10 December 2020, Volume 34 Issue 12
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2629-2637. https://doi.org/10.11869/j.issn.100-8551.2020.12.2629Phytic acid is regarded as anti-oxidative compound in crop seeds, and it is benefit to the storage and germination activity of seeds, while the mechanism is unclear. In order to know the differences of antioxidant compounds between low phytic acid mutents and wild type parents, in this study, three low phytic acid mutants Gm-lpa-ZC-2, Gm-lpa-TW-1, Gm-lpa-TW-1-M and two wild type parents Zhechun No.3, Taiwan75 were used to anlyze the anti-oxidative performance of phytic acid during seed development. The results showed that the total anti-oxidative ability was mainly affected by peroxidase activity and catalase activity rather than the content of non-enzyme antioxidant glutathione. The decline in total anti-oxidative ability resulted in the gradually increase of lipid oxides, malondialdehyde and protein carbonylation products with the maturity of the seeds. Comparing the different mutants and wild type parents, we found that lpa mutants Gm-lpa-ZC-2, Gm-lpa-TW-1-M and parent Zhechun No.3, Taiwan75 had higher total anti-oxidative ability and higher germination activity, mutant Gm-lpa-TW-1 showed the lower total anti-oxidative ability and lower germination activity. It indicated that the antioxidant level of soybean seeds was positively correlated with germination activity, but had no correlation with phytic acid content. We speculated that phytic acid is not a main factor affecting the antioxidant capacity and germination activity of soybean seeds. The results of this study provide a reference for further exploration of the mechanisms of the decline in germination activity of low phytic acid crops and breeding new soybean varieties with high seed germination activity and low phytic acid.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2638-2646. https://doi.org/10.11869/j.issn.100-8551.2020.12.2638Salt overly sensitive 1 (SOS1) gene, encoding a Na+/H+ antiporter protein, is an essential gene for plant salt tolerance and plays an important role in biological processes of plants against abiotic stress. Bioinformatics and molecular biology methods were used to study the sequence characteristics and functions of SOS1 gene in Cucurbita maxima. In this study, the full-length cDNA sequence of Na+/H+antiporter gene of Cucurbita maxima was cloned, named as CmaSOS1 and the GenBank accession number is NW_019272028. Sequence analysis showed that the cDNA of CmaSOS1 gene is 3 940 bp in length and contains a 3 429 bp open reading frame (ORF, 162 to 3 590 bp), encoding 1 142 amino acid residues of CmaSOS1 protein. CmaSOS1 has 23 exons and 22 introns with a total length of 46 314 bp at the DNA level. Bioinformatics analysis indicated that the estimated molecular weight and theoretical isoelectric point (pI) of CmaSOS1 protein are 126.7 kDa and 5.92, respectively. The putative protein CmaSOS1 belongs to Na_H_Exchanger superfamily and CAP_ED superfamily, containing 12 transmembrane domains. CmaSOS1 belongs to hydrophobic stable protein, the mainly secondary structure elements are random coil and alpha helix. By multiple sequence alignment and phylogenetic tree analysis, CmaSOS1 has a high homology with Na+/H+ antiporter from Cucurbita moschata, Cucurbita pepo, Cucumis melo, Cucumis sativus and Momordica charantia in the same family of cucurbitaceae with the amino acid sequence identities of 98%, 98%, 90%, 89% and 89%, respectively. Real-time quantitative PCR (RT-qPCR) analysis revealed that the expression of CmaSOS1 gene was higher in roots and leaves, but lower in stems, flowers and fruits. Additionally, the expression of CmaSOS1 was up-regulated by NaCl and PEG treatments, suggesting that this gene might play an important role in the resistance to salt stress and drought stress of Cucurbita maxima. This study provided a foundation for further revealing the function of CmaSOS1 under abiotic stress.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2647-2657. https://doi.org/10.11869/j.issn.100-8551.2020.12.2647DREB transcription factors play an important role in the regulation of stress signal transduction in plants. Studying the response of DREB transcription factors to abiotic stress is helpful to understand the molecular regulation mechanism of AP2/ERF transcription factors under stress in tea plants. A gene encoding AP2/ERF transcription factor, CsDREB-A2, was cloned from the cDNA of Longjing43. The sequence characteristics of CsDREB-A2 were analyzed. The expression profiles of CsDREB-A2 gene under different abiotic stresses were detected by real-time quantitative PCR. The results showed that the open reading frame of CsDREB-A2 gene was 1 056 bp, encoding 351 amino acids, containing AP2 DNA-binding domain, and with typical YRG elements and WLG motifs. The 14th and 19th amino acids of AP2 domain is valine and glutamic acid, respectively. Evolutionary analysis of transcription factors of AP2/ERF family in Arabidopsis thaliana indicated that CsDREB-A2 transcription factor belonged to A2 group of DREB subgroup. CsDREB-A2 was a hydrophilic protein with a molecular weight of 39 080 Da and theoretical isoelectric point of 5.32. It was mainly composed of alpha-helix and random coil. The disorder characteristic was obvious, and there was a LM disorder region. It may be located in the nucleus, and there was no signal peptide and transmembrane structure, which belonged to non-secretory protein. The results of real-time quantitative PCR showed that CsDREB-A2 gene could be induced rapidly under high temperature (38°C) and drought (200 g·L-1 PEG) treatments. The expression level was significantly higher than that of the control, reaching the maximum value at 4 h and 2 h, respectively, which was 20.70 and 42.90 times of the control. It is speculated that the ABA signaling pathway regulates the drought tolerance of plants under osmotic stress. The expression of CsDREB-A2 gene was mainly inhibited under high salt treatment (200 mmol·L-1 NaCl). It was speculated that CsDREB-A2 gene might have a negative regulatory domain to reduce the expression of CsDREB-A2 gene under salt stress. This study provides potential theoretical references for studying the molecular regulation mechanism of DREB transcription factors in stress resistance of tea plants.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2658-2672. https://doi.org/10.11869/j.issn.100-8551.2020.12.2658In order to explore the associated loci and elite alleles for important agronomic traits of pepper, including plant height, first flower node, fruit weight, fruit length, fruit diameter, fruit shape index and pericarp thickness, the genotyping data of 58 SSR markers which distributed on 12 chromosomes in 194 Capsicum annuum core collections were used to detect association with 7 phenotypic traits by using GLM (general linear model, GLM) and MLM(mixed linear model, MLM) methods. The results showed that 20 associated SSR loci were detected by GLM methods, which explain 2.09%~21.91% of the phenotypic variance; 17 associated SSR loci were detected by MLM methods, which explain 2.07%~7.24% of the phenotypic variance; 12 loci were detected by both methods; elite alleles such as TC7268Sa, CAMS-327a, HpmsE132a, ge35-141pmH0135Ca, CAMS-454c and Hpms2-24a were explored based on the phenotypic effect of each associated locus; 28 typical excellent carrier materials, including germplasm B003, B010, B015, B020, B022, B042, B048, B052, B097, B111, B134, B138, B166, B178, B351, B352, C005, C014, V06C0007, V06C0295, V06C1082, V06C1088, V06C1187, V06C1321, V06C1600, V06C1707, V06C1719 and V06C1898 were selected based on these elite alleles. The results in this study provided theoretical guidance and valuable natural resources for the excavation of excellent genes, marker-assisted selection breeding and pyramiding breeding for related agronomic traits in pepper.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2673-2680. https://doi.org/10.11869/j.issn.100-8551.2020.12.2673In order to deeply analyze the genetic basis of plant architecture and yield, and to explore the relationship between them. In this study, genome-wide association analysis were performed associating 5 related traits of 204 maize inbred to 558 529 single nucleotide polymorphism markers (SNPs) distributed on the whole maize genome using Q+K model. The results showed that the traits were basically normal distribution, and there were abundant variations among the traits, with the coefficient range of 9.00%-50.00%. Through correlation analysis and heat map hierarchical cluster analysis, it can be seen that plant architecture and yield-related traits are closely related to each other, and traits are interrelated and coordinated with each other. The principal component analysis shows that 2 principal components with a cumulative contribution rate of 71.667% of population variance have been screened out, which can represent the vast majority of information of 5 related traits. With P≤1×10-5 as the significant threshold, a total of 13 significant SNP loci were detected among plant height, ear height and ear weight, which were distributed on chromosomes 3, 5, 6 and 7, while no significant SNP loci were detected between the leaf number and leaf number above ear. Through the search of candidate genes in the range of 50 kb in the upstream and downstream of SNP, a total of 39 related genes were found, including 12 annotated genes, and the best candidate genes for plant height and panicle height were predicted. In this study, the genome-wide association analysis of plant type and yield traits in maize can lay a good foundation for the verification and the development of gene functions in the future.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2681-2691. https://doi.org/10.11869/j.issn.100-8551.2020.12.2681In order to investigate the effect of freezing methods on muscular differential proteins of Solenocera melantho, the technology of label-free quantitative proteomics was used to study, the expression of differential proteins in Solenocera melantho treated by four freezing methods, including liquid immersion freezing, vacuum packaging combined with immersion freezing, still air freezing, and vacuum packaging combined with air freezing. The results showed that compared with fresh Solenocera melantho there were 269, 162, 299 and 289 differential proteins in shrimp muscles treated by four freezing methods, respectively. Among them, there were 100, 59, 63 and 61 proteins was up-regulated and 169, 103, 236 and 228 proteins was down-regulated. Two differential proteins, glycerol-3-phosphate dehydrogenase(NAD+) and thymosin beta, were screened to be the expected indicator protein markers related to frozen quality of Solenocera melantho. This study provides a theoretical basis for in-depth understanding of the quality change mechanism of Solenocera melantho under different freezing treatment and for finding indicator proteins related to freshness, and also provides a reference for the improving freezing process technology.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2692-2700. https://doi.org/10.11869/j.issn.100-8551.2020.12.2692In order to understand the related genomics of okra germplasm 12C2 resistance for Meloidogyne incognita, the differential expression genes (DEGs) was studied using Illumina Hiseq TM2500 high-throughput sequencing technology. The results showed that there were 71.49 Gb glean data from the root tip treated and untreated with M. incognita after 18 h, the base percentage of Q30 was more than 94.0%. Among them, there were 2 318 DEGs, including 1 156 up-regulated genes and 1 162 down-regulated genes, among which 2 202 genes were annotated. The GO, KOG and KEGG are annotated according to the sequence of unigene library. The cell wall metabolism-related genes, including endoglucanase gene family, polygalacturonase gene family, glucan endo-1,3-beta-glucosidase gene family and pectate lyase gene family were down-regulated. Among the plant hormone metabolism-related genes, auxin responsive protein gene and auxin influx carrier gene were down-regulated, and jasmonic acid synthase gene was up-regulated. WRKY and MYB gene family that regulate the expression of related genes were down-regulated. Annexin gene family and cyclin gene family involved in the expression of plant cells related genes were up and down-regulated, respectively. The results would provide a foundation for studying on genomics and molecular biology of okra resistance for M. incognita.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2701-2707. https://doi.org/10.11869/j.issn.100-8551.2020.12.2701To obtain Beauveria bassiana strains with good biological characteristics and high virulence to armyworm, the dominant strains were selected by examining the spore production, germination rate and growth rate from eight Beauveria bassiana strains, which then were applied to test the lethality to the 3rd larvae of armyworm. The activities of antioxidant and detoxifying enzymes in the 3rdlarvae of armyworm infected by the highest virulent isolate were also assayed. The results showed that the eight Beauveria bassiana strains showed significant differences in all the growth characteristics. Growth rate, spore production, and spore germination rate of strains Bb314, Bb345, Bb412 and Bb378 were higher than those of the other four strains. With regard to the lethality to larvae, the strain Bb314 showed the highest lethality (69%) to the 3rdlarvae of armyworm. After infected by strain Bb314, activities of polyphenol oxidase and peroxidase in the 3rdlarvae increased significantly at the early stage, and reached to their peaks at 36 h. The activity of catalase enzyme in the 3rdlarvae infected by Bb314 were lower than that of control at the beginning of infection (24 h), but reached to the highest activities at 48 h after infection. The activities of glutathione-S-transferase and carboxylesterase reached their peak values at 36 h and 48 h respectively after Bb314 treatment, which were dramatically higher than those of the control without infection. These results indicated that the strain Bb314 might influence the activities of antioxidant and detoxifying enzymes in armyworm, which in return affected the physiological metabolism of armyworm. This study provides a reference for the development of potential strains for biological control of armyworm.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2708-2724. https://doi.org/10.11869/j.issn.100-8551.2020.12.2708With the rapid development of genetic engineering, immunology and molecular biology technologies, the types of vaccines are increasing, and the methods are being continuously established and optimized. Using transgenic plants as bioreactors to produce transgenic plant vaccines has become one of hot topics today. The preparation of transgenic plant vaccines mainly comprises of determining the target antigen, selecting the recipient plant, constructing the plant expression vector, transforming, expressing, detecting and so on. Nowadays, genetically modified plant vaccines can be broadly classified into bacterial vaccines, viral vaccines, parasitic vaccines, contraceptive vaccines and diabetes vaccines by function, the corresponding antigens have been successfully expressed in plants. After a series of biological or clinical trials, obvious immune responses were produced in the bodies, which played a role in resisting pathogenic microorganisms, preventing and controlling parasites, contraception, and preventing and treating diabetes respectively during the experiment. The shortcomings of transgenic plant vaccines will be continuously overcome by optimizing the promoter, selecting high expression receptor plants, using exogenous protein chloroplast expression, knocking out resistance genes in transgenic plant and other new methods. This paper mainly reviews the basic procedures and research progress of transgenic plant vaccines, so as to provide references and ideas for the development and application of transgenic plant vaccine in the future.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2725-2733. https://doi.org/10.11869/j.issn.100-8551.2020.12.2725To improve the fresh-keeping effect of citrus, the effects of lemon essential oil and its mixture with chitosan, calcium chloride and natamycin on postharvest storage quality of Ponkan mandarin were investigated in this study. The results showed that all the treatments could reduce the rate of fruit decay and weight loss, inhibited respiration rate, and delayed the decompostion of titratable acids and Vc, which helped to maintain nutritional value and preserve sensory quality of ponkan. In addition, lemon essential oil and its mixture also significantly enhanced the activities of SOD, CAT and POD, and inhibited the increase of relative electric conductivity and accumulation of MDA content during storage. Specially, the ponkan treated by the mixture with 1% lemon essential oil, 1% chitosan, 1% calcium chloride and 300 mg·L-1 natamycin had the highest contents of titratable acids and Vc, the lowest rate of fruit decay and weight loss, MDA content and relative electric conductivity, and better activities maintenance of SOD, CAT and POD, all of which suggested that this mixture had the best fresh-keeping effect for the storage of ponkan. These results will provide theoretical evidence for using lemon essential oil mixture as preservative for the storage of fruits and vegetables.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2734-2741. https://doi.org/10.11869/j.issn.100-8551.2020.12.2734In order to investigate the quality and microstructure changes of pacific white shrimp (Litopenaeus vannamei) during cold-chain transportation, the changes in color, texture, total volatile basic nitrogen (TVB-N) value and protein composition during 0℃ storage were analyzed in this study. The microstructure of shrimp muscle was observed using scaning electron microscope(SEM). Results showed that during 0℃ storage, the L* value, texture characteristics, myofibrillar protein and myostomin contents of shrimp showed a declining trend with storage time.The TVB-N value had a positive correlation with the storage time. The color, texture characteristics and muscle fiber structure changed obviously after the 4 days. The myofibrillar protein and myostomin contents significantly decreased, and alkali-soluble protein content increased. The proteins degraded significantly after the 6 days. Storage at 0℃ effectively preserved the freshness and quality of pacific white shrimp during short-term storage for 4 days, but 0℃ was not suitable for long-term storage. The results of this study can be useful for the quality evaluation of Litopenaeus vannamei during cold-chain transportation.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2742-2748. https://doi.org/10.11869/j.issn.100-8551.2020.12.2742To investigate the effect of oxalic acid treatment on chilling injury and cell wall metabolism of Guiqi mango fruit under low temperature storage, Guiqi mangoes were dipped in 5 mmol·L-1 oxalic acid solution and dipped in water as control, then stored at 4℃, and the changes in chilling injury index, MDA content, relative conductivity, firmness, cell wall components, activities of cell wall metabolize enzymes were analyzed during storage. The results showed that oxalic acid treatment significantly reduced chilling injury index, MDA content, relative conductivity propectin and cellulose content of Guiqi mango after low temperature storage for 14 days,and significantly reduced the fruit hardness after low temperature storage for 28 days , while obviously increased the water soluble pectin content and the activities of polygalacturonase (PG), pectin methyl enzyme (PME), and cellulase (Cx) after low temperature storage for 14 days, and significantly increased the activities of β-galactose glucoside enzyme (β-Gal) after low temperature storage for 21 days. It suggested that oxalic acid treatment could alleviate chilling injury in Guiqi mango, and maintain high activities of degradation enzymes in cell wall and high water soluble pectin content. The results of this study could provide a theoretical basis for revealing the mechanism of oxalic acid reducing chilling injury of mango fruits, as well as a theoretical reference for the application of oxalic acid to the storage and preservation of other cold-sensitive fruits.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2749-2755. https://doi.org/10.11869/j.issn.100-8551.2020.12.2749In order to realize the early warning of cucumber spoilage during storage, the hyperspectral data of the same batch of cucumbers with different storage days were collected and preprocessed by Savitzky-Golar method. The characteristic wavelengths suitable for cucumber spoilage early warning detection were extracted by partial least squares regression coefficient method. Then, on the premise of choosing the benchmark spectral data of cucumber spoilage, the early warning model for cucumber spoilage during storage was constructed by Mahalanobis distance (MD). The results showed that with the increase of storage days, the MD between the spectral data of cucumber and the benchmarks spoilage storage day became smaller, which indicated that the cucumbers were closer to spoilage. The predicted result was in good agreement with the actual situation of cucumber storage, which indicated that the MD between different storage days before spoilage and the benchmark spectral value of spoilage could effectively realize the cucumber spoilage early warning. The results of this study provided a means for the prediction of spoilage during the actual storage of cucumber using the hyperspectral fusion MD method.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2756-2761. https://doi.org/10.11869/j.issn.100-8551.2020.12.2756In order to understand the biological activity of peanut albumin, the storage protein in peanut seeds was preliminarily separated by ammonium sulfate precipitation method, and the peanut albumin was purified by DEAE-52 column. In addition, the antioxidant and DNase activities of peanut albumin in vitro were analyzed. The results showed that 65% ammonium sulfate had the best separation effect. The purified peanut albumin was composed of three subunits with relative molecular masses of 14.5, 15.5, and 17.2 kDa, respectively. Peanut albumin had higher antioxidant activity in vitro, and the scavenging rate of DPPH and hydroxyl radicals was positively correlated with the concentration of peanut albumin. As the albumin concentration increased from 0.02 mg·mL-1 to 0.10 mg·mL-1, the DPPH free radical scavenging rate increased from 26.3% to 45.0%, and the hydroxyl radical scavenging rate increased from 10.8% to 93.5%. The DNase activity was also positively correlated with the concentration of peanut albumin. As the albumin concentration increased from 0.1 mg·mL-1 to 0.6 mg·mL-1, the electrophoretic bands of albumin and plasmid mixture gradually darkened. Peanut albumin at the concentration of 0.8 mg·mL-1 caused the electrophoresis band of mixture to disappear, and the plasmid was completely degraded. All of the four metal ions of Ca2+, Mg2+, K+ and Na+ enhanced the activity of albumin DNase, and the descending order of enhanced ability was Mg2+>Ca2+>Na+>K+. This study provides a theoretical basis for the function research and application of peanut albumin.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2762-2768. https://doi.org/10.11869/j.issn.100-8551.2020.12.2762To study the optimal extraction method of extracting genomic DNA from dried mutton, conventional phenol-chloroform extraction method, magnetic beads method, modified CTAB method and centrifugal column method were used to extract the genomic DNA from dried mutton, respectively. The concentration, purity, integrity, extraction time and PCR amplification effect of mutton genomic DNA extracted by the four methods were compared. The results showed that the extraction effect of DNA by magnetic bead method was better than other methods with DNA concentration of 118.87 ng·μL-1 and A260/A280 value of 1.89. This method also had several advantages such as short extraction time, high efficiency and less pollution. Our study provides scientific guidance for mass extraction and detection of genomic DNA from dried mutton in practical.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2769-2779. https://doi.org/10.11869/j.issn.100-8551.2020.12.2769To explore the effects of inulin on the texture and flavor quality of low-fat emulsified sausage, the pork ham was used as raw material, various amounts (0%, 1%, 2%, 3%, 4% and 5%) of inulin were introduced to the low-fat emulsified sausage in this study, and its effects on the basic nutrients, color, cooking loss, texture characteristics, microstructure, flavor and sensory quality of meat emulsion were investigated. The results showed that with the increase of inulin in low-fat emulsified sausage, the content of water and protein increased firstly and decreased . The appropriate addition of inulin could reduce the cooking loss of low-fat emulsified sausage; the addition of inulin increased the hardness and chewiness, and reduced the cohesiveness. Scanning electron microscopy showed that the microscopic pores formed by the addition of 4% inulin were the minimal and dense. The results of flavor and sensory evaluation showed that when the amount of inulin added was 5%, the content of flavor components such as aldehydes and alcohols reached the highest. When the amount of inulin was ≥3%, there was no significant difference in total sensory evaluation scores compared with the control group. In summary, the addition of inulin to the low-fat emulsified sausage was beneficial to reduce the cooking loss, and improve the texture characteristics, flavor and sensory quality of the low-fat emulsified sausage. The results of this paper can provide a theoretical basis for the production of low-fat meat products.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2780-2792. https://doi.org/10.11869/j.issn.100-8551.2020.12.2780In order to establish a synthetic method for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)-rich structured phospholipids , phospholipids of Antarctic krill was used as raw material, and the synthesis parameters of EPA/DHA rich structural phospholipids were optimized by response surface methodology. Gas chromatography (GC) and hydrophilic interaction chromatography and mass spectrometry (HILIC-MS) were used to analyze structures. The results showed that the optimal conditions were as follows: substrate mass ratio of free fatty acids to phospholipids 5.15, temperature 55.22℃, water addition 0.92 wt%, enzyme loading 20 wt%, hexane addition 3 mL and reaction time 24 h, under which the incorporation rate of EPA/DHA in the structural phospholipids was 64.35%. According to the results of GC and HILIC-MS, 40:10 (20:5/20:5) (18.46%), 42:11 (20:5/22:6) (12.78%) and 38:6 (18:1/20:5&16:0/22:6) (7.07%) were the main components of phosphatidylcholine (PC), while 20:5 (20:5/0:0) (34.40%), 22:6 (22:6/0:0) (25.99%) and O-16:0 (O-16:0/0:0) (10.22%) were the main components of lyso-phosphatidylcholine (LPC). Structured phospholipids with long fatty acids chains (average single chain length of fatty acids≥20) increased by 33.12% and 37.28% in PC and LPC, respectively. Phospholipids with highly unsaturated fatty acyl chains (double bonds≥10) increased by 27.53% in PC. The results demonstrated that this method could increase the content of EPA and DHA in structured phospholipids. This study provided theoretical foundation for further exploring and enriching the enzymatic synthesis mechanism and practice of EPA/DHA-rich structured phospholipids.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2793-2799. https://doi.org/10.11869/j.issn.100-8551.2020.12.2793To determine the effects and synergistic mechanism of nitrification inhibitor 2-chloro-6-trichloromethylpyridine (CP) on greenhouse vegetable productionfield experiments were carried out and the 15N stable isotope tracer technique was used to study the effects of CP on nitrogen fate and synergistic mechanism in tomato cultivation under the treatments of recommended (180 kg·hm-2) and conventional (300 kg·hm-2) nitrogen application rates. The results showed that the tomato yields were increased by 17.3% and 31.4%, the nitrogen recovery rates were increased by 8.6 and 9.2 percent; the ammonia volatilization emissions were increased by 2.47 kg·hm-2 and 3.65 kg·hm-2; other nitrogen losses were altogether reduced by 15.5 kg·hm-2 and 27.6 kg·hm-2 by in the treatments of the nitrogen rate of 180 and 300 kg·hm-2 with CP applications. The use of CP promoted the transfer of nitrogen from stem and leaf to fruit, reduced nitrogen losses and increased nitrogen utilization efficiency, which may be one of the mechanisms of its synergistic effect. The economic benefit brought by CP is significantly higher than its cost, which is worthy of application and promotion in vegetable production.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2800-2812. https://doi.org/10.11869/j.issn.100-8551.2020.12.2800In order to study the regulation mechanism of nitrogen metabolism in different nitrogen-efficient varieties, the high-nitrogen high-efficiency corn variety Xianyu 335 and the low-nitrogen high-efficiency corn variety Jingnongke 728 were used as test materials. Five nitrogen fertilizer applications were tested: 120 kg·hm-2, 180 kg·hm-2, 240 kg·hm-2, 300 kg·hm-2, and 360 kg·hm-2 (NCK). Using the local field nitrogen fertilizer application (NCK) as control, we explored the responses characteristics of different genotypes of maize on nitrogen transport, key enzyme activities, and key enzyme genes of nitrogen metabolism to reduced nitrogen fertilizer application. Our results showed that when the nitrogen fertilizer application was 240-300 kg·hm-2, the nitrogen content of Xianyu 335 reached its maximum value at each growth stage, and yield reached a high level. When the nitrogen fertilizer application was 180-240 kg·hm-2, the nitrogen content of Jingnongke 728 reached its maximum value at each growth stage, and yield reached a high level. Under low nitrogen conditions, compared with Xianyu 335, nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamic acid synthetase (GOGAT), and asparagine synthetase (AS) of Jingnongke 728 maintained high enzymatic activity throughout the entire maize growth period. Compared to the elongation stage, the expression of the NR gene of Jingnongke 782 was significantly increased in the flare opening stage. The expression of GOGAT1 and GOGAT2 genes of both varieties were significantly up-regulated from the flare opening stage to the filling stage. During the silking stage and the filling stage, the expression of the GS1-3 genes in Jingnongke 728 was significantly up-regulated. During the filling stage, the expression of the GS1-3 gene of Xianyu 335 was significantly up-regulated. Compared to the elongation stage, the expression of GS1-4 genes of both varieties was significantly down-regulated in other growth stages. The expression of AS1 and AS3 genes of Jingnongke 728 were significantly up-regulated in the filling stage compared to the elongation stage. Compared to other growth stages, the expression of the AS1 gene of Xianyu 335 was significantly up-regulated in elongation stage. There were differences in the response of different genes to nitrogen fertilizer at different growth stages in maize. The results of this study demonstrate that significant differences were obseved in the regulation of nitrogen uptake by key nitrogen metabolism enzyme genes in different nitrogen-efficient varieties of maize. This study provided the basis for understanding the regulate characteristics of nitrogen uptake of different nitrogen efficient varieties.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2813-2822. https://doi.org/10.11869/j.issn.100-8551.2020.12.2813In order to elucidate the effect of nitrogen rate and harvesting time on the vitamin content in young stem of oil-vegetable double usage type rapeseed, a field experiment was conducted using Fuxi 1 as plant material with a split plot design that was composed of three nitrogen rates as main plot, 120, 180, and 240 kg·hm-2, and four harvesting times, using plant height of 20, 30, 40, and 50 cm as sub plot. Change of vitamin family compound contents in young stem was analyzed; activities of key enzymes including GalLDH, AAO, APX, DHAR, and MDHAR in vitamin C biosynthesis and metabolism were compared; expression levels of vitamin family genes under nitrogen rates and plant height treatments were also assayed. Results showed that ascorbic acid content in the young stem of rapeseed decreased as nitrogen rate increased. Content of dehydroascorbic acid increased as nitrogen rate increased when the young stem was harvested at 20 cm of plant height while that was decreased when it was harvested above 30 cm of plant height. Contents of vitamin E and vitamin B6 were increased and then decreased and content of vitamin B1 in young rapeseed stem increased as nitrogen application rate increased. The activity of key enzyme, GalLDH, for vitamin C biosynthesis in young rapeseed stem slightly increased and then decreased as nitrogen application rate increased. The activities of vitamin C metabolic key enzymes AAO and DHAR increased as nitrogen application rate increased while APX and MDHAR increased firstly and then decreased. The vitamin family genes were positive regulated in the young rapeseed stem by increased nitrogen application at 30 and 40 cm plant height while that were negative regulated at 20 and 50 cm plant height. As for the harvesting time, vitamin content in young rapeseed stem at 30 to 40 cm was in generally higher than that at 20 and 50 cm plant height. The vitamin family genes up-regulated as the harvesting plant height increased in the young rapeseed stem under the same nitrogen application rate. In conclusion, the reduction of GalLDH activity and the equilibrium of enzymatic systems between AAO/DHAR and APX/MDHAR resulted in the decrease of vitamin C content in young rapeseed stem. The results provide the information for the high quality cultivation of oil-vegetable double usage type rapeseed.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2823-2830. https://doi.org/10.11869/j.issn.100-8551.2020.12.2823In order to provide a reasonable mode for the development of machine transplanting technology, super early indica rice Zhongzao39 was raised in three modes, such as tray-overlaying seedling raising mode(DP), swing-plate seedling raising mode (BP), and traditional seedling raising mode (CK). The differences of temperature and humidity during seedlings emergence stage, seed emergence characteristics, seedling quality, transplanting quality and rice yield were investigated among different seedling raising modes. The results showed that, the temperature and humidity were fluctuated with day and night alternation in the traditional seedling raising mode: the temperature was kept in 29 to 32℃ in the seedling emergence room for DP, and the relative humidity was kept in 70% to 90%, which was the best condition for the seedling emergence. The seedling emergence rate of DP was 19.45% and 15.70% higher than BP and CK, respectively, which was due to the higher activity of α-amylase activity increase. For seedling characteristics of 30 days, the seedling height of DP treatment was 0.32 and 0.41cm higher than BP and CK, and presented a higher percentage of standard seedlings in DP than in BP and CK. The transplanting quality among all treatment showed that the seedling number per hill followed the order of DP > BP > CK, and missing seedling percentage abided by CK>BP>DP, which indicated the low missing seedling percentage related to high seedling emergence in DP. The treatments could be ranked from highest yield to lowest, as follows: DP > BP > CK. The yield of DP was higher 4.5% and 13.1% than BP and CK owing to the higher number of effective panicles in DP, respectively. The study indicated that, application of tray-overlaying seedling raising mode could enhance the seedling emergence rate, reduce the emergence duration, and increase the uniformity of seedlings, meanwhile the mode could significantly reduce the seedling missing percentage, and contribute to yield formation by increasing the number of effective panicles.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2831-2838. https://doi.org/10.11869/j.issn.100-8551.2020.12.2831In order to understand the changes of microbial community functional diversity in the soil aggregates after turning from upland into paddy tillage in black soil region of Northeast China, taking the black soil turned from upland (mainly planting corn) into paddy tillage (abbreviated as “land to paddy”) in Northeast China as a study object, the changes in microbial diversity index and the ability of carbon source utilization in all soil aggregates after “land to paddy” were investigated by using the Biolog-Eco microplate technique. The results showed that there was significant increased in the soil water-stable macro-aggregates number after “land to paddy” increased the content of soil organic carbon (SOC) in all soil aggregates. The average colour change rate of soil microbial community in all soil aggregates of different grain sizes in upland and paddy fields (AWCD) followed the order of upland silt + clay > upland macro-aggregates > upland micro-aggregates > paddy tillage macro-aggregates > paddy tillage silt + clay > paddy tillage micro-aggregates. The microbial diversity index and the ability of carbon source utilization in all soil aggregates obviously decreased by “land to paddy”, especially the carbon source of amino acids and carbohydrates. Results of principal component analysis showed that the function of carbon source utilization in all soil aggregates in upland and paddy tillage had changed. In summary, “land to paddy” obviously changed the microbial functional diversity in soil aggregate of black soil, and decreased the ability of carbon source utilization for soil microbial metabolic activity. This study provides a theoretical reference for the sustainable land utilization of Northeast China.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2839-2849. https://doi.org/10.11869/j.issn.100-8551.2020.12.2839To compare the mulching effects of different materials in a rain-sheltered vineyard, with the Summer Black grape orchard as the test object, the straw mulching(SM), white plastic film mulching(WM), reflective plastic film mulching(RM) and ground cloth mulching (CM) were adopted in a field experiment with the bare ground as a control (CK). The seasonal variation characteristics of near-surface air temperature and air relative humidity, soil temperature, soil moisture and soil enzyme activities under different mulching treatments were determined. The results showed that, the average near-surface air temperature increased by 0.15℃, 0.52℃ and the air humidity decreased by 4.06% and 4.68%, respectively in WM treatment and RM treatment from March to October, while the average near-surface air temperature increased by 0.29℃, 1.02℃ and the air humidity decreased by 2.67% and 7.94% respectively in CM treatment and SM treatment from March to October. In WM treatment, the average soil temperature of 5~25 cm soil layers from March to October increased by 1.38℃, and the soil moisture of 0~60 cm soil layers increased by 2.77 percent in May compared with the control. In SM, CM and RM treatment, the average soil temperature from March to September decreased by 3.50℃, 2.56℃ and 1.00℃, respectively, and the soil temperature in October increased by 0.34℃, 0.46℃ and 0.11℃, respectively, and the soil moisture content of 0~60 cm soil layers in May increased by 4.24, 4.06 and 5.60 percent, respectively, compared with the control. The activities of urease, protease, invertase and acid phosphatase in soil of all treatments were higher in summer and lower in spring and autumn. The catalase activity of SM treatment was higher in summer, while that of other treatments was higher in spring. The average value of soil enzyme index from March to September was SM>CM>WM>RM>CK, which increased by 81.26%, 27.91%, 25.74% and 14.55%, respectively, compared with CK. Catalase could be used as an indicator for the soil enzyme activity difference in sheltered vineyard. The research provides theoretical and practical reference for the choice of mulching materials in rain-sheltered vineyard.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2850-2857. https://doi.org/10.11869/j.issn.100-8551.2020.12.2850This study aimed to explore the regulation effect and photosynthetic mechanism of different color plastic film mulching on cotton yield. A field trial was set up with 6 treatments: No mulching (CK), white film (WF), black film(BF), silver film (SF), green film (GF) and red film (RF). Light quality characteristics of cotton canopy, cotton canopy morphology, photosynthetic characteristics, fluorescence characteristics, dry matter accumulation and distribution, yield components and other parameters were measured. The results showed that covering different color mulch could change the red and far red light intensity of the canopy, compared with the non-cover film, and the light interception could be improved by increasing the number of branches and leaf area index and decreasing the inclination angle of fruit branch and main stem. At the same time, the increase of SPAD value, net photosynthetic rate and photoelectron transfer rate of leaves enhanced the ability of photosynthetic products synthesis of source organs, and increased the partition coefficient of dry matter in leaves and flower and boll. Finally, the yield of seed cotton increased by 8.4% and 24.5%. Because of the high reflected intensity of red and far red light, the red mulching film was superior to the other color mulching film in terms of photosynthetic rate, fluorescence characteristics and dry matter accumulation. The highest yield was 3 153.6 kg·hm-2, black film, the second was 3 123.7 kg·hm-2, green film, and the lowest was green film. Commprehensive cotton yield and dry matter quality, cotton covered with redplastic and black plastic film can increase of cotton yield and improve its production efficiency.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2858-2864. https://doi.org/10.11869/j.issn.100-8551.2020.12.2858In order to investigate the effects of phytohormone abscisic acid (ABA) on the tomato fruit quality, the visual and nutritional quality of ABA biosynthetic deficiency mutants, not and flc, and their wild types at different ripening stages as well as the fruits at different days after 100 μM ABA treatment were analyzed. The results showed that endogenous ABA deficiency significantly decreased the fruit weight and promoted the fruit longtitudinal elongation, but had no effect on fruit firmness. ABA affected the soluble solids content of tomator fruits and promoted the accumulation of reducing sugar in the color-breaking periods. Moreover, the contents of lycopene, β-carotene, lutein and total carotenoids greatly increased in two ABA deficiency mutants when compared with their wild types. Meanwhile, the contents of lycopene, β-carotene and total carotenoids significantly decreased after exogenous 100 M ABA treatment. Taken together, ABA increased the fruit weight and inhibited the fruit longitudinal elongation in terms of fruit visual regulation. ABA also promoted the reduced sugar accumulation and decreased the carotenoid accumulation in tomato fruits in term of fruit nutritional quality. These findings will provide the theoretical basis and technical support for the improvement of fruit quality via regulation of ABA.
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Journal of Nuclear Agricultural Sciences. 2020, 34(12): 2865-2871. https://doi.org/10.11869/j.issn.100-8551.2020.12.2865To explore effects of grapevine branch mulching on soil bacterial community structure in vineyards, this study was conducted in a 5-year-old Cabernet Sauvignon vineyard in the eastern foot of Helan Mountain, Ningxia. Three treatments were designed with: grapevine branch mulching, corn straw mulching and clear tillage. Two years later, high-throughput sequencing was used to analyze soil bacterial community structure and its relationship with soil physical and chemical properties. The results showed that 56 phylums of bacteria were detected in soil samples from the vineyard. Proteobacteria, Acidobacteria, Actinobacteria and Chloroflexi were the dominant bacteria with the abundance more than 10% in all treatments. Proteus and Actinomycetes were positively correlated with soil organic matter content; Acidobacterium was negatively correlated with pH value; and Curvularia was negatively correlated with soil organic matter content. The linear discriminant analysis showed that there were 7 dominant bacteria in maize straw mulching treatment, while only one dominant strain in grapevine branch mulching treatment. The above results showed that both mulching treatments could increase the abundance and diversity of soil bacterial community, and corn straw mulching had a better effect. This study provides a theoretical and practical basis for the application of vineyard intra-row mulching technology and the sustainable cultivation of wine grape in the eastern foot of Helan mountain, Ningxia.
