Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' pote...Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' potential in the field of tribology and their application in ultra-charge/discharge devices. In this paper, a novel surface-enhanced Raman scattering technique that involves coating the sample with nanoscopic gold particles is proposed to characterize the NDs after different annealing treatments. Conventional Raman and surfaceenhanced Raman spectra were obtained, and the changes of peak parameters as the function of annealing temperature were evaluated. It was found that the widths of the D and the G peaks decreased with increasing annealing temperature, reflecting an improved order in the sp^2-hybridized carbon during the transformation from NDs to carbon onions. After annealing at 1700 ℃, the sp^2?carbon was highly ordered, indicating desirable electrical conductivity and lubricity. With increasing annealing temperature, the D peak showed a blue shift of almost30 cm^(-1), while the G peak merely shifted by 5 cm^(-1). For annealing temperatures above 1100 ℃, an increase of intensity ratio ID/IGwas observed. Compared to the uncoated area, red shifts of 0.5-2 cm^(-1) and of 5-9 cm^(-1) for the G and D peaks, respectively, were detected for the gold-coated area, which was due to the coupling of the plasmons and the phonons of the samples.展开更多
Microbial counts （total aerobic psychrotrophic count （TPC）, lactic acid bacteria （LAB）, coliforms, pseudomonads, yeasts） and sensory properties of sliced onions stored at different temperatures and air compositi...Microbial counts （total aerobic psychrotrophic count （TPC）, lactic acid bacteria （LAB）, coliforms, pseudomonads, yeasts） and sensory properties of sliced onions stored at different temperatures and air compositions were investigated. Microbial counts were fitted to the modified Gompertz equation and the growth parameters of microorganisms (the initial cell number （N0）, maximum cell number (Nmax), maximum specific growth rate (μmax), lag-phase （（λ）） were obtained as derived parameters. The relationships between growth parameters of microorganisms and the microbial or sensory shelf life were built. The results showed that microbial counts increased and sensory qualities decreased during storage. TPC was predominant bacteria associated with spoilage of sliced onions under tested temperatures and air conditions. High correlation coefficients （r） were found between the lag time （λ） of TPC, coliforms, pseudomonads, yeasts and the microbial or sensory shelf life. The correlations between microbial or sensory shelf life and μmax of five microorganisms were between -0.69 and -0.86. The initial microbial counts （N0） of five microorganisms strains only showed a little correlation, and the maximum microbial counts (Nmax) showed no obvious correlation with shelf life except for LAB and yeasts.展开更多
[Objective] This study aimed to compare the similarities and dissimilarities in karyotypes of purple and white onions,so as to lay foundation for further studying its genetic improvement and breeding more onion variet...[Objective] This study aimed to compare the similarities and dissimilarities in karyotypes of purple and white onions,so as to lay foundation for further studying its genetic improvement and breeding more onion varieties.[Method] Sections of root-tip cells were prepared by normal wafer method.Photomicrography was adopted to produce the high-quality chromosome specimen.Finally,karyotype analysis was conducted using Adobe Photoshop.[Result] Chromosome karyotype analysis on the root-tip showed that the chromosome number of both purple and white onions was 2n=2x=16.Among the 16 chromosomes of both the onions,no satellite chromosome was found.By measuring and calculating,it was found that the karyotype of the studied white union belonged to the lowly evolutional 2A type,and its karyotype formula was 2n=2x=16=14 m ＋2St,with the karyotype asymmetry coefficient of 58.67%.No obvious centromere was observed in the sections of purple onion.[Conclusion] The karyotypes of white and purple unions are similar and we can infer from this fact that the reason of different characters between both the onions is not due to the chromosome aberration.This karyotype formula and asymmetrical karyotype coefficient have some reference values on the identification of onion variety resources.展开更多
The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the rel...The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.展开更多
Onion（Allium cepa L.） is a very important vegetable crop widely cultivated throughout the world. In this study, we measured total anthocyanins and flavonols of onions of three colors. The fresh weight（FW） of total...Onion（Allium cepa L.） is a very important vegetable crop widely cultivated throughout the world. In this study, we measured total anthocyanins and flavonols of onions of three colors. The fresh weight（FW） of total anthocyanins were（29.99±1.19）,（9.64±1.30） and（0.75±0.40） mg 100 g^–1 fruit in red, yellow and white onions, respectively. Likewise, the FW of total flavonoids were（111.10±5.98）,（36.64±3.59）, and 0 mg 100 g^–1 in red, yellow and white, respectively. Four types of anthocyanins（delphinidin 3,5-diglycosides, cyanidin 3,5-diglycosides, cyanidin 3-glycosides and cyanidin 3-（6′′-malonyl）-glucopyranoside） and two kinds of flavonoids（quercetin and quercetin 3-glycosides） were identified in two varieties（red and yellow bulb） of onions by HPLC/DAD-ESI/MS. The total polyphenol contents were also measured by means of Folin-Ciocalteu method. Moreover, all the concentrations of anthocyanins, flavonoids and polyphenols showed significantly positive correlations with antioxidant activities measured by DPPH˙, ABTS˙＋ and FRAP assays. This study provided information on anthocyanin and flavonoids compositions that will be useful for onion breeding.展开更多
Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at d...Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.展开更多
The content of polyphenolic substances in commercial onions has been determined. The antioxidant activity of their ethanolic extracts, as well as their effects on the oxidation of edible corn oil during accelerated ag...The content of polyphenolic substances in commercial onions has been determined. The antioxidant activity of their ethanolic extracts, as well as their effects on the oxidation of edible corn oil during accelerated ageing was studied. Maceration of taxonomically identified commercial vegetable samples, previously peeled and thinly sliced, was carried out at ambient temperature, out of direct light, with occasional agitation and ultrasound, employing 95% ethyl alcohol as the extraction solvent, allowing them to stand for 7 days. The total polyphenolic contents were determined on the filtrated extracts using the Folin-Ciocalteau method. The antioxidant activity was evaluated on emulsions of ethanolic extracts of onion prepared in edible commercial corn oil, using sorbitan monooleate as emulsifying agent. The peroxide values were analyzed using the iodometric method;oxidation induction times were obtained from the peroxide evolution graphs, using the tan- gent method. Oil samples emulsified with ethanolic onion extracts showed an extension of the induction period. A 7-day ageing study at 45?C was additionally performed to determine the conjugated dienes on pure commercial corn oil and its emulsions by visible spectrophotometry. The spectral analysis showed an increase of the measured absorbancies in oil samples without additives and no change for the oils emulsified with onion extract. An increasing of diene values was observed for corn oil without additives during ageing;no changes in the value were observed in oils emulsified with onion extracts.展开更多
This research was carried out to assess the effect of different varieties and mulching types on insect and disease infestation,and the yield of onions.The experiment was conducted in Sangkat TuekVil,KrongSiem Reap,in ...This research was carried out to assess the effect of different varieties and mulching types on insect and disease infestation,and the yield of onions.The experiment was conducted in Sangkat TuekVil,KrongSiem Reap,in Cambodia.A 2×4 factorial in RCBD(Randomized Complete Blocks Design)was used to layout the trial,in which two varieties(Texas Early Grano 502 PRR and Earth F1)and four mulch types(non-mulch,rice Straw,silver plastic mulching and black plastic mulching)were used as the treatments.Application of these treatments was to enhance soil temperature,leaf number plant-1,stand count,bulb diameter,single bulb weight,insect incidence,disease incidence and bulb yield are different to all treatments.As the result,the bulb yields of onions among these treatments were found superior in Texas Early Grano 502 PRR combined with Black Plastic mulch followed by Texas Early Grano 502 PRR combined with silver plastic mulch and Texas Early Grano 502 PRR combined rice straw mulch,whereas the lowest was found in Earth F1combined with non-mulch.展开更多
In green onion harvesting,the problems of easy dumping and low rate of clean digging can be encountered.In this paper,a kind of harvesting device for digging and pulling green onions,referred to simply as"the dev...In green onion harvesting,the problems of easy dumping and low rate of clean digging can be encountered.In this paper,a kind of harvesting device for digging and pulling green onions,referred to simply as"the device",was designed.The device mainly consists of a digging shovel,screen bars,clamping conveyor belt,etc.This paper focuses on the analysis of the model forces of green onions and soil in the two states of the onion digging process without dumping and clamping.The key factors affecting the model state of onions and soil were identified as:screen bar length l_(2),screen bar inclination angleβ,and pulling point position x.Based on the discrete element simulation technology of EDEM,the mechanism-crop-soil model was established,and a single-factor simulation test was conducted to determine the range of values for each factor.Taking the advantages of field test and three-factor five-level orthogonal experimental design,the parameter combinations of green onion harvesting operation evaluation indices were optimized,including a pulling point position of 166 mm,screen bar length of 242 mm,and screen bar inclination angle of 14°.As the results of the field test show,the harvester operation was stable without congestion or damage,the harvesting effect of green onions was improved,and the clean digging rate reached 100%,which meets the agronomic requirements for onion harvesting and the expectations of users.展开更多
In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green ...In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green onions as the research object,and the main factors affecting the digging and harvesting effect were determined as the angle of digging,the dip angle of clamping carrier and the length of shovel.Thus,a complex simulation model of soil-green onion-digging mechanism system reflecting the state of harvesting was established,and the model was verified by testing soil compactness.The simulation tests were carried out by means of the complex simulation model of soil-green onion-digging mechanism system,making it clear that digging angle and the length of shovel have a extremely significant impact on the digging resistance,and the dip angle of the clamping carrier had a significant impact on the digging resistance.Through target optimization,the optimal combination of digging parameters was obtained,namely,the digging angle of 20°,the dip angle of clamping carrier of 25°and the shovel length of 70 mm,with the digging resistance of 1394 N at this moment.The field digging resistance test has showed that the average digging resistance is 1543 N with the average clamping damage rate of 1.27%and the average clamping loss rate of 0.44%,which can meet the requirements of green onion harvesting.展开更多
We supercooled fresh-cut onion at−5℃ for 12 h.After supercooling,the electric impedance properties of the samples were evaluated by electrical impedance spectroscopy over the frequency range of 42 Hz−5 MHz.The time-t...We supercooled fresh-cut onion at−5℃ for 12 h.After supercooling,the electric impedance properties of the samples were evaluated by electrical impedance spectroscopy over the frequency range of 42 Hz−5 MHz.The time-temperature profiles of samples indicated that the freezing point and supercooling point were−2.3℃±0.7℃ and−6.9℃±1.0℃,respectively.The results indicated that 34 of the 36 supercooled samples exhibited a definite circular arc in the Cole-Cole plot,which suggested that the cell membrane remained intact during supercooling.In the other two samples which did not exhibit a definite circular arc,the cell membrane had sustained serious damage during supercooling.Furthermore,there was large difference in drip loss percentage between supercooled samples exhibited a definite circular arc in the Cole-Cole plot and samples not exhibiting a definite circular arc.Our results suggest that fresh-cut onions can be supercooled at−5℃.展开更多
The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomi...The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomic radius,higher metal coordinated numbers,lower metal valence states and other features allow the group IVB metal-based Keggin(IVB-Keggin)more space and unknown in terms of structure and performance.Herein,density functional theory(DFT)calculations were performed to explore the influences including cores,shells,caps,and terminal ligands,et al.on IVB-Keggin,and analyze the possibility of novel structure synthesis.From the perspective of multi-layer onion-like clusters,molecular energy level,host-vip interaction energy,surface charge and covalent bond polarity can be further adjusted to achieve the oriented design of functional IVB-Keggin.These insights are expected to provide theoretical support for experimental synthesis,opening a new perspective to understand the growth of Keggin.展开更多
In this paper, the management points and cultivation difficulties of onion in different stages were discussed in detail from the aspects of onion cultivation seasons, cultivation methods, sowing and seedling raising, ...In this paper, the management points and cultivation difficulties of onion in different stages were discussed in detail from the aspects of onion cultivation seasons, cultivation methods, sowing and seedling raising, proper planting, field water and fertilizer management, stalk removal period, pest control, timely harvest and so on. This paper provides theoretical guidance for the high quality and high yield of onion in Huang-Huai area and data reference for further improvement of high-yielding onion cultivation technique system.展开更多
Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extract...Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extracts as an antibulbing substance,the amount of which was synchronized with the bulb formation.Since allene oxide synthase inhibitor canceled the antibulbing activity ofα-linolenic acid,it was disclosed that jasmonic acid concerns this regulation.Structure-activity-relationship study revealed that its(3R,7S)stereochemistry is necessary for showing its antibulbing activity.It is concluded that(3R,7S)-jasmonate derived fromα-linolenic acid actually participates in the regulation of bulb formation.展开更多
Water eutrophication is generally caused by the phosphorus excessive concentration. This phenomenon may affect the water quality. Hence, phosphorus removal from dam water which is affected by agricultural activities i...Water eutrophication is generally caused by the phosphorus excessive concentration. This phenomenon may affect the water quality. Hence, phosphorus removal from dam water which is affected by agricultural activities is not well known. The present work aimed to remove phosphorus from water using green Fe3O4 nanoparticles. Green iron oxide nanoparticles were prepared using the white and purple onion peels extracts. The stable iron oxide was selected using the antioxidant activity against 1,1-Diphenyl-2-Picrylhydrazyl. The SEM, XRD and FTIR analysis were used to characterize the nanoparticles. Phosphorus adsorption experiments were done in aqueous and real water solutions. The results showed that green iron oxide mediated by purple onion peels extracts possessed better antioxidant activities. The green magnetite (Fe3O4) nanoparticles obtained with the purple onion peels extracts have an average size of 15.81 nm and their surface were covered by phytochemicals compounds. In aqueous media, the optimum initial concentration of phosphate was 10 mg/L with a maximum adsorption percentage of 92%. The phosphate adsorption in aqueous solution by Fe3O4 was well described by the Freundlich model. The maximum adsorption capacity was 32.05 mg/g. In addition, the results also revealed that the maximum adsorption percentage of phosphorus in the dam water was 50.13%. Green Fe3O4 is therefore a good agent for removing phosphorus from polluted dam water.展开更多
In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including o...In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including onion. The main objective of this study, conducted in the experimental site of Djibo Hamani University of Tahoua in Niger, was to evaluate the effects of organic fertilizer on the growth and yield of onion crops irrigated with saline water. The experiment was performed in split-plot design to test tree type of fertilizer (chemical fertilizer, compost and millet glumes) and four (04) levels of irrigation water salinity in electrical conductivity values (ECw) (S0 = 0.28 dS/m as control, S1 = 2 dS/m, S2 = 4 dS/m and S3 = 6 dS/m). The growth parameters and bulb yield were evaluated during 4 months of onion cropping season. The results showed that the use of irrigation saline water significantly decreased the growth and bulb yield of onion crops. The yield in onion bulbs is 1.55 to 3.94 times higher with control (0.28 dS/m) than that with high saline water (ECw = 6 dS/m). Compared to control in irrigation water, the reduction in fresh onion bulb yield was 38.8, 52.6 and 63.5% respectively for ECw of 2, 4 and 6 dS/m. Furthermore, the application of organic fertilizers, particularly compost, improves salt-tolerance of onion crops in order to promote growth and bulb yield. Indeed, when irrigating onion crops with saline water (ECw of 2, 4 and 6 dS/m), the onion bulb yield is significantly higher under compost than under chemical fertilizer and glumes. At high irrigation saline water (ECw = 6 dS/m), the yield in onion bulbs is 1.9 and 2.1 times higher under compost than that under chemical fertilizer and glumes respectively. Thus, the compost is the promising organic amendment in a semiarid region of Tahoua in Niger to reduce the adverse effects of irrigation saline water on onion crop production.展开更多
Onions are a horticultural crop of great economic, dietary and medicinal importance, and are highly prized by the Ivorian population. However, production remains low, due to a number of constraints, including parasiti...Onions are a horticultural crop of great economic, dietary and medicinal importance, and are highly prized by the Ivorian population. However, production remains low, due to a number of constraints, including parasitic attacks. The most frequent is fusariosis caused by Fusarium sp., a pathogen that causes enormous damage to onion crops. Faced with these attacks, chemical control appears to be ineffective, with consequences for human health and the environment. This is why the search for effective alternative methods that respect the environment and human health is so necessary. It is in this context that this study was carried out, with the general aim of controlling fusarium wilt in onion crops, with a view to improving onion production in Ivory Coast through the use of effective microorganisms. The experimental set-up used for this purpose was a fisher block with complete randomization, comprising three replicates. A fungal spore concentration of 106 spore/mL of Fusarium sp., three doses (1%;2.5% and 5% v/v) of EM and one dose of a chemical fungicide (30 mL/16L) were tested on young onion plants. Each block consisted of nine sub-plots with nine treatments. Health parameters (incidence and severity) and agronomic parameters (growth and yield) were assessed. Microbiological analysis of the EM revealed the presence of nine morphotypes of Trichoderma sp., Aspergillus clavatus, Aspergillus flavus, Aspergillus sp., Penicillium sp., Rhizopus sp., lactic acid bacteria of the Bacillus family and the yeast Saccharomyces cerevisiae. Field experimentation showed that the 5% EM microbial solution reduced the incidence and severity of fusariosis compared with the chemical fungicide, and proved to be the best. This dose reduced yield losses by 7.14%, while improving onion growth and yield by over 5%. The results demonstrated the ability of the EM solution to effectively control the causal agent of basal rot in onion crops.展开更多
The paper describes some implementation aspects of an algorithm for approximate solution of the traveling salesman problem based on the construction of convex closed contours on the initial set of points (“cities”) ...The paper describes some implementation aspects of an algorithm for approximate solution of the traveling salesman problem based on the construction of convex closed contours on the initial set of points (“cities”) and their subsequent combination into a closed path (the so-called contour algorithm or “onion husk” algorithm). A number of heuristics related to the different stages of the algorithm are considered, and various variants of the algorithm based on these heuristics are analyzed. Sets of randomly generated points of different sizes (from 4 to 90 and from 500 to 10,000) were used to test the algorithms. The numerical results obtained are compared with the results of two well-known combinatorial optimization algorithms, namely the algorithm based on the branch and bound method and the simulated annealing algorithm. .展开更多
基金supported by National Natural Science Foundation of China (No. 51575389, 51761135106, 51511130074)National Key Research and Development Program of China (2016YFB1102203)State key laboratory of precision measuring technology and instruments (Pilt1705)
文摘Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' potential in the field of tribology and their application in ultra-charge/discharge devices. In this paper, a novel surface-enhanced Raman scattering technique that involves coating the sample with nanoscopic gold particles is proposed to characterize the NDs after different annealing treatments. Conventional Raman and surfaceenhanced Raman spectra were obtained, and the changes of peak parameters as the function of annealing temperature were evaluated. It was found that the widths of the D and the G peaks decreased with increasing annealing temperature, reflecting an improved order in the sp^2-hybridized carbon during the transformation from NDs to carbon onions. After annealing at 1700 ℃, the sp^2?carbon was highly ordered, indicating desirable electrical conductivity and lubricity. With increasing annealing temperature, the D peak showed a blue shift of almost30 cm^(-1), while the G peak merely shifted by 5 cm^(-1). For annealing temperatures above 1100 ℃, an increase of intensity ratio ID/IGwas observed. Compared to the uncoated area, red shifts of 0.5-2 cm^(-1) and of 5-9 cm^(-1) for the G and D peaks, respectively, were detected for the gold-coated area, which was due to the coupling of the plasmons and the phonons of the samples.
基金Item supported by the agricultural keyproject of science and technology commission of Shanghai (No.03319419)
文摘Microbial counts （total aerobic psychrotrophic count （TPC）, lactic acid bacteria （LAB）, coliforms, pseudomonads, yeasts） and sensory properties of sliced onions stored at different temperatures and air compositions were investigated. Microbial counts were fitted to the modified Gompertz equation and the growth parameters of microorganisms (the initial cell number （N0）, maximum cell number (Nmax), maximum specific growth rate (μmax), lag-phase （（λ）） were obtained as derived parameters. The relationships between growth parameters of microorganisms and the microbial or sensory shelf life were built. The results showed that microbial counts increased and sensory qualities decreased during storage. TPC was predominant bacteria associated with spoilage of sliced onions under tested temperatures and air conditions. High correlation coefficients （r） were found between the lag time （λ） of TPC, coliforms, pseudomonads, yeasts and the microbial or sensory shelf life. The correlations between microbial or sensory shelf life and μmax of five microorganisms were between -0.69 and -0.86. The initial microbial counts （N0） of five microorganisms strains only showed a little correlation, and the maximum microbial counts (Nmax) showed no obvious correlation with shelf life except for LAB and yeasts.
基金Supported by Scientific Research Foundation for Doctors of Qufu Normal University~~
文摘[Objective] This study aimed to compare the similarities and dissimilarities in karyotypes of purple and white onions,so as to lay foundation for further studying its genetic improvement and breeding more onion varieties.[Method] Sections of root-tip cells were prepared by normal wafer method.Photomicrography was adopted to produce the high-quality chromosome specimen.Finally,karyotype analysis was conducted using Adobe Photoshop.[Result] Chromosome karyotype analysis on the root-tip showed that the chromosome number of both purple and white onions was 2n=2x=16.Among the 16 chromosomes of both the onions,no satellite chromosome was found.By measuring and calculating,it was found that the karyotype of the studied white union belonged to the lowly evolutional 2A type,and its karyotype formula was 2n=2x=16=14 m ＋2St,with the karyotype asymmetry coefficient of 58.67%.No obvious centromere was observed in the sections of purple onion.[Conclusion] The karyotypes of white and purple unions are similar and we can infer from this fact that the reason of different characters between both the onions is not due to the chromosome aberration.This karyotype formula and asymmetrical karyotype coefficient have some reference values on the identification of onion variety resources.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2019YFE0122900)the National Natural Science Foundation of China(No 51971162,U1933112,51671146)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M671208)Open access funding provided by Shanghai Jiao Tong University
文摘The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest,China(20090318)the Yangzhou Agricultural Science and Technology Research Projects,China(YZ2014170)
文摘Onion（Allium cepa L.） is a very important vegetable crop widely cultivated throughout the world. In this study, we measured total anthocyanins and flavonols of onions of three colors. The fresh weight（FW） of total anthocyanins were（29.99±1.19）,（9.64±1.30） and（0.75±0.40） mg 100 g^–1 fruit in red, yellow and white onions, respectively. Likewise, the FW of total flavonoids were（111.10±5.98）,（36.64±3.59）, and 0 mg 100 g^–1 in red, yellow and white, respectively. Four types of anthocyanins（delphinidin 3,5-diglycosides, cyanidin 3,5-diglycosides, cyanidin 3-glycosides and cyanidin 3-（6′′-malonyl）-glucopyranoside） and two kinds of flavonoids（quercetin and quercetin 3-glycosides） were identified in two varieties（red and yellow bulb） of onions by HPLC/DAD-ESI/MS. The total polyphenol contents were also measured by means of Folin-Ciocalteu method. Moreover, all the concentrations of anthocyanins, flavonoids and polyphenols showed significantly positive correlations with antioxidant activities measured by DPPH˙, ABTS˙＋ and FRAP assays. This study provided information on anthocyanin and flavonoids compositions that will be useful for onion breeding.
基金Supported by the Scientific Research Projects of Basic Scientific Research Business Expenses of Undergraduate Universities in Heilongjiang Province(135309363)Fundamental Research Business Expenses of Heilongjiang Provincial Universities(Specialized Subjects of Plant Food Processing Technology)(YSTSXK201889)+2 种基金Heilongjiang General Undergraduate Universities Young Innovative Talents Training Plan(UNPYSCT-2018101)Natural Science Foundation of Heilongjiang Province(LH2019C067)Science and Technology Plan Project of Qiqihar City(NYGG-201915)。
文摘Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.
文摘The content of polyphenolic substances in commercial onions has been determined. The antioxidant activity of their ethanolic extracts, as well as their effects on the oxidation of edible corn oil during accelerated ageing was studied. Maceration of taxonomically identified commercial vegetable samples, previously peeled and thinly sliced, was carried out at ambient temperature, out of direct light, with occasional agitation and ultrasound, employing 95% ethyl alcohol as the extraction solvent, allowing them to stand for 7 days. The total polyphenolic contents were determined on the filtrated extracts using the Folin-Ciocalteau method. The antioxidant activity was evaluated on emulsions of ethanolic extracts of onion prepared in edible commercial corn oil, using sorbitan monooleate as emulsifying agent. The peroxide values were analyzed using the iodometric method;oxidation induction times were obtained from the peroxide evolution graphs, using the tan- gent method. Oil samples emulsified with ethanolic onion extracts showed an extension of the induction period. A 7-day ageing study at 45?C was additionally performed to determine the conjugated dienes on pure commercial corn oil and its emulsions by visible spectrophotometry. The spectral analysis showed an increase of the measured absorbancies in oil samples without additives and no change for the oils emulsified with onion extract. An increasing of diene values was observed for corn oil without additives during ageing;no changes in the value were observed in oils emulsified with onion extracts.
文摘This research was carried out to assess the effect of different varieties and mulching types on insect and disease infestation,and the yield of onions.The experiment was conducted in Sangkat TuekVil,KrongSiem Reap,in Cambodia.A 2×4 factorial in RCBD(Randomized Complete Blocks Design)was used to layout the trial,in which two varieties(Texas Early Grano 502 PRR and Earth F1)and four mulch types(non-mulch,rice Straw,silver plastic mulching and black plastic mulching)were used as the treatments.Application of these treatments was to enhance soil temperature,leaf number plant-1,stand count,bulb diameter,single bulb weight,insect incidence,disease incidence and bulb yield are different to all treatments.As the result,the bulb yields of onions among these treatments were found superior in Texas Early Grano 502 PRR combined with Black Plastic mulch followed by Texas Early Grano 502 PRR combined with silver plastic mulch and Texas Early Grano 502 PRR combined rice straw mulch,whereas the lowest was found in Earth F1combined with non-mulch.
基金supported by the Taishan Scholar Youth Expert Project(Grant No.tsqn202306243)the National Natural Science Foundation of China(Grants No.52275258 and No.51775290)the Open Fund of Collaborative Innovation Center for Shandong’s Main Crop Production Equipment and Mechanization(Grant No.SDXTZX-10).
文摘In green onion harvesting,the problems of easy dumping and low rate of clean digging can be encountered.In this paper,a kind of harvesting device for digging and pulling green onions,referred to simply as"the device",was designed.The device mainly consists of a digging shovel,screen bars,clamping conveyor belt,etc.This paper focuses on the analysis of the model forces of green onions and soil in the two states of the onion digging process without dumping and clamping.The key factors affecting the model state of onions and soil were identified as:screen bar length l_(2),screen bar inclination angleβ,and pulling point position x.Based on the discrete element simulation technology of EDEM,the mechanism-crop-soil model was established,and a single-factor simulation test was conducted to determine the range of values for each factor.Taking the advantages of field test and three-factor five-level orthogonal experimental design,the parameter combinations of green onion harvesting operation evaluation indices were optimized,including a pulling point position of 166 mm,screen bar length of 242 mm,and screen bar inclination angle of 14°.As the results of the field test show,the harvester operation was stable without congestion or damage,the harvesting effect of green onions was improved,and the clean digging rate reached 100%,which meets the agronomic requirements for onion harvesting and the expectations of users.
基金sponsored by the National Natural Science Foundation of China(Grant No.52275258)Taishan Scholar Youth Expert Project,Qingdao City Science and Technology to Benefit the People Demonstration and Guidance Special Project(Grant No.22-3-7-xdny-14-nsh)the National Natural Science Foundation of China(Grant No.51775290).
文摘In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green onions as the research object,and the main factors affecting the digging and harvesting effect were determined as the angle of digging,the dip angle of clamping carrier and the length of shovel.Thus,a complex simulation model of soil-green onion-digging mechanism system reflecting the state of harvesting was established,and the model was verified by testing soil compactness.The simulation tests were carried out by means of the complex simulation model of soil-green onion-digging mechanism system,making it clear that digging angle and the length of shovel have a extremely significant impact on the digging resistance,and the dip angle of the clamping carrier had a significant impact on the digging resistance.Through target optimization,the optimal combination of digging parameters was obtained,namely,the digging angle of 20°,the dip angle of clamping carrier of 25°and the shovel length of 70 mm,with the digging resistance of 1394 N at this moment.The field digging resistance test has showed that the average digging resistance is 1543 N with the average clamping damage rate of 1.27%and the average clamping loss rate of 0.44%,which can meet the requirements of green onion harvesting.
基金This work was supported by JSPS KAKENHI,grant number JP16H05001[Grant-in-Aid for Scientific Research(B)]JP16K15010[Grant-in-Aid for Exploratory Research].
文摘We supercooled fresh-cut onion at−5℃ for 12 h.After supercooling,the electric impedance properties of the samples were evaluated by electrical impedance spectroscopy over the frequency range of 42 Hz−5 MHz.The time-temperature profiles of samples indicated that the freezing point and supercooling point were−2.3℃±0.7℃ and−6.9℃±1.0℃,respectively.The results indicated that 34 of the 36 supercooled samples exhibited a definite circular arc in the Cole-Cole plot,which suggested that the cell membrane remained intact during supercooling.In the other two samples which did not exhibit a definite circular arc,the cell membrane had sustained serious damage during supercooling.Furthermore,there was large difference in drip loss percentage between supercooled samples exhibited a definite circular arc in the Cole-Cole plot and samples not exhibiting a definite circular arc.Our results suggest that fresh-cut onions can be supercooled at−5℃.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.22225109,22071109,92061101,22173016 and 22301084)the China Postdoctoral Science Foundation(No.2023M741232)。
文摘The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomic radius,higher metal coordinated numbers,lower metal valence states and other features allow the group IVB metal-based Keggin(IVB-Keggin)more space and unknown in terms of structure and performance.Herein,density functional theory(DFT)calculations were performed to explore the influences including cores,shells,caps,and terminal ligands,et al.on IVB-Keggin,and analyze the possibility of novel structure synthesis.From the perspective of multi-layer onion-like clusters,molecular energy level,host-vip interaction energy,surface charge and covalent bond polarity can be further adjusted to achieve the oriented design of functional IVB-Keggin.These insights are expected to provide theoretical support for experimental synthesis,opening a new perspective to understand the growth of Keggin.
基金Supported by Shangqiu Science and Technology Key Project(2023061827)。
文摘In this paper, the management points and cultivation difficulties of onion in different stages were discussed in detail from the aspects of onion cultivation seasons, cultivation methods, sowing and seedling raising, proper planting, field water and fertilizer management, stalk removal period, pest control, timely harvest and so on. This paper provides theoretical guidance for the high quality and high yield of onion in Huang-Huai area and data reference for further improvement of high-yielding onion cultivation technique system.
基金Supported by the Naito FoundationGrant-in-Aid for Scientific Research (22K05448)from Japan Society for the Promotion of Science.
文摘Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extracts as an antibulbing substance,the amount of which was synchronized with the bulb formation.Since allene oxide synthase inhibitor canceled the antibulbing activity ofα-linolenic acid,it was disclosed that jasmonic acid concerns this regulation.Structure-activity-relationship study revealed that its(3R,7S)stereochemistry is necessary for showing its antibulbing activity.It is concluded that(3R,7S)-jasmonate derived fromα-linolenic acid actually participates in the regulation of bulb formation.
文摘Water eutrophication is generally caused by the phosphorus excessive concentration. This phenomenon may affect the water quality. Hence, phosphorus removal from dam water which is affected by agricultural activities is not well known. The present work aimed to remove phosphorus from water using green Fe3O4 nanoparticles. Green iron oxide nanoparticles were prepared using the white and purple onion peels extracts. The stable iron oxide was selected using the antioxidant activity against 1,1-Diphenyl-2-Picrylhydrazyl. The SEM, XRD and FTIR analysis were used to characterize the nanoparticles. Phosphorus adsorption experiments were done in aqueous and real water solutions. The results showed that green iron oxide mediated by purple onion peels extracts possessed better antioxidant activities. The green magnetite (Fe3O4) nanoparticles obtained with the purple onion peels extracts have an average size of 15.81 nm and their surface were covered by phytochemicals compounds. In aqueous media, the optimum initial concentration of phosphate was 10 mg/L with a maximum adsorption percentage of 92%. The phosphate adsorption in aqueous solution by Fe3O4 was well described by the Freundlich model. The maximum adsorption capacity was 32.05 mg/g. In addition, the results also revealed that the maximum adsorption percentage of phosphorus in the dam water was 50.13%. Green Fe3O4 is therefore a good agent for removing phosphorus from polluted dam water.
文摘In arid and semiarid regions such as Niger, irrigated agriculture leads to soil salinization, particularly through irrigation water salts, and has adverse effects on crop production such as vegetable crops including onion. The main objective of this study, conducted in the experimental site of Djibo Hamani University of Tahoua in Niger, was to evaluate the effects of organic fertilizer on the growth and yield of onion crops irrigated with saline water. The experiment was performed in split-plot design to test tree type of fertilizer (chemical fertilizer, compost and millet glumes) and four (04) levels of irrigation water salinity in electrical conductivity values (ECw) (S0 = 0.28 dS/m as control, S1 = 2 dS/m, S2 = 4 dS/m and S3 = 6 dS/m). The growth parameters and bulb yield were evaluated during 4 months of onion cropping season. The results showed that the use of irrigation saline water significantly decreased the growth and bulb yield of onion crops. The yield in onion bulbs is 1.55 to 3.94 times higher with control (0.28 dS/m) than that with high saline water (ECw = 6 dS/m). Compared to control in irrigation water, the reduction in fresh onion bulb yield was 38.8, 52.6 and 63.5% respectively for ECw of 2, 4 and 6 dS/m. Furthermore, the application of organic fertilizers, particularly compost, improves salt-tolerance of onion crops in order to promote growth and bulb yield. Indeed, when irrigating onion crops with saline water (ECw of 2, 4 and 6 dS/m), the onion bulb yield is significantly higher under compost than under chemical fertilizer and glumes. At high irrigation saline water (ECw = 6 dS/m), the yield in onion bulbs is 1.9 and 2.1 times higher under compost than that under chemical fertilizer and glumes respectively. Thus, the compost is the promising organic amendment in a semiarid region of Tahoua in Niger to reduce the adverse effects of irrigation saline water on onion crop production.
文摘Onions are a horticultural crop of great economic, dietary and medicinal importance, and are highly prized by the Ivorian population. However, production remains low, due to a number of constraints, including parasitic attacks. The most frequent is fusariosis caused by Fusarium sp., a pathogen that causes enormous damage to onion crops. Faced with these attacks, chemical control appears to be ineffective, with consequences for human health and the environment. This is why the search for effective alternative methods that respect the environment and human health is so necessary. It is in this context that this study was carried out, with the general aim of controlling fusarium wilt in onion crops, with a view to improving onion production in Ivory Coast through the use of effective microorganisms. The experimental set-up used for this purpose was a fisher block with complete randomization, comprising three replicates. A fungal spore concentration of 106 spore/mL of Fusarium sp., three doses (1%;2.5% and 5% v/v) of EM and one dose of a chemical fungicide (30 mL/16L) were tested on young onion plants. Each block consisted of nine sub-plots with nine treatments. Health parameters (incidence and severity) and agronomic parameters (growth and yield) were assessed. Microbiological analysis of the EM revealed the presence of nine morphotypes of Trichoderma sp., Aspergillus clavatus, Aspergillus flavus, Aspergillus sp., Penicillium sp., Rhizopus sp., lactic acid bacteria of the Bacillus family and the yeast Saccharomyces cerevisiae. Field experimentation showed that the 5% EM microbial solution reduced the incidence and severity of fusariosis compared with the chemical fungicide, and proved to be the best. This dose reduced yield losses by 7.14%, while improving onion growth and yield by over 5%. The results demonstrated the ability of the EM solution to effectively control the causal agent of basal rot in onion crops.
文摘The paper describes some implementation aspects of an algorithm for approximate solution of the traveling salesman problem based on the construction of convex closed contours on the initial set of points (“cities”) and their subsequent combination into a closed path (the so-called contour algorithm or “onion husk” algorithm). A number of heuristics related to the different stages of the algorithm are considered, and various variants of the algorithm based on these heuristics are analyzed. Sets of randomly generated points of different sizes (from 4 to 90 and from 500 to 10,000) were used to test the algorithms. The numerical results obtained are compared with the results of two well-known combinatorial optimization algorithms, namely the algorithm based on the branch and bound method and the simulated annealing algorithm. .
