10 September 2020, Volume 34 Issue 9
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1873-1880. https://doi.org/10.11869/j.issn.100-8551.2020.09.1873In order to obtain strains with high yield of IAA, a growth-promoting strain which was isolated from the tobacco rhizosphere soil with the ability of producing IAA and solubilizing organic-phosphorus, was mutagenized by ultraviolet and diethyl sulfate mutagenesis. Meanwhile, the fermentation conditions of the target strain were optimized by orthogonal design. The results showed that the mutagenesis by UV and diethyl sulfate could effectively increase the yield of IAA. The mutagenic conditions are irradiation with UV (15 W, 30 cm) for 1 minute or treatment with 2 mg·mL-1 DES for 30 min. As a result, a strain UV19 with high IAA yield was obtained. And its IAA yield was 33.77 mg·L-1, which was 299.48% of that of the initial strain. After 10 generations of subculture, the abilities of IAA-producing production and soluble organophosphorus traits of the strain were stably hereditary. The optimum conditions for IAA fermentation were as follows: 10% liquid loading, initial pH value 8.0, cultivated at 25℃ for 96 h with 3% inoculation concentration in LB medium containing 500 mg·mL-1 tryptophan. The yield of IAA after optimization was as high as 75.47 mg·L-1, which was 2.23 times of that before optimization. The research results provide basic materials and test methods for IAA production by bacterial fertilizer and biological method.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1881-1888. https://doi.org/10.11869/j.issn.100-8551.2020.09.1881MAPK cascade signals are involved in the regulation of a variety of stresses, growth and development, anthocyanin synthesis pathways in plants. In order to know the function of SlMAPK6 in tomato, three target sites were designed for fixed-point editing SlMAPK6 by using CRISPR/Cas9, and mutant CRISPR-3 and CRISPR-7 were obtained The results of PCR and sequencing showed that the SlMAPK6 knockout vector was successfully constructed. Through kanamycin gene screening, target site amplification, sequencing and off-target effect analysis of T1 plants, the dwarf tomato plants were mutated successfully and did not miss the target. Through phenotypic observation and measurement, compared with the wild type control, all the mutants showed more flourished root system and lateral branches. The results showed that SlMAPK6 played an important role in the process of tomato plant morphogenesis, which laid a foundation for further exploring the role of SlMAPK6 in tomato growth and development.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1889-1897. https://doi.org/10.11869/j.issn.100-8551.2020.09.1889DNA-binding one zinc finger (Dof) protein is a class of plant-specific transcription factors, which N-terminal has a highly conserved C2-C2 single zinc finger domain, and the amino acid of the C-terminal transcriptional regulatory region is highly diversity. It plays an important role in plant photosynthesis, cell cycle and stress response. In this study, the candidate LjDof gene was screened by bioinformatics using the sequencing data of Lonicera japonica Thunb., and its physical and chemical properties, subcellular localization, homologous sequence alignment, conserved motif, phylogenetic development and expression pattern were analyzed. Studies have shown that the Dof transcription factor family in Lonicera japonica Thunb. contains 11 genes, which encode proteins of 157-492 AA and the PI are 5.45~9.48, all of these genes are unstable hydrophilic proteins. Subcellular localization showed that LjDof genes were located in the nucleus, and some were located in other parts. The homologous alignment and Motif analysis revealed that 11 LjDof genes contained complete C2-C2 single zinc finger structure. Phylogenetic analysis showed that Lonicera japonica Thunb. Dof proteins are divided into five sub-categories. The results of RT-qPCR and model of expression have showed that the LjDof genes have different expression patterns in Lonicera japonica Thunb.at different time under low temperature stress. This study provides the basis for further study of the function of Lonicera japonica Thunb.Dof genes in response to low temperature.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1898-1905. https://doi.org/10.11869/j.issn.100-8551.2020.09.1898Uroporphyrinogen decarboxylase (UROD) is a key enzyme for the synthesis of chlorophyll, light-sensitive pigment and heme. In order to study the functions of the UROD gene especially in the variations of the leaf color of Cymbidium hybrid, Cymbidium hybrid K21 and its leaf color mutant K21-1 were used as materials, based on the transcriptome sequencing results, ChUROD gene was isolated, its sequence information was analyzed and its expression in different tissues and different varieties were detected by qRT-PCR, furthermore, the related physiological characters were determined. The results showed that ChUROD contains one 1 191 bp open reading frame which encoding 396 amino acids. The ChUROD protein has a molecular weight of 43.78 kD belongs to the URO-D-CIMS-like family. The phylogenetic analysis showed that the ChUROD protein of Cymbidium hybrid was closely related to UROD of Cymbidium sinense. qRT-PCR results indicated that the relative expression of ChUROD gene in leaves of K21 were significantly higher than pseudobulbs and roots, and the relative expression level of ChUROD gene in leaves of K21 was significantly higher than that in K21-1. According to the results of the determination of the UROD enzyme concentration, UrogenⅢ content, CoprogenⅢ content and chlorophyll content, the trend of UROD enzyme concentration was consistent with the relative expression of ChUROD gene. The decarboxylation of UrogenⅢ to produce CoprogenⅢ was hindered and UrogenⅢ was accumulated in yellow leaves of K21-1; the contents of chlorophyll a and chlorophyll b in yellow leaves of K21-1 were significantly lower than that in green leaves. The results suggested the ChUROD gene may play an important role in the variation of the leaf color of K21-1. The results provided a reference basis for the function verification of ChUROD gene and mechanism research of leaf color variation in Cymbidium hybrid.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1906-1920. https://doi.org/10.11869/j.issn.100-8551.2020.09.1906Ascorbate peroxidase (APX) is a key enzyme for scavenging hydrogen peroxide in plants, especially in chloroplasts. In order to explore the characteristics and expression patterns of APX family genes in Brassica crops, 10, 9 and 22 APX family genes were identified from B. rapa, B. oleracea and B. napus by bioinformatics in this study. The sequence characteristics, chromosome distribution, CDS motif, protein motif, protein tertiary structure and phylogenetic relationships of 41 APX family genes were predicted and analyzed, and the expression patterns of these genes under high temperature, drought and biotic stress were analyzed by gene expression database. The results showed that APX can be divided into eight subfamilies in the phylogenetic tree and dispersed on different chromosomes. These APX genes possess relatively stable CDS conserved domains, protein conserved domains and tertiary structures, all of which have peroxidase domains. At the back end of the peroxidase domain, there is a conserved domain Motif6 with a helical structure. The Ka/Ks values of the APX gene were much less than 1, indicating that the APX family genes are undergoing purification selection as a whole. Most of the APX1 and APX2 genes were up-regulated under heat stress. Among them, BrAPX2a was strongly responded to heat stress in the embryo and endosperm of Chinese cabbage, but it was weakly expressed in other parts of Chinese cabbage, and it had certain tissue specificity. The genes such as APX3 and APX4 had no obvious response to drought and heat stress; the three APX1 genes in cabbage were up-regulated in the stress of whitefly. The results of this study provide a reference for cloning, expression and function of APX family members of Brassica crops.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1921-1932. https://doi.org/10.11869/j.issn.100-8551.2020.09.1921In order to map and excavate the QTL for high combining ability of rice yield traits, a recombinant inbred lines (RIL) were constructed by crossing Luhui 8285 and Yanghui 34, and RIL hybridized with Lu98A, Ⅱ-32A and Gang 46A according to NCII design, the constructed diallel crossing population was used as the experimental material. Eight yield-associated traits including biological yield per plant(BYP),harvest index(HI), yield per plant(YP), effective panicles per plant(EP), spikelets per panicle(SP), full grains per panicle(FGP), seed setting rate(SSR) and 1 000-grain weight(TGW) were mapped for general combining ability(GCA) under three environments(Deyang, Suining and Luzhou). The results showed: a total of 50 QTLs were detected for the GCAs of the eight yield related traits, the phenotypic variance explained by a single QTL ranged from 3.26% to 34.26%. There were 5 QTLs (qEP2-2, qSP2-2, qFGP2-2, qTGW1 and qTGW2) detected under three environments, 5 QTLs (qHI3, qEP7, qSP7, qSSR12-1 and qTGW3-2) detected under two environments, and the other QTLs were only detected under single environment. There were 27 QTLs which were positive alleles from Luhui 8258. All these results provided theoretical basis and technical support for fine mapping, cloning and molecular marker-assisted selection on rice yield-associated traits of GCA.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1933-1942. https://doi.org/10.11869/j.issn.100-8551.2020.09.1933In order to explore the function of sorghum disease resistant gene SbSGT1 of sorghum, the full-length SbSGT1 gene was amplified from sorghum BTx623 by RNA reverse transcription, and analyzed by bioinformatics. The pET-28a-SbSGT1 recombinant plasmid was further constructed for prokaryotic expression, and the expression strain, induction temperature and induction concentration of isopropyl-β-D-thiopyranogalactoside(IPTG) were optimized. The results showed that SbSGT1 was 1095 bp in length and encoded 364 amino acids. The theoretical molecular size of SbSGT1 was about 40.45 kDa and the isoelectric point of SbSGT1 was 5.0. Phylogenetic tree analysis showed that SbSGT1 was highly related to maize and rice; protein sequence analysis showed that SbSGT1 was a hydrophilic protein, which was located in the cytoplasm; secondary structure prediction showed that α helix and irregular curl accounted for the highest proportion, reaching up to 43.41% and 45.88% respectively. The results of prokaryotic expression showed that the best expression strain of SbSGT1 was Escherichia coli BL21 (DE3), and the best induction temperature and IPTG were 25℃ and 0.8 mmol·L-1 respectively. This study laid a foundation for the further exploring of the biological function of SbSGT1 gene in sorghum disease resistance mechanism.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1943-1950. https://doi.org/10.11869/j.issn.100-8551.2020.09.1943The objective of this study is to establish a quick and accurate detection technique for Potato leafroll virus (PLRV) by reverse transcription loop-mediated isothermal amplification (RT-LAMP). The RT-LAMP detection system of PLRV that based on the conserved region ORF3 of PLRV CP gene was developed, and the specificity, sensitivity and practical detection were evaluated. The results showed that with the established RT-LAMP method, after amplification at 62℃ for 50 min, the products was detected according to the color by adding SYBR Green I to the reaction, the positive sample showed green and the negative sample appeared brown. This visualized method suggested that it can be used to detect PLRV directly. The developed RT-LAMP showed highly specific for PLRV by using different RNA templates from PLRV, and had no cross reaction with Potato virus X (PVX), Potato virus Y (PVY), Potato virus S (PVS), Potato virus A (PVA), Potato virus M (PVM) and the healthy control. Furthermore, the sensitivity of RT-LAMP was 100-fold higher than that of conventional RT-PCR. When detecting 90 field samples, the result obtained by RT-LAMP was totally coincident with that by RT-PCR. The visualized RT-LAMP detection for PLRV using SYBR Green as color indicator is specific, sensitive, simple and low-cost, and can meet the needs of scientific research and grass-roots units for the rapid diagnosis and detection of PLRV.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1951-1965. https://doi.org/10.11869/j.issn.100-8551.2020.09.1951To understand the salt-tolerant mechanism of woody plant, the differences in growth of Populus Nanlin 895 (salt-insensitive clone hybrids of Populus deltoides Bart.CV. x Populus euramericana (Dode) Guineir CV) with 100 mmol·L-1 NaCl treatment and without treatment were investigated, metabolite profiles were analyzed using a metabolomics analysis based on ultra performance liquid chromatography coupled with tandemquadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and gene expression were analyzed by real-time qPCR. The results showed after treatment for 16 d, the growth of Populus were stunted, but the malondialdehyde content in leaf and root were similar as the control. Supervised orthogonal partial least squares discriminant analysis(OPLS-DA)identified the differential metabolites between the control and the treatment, five pathways maybe regulated by salt were identified. Differential metabolites profiling showed that 2-oxoglutarate, phosphatidylcholine (PC) and raffinose family oligosaccharides (RFOs) were accumulated while malic acid and fumarate were declined in plants under salt stress. The levels of nucleic acids, cytokinin B, amino acids and most differently expressed phenolics were reduced. Gene expression profiling exhibited up-regulation of genes involved in tricarboxylic acid (TCA) cycle, RFOs biosynthesis, fructose metabolism and main pathway of glutamate biosynthesis, while down-regulation of genes encoding fucokinase, involved in phenolic biosynthesis and the bypass of glutamate biosynthesis. Our results extend the understanding of mechanisms in salt tolerance of Populus and provide a theoretical foundation for the development of poplar resources.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1966-1974. https://doi.org/10.11869/j.issn.100-8551.2020.09.1966In order to explore the molecular mechanism of Issatchenkio orientalis (Io 166) tolerant to acetic acid under mixed fermentation of fruit wine yeast, the differentially expressed protein was analyzed by TMT technique, and the proteomics under acetic acid stress was studied. The results showed that the growth of Io 166 was inhibited at the exponential growth phase under acetic acid stress, but Io 166 gradually adapted to acetic acid stress and resistant to acetic acid. After 4-h acetic acid stress, 461 differentially expressed proteins were identified, among which 327 proteins were up-regulated and 134 proteins were down-regulated. Annotation and statistical analyses suggest that the synthesis of glutathione increased, several proteins with antioxidant properties (such as PXP9, HYR1, CCP1) were up-regulated under acetic acid, which played a key role in the tolerance to acetic acid. In addition, proteins associated with amino acid biosynthesis (such as arginine) and metabolic processes were differentially expressed, and HSP proteins were highly expressed to handle aggregation and misfolding. The results of this study provide theoretical basis for I. orientalis tolerance to acetic acid, meanwhile it has potential application for improving the tolerance of I. orientalis to acetic acid in fruit wine fermentation.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1975-1982. https://doi.org/10.11869/j.issn.100-8551.2020.09.1975In order to improve the separation efficiency of camellia oleifera shell lignocellulose. Herein, the camellia oleifera shell was used as material to study the changes of crushing energy consumption, particle size distribution and chemical composition with pretreatment of different irradiation dose (0, 200, 400, 600, 800 kGy), and the co-separation process of camellia oleifera shell lignocellulose with formic acid and irradiation was studied in this research. The results showed that the crushing energy consumption of camellia oleifera shell was decreased and the proportion of small particle sample was increased with the increase of irradiation dose. The crushing energy consumption of 400 kGy irradiated camellia oleifera shell could save 43.59% compared with the control, and the proportion of d<0.075 mm particles for crushed camellia oleifera shell reached to 41.38% when the irradiation dose was 800 kGy. The lignocellulose was degraded, and the content of water-soluble components, soluble monosaccharides and polysaccharides were increased after irradiation treatment.The optimal process for the separation was determined as irradiation dose 400 kGy, reaction temperature 100℃, and reaction time 3 h, under which the extraction rate of cellulose, lignin and xylose from camellia oleifera shell were 89.94%, 47.74% and 96.37%, respectively, and the purity of cellulose and lignin were 45.05% and 91.92%, respectively. This study is of great significance for the efficient separation and ultilization of the full composition of camellia oleifera shell lignocellulose.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1983-1989. https://doi.org/10.11869/j.issn.100-8551.2020.09.1983The aim of this study was to explore the changes of stable carbon and nitrogen isotopes beef and its by-products, and to confirm the stability and effectiveness of stable carbon and nitrogen isotopes in the geographical traceability of beef processing products. The beef was treated by three processing methods, i.e, boiling, roasting and frying for different time. The boiling and roasting time was 5, 10, 15, 20, 25 and 30 min respectively, and the frying time was 1, 2, 3, 4 and 5 min respectively. The δ13C and δ15N values in defatted beef, crude fat and residue were determined by Element Analyzer-Isotope Ratio Mass Spectrometry (EA-IRMS). The results showed that the δ13C values in cooked defatted beef of boiling, roasting and frying for different time intervals were not significantly different (P>0.05), and there was no significant change of δ13C values in the crude fat after boiling and roasting at different time. The δ13C value in the crude fat of fried beef was mainly affected by the vegetable oil. The δ15N value of boiling beef was significantly different after 25 min and 30 min, but the average change was only 0.3‰~0.9‰. The stable carbon and nitrogen isotopes of boiled beef were less fractionated during different processing, thus they can be used for the beef geographical origin traceability of semi-finished products and processed products.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1990-1995. https://doi.org/10.11869/j.issn.100-8551.2020.09.1990The combination modification of dynamic high pressure microfluidization and transglutaminase (DHPM-TG) was used to modify fish gelatin. Results showed that lightness, intrinsic viscosity, and melting temperature values of fish gelatin were increased with TG contents, while gel strength and hardness were increased firstly and then decreased. Compared with TG modified fish gelatin, DHPM-TG significantly improved the intrinsic viscosity, melting temperature, gel strength, hardness and chewiness of fish gelatin gels. DHPM-TG modified fish gelatin showed similar melting temperature and gel strength with pig skin gelatin. In addition, environmental scanning electron microscopy showed that DHPM-TG modified fish gelatin had more compact structure. In conclusion, DHPM-TG complex modification could significantly improve the gel properties of fish gelatin, and the results of this study provide a theory support for the production of high-quality fish gelatin that can replace mammalian gelatin.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 1996-2002. https://doi.org/10.11869/j.issn.100-8551.2020.09.1996To explore the inhibitory effect and related inactivation mechanism of intense pulsed light (IPL) on the endogenous enzyme activity in fruits and vegetables, the effect of IPL treatment on the activity of polyphenol oxidase (PPO) was investigated by spectrophotometry, and the structure properties of PPO under different IPL treatment was also analyzed by ANS fluorescent probe, intrinsic ?uorescence spectroscopy, gel electrophoresis and circular dichroism (CD) spectra. The results showed that PPO activity decreased with the increase of single pulsed energy, pulse times and the reduction of pulse distance. After IPL treatment, the optimal emission wavelength of PPO was red-shifted, and the surface hydrophobicity, the content of free sulfhydryl and β-structure were increased, while the intrinsic fluorescence intensity and the content of α-helix were decreased. Meanwhile, the electrophoresis pattern showed that oxidative degradation of PPO protein occurred. The above results indicated IPL treatment could change the secondary and tertiary structure of PPO, promote protein oxidative degeneration, and decrease the enzyme activity. This study provides a theoretical basis for the study of IPL technology in inhibiting endogenous enzyme activity and reveals related inactivation mechanisms.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2003-2010. https://doi.org/10.11869/j.issn.100-8551.2020.09.2003In order to improve the cold storage quality of Myrica rubra, the effects of pre-harvest spray rutile nano TiO2 with 2 levels of size (40 nm, 60 nm) and 2 levels of concentration (0.05%, 0.10%) on the quality, physiological and biochemical indexes of Myrica rubra during cold storage were studied by the path analysis method. The results showed that spraying 60 nm, 0.05% rutile nano-TiO2 before harvest, the total soluble solid (TSS) content of Myrica rubra was 21.9% higher than that of the control group, which was conducive to early maturity of Myrica rubra. The TSS content of Myrica rubra after 15 days cold storage was 13.7% higher than that of the control group, and the moldy rate was 9.5 percent point lower than that of the control group. Spraying 40 nm, 0.10% rutile nano-TiO2 on the surface of Myrica rubra could kill mold and improve its storage property. The hardness, TA and Vc content of the Myrica rubra after 15 days cold storage were 19.5%, 33.2% and 5.6% higher than those of the control group, respectively, which delayed the increase of reducing sugar(RS)and TSS content. And the moldy rate of the Myrica rubra was 19.5 percent point lower than those of the control group. The results of stepwise regression and path analysis showed that RS content was the decision factor affecting the good fruit rate of cold storage Myrica rubra, and the TSS content was the limiting factor affecting the fluctuation of good fruit, which mainly played an indirect negative effect through the increase of RS content. The content of TA was a decision factor affecting the moldy rate and soft fruit cracching rate of cold stored Myrica rubra. The results of this study provide a way to promote the early maturity of Myrica rubra and improve its cold storage properties.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2011-2020. https://doi.org/10.11869/j.issn.100-8551.2020.09.2011To prolong the shelf life of turbot, Nisin, sodium lactate and sodium alginate were selected for single factor experiments. The compounded biological preservatives were optimized through response surface Box-Behnken experiment design. A quadratic polynomial regression model was established using the total volatile basis nitrogen of turbot which had been cold stored for 9 days as evaluation index. And the preservation effect of the optimal proportion compounded biological preservatives was verified by determining the indexes including of aerobic bacterial count, pH value, TVB-N, sulfhydryl content, water-holding capacity, water transport and muscle structure. Through variance analysis and regression fitting, the results showed that the optimal amount of composite biological preservative was composed of 0.04% nisin, 5.92% sodium lactate and 1.06% sodium alginate, and The TVB-N of turbot cold stored for 9 days had a minimum value of 18.37 mg·100g-1. Moreover, Nisin and sodium lactate had significant interaction on the preservation of turbot (p <0.05) and the response surface model was well fitted with the actual situation. The shelf life of turbot treated with the chosen composite biological preservatives at 4℃ could be prolonged to 14 days. This study provided a theoretical basis and technical support for using edible coatings to obtain high quality aquatic products.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2021-2031. https://doi.org/10.11869/j.issn.100-8551.2020.09.2021In order to develop and utilize the small yellow croaker scraps to prepare concentrated fish soup, the enzymatic hydrolysis of the small yellow croaker scraps was carried out and the functional activity of the hydrolysate was studied. Taking the amino nitrogen content as an index, the effects of enzyme type and dosage, ratio of material to liquid, pH and time on enzyme efficiency were investigated through single factor and response surface tests. DEAE chromatography column was used to separate and purify the enzymatic hydrolysate. SDS-PAGE gel-electrophoresis was used to determine the molecular weight of the enzymatic hydrolysate. The influence of OH and DPPH radical scavenging rate on the growth curve of bacteria was determined. The antioxidant and antibacterial properties were also analyzed. The results showed that the amino nitrogen content in the hydrolysate of small yellow croaker was 0.545 2 g·100 g-1 with alkaline protease as enzyme preparation, the ratio of enzyme to substrate protein was 322 U·g-1, the ratio of solid to liquid (m:v) was 1:2, under the pH value of 11, temperature of 55℃ and time of 2 hours. The enzymatic hydrolysate of small yellow croaker was separated by DEAE column and four groups of polypeptides Ⅰ, Ⅱ, Ⅲ and Ⅳ were obtained, in which the molecular weight of the component Ⅲ polypeptides was less than 3.3 kDa.When the content of amino nitrogen in the hydrolysate was 8.62 and 25.59 mg·mL-1respectively, the scavenging rate of ·OH and DPPH was about 80% and 61%; the component Ⅲ polypeptide had different degrees of growth inhibition on Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Saccharomyce. The study laid theoretical foundation for the development of concentrated fish soup and other comprehensive utilization of small yellow croaker scraps.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2032-2044. https://doi.org/10.11869/j.issn.100-8551.2020.09.2032To explore the effect and molecular mechanism of inulinase to reduce the content of N-glycolylneuraminic acid (Neu5Gc) in red meat. Firstly, Neu5Gc standard sample was detected by the liquid phase mass spectrometry after treatment with inulinase. Secondly, the exo-inulinase (PDB code:1Y9G) and endo-inulinase (PDB code: 3SC7) were selected to perform molecular docking and molecular dynamics simulation with Neu5Gc, and the inulinase active residues that bind with Neu5Gc was verified by amino acid virtual mutation. Finally, the intensity and distribution of intermolecular weak interactions between Neu5Gc and inulinase active residue complexes after dynamic equilibrium was analyzed by density functional theory (DFT) and independent density gradient (IGM) theory. The experimental results showed that the average Neu5Gc content reduction rates of the exo-and endo-inulinases were 55.33% and 43.81%, respectively. The theoretical calculations showed that Neu5Gc could stably bind into the enzyme active pocket with inulinase active site residues through intermolecular weak interactions, which mainly related to Neu5Gc hydroxyl oxygen and amide nitrogen. The binding energy of Neu5Gc with exo-and endo-inulinase complex in water environment were -22.71 and -8.46 kJ·mol-1, respectively. The results of this study provided a reference for the rational design of inulinase and application in the control of red meat safety.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2045-2050. https://doi.org/10.11869/j.issn.100-8551.2020.09.2045The purpose of this study was to establish an ultra-high performance liquid chromatogram-tandem mass spectrometry (UPLC-MS/MS) method for the determination of 5 sedative drug residues including promethazine sulfoxide, promethazine, chlorpromethazine, quaaludes and diazepam in animal urine. After purification by solid phase extraction, UPLC-MS/MS was used to detect residues of 5 sedatives in the urine of pigs, cattle and sheep. The results showed that impurities can be effectively removed after centrifugation, pH adjustment and purification by Oasis MCX SPE column. The five sedatives suggested good linear relationship in the range of 0.6-20 g·L-1, and the correlation coefficient (R2) was greater than 0.993. Besides, the detection limits and quantitative limits of the 5 sedatives were 0.1 and 0.6 g·L-1, respectively. The recoveries of the 3 spiked levels at 0.6, 2.5 and 9.0 g·L-1 ranged from 64.6% to 110.2%, with relative standard deviation (RSD) less than 6.0%. This method can be used for the accurate detection of sedative drug residues in the urine of different animals.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2051-2058. https://doi.org/10.11869/j.issn.100-8551.2020.09.2051To determine effects of mechanized side deep placement of nitrogen (N) fertilizer on the yield formation and N utilization of direct-seeded rice cultivated on the Chuanxi Plain. A field experiment was conducted using the conventional Indica rice cultivar ‘Huanghuazhan’ planted in a randomized block design with five N treatments: no N fertilizer (N0), urea surface broadcasting twice (TF), urea surface broadcasting one time (UB), urea mechanical side deep placement (UM), and urea and slow-release urea mechanical side deep placement (SRUM). The effects of the different N application methods on dry matter and N accumulation, transport, and distribution, as well as the yield formation and N use efficiency of mechanized direct-seeded rice were determined. The five treatments were ranked, from highest total dry matter accumulation, N uptake, N recovery efficiency, N agronomic use efficiency, and grain yield of direct-seeded rice to lowest, following the order of : SRUM>UM>TF>UB>N0. The apparent N translocation in the stem and leaves and its contribution to grain N accumulation were significantly higher in the mechanical side deep placement treatments (SRUM and UM) than in the other treatments, and dry matter translocation was significantly higher in the SRUM treatment than in the UB and UM treatments (28.97% and 4.17% higher, respectively). The number of effective panicles was significantly higher in the SRUM and UM treatments than in the other treatments (P<0.05), and their yields were 8.00% and 12.95% higher, respectively, than that of the UB treatment. Compared with the TF treatment, the UM and SRUM treatments resulted in higher N recovery efficiency (11.35% and 46.94% higher, respectively) and higher agronomic use efficiency of N fertilizer (7.22% and 25.88% higher, respectively). Compared with other treatments, the SRUM treatment significantly increased the number of effective panicles, dry matter accumulation, N uptake, apparent N and dry matter translocation in stems and leaves during the grain filling stage, yield, and N use efficiency. Hence, SRUM not only reduced the number of fertilizer applications required for mechanized direct-seeded rice, but also increased production and efficiency. Therefore, this method is suitable for widespread application. This information can provide a theoretical basis for improving and simplifying the production of direct-seeded rice in Chuanxi Plain.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2059-2070. https://doi.org/10.11869/j.issn.100-8551.2020.09.2059In order to explore the scientific irrigation and fertilization system of water saving, fertilizer saving, high yield and high efficiency for planting processing tomato in Northern Xinjiang, water nitrogen coupling test was carried out at Shihezi University water saving irrigation test station in 2017-2018. Four irrigation levels and three nitrogen application gradients were designed to analyze the growth physiological indexes, quality factors and economic benefits of processing tomato under different water and nitrogen treatments. The results showed that the suitable coupling of water and nitrogen had a significant effect on plant height and stem diameter (P<0.01). The effect of irrigation on the photosynthetic index of processing tomato was significant, and the effect of water nitrogen coupling on net photosynthetic rate and transpiration rate were significant (P<0.05). The lower and higher nitrogen application rate is not conducive to the increase of yield, fruit quality and irrigation water use efficiency of processing tomato. Based on the comprehensive evaluation method of fuzzy mathematics, when considering the comprehensive benefits of water saving, fertilizer saving, economy and environment, the irrigation amount should be 4 500 m3·hm-2 and the nitrogen amount should be 225 kg·hm-2. In conclusion, appropriate irrigation and nitrogen application can improve the economic benefits of crops and farmers' enthusiasm for planting. The results of this study have far-reaching significance for improving fertilizer pollution and water and fertilizer utilization efficiency in Northern Xinjiang.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2071-2079. https://doi.org/10.11869/j.issn.100-8551.2020.09.2071In order to understand the nutritional quality of young stem and explore the relationship between nutritional quality/yield of young stem and the environment in “seed-vegetable” dual functional rapeseed genotypes, field experiments were conducted including nutritional quality comparison of young stem including total soluble sugar, vitamin C, vitamin B1, vitamin B6, available Zn, and total Se content among rapeseed (Brassica napus L.), Brassica parachinensis L. Bailey, and Brassica campestris L. var. Shanghaiqing; ecological effects on the quality including carbohydrate, vitamin, and microelement contents and yield of young stem, seed yield, and economic costs of 6 rapeseed cultivars (lines). Results showed that the nutritional quality of young stem in rapeseed was the best while that was the worst in B. campestris. The total soluble sugar content, vitamin C, vitamin B1, vitamin B6, available Zn, and total Se content in young stem of rapeseed was 1.82-, 2.61-, 4.44-, 1.68-, 1.81-, and 1.67-fold higher than that in B. campestris. There was no significant difference in fructose content between Hangzhou and Lishui in young stem of 6 rapeseed genotypes. However, total soluble sugar, sucrose, starch, vitamin C, vitamin B1, and vitamin B6content in young stem of 6 rapeseed genotypes in Lishui was significantly higher than that in Hangzhou. As for the micro-elements including available Fe, available Cu, available Zn, and total Se content in young stem of rapeseed genotypes in Hangzhou was significantly higher than that in Lishui. However, there was a reverse trend in the available Mn content. The results suggested that the nutrients including carbohydrates and vitamins needed biosynthesis and transportation in the young stem of rapeseed in Lishui had much significantly advantages than that in Hangzhou, however, the elements absorbed from soil had an opposite trend. Both seed and yound stem of rapeseed yield of “seed-vegetable” dual functional rapeseed genotypes were significantly affected by different growth ecological areas. Furthermore, the costs were doubled through harvesting seeds of rapeseed combined with harvesting one season of young stem of 6 rapeseed genotypes. Our result highlights the utilization of “seed-vegetable” dual functional rapeseed genotype and the cultivation of high yield and quality of this type of rapeseed in different ecological areas.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2080-2087. https://doi.org/10.11869/j.issn.100-8551.2020.09.2080In order to shorten the growth period of early rice in “potato-rice-rice” triple cropping, make the connection of "potato-rice-rice" more smoothly, and improve overall economic benefits, in this study, different economic crops were used to replace early rice, and field trials were conducted in Huidong County in 2016 and Baiyun District in 2017, respectively. A total of five treatments were set up in the trial: T0 (blank control, no crops), conventional treatment TCK(early rice), T1 (cucumber), T2 (beans), T3 (sweet corn), to explored the growth period, yield, planting benefits, fertilizer efficiency and the differences in soil enzyme activity in different spring-sown economic crops. The results showed that planting cucumber, beans and sweet corn instead of early rice could increase the economic benefits and shorten the growth stage significantly. Among them, the sweet corn (T3) as an economic crop displayed the best results. Compared with spring rice (TCK), planting sweet corn increased the planting benefit by 1.32~3.72 yuan·m-2, shortened the growth period by 37~43 days, improved the harvest index 18.6%~20.1%, increased the contents of available phosphorus and available potassium, and increased the activities of urease, phosphatase and catalase in soil. In summary, the model of three-crop rotation of “economic crops-mid-late rice-winter potato” formed by sweet corn and other economic crops instead of early rice made the crop stubble connection more smooth, and improved the overall economic benefits of the triple cropping, which had a positive effect on increasing farmers’ income. This study provides theoretical and practical basis for optimizing the planting pattern of “potato-rice-rice” triple cropping area in Guangdong province and even South China.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2088-2094. https://doi.org/10.11869/j.issn.100-8551.2020.09.2088In order to study effects of five nitrogen application rates(0,90,180,270,360 kg·hm-2)on biomass accumulation, growth rate, yield and fiber quality of direct sowing cotton rape was investigated in this study by applying field experiments at Changde in 2016 and 2017. The results showed that the biomass accumulation of vegetative organs was positively correlated with nitrogen application rate in the range of 0~360 kg·hm-2. The biomass of reproductive organs accumulated the most at 270 kg·hm-2, furthermore, lint yield, boll number and boll weight reached the maximum when applied at 270 kg·hm-2 nitrogen application rate. The lint percentage was positively correlated with nitrogen application rate in the range of 0~270 kg·hm-2, but there were no differences among all the treatments. Under the condition of 270 kg ·hm-2 nitrogen application rate, the fiber length and breaking ratio strength were the highest. It was concluded that the yield and quality of cotton could be improved by applied appropriate nitrogen application rate which was beneficial to the improvement of fiber length, breaking ratio strength and micronaire, while appropriate nitrogen had no effect on the elongation and uniformity. The results of this study provide technical references for the rational management of nitrogen fertilizer in cotton areas around Dongting Lake.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2095-2102. https://doi.org/10.11869/j.issn.100-8551.2020.09.2095In order to study effects of different LED red and blue light ratio on the growth and physiological characteristics of rice seedlings, Xiangzaoxian 45 was used as the experimental material by adding different proportions of red light R (main wavelength 662nm) and blue light B (main wavelength 457nm) on the basis of white light. Six proportions of light quality were set T1, white light: blue light=2:1 (light quality ratio); T2, white light:blue light=1:2; T3, white light:red light=7:1; T4, white light:red light=2:1; T5, White light:red light=3:2; T6, white light:red light=1:2, respectively. The effects of different light quality ratios on the morphological and physiological characteristics of rice seedlings were studied by using white light (W) as a control. The results showed that increasing the proportion of red light increased the plant height, the length of the second leaf, the leaf area, the seedling index, the fresh weight of underground part, the total length of root, the total number of roots, the surface area of root, the chlorophyll content and the Hydrogenase (CAT) activity of leaf. Increasing blue light inhibited the plant height, first leaf sheath length of rice seedlings were increased as wellas the total number of roots, root surface area, root volume, and chlorophyll content. The stem width and seedling index of T2 treatment were the highest, which increasing by 23.1% and 51.6%, respectively. T3 and T4 treatments were beneficial to biomass accumulation, increasing leaf area and antioxidant enzyme activity, and increasing leaf area of T3 and T4 by 46.9% and 45.6%, respectively, compared with CK. In summary, LED red light enhances the leaf area of rice leaves and antioxidant enzyme activity of rice leaves in addition to promote the dry matter accumulation of seedlings and the development of root system, and LED blue light can increase stem base width and seedling index for improving the morphology of rice seedlings and cultivating strong seedlings. This study provides a theoretical basis for optimizing the illumination parameters of rice planting.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2103-2111. https://doi.org/10.11869/j.issn.100-8551.2020.09.2103In order to explore the potential ecological risk of heavy metal pollution in soil and the health risk of heavy metals in edible Phyllostachys violascens shoots under mulching cultivation and the application of lime nitrogen, three main Phyllostachys violascens shoot producing areas in Deqing County, Zhejiang Province were selected to be sampling sites. The contents of Cr, As, Hg, Ni, Cd and Pb in Phyllostachys violascens soil and Phyllostachys violascens shoots under three different management modes (no mulching, mulching and applying lime nitrogen after mulching cultivation) were determined by ICP-MS method. The results demonstrated that heavy metal content in the soil of three different management modes followed the order of was Cr > Pb > Ni > As > Cd > Hg, mulching led to the soil acidification and heavy metal enrichment, but the application of lime nitrogen could diminish the enrichment level of the soil. After mulching cultivation, the maximum contents of six heavy metals in bamboo shoots were 0.23, 0.06, 0.01, 0.65, 0.04 and 0.10 mg·kg-1, respectively. Within the limits of the Standard Forest Food Quality and Safety guidelines (LY/T 1777-2008) and the Food Safety National Standard Food contaminant limits (GB 2762-2012). Lime nitrogen can reduce the accumulation of heavy metals in bamboo shoots under mulching cultivation. The comprehensive potential ecological hazard index of heavy metals in soil under mulching cultivation decreased significantly after the application of lime nitrogen. The health hazard index (HI) of 6 heavy metals ingested by bamboo shoots was lower than the maximum acceptable level recommended by US EPA (1.0), and there was no significant health risk. The results showed that the application of lime nitrogen could alleviate the pollution of heavy metals caused by mulching cultivation.This study provides a scientific basis for the application of lime nitrogen in forestry production.
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Journal of Nuclear Agricultural Sciences. 2020, 34(9): 2112-2123. https://doi.org/10.11869/j.issn.100-8551.2020.09.2112Taking 6-year old jujube cultivar Lingwuchangzao (Zizyphus jujube Mill cv.Lingwuchangzao) saplings as experimental subjects, we studied the effect of sugar accumulation, key sucrose enzymes metabolism and related genes expression of Lingwuchangzao on the response of the conditions of elevated air temperature and soil drought. A two-factor experiment of atmospheric temperature and soil water content were set up to study the content of glucose, fructose, sucrose, starch, invertase (AI, NI), sucrose synthase (SS-s, SS-c), sucrose phosphate at different ripening stages synthetase (SPS) and other key enzyme activity changes, and analyze gene expression characteristics from the molecular level. The results showed that compared with the natural air temperature environment (T1), the contents of glucose, fructose, sucrose, starch and the activities of NI, SPS and SS-s increased by 0.18%~22.02%, 0.97%~21.97%, 0.43%~85.30%, 5.39%~49.06%, 0.60%~28.53, 0.01%~31.21% and 0.77%~25.31%, respectively, under the raising the air temperature (T2). Compared with normal soil water supply conditions (D1), the contents of fructose, sucrose, starch, and the activities of NI, SS-c increased by 44.26%, 49.56%, 38.20%, 56.04%, and 45.36%, respectively, under the moderate drought (D2). When the air temperature increased by about 2.0℃, ZjNI 1 and ZjNI 2 in ZjNI gene were up-regulated to 14.25 and 14.52 times, respectively. ZjSPS 1 and ZjSPS 4 in ZjSPS gene were up-regulated by 24.36 and 93.70 times, respectively, and ZjSS 1 and ZjSS 3 in ZjSS gene were up-regulated by 131.29 times and 81.38 times, respectively, under elevated temperature accompanied by severe drought. In conclusion, the effect of drought on sugar content and key enzyme activity in fruit of Lingwuchangzao was significant. The elevated temperature slowed the promotion effect of moderate drought on sugar accumulation, and intensified the inhibiting effect of severe drought on sugar accumulation. The increased temperature and drought promoted the up-regulation of gene expression of key enzyme of sucrose metabolism. This study indicated that the elevated temperature and drought were the most significant factors to the fruit nutrition quality of jujube cultivar Lingwuchangzao, which will provide theoretical guidance and technological support for Lingwuchangzao industry in Ningxia to global climate change.
