10 May 2023, Volume 37 Issue 5
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Effect of Mycorrhizal Fungi on the Germination of Dendrobium candidum Seeds After 60Co-γ IrradiationJournal of Nuclear Agricultural Sciences. 2023, 37(5): 889-896. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0889
To understand the effects of 60Co-γ irradiation on seed germination and seedling formation of Dendrobium candidum， as well as the effect of orchid mycorrhizal fungi on the germination of irradiated seeds， D. candidum seeds were irradiated with 60Co-γ rays at doses ranging from 20 to 120 Gy. The irradiated seeds were then treated with two methods： asymbiotic germination on 1/2 MS medium or OMA medium and symbiotic germination with Tulasnella sp. JL2 or JL4. The germination rates and seedling formation rates of irradiated seeds with two culture methods were compared and analyzed， and the phenotypic changes of seedlings were observed. The results showed that the semi-lethal dose ofasymbiotically germinated seeds on 1/2 MS medium was 62 Gy， and the semi-lethal dose of symbiotically germinated seeds was 69 Gy （JL2） and 63 Gy （JL4）， respectively. With increasing irradiation dose， seed germination rates were decreased. Low dose （20 Gy） treatment increased seedling formation rates， while high dose treatments inhibited seedling formation rates（90， 120 Gy）. After 115 days of growth， the seedling formation of seeds treated with 20 Gy ray was much improved than the 0 Gy control， reached up to 18.26% （1/2 MS）， 15.00% （JL2）， and 17.86% （JL4）， respectively. Seedlings germinated after high dose （90， 120 Gy） treatments had more pronounced phenotypic changes during symbiotic germination， including taller seedlings and sturdier pseudobulb. We combined seed irradiation with orchid mycorrhizal fungi symbiotic germination in this study， which offers a technical reference and scientific foundation to promote the recovery of irradiated D. candidum seeds， improve the irradiation mutagenesis efficiency， and effectively produce new D. candidum germplasm.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 897-906. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0897
In order to obtain new materials of homologous tetraploid nonbearing Chinese cabbage Lcx025b with high quality anthocyanin， the cotyledon growth point of diploid Lcx025b seedlings was treated with colchicine solution of 0.2% （w/v） concentration. The homologous tetraploid plants were screened and identified by morphological， cytological and flow cytometry methods. The diploid and tetraploid plants were compared and analyzed by agronomic traits， nutritional quality， photosynthetic characteristics and disease resistance. The results showed that compared with diploid plants， tetraploid plants showed giant morphology， the ratio of length to width of leaves decreased significantly， the leaves tended to be oblate， the flower organs， seed pods and seeds increased significantly， and the color of cabbage moss deepened. Stomatal density decreased and stomatal density increased significantly. The pollen grains showed obvious irregularity. The number of chromosomes in root tip cells of tetraploid plants and the fluorescence intensity of DNA of tetraploid plants analyzed by flow cytometry were twice that of diploid plants. In terms of nutritional quality， the contents of soluble sugar and chlorophyllin increased significantly， the contents of cellulose and nitrate nitrogen decreased significantly， and the contents of soluble protein and chlorophyll had no significant difference. Combined with the light response curve analysis， the tetraploid has stronger photosynthetic capacity and higher adaptability. In addition， the resistance of tetraploid plants to P. cinerea was obviously better than that of diploid plants. In conclusion， through this study， a new material of homologous tetraploid Lcx025b with high anthocyanin， purple cai-tai， was obtained， which provided important material support for the innovation of germplasm resources of non-knoting Chinese cabbage.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 907-916. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0907
To obtain mutants with enhanced erythritol production， 60Co-γ radiation combined with atmospheric room temperature plasma （ARTP） mutagenesis was performed and Yarrowia lipolytica WT5 were used as a start strain. Further more， the medium compositions were optimized by single factor test combined and Plackett-Burman analysis， and the cultivation mode for erythritol production was improved. The results showed that dual-mutation of 60Co-γ irradiation and ARTP was efficient for obtaining mutants with improved erythritol production， of which the best dose and treatment time were 1 200 Gy and 60 s， respectively. Notably， a strain named as CA20 capable of producing erythritol with a final concentration of 60.80 g·L-1， 2.41-fold of that of WT5. Moreover， with 21 mL of an optimized medium containing glucose 243 g·L-1， yeast extract 1.92 g·L-1， peptone 2.98 g·L-1， （NH4）2SO4 4.7 mg·L-1， NaCl 6.85 g·L-1， KH2PO4 3.3 mg·L-1， vitamin B1 0.65 mg·L-1， inositol hexaphosphate 49 mg·L-1， Span 20 193 mg·L-1， Tween 80 7 mg·L-1， MgSO4 0.42 mg·L-1 and FeSO4 0.002 mg·L-1， an initial pH of 5.98， erythritol with a final concentration and yield of 122 g·L-1 and 0.57 g·g-1 respectively was obtained. In addition， in a 3.7-L fermenter， the erythritol production of CA20 could be significantly enhanced via a two-stage pH regulation method， the concentration and yield of erythritol can reach up to 156 g·L-1 and 0.58 g·g-1， respectively， significantly higher than that obtained from batch fermentation （131 g·L-1 and 0.54 g·g-1）. These results provide important clues for breeding strains with high production of erythritol.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 917-926. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0917
The ATP-binding cassette subfamily G （ABCG） plays a crucial role in the transport of substances in plant. In order to explore the molecular characteristics， expression patterns and regulatory relationships of ABCGs in moso bamboo （Phyllostachys edulis）， bioinformatics methods were used to identify the gene members of ABCG subfamily in moso bamboo. Moreover， the comprehensive analysis of the gene structure， physiochemical properties of protein and phylogenetic relationship was conducted， and the gene expression patterns were analyzed by quantitative real-time PCR （qRT-PCR）. Furthermore， the regulatory relationship between transcription factors and ABCG gene was verified by yeast one-hybrid assay. The results showed that there were 77 ABCGs identified in
moso bamboo （PeABCG1~PeABCG77）. A variety of hormone， abiotic stress response elements were found in the promoters of PeABCGs， among which the ABRE element in response to the abscisic acid （ABA） was the most， and appeared in the promoters of 74 PeABCGs. Phylogenetic analysis showed that PeABCGs were divided into white-brown complex （WBC） and pleiotropic drug resistance （PDR） subgroups， which were closely related to those of rice. The results of qRT-PCR demonstrated that six of seven PeABCGs associated with ABA transport were up-regulated under ABA treatment， whereas PeABCG34 was undetected. All the expressions of seven PeABCGs were induced by low temperature. The expression of two PeABCGs was inhibited， while those of other five genes were induced with different levels of drought treatment. Besides， the expressions of PeABCG15 in shoots was continuously up-regulated with the increasing degree of lignification， consistent with the expression trend of PeKNAT3 and PeMYB42 involved in regulating lignin synthesis. It was confirmed that PeKNAT3 and PeMYB42 could bind to the promoter of PeABCG15 by yeast one-hybrid assay. These results suggested that PeABCGs may participate in the resistance of moso bamboo in two ways： ABA-mediated and non-ABA-mediated， among which PeABCG15 was induced by ABA and may be involved in stress resistance by promoting lignin synthesis. These findings would provide references for revealing the biological functions of ABCG in moso bamboo. -
Journal of Nuclear Agricultural Sciences. 2023, 37(5): 927-935. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0927
Bacterial wilt caused by plant pathogenic Ralstonia spp. is one of the most important diseases affecting the production of many important crops worldwide. With the advantage of being environmentally friendly， biological control of bacterial wilt is one of the hot research areas， and the secretion of bacteriostatic active substances is considered to be the main mechanism of biocontrol bacteria to inhibit pathogenic bacteria. In present study， Brevibacillus brevis B011， which had good antagonistic activity against Ralstonia solanacearum， was isolated and identified. Membrane filtration， ion exchange chromatography and high performance liquid chromatography were conducted to separate and purify the main active constituents from the broth of B. brevis B011. The chemical structures of purified active compounds were identified by tandem mass spectrometry and nuclear magnetic spectroscopy. On the basis of the complete genome sequence of strain B011， the putative genes involved in the biosynthesis of active compounds and their synthesis pathways were predicted. The results showed that among the secondary metabolites of B. brevis B011， the active constituents for inhibiting bacterial wilt was edeine A， and N-acetyltryptamine ［n-（2-（1H-indol-3-yl） ethyl） acetamide］. There was a complete gene cluster for edeine synthesis in the genome of strain B011， including 17 genes， edeA-edeQ. The structure of potential biosynthetic genes in the cluster was complete and the sequences were highly conserved. Decarboxylase coding genes of 17 and 54 acetyltransferase coding genes were predicted to be involved in the tryptophan decarboxylation reaction and tryptophan acetyl transfer reaction respectively in B. brevis B011 genome， but the functional genes involved in the biosynthesis of active compounds was needed to be further studied. The results can provide the theoretical guidance for the application of the strain B. brevis B011 and its active compounds， and also lay a foundation for further analysis of its biosynthetic pathway and directional modification of active compounds by synthetic biological methods.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 936-943. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0936
In order to clarify the resistance level and mechanism of Abutilon theophrasti to atrazine in corn field， whole-plant assay was used to evaluate the resistant level of six A. theophrasti populations collected from different areas of Hebei Province to atrazine in this study. Non-target-site resistance （NTSR） mechanism was studied through determining the activities of the detoxification metabolizing enzymes glutathione-S-transferases （GSTs） and cytochrome P450 oxidases （P450s） in A. theophrasti with Enzyme-linked immunosorbent assay （ELISA） method. In addition， sequence alignment and expression assay were conducted on the target gene psbA. The results showed that HB-3 population was susceptible to atrazine with GR50 value of 1 662.75 g·hm-2， while HB-6 population showed a high level of resistance with GR50 value of 84 721.13 g·hm-2 and resistance index （RI） of 50.95. GSTs inhibitor NBD-Cl and P450s inhibitor malathion could increase the toxicity of atrazine to the resistant population （R） HB-6， the GR50 values was decreased by 11.61 times （GSTs） and 27.77 times （P450s）， respectively. Besides， GSTs and P450s activities of R population were higher than those of S population. No mutation was detected on the Ser-264 amino acid site of psbA gene in R population. Furthermore， the expression of psbA gene in the R population was lower than that of in the S population after treatment with atrazine. To the best of our knowledge， it was the first report that the resistance of A. theophrasti to atrazine was caused by the enhanced detoxification metabolism mediated by GSTs and P450s， which laid a theoretical foundation for the scientific control of A. theophrasti and the reduced application of atrazine.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 944-954. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0944
General combining ability （GCA） is an important index to evaluate the utilization value of parental inbred lines. In order to analyze the genetic mechanism of combining ability of maize， 537 hybrid combinations obtained from NCII genetic mating design were used as materials， seven multi-locus genome-wide association study （MGWAS） methods were used to identify significant loci for GCA of kernel row number， kernel length， and kernel width in Xinxiang， Zhoukou， and combined environment， combining with 11 734 high-quality single nucleotide polymorphism （SNP） markers obtained from the maize 5.5K liquid breeding chip. Based on MGWAS， five genomic selection methods were used to predicting the GCA effects. The results showed that 46 SNPs were detected and significantly associated with GCA of kernel row number and two kernel traits （P<8.52×10-7）. Among them， ten loci were detected using two-to-five MGWAS methods simultaneously， and eight SNPs were co-located in at least two environments. Six SNPs （1_43440622， 2_69742504， 2_71037706， 2_197716855， 5_219239213， and 8_134634317） were both environment-stable and MGWAS method-stable loci， which were important loci controlling the GCA effects of kernel row number and kernel traits. The prediction accuracy of GCA for kernel row number and kernel width was high when using five random effect models， with a value of 0.62~0.74， and the prediction accuracy of GCA for kernel length was low， with a value of 0.28~0.45. In most cases， adding significant SNPs identified from different MGWAS as fixed effects into genomic best linear unbiased prediction(GBLUP) and reproducing kernel Hilbert space(RKHS) improved the prediction accuracy of GCA for kernel row number and two kernel traits in the three environments， with the percentage increase of 0.66%~15.96% for kernel row number and kernel width and 9.26%~83.05% for kernel length. The results of this study provide important gene information and technical guidance for subsequent gene function verification and genomic selection-assisted breeding of key loci.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 955-961. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0955
To rapidly and simultaneously detect sweet potato leaf curl virus （SPLCV） in a large number of samples， a rapid detection method for PCR-chromatographic strip based on cp gene of SPLCV was established in this paper. Firstly， we constructed the recombinant plasmid of the cp gene of SPLCV as the positive control and optimized the amplification conditions of the labeled specific primers. The results showed that 57 ℃ was the optimum annealing temperature. The results of the specificity test showed that SPLCV could be specifically detected by this method， and there was no cross-reactions with other sweet potato viruses such as Sweet potato symptomless virus 1（SPSMV-1）， Sweet potato badnavirus B（SPBV-B）， Sweet potato feathery mottle virus（SPFMV）， Sweet potato chlorotic stunt virus（SPCSV） and Sweet potato latent virus（SPLV）， that indicated the primers had good specificity. Secondly， we constructed a PCR-chromatography rapid detection system. The results showed that 20 μg digoxin antibodies were the optimal antibody labeling amount for 0.1 mg carboxyl magnetic particles. The specific amplified products were visualized in the newly constructed chromatographic system after about 3 min. The sensitivity results showed that the minimum detection limit was 0.000 1 ng·μL-1 of SPLCV genomic DNA， which was 10 times lower than that of normal gel detection. That indicated this system is highly sensitive. In summary， the tomographic strip detection system established in this study has the characteristics of visibility， high sensitivity， and rapidity， and can be used to detect a large number of samples at the same time， which meets the demand of detecting a large number of virus-free sweet potato seedlings before put on the market.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 962-970. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0962
In order to investigate the effects of high-energy electron-beam irradiation on quality of Eucommia ulmoides leaves from Sichuan， samples were irradiated at different irradiation doses （0， 2， 4， 6， 8kGy）. The microbial count， active ingredients， high performance liquid chromatography （HPLC） fingerprint， color， moisture and extract were measured. The result showed that the total aerobic microbial count， total yeast and mold count were significantly reduced by the electron-beam irradiation treatment （P<0.05）. Chlorogenic acid and rutin measured by HPLC were not significantly affected by electron-beam irradiation， but was no significant linear correlation with the irradiation dose （P>0.01）. The similarity of fingerprints of Eucommia ulmoides leaves and its extracts treated with different electron-beam irradiation doses was greater than 0.90. With the increase of irradiation dose， the Hunter color values were lighter and then darker， with the a* and b* values showing a decrease and then increase trend. The moisture and alcohol-soluble extracts are in line with the provisions of the 2020 edition of the Chinese Pharmacopoeia. Electron-beam irradiation at the dose of 2 kGy can effectively reduce the number of microbial loads， and has no significant effect on the active ingredient contents and fingerprint. In summary， the electron-beam irradiation at 2 kGy dose can significantly reduce the number of Eucommia ulmoides leaves microbial population， and ensure its quality. This study provided a reference for the application of electron-beam irradiation technology in Eucommia ulmoides leaves storage.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 971-980. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0971
In order to understand the effects of radiation irradiation on lignocelluloses more comprehensively， the structure and enzymatic properties of Phragmites australis lignocelluloses（PAL） treated with γ irradiation and electron beam were analyzed by SEM， FT-IR， XRD and HPLC.The results showed that both γ irradiation and electron beam could degrade PAL， in which some cellulose and hemicellulose were decomposed to water-soluble substances after irradiation， and the degradation level was positively correlated with the absorbed dose. When the absorbed dose was 500 kGy， the soluble fraction of PAL irradiated by γ irradiation and electron beam were 2.44 and 1.98 times that of the control respectively.The microstructure of PAL was disrupted after γ irradiation and electron beam irradiation， the number of molecules in the PAL increased， and the cellulose crystalline index decreased， while the allomorph of cellulose remained unchanged. As the absorbed dose increased from 200 kGy to 500 kGy， the enzymatic conversion of cellulose and hemicellulose gradually increased. When the absorbed dose was 500 kGy， the enzymatic hydrolysis conversion rates of cellulose irradiated by γ ray and electron beam were 16.68% and 18.84% respectively， which were 2.32 and 2.62 times that of untreated PAL， and the hemicellulose conversion rates were 21.38% and 21.74% respectively， which were 3.82 and 3.88 times that of untreated PAL. The effects of equal absorbed dose of γ irradiation and electron beam irradiation on the main chemical components and physicochemical structure of PAL were similar. In the dose range of 200~400 kGy， there was no significant difference between γ irradiation and electron beam in promoting the enzymatic efficiency of celluloseand hemicellulose， while when the absorbed dose was 500 kGy， the effect of electron beam irradiation on the enzymatic promotion of PAL cellulose was significantly better than that of γ irradiation.This study provides a theoretical basis for the application of irradiation technology in lignocellulose pretreatment.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 981-989. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0981
To obtain potato cultivars with different processing purposes， 12 potato tubers were evaluated with different cooking treatments. Atlantic and Burbank were used as control for steaming and baking respectively. Potato tubers were steamed and backed at different temperature for varied time，and the dry matter content and starch content of the tubers were measured. The texture of processed tubers， including hardness， adhesiveness and cohesiveness were analyzed. The color of processed tubers was evaluated. The correlation between tuber texture parameters and components， and the principal component analysis was carried out for the different processing conditions under steaming and baking. The results showed that starch content， the dry matter content， the hardness， the adhesiveness， and the cohesiveness of twelve potato varieties （lines） after steamed was among 50.76%~83.69%， 15.77%~31.64%， 936.65 N~12 231.82 N， 13.07~163.66， 0.07~0.14， respectively. The texture parameters （hardness 7 240.81 N， adhesiveness 53.23， cohesiveness 0.07） of Atlantic steamed at 110℃ for 30 min were used as the control. The texture parameters of Gannongshu 7 （hardness 6 978.40 N， adhesiveness 52.27， cohesiveness 0.09） and H0916 （hardness 7 629.74 N， adhesiveness 63.16， cohesiveness 0.07） were similar to those of Atlantic. The starch content， the dry matter content， hardness， adhesiveness， and cohesiveness of twelve potato varieties （lines） after baking was 46.12%~70.57%， 18.49%~38.66%， 1048.07 N~6 997.73 N， 11.25~91.88， 0.05~0.27， respectively. The texture parameters of Burbank （hardness 3 055.38 N， adhesiveness 60.37， cohesiveness 0.09） after baked at 200 ℃ for 50min were used as the control. The texture parameters （hardness 2 619.31 N， adhesiveness 63.11， cohesiveness 0.09） of Gannongshu 7 were similar to Burbank， the surface brown area of potato meat was small. After steaming at 110 ℃ for 30 min， there was a positive correlation between starch and dry matter. After baked at 200 ℃ for 50 min， hardness was negatively correlated with dry matter and adhesiveness， and positively correlated with cohesiveness. One principal component was obtained by principal component analysis， which was hardness，with variance contribution rate of 50.597%. The texture parameters of each variety were closest to the ideal variety Burbank when steamed at 110 ℃ for 30 minutes and baked at 200 ℃ for 50 minutes. The tuber had a low degree of brown， which was the optimized steaming and baking conditions. Gannongshu 7 was an ideal variety for steaming and baking， and the results provided the basis for selecting potato varieties with different cooking purposes.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 990-998. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0990
In order to reduce the nutritional loss of mussel meat caused by traditional thermal shucking， and improve its processability and nutritional flavor， laser technology was used to realize mussel shucking， which was further combined with blanching or steam technology to improve the efficiency and continuity of shucking operation. The effects of laser shucking， laser-bleaching shucking and laser-steam shucking on the sensory， nutritional and taste quality of mussel meat were investigated using the traditional boiling shucking and the manual shucking as control. The results showed that when the laser power was 40 W and the treatment time was 0.5 s， the shucking rate of the adductor muscle was 100%， and the color and odor sensory scores were high. The hardness， springiness and chewiness of mussel meat obtained by laser and its combined shucking technologies were close to fresh mussel meat， and the loss of protein， fat， carbohydrate and 5'-nucleotide was reduced compared with boiling shucking method. Laser-bleaching shucking and laser-steam shucking also increased the content of free amino acids in mussel meat （P<0.05）. Therefore， laser and its combined shucking technologies could effectively improve the shucking rate， reduce the nutritional loss of mussel meat during processing， and obtain fresh shucked mussel meat with good quality. The results of this study provide a theoretical basis for the further application of laser technology in shellfish shucking.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 999-1004. https://doi.org/10.11869/j.issn.1000-8551.2023.05.0999
To explore the effect of compound phosphate on the water distribution and microstructure of quantitatively marinated sauce beef， low field nuclear magnetic resonance （LF-NMR） was used to analyze the water distribution and migration of beef with different amounts of phosphate addition. The effect of different phosphate addition on the microstructure and texture characteristics of quantitatively marinated sauce beef was studied. The results showed that the cooking loss rate decreased， while the water content and yield increased with increased amounts of compound phosphate. However， these indexes did not change significantly when the addition of compound phosphate was more than 0.4%. The composite phosphate decreased the transverse relaxation time （T21） of the bonded water and the transverse relaxation time （T22） of the non-flowing water， and increased the percentage of the area of transverse relaxation peak （P22） of less-mobile water， which lead to the conversion of free water into non-flowing water. The hardness and chewiness decreased while the springiness and cohesiveness increased， and the muscle fiber tissue of sauced beef gradually becomes flat， smooth， dense and uniform. Therefore， the optimal addition amount of compound phosphate in quantitatively marinated sauce beef was 0.4%. This study could provide a basis for the quality improvement of sauced beef and the upgrading of marinating technology.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1005-1011. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1005
To explore the shelf life of braised braised beef at different temperatures， the processed braised beef was vacuum packaged and sterilizated using boiling water （repeated twice with 48 hours apart）. The shelf life prediction model was established using the total number of colonies. The sterilized braised beef products were stored in thermostatic incubators at 4， 10， 15， 20 and 25 ℃ respectively， and the change of the total number of colonies during storage was measured. With the increase of storage temperature， the maximum growth rate of microorganisms increased， the lag period was shortened， and the shelf life was shortened as well； The first order model （modified Gompertz model） and the second order model （Belehradek model） were established. The modified Gompertz model， except that the microbial growth curve at 4 ℃ could not be fitted， which had a good fitting effect for the other four temperatures （correlation coefficient R2>0.9）. The model validation was also passed （the range of accurate factor Af and deviation factor Bf were between 1.1~1.9 and 0.75~1.25 respectively）. Combining the first and second level models， the shelf life prediction model of braised beef with brown sauce was established. The model also passed the validation （the relative error between the predicted value and the measured value was within 10%）. The predicted shelf life at 25， 20， 15 and 10 ℃ was 15.93， 31.00， 64.05 and 185.76 days respectively. In this study， the shelf life prediction model of braised beef at 10~25 ℃ was obtained， which provided a theoretical basis for the storage time of braised beef at different temperatures.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1012-1021. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1012
In order to explore the quality changes of sand crab （Ovalipes punctatus） during chilled storage， the quantitative description analysis （QDA）， physical and biochemical properties were used to analyze the quality changes in the cephalothorax and pincer muscle of sand crabs during chilled storage. According to the results， the sensory score， water holding capacity， moisture content， water-soluble and slat-soluble protein content， Ca2+-ATPase activity， and total sulthydryls and active sulthydryls content decreased significantly （P < 0.05） during 5 days of chilled storage. However， the water activity， pH value， total volatile base nitrogen （TVB-N） content， and trimethylamine nitrogen （TMA） content in the crab muscle were gradually increased with the storage period prolonged. Based on the sensory score， physical and biochemical analysis， and the degradation of myofibrillar proteins， the muscle quality of sand crab deteriorated greatly and was not suitable for consumption， especially after 3 days of storage. The changes in SDS-PAGE pattern in sand crab also indicated degradation of the protein during chilled storage. According to the QDA analysis， it can be concluded that the flavor of cephalothorax muscle is better than that of the pincer muscle. It can be concluded that the cephalothorax muscle deteriorates faster than the pincer muscle of sand crab during 4 ℃ chill storage.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1022-1029. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1022
In order to make full use of rice husk resources and realize comprehensive utilization of agricultural waste the tulip variety Purissma was planted in the field as the test material to study effect of combined application of rice husk and compound fertilizer on physiological characteristics of tulips and weed control， and thereby to find a new way for regulating tulip growing environment and reducing the amount of fertilization. Seven treatments were set up in the experiment of applying compound fertilizer with rice husk： the control （CK： no rice husk or compound fertilizer）； application of rice husk alone （T2： 0.5 kg·m-2）； rice husk and compound fertilizer （T3： 0.5 kg·m-2 of rice husk + 0.03 kg·m-2 of compound fertilizer； T4： 0.5 kg·m-2 of rice husk+0.06 kg·m-2 of compound fertilizer； T5： 0.5 kg·m-2 of rice husk + 0.09 kg·m-2 of compound fertilizer； T6： 0.5 kg·m-2 of rice husk + 0.12 kg·m-2 of compound fertilizer； T7： 0.5 kg·m-2 of rice husk + 0.15 kg·m-2 of compound fertilizer）. The rice husk covering experiment involved 4 treatments： the control （CK： no rice husk covering）； rice husk covering （A： 0.25 kg·m-2 of rice husk； B： 0.5 kg·m-2 of rice husk； C： 1.5 kg·m-2 of rice husk）. The results showed that the combined application of rice husk and compound fertilizer promotes the growth of tulips. T6 and T7 performed the best effect in different periods. Meanwhile， the combined application of rice husk and compound fertilizer increases the diameter of tulip bulbs； the tulip bulbs in T7 are the largest， up to 39.8 mm in diameter， 15.13% larger than CK. Judging by bulb dry weight， flower diameter and flower height， T7 is 46.76%， 8.24% and 3.64% better than CK， respectively. All 6 treatments reduce soil compactness to some extent； pH value drops as the concentration of the compound fertilizer increases； across the treatments， compared with CK， T2 shows a decline of 27.27% in EC value while other treatments show no significant differences therein. Moreover， rice husk covering can well control grass weeds and broadleaf weeds in the field. All 3 treatments significantly reduce weed density and fresh weight； treatment C shows the best effect， reducing weed density and fresh weight by 59.81% and 65.09% respectively compared with CK. In terms of the plant control effect and fresh weight control effect on 2 main types of weeds， compared with CK， treatment A shows the weed control effects of 26.47% and 36.09%， respectively； treatment B shows the weed control effects of 37.29% and 45.73%， respectively； treatment C shows the weed control effects of 59.81% and 65.19%， respectively. The treatments are significantly different （P<0.05）. In short， the combined application of rice husk and compound fertilizer can promote the growth of tulips， optimize fertilizer utilization， improve soil environment， and suppress the growth of weeds.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1030-1039. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1030
To clarify effect of water-soluble topdressing and root-promoting agents on the growth of flue-cured tobacco， a double-factor experiment was conducted to investigate the effects of three kinds of root-promoting agents including mineral humic substances， hymexazol-isoprothiolane， and chitosan， and two kinds of fertilization modes including water-soluble topdressing and traditional topdressing， and their interactions on the growth of tobacco roots， agronomic characters and SPAD values by using Yunyan 87 as material. The effect of fertilization modes， root-promoting agents and their interaction on the growth of flue-cured tobacco was evaluated by the value of pEta2（Partial η2）. The results showed that water-soluble topdressing mode was better than the traditional topdressing mode in promoting the growth of tobacco roots and above-ground. The application of root-promoting agents can promote the growth of tobacco roots and above-ground parts， and improve the SPAD value of tobacco leaves， particularly the application of mineral humic substances and hymexazol-isoprothiolane. The contribution of fertilization modes， root-promoting agents， and their interactions to the tobacco root growth were 27.64%， 39.24% and 33.12%， respectively， and that of the above-ground parts of tobacco were 17.85%， 56.79% and 25.36%， respectively， and contribution of the SPAD value of tobacco leaves were 14.49%， 51.40% and 34.11%， respectively. It shows that root-promoting agents had the most significant effect on tobacco growth， followed by their interactions and fertilization modes. Therefore， using water-soluble topdressing mode combined with mineral humic substances or hymexazol-isoprothiolane can promote the growth of flue-cured tobacco. This study provides a theoretical basis for high quality and suitable yield of tobacco production in Hunan paddy-tobacco fields.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1040-1047. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1040
It is very important to use lignin， a cheap and environmentally friendly raw material， as the coating material of coated urea and to improve the preparation process of coated urea. In this experiment， lignin， stannous octoate， hexamethylene isocyanate and polyethylene glycol are used as raw materials to obtain lignin-based membrane， which was used as the inner layer of coated urea. Subsequently， the epoxy resin-based coating liquid was sprayed on the surface of the lignin-based coated urea particles as an outer layer to obtain a lignin/epoxy resin-based composite coated urea. The optimal preparation conditions of the coated urea were explored by adjusting the molar ratio of -NCO/-OH and the coating rate， and the cumulative nutrient release rate was tested by static water culture test. On this basis， the coated urea with optimal nutrient release performance was selected to evaluate the difference between its surface morphology and compressive properties. When the molar ratio of -NCO/-OH was 1.50， the maximum pyrolysis temperature and water contact angle of the lignin-based membrane were 404.31 ℃ and 82.36°， respectively. The results of hydrostatic test showed that the molar ratio of -NCO/-OH and the coating rate were positively correlated with the nutrient release period of the coated urea. Under the conditions of -NCO/-OH molar ratio of 1.50， resin content of 50%， and coating rate of 7%， the nutrient release performance of the coated urea was the optimal， and the time required to release 80% of the nutrients was more than 30 days. Coated urea prepared in this study meets the national standard of controlled release fertilizer.This study will provide theoretical basis and technical support for development of green and economical coated urea.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1048-1055. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1048
To determine the reasonable nitrogen （N） application rate for drip-irrigated sugar beet （Beta vulgaris L.） in Ta’e Basin， Xinjiang， a field experiment was conducted during 2020—2021. Five N application rates ［0 （N0）， 75 （N75）， 150 （N150）， 225 （N225） and 300 kg·hm-2 （N300）］ were set. The biomass and N concentration of plant in seedling stage， root tuber formation and differentiation stage， leaf cluster rapid growth stage， root tuber expansion stage， sugar accumulation stage and harvest stage were analyzed. The critical N concentration model based on biomass were developed. The N nutrition index （NNI） was calculated， and its relationship with relative biomass and relative yield were analyzed， respectively， and then the N nutrition status of sugar beet was determined. The results showed the plant biomass increased significantly when N application rate increased from 0 to 225 kg·hm-2， while it did not increase significantly when N application rate increased from 225 to 300 kg·hm-2. From the seedling stage to harvest stage， the plant biomass of N225 treatment increased by 82.55%， and that of N300 treatment increased by 86.44%， respectively， compared with N0 treatment. The variation of plant biomass with different N application rates during the whole growth stage of sugar beet followed the order of N0<N75<N150<N225≈N300. The determination coefficient R2 of critical N concentration model of sugar beet based on biomass was 0.974 and the test parameter n-RMSE was 16.26%， which showed good stability of the model. The recommended N application rate based on NNI was 150~225 kg·hm-2. A significant correlationship was found between NNI and relative biomass， relative yield. In conclusion， the developed critical N concentration model and NNI could be used as a diagnostic tool to detect N nutrition and a theoretical basis to manage nitrogen fertilizer of sugar beet in Ta’e basin， Xinjiang.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1056-1066. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1056
To study effects of low light before and after anthesis on the starch properties of different wheat cultivars， the experiment was carried out in the Xichang Academy of Agricultural Sciences base from 2020 to 2021， and was laid out in a two-factor split-plot design， with Shumai482， Chuanmai39， Mianmai51 and Changmai34 as the main plots and the sub-plots as shading stage， which were jointing-flowering stage （S1） and jointing-maturity stage （S2）， and normal light was used as control （CK）. The results showed that shading during different stage significantly inhibited the accumulation of starch in wheat grains. Compared with CK， the starch content at S1 and S2 decreased by 2.96% and 5.34%， respectively， but there was no significant change in amylose/amylopectin ratio. The number， volume and surface area distribution of A-type starch granules （<10 μm） under S2 treatment were 0.10%， 4.49%， and 5.01% higher than CK， respectively， but starch quality became worse， because the α-amylase activity increased by 36.6%， and the falling number， starch past viscosity swelling power decreased. Under S1 treatment， starch quality improved because the α-amylase activity of Mianmai51 was 28.6% lower than CK， while the pasting viscosity， swelling power， falling number increased. Mianmai51 was more sensitive to light changes， and its α-amylase activity was 1.55～2.61 times those of other cultivars， and the peak viscosity， the falling number and swelling power were 948.1～1 597.8 cp， 108～211 s， 2.95～3.88 g·g-1 lower than those of other cultivars. Correlation analysis showed that the falling number had a very significant positive correlation with swelling power and some RVA parameters such as the peak viscosity， but α-amylase activity was negatively correlated with it. The study showed that low light at grain filling stage deteriorated wheat processing quality by reducing starch content and increasing α-amylase activity， lower falling number cultivar Mianmai51 had poor environmental stability. It was recommended to choose higher falling number cultivar to reduce the adverse effect of low light during grain filling stage on starch quality. This study will help deepen the wheat starch quality research and guide wheat production in low-light areas.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1067-1075. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1067
To study the physiological and biochemical responses and resistance of common green seaweeds to simulated acid rain stress， the maximum photochemical quantum yield， relative conductivity， soluble protein and sugar contents， and antioxidant enzyme activity of one species of Enteromorpha and three species of Ulva were measured under five different pH levels. The results showed that the simulated acid rain inhibited the maximum photochemical quantum yield （Fv /Fm ）， and the inhibition amplitude increased with the increase of acidity and treatment time. The Fv /Fm of Ulva treated with simulated acid rain at pH 3.5 for 30 min was 2.8 times higher than that of Enteromorpha. Relative conductivity was directly proportional to the acidity of simulated acid rain and the treatment time， and plasma wall separation occurred to varying degrees. Simulated acid rain at pH 4.5 reduced the contents of chlorophyll a， carotenoids and soluble sugar in the seaweed， and the reduction of Enteromorpha was significantly higher than that of Ulva. However， the soluble protein content in the seaweed increased under acid rain treatment， which was more significant with time extension. Simulated acid rain at pH 4.5 inhibited the activities of catalase and superoxide dismutase， but increased the activity of peroxidase of seaweeds， and the treatment time was positively correlated with the activity of peroxidase， but negatively correlated with the activities of superoxide dismutase and catalase. In summary， pH 4.5 can be used as physiological and biochemical test conditions for common green seaweeds to simulated acid rain stress， and four species of green seaweeds have different responses to simulated acid rain stress. Compared with Enteromorpha， Ulva has better tolerance to simulated acid rain. Our results provided a theoretical basis for understanding the ecological distribution characteristics and potential population changes of seaweeds in the intertidal zone.
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Journal of Nuclear Agricultural Sciences. 2023, 37(5): 1076-1087. https://doi.org/10.11869/j.issn.1000-8551.2023.05.1076
Mulching technique is a widely used agricultural technology. The traditional plastic film currently in use brings huge economic benefits， but also induces serious ecological pollution problems and affects the sustainable development of agriculture， so the development of environmentally degradable mulching films is an inevitable trend. This study systematically describes the research progress and application status of the preparation materials， preparation technologies and products of photodegradable mulching film， biodegradable mulching film， photo/biodegradable mulching film， liquid mulching film and plant-fiber mulching film at home and abroad， as well as the advantages and shortcomings of the five types of degradable mulching films， and provides an outlook on the research direction and development prospects of plant-fiber mulching film. The results of this study provide a theoretical basis for further development of green， environmentally friendly and completely biodegradable agricultural mulching films to promote green and sustainable development of agriculture.
