles from four kinds of fish. The ∑PUFA and ∑EPA+DHA content of HF1 were higher than that in its parents, and were significant higher when compared with that of HF2. Furthermore, ∑SFA:∑MUFA:∑PUFA of HF1 was 1:1.88:1.02, which was closer to the ideal diet of human body than that of its parents and HF2. In general, HF1 had high nutritional value such as low moisture, high fat, high protein, high EPA+DHA and balanced fatty acids composition when compared with parents. In addition, HF2 had low moisture, low fat, high protein and balanced amino acids composition as well as the best edible quality. They all can provide high-quality aquatic protein for different demand of market and have good prospects for development and utilization. References | Related Articles | Metrics

Select

Identification and pathological observation of Citrobacter freundii from Pelodiscus sinensis HUANG Liping, AN Lili, LI Fang, YANG Chengnian, LI Hong, LYU Guangjun, XIANG Xiao, SUN Hanchang, ZHAI Xuliang, ZHU Chengke 2020, 32(7):  1176-1186.  DOI: 10.3969/j.issn.1004-1524.2020.07.06 Abstract ( 685 )   HTML ( 5 )   PDF (5287KB) ( 1837 )   In order to determine the cause of death about the simulated ecological Pelodiscus sinensis in Chongqing, the pathogenic bacteria named strain PS01 was isolated from the intestinal and pharynx of deseased P. sinensis. The pathogen isolation, artificial infection, physical and chemical characteristics of isolated bacteria, sequence analysis of 16S rRNA and gyrB, drug sensitivity test and pathological section were carried out and investigated. The results showed that artificial infection symptoms with P. sinensis were similar to the natural symptoms. The phylogenetic tree constructed by 16S rRNA and gyrB sequences was the same as C. freundii, with a similarity of 99.7% and 98.7%. Pathological observation showed, there were various degrees of damage such as cytopathic and necrotic and so on. The pathological observation showed that the liver, spleen, kidney, ancreas, and intestinal had different degrees of lesions of the diseased C. freundii, among them, the three tissues of intestine, liver and spleen were the most serious. Most of intestinal villi were necrotic and shed, hepatocytes swell, nucleus vacuoles, mixed distribution of red and white marrow of spleen, mild pancreatic and renal lesions, pancreatic cells and renal tubular epithelial cells swell, no significant change was observed in other tissues. The drug susceptibility test showed that the strain PS01 was highly sensitive to 18 antibacterial drugs, such as doxycycline; and middle sensitive to 3 antibacterial drugs, such as florfeniol; resistant to 18 antibacterial drugs, such as sulfamethoxazole compound. This study proved that the disease of P. sinensis caused by C. freundii in Chongqing, whose half-lethal concentration for Chinese sturgeon of about 30 g was 9.3×104 CPU·g-1, which had strong pathogenicity and could cause multiple tissue lesions of P. sinensis. References | Related Articles | Metrics

Select

Malformation grade of western honeybee, Apis mellifera, infected by mite, Varroa destructor HU Zongwen, YANG Juan, MIAO Chunhui, HUANG Xinqiu, YANG Shuang 2020, 32(7):  1187-1195.  DOI: 10.3969/j.issn.1004-1524.2020.07.07 Abstract ( 572 )   HTML ( 1 )   PDF (1164KB) ( 1749 )   In order to investigate the malformation grade and morphological difference of honeybee worker, Apis mellifera, infected by ectoparasitic mite, Varroa destructor, the honeybee morphologic value by Ruttner (1988) were referred to measure the size of proboscis, wings, hindleg, targit, sternit and then the malformation for foragers, normal younger bees, climbing bees and malformed bees was graded. The results showed that economic performance disappeared for malformed bees whose hind leg length (8.188±0.122) mm, area of wax mirror (2.451 mm2) and cubital index (-0.501) was less than normal young bees, foragers, climbing bees. The area of wax mirror (3.072 mm2), 1/width sternit 6(93.686) of climbing bees was more than others but the body size/leg (56.759) was the smallest. In terms of morphology and structure, the imbalance between the back and the legs may cause the crawling of worker bees. Eight major components for malformed bees were established by high than 85% accumulated contribution rates of correlated matrix. The cluster analysis didn't distinguish the climbing bees with normal bees and discriminated analysis revealed three grades for malformation workers in which A type was close to normal bees, B type was medium and had an incomplete wings, C type had complete absent wings and shortened the leg and abdomen. The wings and abdomen previous variations showed vulnerability and malformation grade that may reflect an adaptive stress tolerance for bee resisted to mite. References | Related Articles | Metrics

Horticultural Science

Select

Effects of plough layer thickness on photosynthetic, fluorescence parameters of leaf and physiological characteristics of root for Cucumis sativus L. LAN Zhiqian, ZHANG Kaige, ZHANG Xueyan 2020, 32(7):  1196-1205.  DOI: 10.3969/j.issn.1004-1524.2020.07.08 Abstract ( 878 )   HTML ( 2 )   PDF (1090KB) ( 1954 )   Long-term and mechanical shallow tillage in highly intensive cultivation mode causes shallower plough layer, deeper plough sole layer , soil quality deterioration and other problems. In this study, the total soil layer was designed to be 50 cm, and plough layer were 10 cm (PL10), 20 cm (PL20), 30 cm (PL30), 40 cm (PL40) and 50 cm (PL50). The photosynthetic, fluorescence, root and plant growth-related parameters were measured in 2017 and 2018 years. The results showed that the shallower plough layer (PL10 and PL20) significantly increased the transpiration rate (Tr) and initial fluorescence value (Fo) of leaf, and significantly increased activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), and malondialdehyde (MDA) content in roots. The middle plough layer (PL30) significantly increased the relative growth rate of plant height (RGH-PH) and stem volume (RGH-SV), improved the net photosynthetic rate (Pn), maximum fluorescence value (Fm), light energy conversion rate (Fv/Fm) and photochemical quenching coefficient (qP) of the leaves, and significantly enhanced the root activity (RA), and proline (Pro), soluble sugar (SS) , soluble protein (SP) contents. The fruit yields (FY) of PL10 and PL20 were higher than those of the other treatments in early harvesting period, and lower than the others in middle and late harvesting period. Moreover, the fruit yield in the deeper plough layers (PL40 and PL50) were opposite to those of the shallower plough layers, PL30 had the highest total fruit yield in two cropping years. Through principal component analysis, the middle plough layer (PL30) and the deeper plough layer (PL50) were significantly different from other treatments. Combining plant growth and root characteristics, plough layer 30 cm was beneficial to the growth and development of cucumber with shallow root system. References | Related Articles | Metrics

Select

Isolation and expression of floral organ development regulating gene LiFUL1 in Lagerstroemia indica L. HUANG Xiaozhen, QIAO Zhongquan, ZENG Huijie, LI Yongxin, HE Gang, WANG Xiaoming 2020, 32(7):  1206-1214.  DOI: 10.3969/j.issn.1004-1524.2020.07.09 Abstract ( 831 )   HTML ( 2 )   PDF (2511KB) ( 1908 )   Flowers of crape myrtle Xiangyun are not strong enough to seeding, the manifestations of Xiangyun are indehiscent anther, pollen abortion and abnormal ovule. Redleaf is common crape myrtle with normal flowering and bearing. Crape myrtle Xiangyun was selected as the experimental material, RT-PCR was employed to isolate a homologous gene of FRUITFULL (FUL) from Xiangyun, named as LiFUL1(GenBank accession No. MN894547). Sequence analysis indicated that length of the open reading frame of LiFUL1 cDNA was 753 bp, which encoded a protein with 251 amino acids, its molecular weight was 28.453 13 ku. Analysis of sequence alignment and conserved structural domain showed that LiFUL1 protein belonged to FUL/AP1, a subfamily of the MADS, for it had both typical MADS-MEF2 and K-box domain, and the highly conserved motif euFUL MOTIF at C terminus. Phylogenetic tree analysis revealed that LiFUL1 of crape myrtle was most closely related to Eucalyptus globulus’s FUL/AP1 sequence. qRT-PCR test demonstrated that expressions of LiFUL1 in Xiangyun were significantly higher than those in crape myrtle Redleaf at calyx differentiation, petals and stamens differentiation, stamens and pistils differentiation stages. Successful expression of LiFUL1 in Escherichia coli using the prokaryotic expression system provided a basis for further study of LiFUL1 gene function. References | Related Articles | Metrics

Environmental Science

Select

Dissolution and release of soil potassium by ectomycorrhizal fungi under Mn2+ stress ZHANG Liang, LI Yuting, XU Xiaofeng 2020, 32(7):  1215-1222.  DOI: 10.3969/j.issn.1004-1524.2020.07.10 Abstract ( 674 )   HTML ( 4 )   PDF (759KB) ( 1806 )   Ectomycorrhizal fungi (ECMF), important components in forest ecosystems, could participate in nutrient absorption and utilization. Pisolithus tinctorius(Pt) and Lactarius deliciosus(Ld) were cultured in liquid Pachlewsk medium with soil as the potassium (K) source under Mn2+ stress, to study the ability and mechanism of two strains to activate insoluble K. The results showed that the biomass of two strains decreased with the increase of Mn2+, and the growth was significantly (P<0.05) inhibited. The biomass of Pt was higher than Ld under all Mn2+ concentrations, indicating that the resistance to manganese toxicity of Pt was stronger than Ld. Oxalic acid and acetic acid were detected in the medium of ECMF. Two strains reduced mineral K, and increased exchangeable K in soil, indicating that the ECMF could activate the insoluble K in soil under Mn2+ stress. Correlation analysis showed that oxalic acid secretion was significantly (P<0.01) positively related to soil exchangeable K, and was significantly (P<0.05) negatively related to soil mineral K. Meantime, the pH in culture medium was significantly (P<0.01) negatively related to exchangeable K in soil. Therefore, the organic acids and hydrogen ions secreted by ECMF were beneficial to the activation of soil insoluble K, in which oxalic acid might play a key role. Due to the different secretion capacity of organic acids and hydrogen ions, the activation abilities of the two ECMF strains were different. References | Related Articles | Metrics

Select

Eco-environmental diversity of wild tea germplasms in Guizhou Province NIU Suzhen, ZHAO Zhifei, SONG Qinfei, CHEN Zhengwu 2020, 32(7):  1223-1232.  DOI: 10.3969/j.issn.1004-1524.2020.06.11 Abstract ( 489 )   HTML ( 2 )   PDF (908KB) ( 1285 )   The eco-environmental factors of wild tea germplasms distributed in 32 geographical locations were studied to evaluate the diversity of distribution characteristics, climatic characteristics and associated plants, and to provide theoretical basis for the protection of wild tea germplasm in Guizhou Province. The results showed that 50% of the wild tea germplasms were arbor type, 0.03% were small arbor type, 49.97% were shrub type. The horizontal distribution range of wild tea germplasms was 104°58'-108°36'E and 24°58'-29°07'N. The vertical distribution range of wild tea germplasms was 615-1 900 m. Most geographical locations located in the humid subtropical monsoon and subtropical monsoon climate areas. Associated plants of woody species were fewer. The numbers of wild tea plants in each geographical location was significantly positive correlated with the contents of total nitrogen, total phosphorus and organic matter in soil, numbers and species of main associated plants. Some wild tea germplasm could survive in extreme climate for a long time, which had unique adaptability to extreme climate. The natural distribution of wild tea germplasm had changed, therefore, it was imperative to strengthen the effective protection and efficient utilization of wild tea trees in Guizhou. References | Related Articles | Metrics

Select

Effect of crop residue compost replacing part of chemical fertilizer and nitrification inhibitor on greenhouse gas emission of winter wheat WU Chengjie, REN Lantian, HAO Bing, SHAO Qingqin, WANG Hong, CHEN Feng, DAI Gaofeng, MEI Shiyuan, ZHANG Congjun 2020, 32(7):  1233-1240.  DOI: 10.3969/j.issn.1004-1524.2020.07.12 Abstract ( 849 )   HTML ( 5 )   PDF (975KB) ( 1977 )   In view of the current situation of excessive chemical fertilizer input, low utilization rate and high greenhouse gas emission in winter wheat production along the Huaihe River, the dynamic changes of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) emission flux and its influence on wheat yield and quality were studied under the design of replacing part of chemical fertilizer by crop residue compost in the main area (T) and dicyandiamide (DCD) as the split plot (D). The results showed that the total greenhouse gas emissions of the treatments of 7.5 t·hm-2 crop residue compost replacing 10% chemical fertilizer+60 kg·hm-2 DCD and 15 t·hm-2 crop residue compost replacing 20% chemical fertilizer+60 kg·hm-2 DCD were significantly (P<0.05) lower than those of the traditional fertilization by 19.01% and 31.76%, respectively. Besides, the amylopectin contents in wheat under the above treatments were significantly (P<0.05) increased by 10.00% and 14.00%, respectively. While, there was no significant decrease in wheat yield. Therefore, it was feasible to reduce greenhouse gas emission by replacing part of chemical fertilizer with crop residue compost along with DCD. This method showed no negative effect on wheat yield and was beneficial for greenhouse gas emission reduction and utilization of crop residue. References | Related Articles | Metrics

Select

Screening, identification and characterization of two halophilic, diesel-degrading bacteria GAO Wenjing, XIAO Lijiao, WANG Shunmin, HAN Qiuxia 2020, 32(7):  1241-1252.  DOI: 10.3969/j.issn.1004-1524.2020.07.13 Abstract ( 614 )   HTML ( 3 )   PDF (4094KB) ( 1627 )   Pollution of diesel has posed a huge threat to human health and ecological environment, the microbial bioremediation has become a common method for controlling diesel pollution. In this experiment, 35 strains were found to have ability to decompose diesel by culturing with diesel as the sole carbon source. Then, one diesel fuel-degrading halophilic bacteria, B-18, was selected using measurement of degradation rate of diesel. By measuring surface tension, oil drain ring diameter and performing immunohemolysis experiments, B-2 was screened out, which was a biosurfactant producer. B-2 showed a degradation rate of 44.80% with 3% diesel, the diameter of the oil drain ring was 6 cm and the surface tension was reduced from 74.88 mN·m-1 to 27.15 mN·m-1, which was identified as Salimicrobium sp. The degradation rate of B-18 for 3% diesel was 54.00%, which was identified as Salinicoccus sp. The result of GC-MS showed that the bacteria could degrade alkanes with a carbon chain length of 14-29. When the concentration of diesel was 5%, the degradation rates of B-2 and B-18 in GM could be increased from 35.52% and 45.62% to 49.08% and 53.46%. The degradation rate by microbial consortium composed of B-2 and B-18 strains could reach 68.50%. The microbial consortium was able to degrade the diesel by 70.45% under optimized conditions, referring to NaCl concentration 100 g·L-1, 37 ℃, pH 7.5. Through scanning electron microscopy (SEM), it was found that B-2 and B-18 had typical morphological changes during the degradation of diesel, and the surface of halophilic bacteria could form sticky substances that to interconnect the individual cells, which accelerated the absorption and degradation of diesel. In high-salt environments, the microbial consortium could be used for bioremediation of diesel contaminated environments. References | Related Articles | Metrics

Foods Science

Select

Effects of overexpression of acyl carrier protein gene in Synechocystis on fatty acids synthesis LU Xiaoyuan, ZHONG Huairong, XIA Zhijie, CAO Yuelei, CHEN Gao, DAI Meixue 2020, 32(7):  1253-1262.  DOI: 10.3969/j.issn.1004-1524.2020.07.14 Abstract ( 484 )   HTML ( 2 )   PDF (1927KB) ( 1600 )   Acyl carrier protein (ACP) is a key protein in fatty acid biosynthesis pathway of microorganisms. In order to promote the accumulation of fatty acids in Synechocystis, the homologous recombinant plasmid ssl2084(+) was successfully constructed for overexpressing the ACP (ssl2084) gene and transformed into wild-type Synechocystis sp. PCC6803. Identification of the ssl2084(+) mutant strain at the DNA and protein levels showed that the ssl2084 gene had been overexpressed. The content and composition of the fatty acids in the mutant strain under different temperatures were detected by liquid chromatography-mass spectrometry (GC-MS). The results showed that the contents of C12:0, C16:0 and C18:0 in ssl2084(+) mutant at 30 ℃ were 1.50, 8.74 and 0.60 mg·g-1, respectively, which increased by 54.71%, 50.82% and 155.86%, respectively, compared with the wild type. Under the condition of low temperature stress culture at 20 ℃, the contents of C12:0, C16:0 and C18:0 reached 1.70, 11.85 and 2.31 mg·g-1, respectively, which increased by 31.94%, 47.35% and 39.90%, respectively, compared with the wild type. The above results indicated that overexpression of ssl2084 gene in Synechocystis sp. PCC6803 could increase the content of medium and long chain fatty acids, and the low temperature condition could further increase the content of medium and long chain fatty acids. References | Related Articles | Metrics

Select

Effect of food improvers on quality characteristics of dried Engraulis japonicas GU Saiqi, WANG Suning, BAO Rongbin, HU Binchao, YANG Xiaoxia, ZHANG Jilei, CHEN Jingying, LIN Zhaoyong, DING Yuting, KE Zhigang 2020, 32(7):  1263-1273.  DOI: 10.3969/j.issn.1004-1524.2020.07.15 Abstract ( 926 )   HTML ( 2 )   PDF (2652KB) ( 1810 )   This study investigated the effects of tea polyphenol (TP), ascorbyl palmitate (AP), glycerol monolaurate-soy protein isolate (GML-SPI) on the quality characteristics of dried Engraulis japonicas, and the indicators including moisture, water activity, total bacterial count (TBC), total volatile basic nitrogen (TVB-N), lipid oxidation indexes, color difference, muscle fiber structure, volatile flavor components as well as sensory evaluation were analyzed. The results showed that none of the three food improvers significantly affected the moisture and water activity of dried Engraulis japonicas. TP and AP could inhibit the growth of TBC and decrease the production of TVB-N, while GML-SPI had the opposite effect. The three food improvers could effectively delay the rate of lipid oxidation, control the degree of color change, and protect the structural integrity of muscle fibers, of which TP was the best. A total of 25 volatile compounds, which could be divided into 5 classes, were identified in dried Engraulis japonicas, among which 5 odor-active-compounds including 3-methylbutanal were further selected. Compared with the control group, the total concentrations and odor activity value (OAV) summation of the volatiles in dried Engraulis japonicas treated by three improvers decreased significantly, among which TP group decreased the most. According to the total sensory score, TP group ranked the highest, AP group the second, GML-SPI group the third. In conclusion, it was determined that 0.03% tea polyphenol solution had the best quality improvement effect on the dried Engraulis japonicas. References | Related Articles | Metrics

Select

Effects of different package methods on microbes of chilled chicken during its shelf life LIU Jun, SHEN Jiamin, SHEN Jianliang, LIU Yali 2020, 32(7):  1274-1280.  DOI: 10.3969/j.issn.1004-1524.2020.07.16 Abstract ( 585 )   HTML ( 3 )   PDF (1439KB) ( 1596 )   The microorganism is the main cause for the chilled chicken decay. To investigate the effects of different package methods on the changes of microbes of chilled chicken during its shelf life, 60 yellow feather broilers with similar weight were randomly divided into three treatments, including treatments with no package, palletizing package, and vacuum package. During the whole experiment, all the chickens were kept at 0-4 ℃, samples were collected on 1, 3, 5, 7 d after treatment and analyzed for the changes of microbes and physicochemical indexes. Psychrobacter sanguinis, Psychrobacter faecalis, Acinetobacter lwoffii, Psychrobacter arenosus, Psychrobacter cryohalolentis, Moraxella osloensis, Pseudomonas azotoformans, Lactococcus raffinolactis, Psychrobacter celer and Escherichia coli were detected as the top 10 dominant bacteria in chilled chicken during its shelf life, which involved families of Aeromonadaceae, Moraxellaceae, Enterobacteriaceae, Pseudomonadaceae and Lactobacillaceae, particularly involved in phylum of Proteobacteria and Firmicutes. Results suggested that palletizing package and vacuum package inhibited the growth of Escherichia coli, particularly decreased the proportion of relative abundance of Psychrobacter sanguinis and Psychrobacter faecalis, which was helpful to suppress the deterioration of chilled chickens. References | Related Articles | Metrics

Select

Establishment of growth model of Staphylococcus aureus in pasteurized milk MENG Siqi, DING Gaolan, XIAO Xingning, XIAO Yingping, YANG Hua, WANG Wen 2020, 32(7):  1281-1288.  DOI: 10.3969/j.issn.1004-1524.2020.07.17 Abstract ( 636 )   HTML ( 3 )   PDF (809KB) ( 1833 )   The enterotoxin of Staphylococcus aureus in pasteurized dairy would cause harm to human health. The growth kinetic of Staphylococcus aureus in pasteurized milk was monitored under 4, 10, 16, 20, 24, 28 ℃, and fitted by the Modified Gompertz model, Logistic model, Huang model and Baranyi model, respectively. The square root model and Arrhenius model were fitted to describe the maximum growth rate (μmax) with temperature. It was shown that the Modified Gompertz model performed the best, as the determination coefficient (R2) was greater than 0.98, and root mean square error (RMSE) was smaller than 4.6. So, the Modified Gompertz model was chosen as the primary model. Compared with the square root model, the Arrhenius model was a better choice, which was indicated as R2=0.99 and RMSE=0.60. The external verification results showed that the accuracy factor (Af) and the bias factor (Bf) of the Arrhenius model were 1.39 and 0.87, respectively, which well indicated its prediction potential. The results of this study offered references to predict the shelf-life of dairy products, and provided parts of the input data for microbial risk assessment of Staphylococcus aureus in pasteurized milk. References | Related Articles | Metrics

Biosystems Engineering

Select

Design and test of matching straw baling device for highland barley combine harvester ZHANG Shilin, DAI Fei, ZHAO Wuyun, TIAN Bin, CHEN Bangshan 2020, 32(7):  1289-1301.  DOI: 10.3969/j.issn.1004-1524.2020.07.18 Abstract ( 560 )   HTML ( 8 )   PDF (5431KB) ( 1569 )   To solve the problems of low degree of straw collection and transportation in the traditional highland barley harvesting operation in the northern Tibetan area, as well as poor walking stability of existing harvesters, a matching straw baling device was designed for highland barley combine harvester. The whole machine was mainly composed of feeding mechanism, compression mechanism and knotter clutch device. Through the selection design of the key components of the prototype, the configuration mode and power distribution of each devices of baling machine were determined. Finite simulation of the vibration characteristics of the whole frame was realized by applying ABAQUS software. To avoid resonance during working, the structure was improved and parameters of rack were optimized by comparing trends in natural frequencies with external excitation frequencies. The motion trail of upper fork and lateral fork of feeding mechanism was obtained by using ADAMS software, which determined structure parameters of two forks to avoid interference during operation. The field test results showed that the straw strapping rate reached 98.3%. The straw bale pass rate reached 94.7%. The straw bale resistance rate exceeded 90%. The efficiency of the whole machine reached 0.7 hm2·h-1. The average straw bale cross-section size was 0.5 m×0.6 m, and the average straw bale density reached 124 kg·m-3. The performance indicators reached the design requirements. This study provided application examples and technical basis for the design and development of integrated work tools for the joint harvesting of highland barley straw and the balling of straw. References | Related Articles | Metrics

Select

Detection of water content in camellia seeds based on hyperspectrum LU Xikun, LUO Yahui, JIANG Pin, HU Wenwu 2020, 32(7):  1302-1310.  DOI: 10.3969/j.issn.1004-1524.2020.07.19 Abstract ( 830 )   HTML ( 3 )   PDF (1055KB) ( 1893 )   In order to detect the water content in camellia seeds quickly and accurately, and also to solve the problems of time-consuming and labor-intensive of traditional drying and detection methods, a non-destructive test method for water content in camellia seeds was proposed based on hyperspectral technology. Camellia seeds were selected as the research object, the water content in camellia seeds was detected, and spectral models were established. The camellia seeds spectrum was pretreated with Savitzky-Golay (SG) convolution smoothing, first-order differential, second-order differential, and multiple scattering correction (MSC), respectively, and effective sensitivity wavelengths were extracted through stepwise regression. Partial least squares regression (PLSR), back propagation (BP) neural network, and radial basis function (RBF) neural network were used to establish prediction models. External verification was conducted for the established models, and the optimal prediction model was selected. It was shown that the spectrally sensitive bands with high correlation coefficients were 410-450, 600-620, 780-880, 940-971 nm, respectively. For the established PLSR model based on spectrum pretreated with MSC, the correlation coefficient and root mean square error were 0.953 4 and 0.22%, respectively, on correction set, and were 0.939 9 and 0.27%, respectively, on validation set, which were higher than those of the established BP neural network and RBF neural network models. Therefore, it was feasible to detect water content in camellia seeds by hyperspectral technology, and the present study could provide basis for the non-destructive online detection of water content in camellia seeds. References | Related Articles | Metrics

Agricultural Economy and Development

Select

Innovation of sci-tech commissioner system from perspective of rural revitalization:taking Zhejiang Province as an example WEI Lingling, TONG Zaikang, LUO Limin, SHEN Xi 2020, 32(7):  1311-1316.  DOI: 10.3969/j.issn.1004-1524.2020.07.20 Abstract ( 553 )   HTML ( 10 )   PDF (882KB) ( 1687 )   The rural revitalization strategy puts forward new requirements for sci-tech commissioner system. The industrial revitalization requires a more complete system and more industrialized science and technology supply capacity. The cultural revitalization and ecological revitalization put forward new demands for humanity and planning and design capabilities. The revitalization of organization and personnel sets new mission for the sci-tech commissioner system. Based on these changes, suggestions on innovation of sci-tech commissioner system were proposed from two dimensions of government and colleges and universities. The fields of revitalization should be expanded to create an upgraded version of sci-tech commissioner system. The multi-stakeholder coordination should be strengthened to stimulate new dynamics in the sci-tech commissioner system. The advantages of colleges and universities should be well played to build a team of dual-qualified sci-tech commissioners. The labor education should be promoted to tap new functions of the sci-tech commissioner system. References | Related Articles | Metrics

Review

Select

Functions of plant MYB transcription factors in response to abiotic stress and plant hormones QIU Wenyi, WANG Shiyu, LI Xiaofang, XU Heng, ZHANG Hua, ZHU Ying, WANG Liangchao 2020, 32(7):  1317-1328.  DOI: 10.3969/j.issn.1004-1524.2020.07.21 Abstract ( 959 )   HTML ( 33 )   PDF (1159KB) ( 2097 )   The expression of a gene is tightly controlled by transcription factors in a spatiotemporal way. When facing adverse environmental conditions such as heat, cold, drought or salt stress, plant cells conduct a physiological change from “fitness” to “stress response” immediately. This fast response relies on complex strategies including the perception and transduction of the stress signal, initiating hormone signaling (abscisic acid, jasmonic acid etc.), transcription factor activation etc. These processes turn out the expression of stress related genes, secondary metabolic transformation, antioxidants accumulation etc. All these efforts confer plants to strive a rebalance of cell homeostasis under stress, and so enable plants to survive. Plant MYB (v-MYB avian myeloblastosis viral oncogene homolog) transcription factors are important participants in these procedures. This manuscript described the plant MYB transcription factor's structure features, classification, and mainly focused on the recent advances in the researches about MYB’s functions in response to abiotic stress and plant hormones. References | Related Articles | Metrics