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25 April 2021, Volume 33 Issue 4 Previous Issue    Next Issue
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Crop Science
Animal Science
Horticultural Science
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Crop Science

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Variation analysis of grain weight, grain shape and protein content in recombinant inbred lines population of tartary buckwheat ZHENG Junqing, LI Ruiyuan, ZHENG Ran, LYU Dan, CHEN Qijiao, SHI Taoxiong, CHEN Qingfu 2021, 33(4):  565-575.  DOI: 10.3969/j.issn.1004-1524.2021.04.01 Abstract ( 1057 )   HTML ( 1511129162 )   PDF (1232KB) ( 2089 )   To reveal grain related traits affecting protein components and select excellent lines of tartary buckwheat, we analyzed the genetic variation and correlation of grain weight, grain shape and protein components using a recombinant inbred lines (XJ-RILs) population derived from a cross of Xiaomiqiao × Jinqiaomai 2. It was found that the 1 000-grain weight, grain length, grain width, length to width ratio, albumin, globulin, gluten and total protein content of Jinqiaomai 2 were significantly (P<0.05) higher than those of Xiaomiqiao, but there was no significant difference in the content of gliadin between the two parents. Among the XJ-RILs population, coefficient variation of grain weight and grain shape ranged from 5.79% to 29.97%. Tremendous transgressive segregation for all traits was observed in the XJ-RILs population. Thousand-grain weight was significantly (P<0.01) positively correlated to grain length, grain width, globulin, gluten, and total protein content. Grain length was significantly (P<0.01) positively correlated to gluten content. Grain width was significantly (P<0.01) positively correlated to globulin and total protein content. Cluster analysis based on the tested traits found that the XJ-RILs population could be divided into twelve groups at the Euclidean distance of 12.10-13.50. The mean value of grain length, length to width ratio, albumin and gluten content of group C9 were high. The mean value of 1 000-grain weight, globulin gluten and total protein content of group C10 were high. The mean value of 1 000-grain weight, grain length, length to width ratio, globulin and gliadin content of group C11 were high. The results could provide important experimental materials for further study on the genotypic differences of protein components content in grains. The excellent lines with protein components would be recommended as basic materials for processing different foods and health products. Figures and Tables | References | Related Articles | Metrics

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Effect of nitrogen application amount on grain filling characteristics of winter wheat at different panicle positions under drip irrigation YAO Zhao, WANG Chongyang, CUI Jing 2021, 33(4):  576-585.  DOI: 10.3969/j.issn.1004-1524.2021.04.02 Abstract ( 860 )   HTML ( 1393065986 )   PDF (864KB) ( 2107 )   In order to explore the effects of nitrogen application on grain filling characteristics of winter wheat under drip irrigation at different panicle positions, Xindong22 and Xindong43 were used as test materials. The grain filling process of winter wheat was fitted by using Logistic equation under five nitrogen application amount (0, 150, 300, 450, 600 kg·hm-2, denoted as N0, N1, N2, N3, N4, respectively). It was shown that under drip irrigation, the grains in the central part of panicles showed advantages in weight. The grain filling parameters in the fast-increasing period and the slow-increasing period varied under different nitrogen application amount for different wheat cultivars. The optimal nitrogen application amount for Xindong22 and Xindong43 was 450 kg·hm-2 and 300 kg·hm-2, respectively. Under these treatments, the grain weight in the upper, middle and lower part of panicle was increased, and the duration of grain filling was extended, so that the yield potential could be realized. Figures and Tables | References | Related Articles | Metrics

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Identification of soybean LAZ1 gene family and functional analysis of GmLAZ1-9 YANG Xinxia, ZHANG Bin 2021, 33(4):  586-594.  DOI: 10.3969/j.issn.1004-1524.2021.04.03 Abstract ( 1877 )   HTML ( 1145143297 )   PDF (9517KB) ( 2160 )   In the present study, the BLAST search was performed in the soybean genome database and LAZ1 gene family members were obtained. Bioinformatics analysis and expression pattern detection were performed, and transgenic Arabidopsis was used to verify gene function. It was shown that a total of 17 soybean LAZ1 genes were identified, namely GmLAZ1-1 to GmLAZ1-17. All of the GmLAZ1 genes were unevenly distributed on 12 chromosomes. The LAZ1 family members in soybean were phylogenetically divided into three evolutionary clades, and the members in the same clades shared similar gene and protein structures. The analysis of cis-regulatory elements indicated that multiple abiotic stress-related cis-acting elements presented in the promoters of soybean LAZ1 genes, such as ABRE, ARE, LTR, G-box, etc. Semi-quantitative PCR results showed that the expression of GmLAZ1-5, GmLAZ1-9, GmLAZ1-11, and GmLAZ1-13 was up-regulated after salt treatment. Moreover, GmLAZ1-9 enhanced salinity tolerance in transgenic Arabidopsis, which provided basis for further exploration of the functions and molecular mechanisms of other LAZ1 genes. Figures and Tables | References | Related Articles | Metrics

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Genetic analysis of stripe rust resistance genes in 2 spring wheat germplasm resources at adult stage ZHAO Ke, LI Qiurong, HOU Lu, BAI Yaobo, JIANG Liling, WEI Youhai, GUO Qingyun 2021, 33(4):  595-601.  DOI: 10.3969/j.issn.1004-1524.2021.04.04 Abstract ( 925 )   HTML ( 201 )   PDF (697KB) ( 2019 )   Analysis of the genetic rules of the stripe rust resistance genes of spring wheat at adult stage can provide theoretical basis for the utilization of stripe rust resistance genes. In this study, stripe rust genes genetic analysis was carried out in the field for 2 years by using F2:3 generation segregating populations made by susceptible variety Taichung29 crossed with MY004730, and ZM018243 crossed with MY004730. Results showed that, disease severity and infection type of the 2 F2:3 populations showed discrete distribution and didn’t conform to normal distribution. It is speculated that resources the stripe rust resistance of MY004730 and ZM018243 at adult stage has qualitative character. Resistance and susceptible segregation ratio of F2:3 population constructed by crossing of Taichung29 and MY004730 was 3R:1S, indicating that resistance of MY004730 to stripe rust at adult plant stage was controlled by 1 dominant gene; while F2:3 population by ZM018243 crossing with MY004730, the single plants/lines resistance and susceptible segregation ratio was 9R:7S, that is conformed to 2 pairs of dominant genes work together. Therefore, it is that ZM018243 may contain 1 pair of dominant stripe rust resistance gene adult plant stage. According to the genetic analysis results, fuether research can be focused on molecular mapping of resistance genes to find markers closely linked to resistance genes, and serve for molecular marker-assisted selection breeding. At the same time, resistant gene aggregation materials can be screened from the resistance-resistance crossing population, hence provide excellent resistance materials. Figures and Tables | References | Related Articles | Metrics

Animal Science

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Validation and function prediction of circ-FBLN2 in duck adipocytes HU Xiaodan, WANG Laidi, YANG Ting, BAI Hao, JIANG Yong, WANG Zhixiu, WANG Shasha, CHEN Guohong, CHANG guobin 2021, 33(4):  602-609.  DOI: 10.3969/j.issn.1004-1524.2021.04.05 Abstract ( 843 )   HTML ( 41 )   PDF (1381KB) ( 1731 )   Circular RNA (circRNA) is a kind of circular non-coding RNA characterized by head to tail connection during the transcription process, which plays an important role in many biological processes and diseases. Based on the results of circRNA sequencing during pre-adipocyte differentiation, circ-FBLN2 encoded by FBLN2 was selected for validation analysis. The conjugated sequence was obtained by PCR amplification and pyrosequencing. And circ-FBLN2 was further verified by RNase R digestion experiment. The results of nuclear and cytoplasmic separation experiment showed that circ-FBLN2 mainly existed in cytoplasm, and its expression level of duck adipocyte was significantly decreased after differentiation. There was a certain difference in the expression level of different tissues in Cherry Valley duck, it was mainly expressed in fat and leg muscle. Bioinformatics analysis showed that the predicted target genes and circ-FBLN2 were involved in MAPK, Toll-like receptor and cytokine-cytokine receptor interaction pathways and other signaling pathways. All these announced that circ-FBLN2 may indirectly regulate the differentiation of duck adipocytes by regulating the target genes. Figures and Tables | References | Related Articles | Metrics

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Effects of oral Panax notoginseng saponins on immunity of large yellow croaker (Pseudosciaena crocea) CHEN Xiuxia, CHI Hongshu, XU Binfu, XIE Anhua, FANG Donglan, GONG Hui 2021, 33(4):  610-617.  DOI: 10.3969/j.issn.1004-1524.2021.04.06 Abstract ( 790 )   HTML ( 60 )   PDF (964KB) ( 1710 )   In this study, large yellow croaker (Pseudosciaena crocea) were fed with diets containing 0,10,50,250 mg·kg-1 Panax notoginseng saponins (PNS) for 14 d. To evaluate the effects of PNS on the immunity of large yellow croaker, the expression of some immune-related genes in the liver, spleen and head kidney tissues, the activities of some serum immune factors and the resistance against Pseudomonas plecoglossicida were determined. Results showed that the activities of serum superoxide dismutase (SOD), lysozyme (LZM), acp acid phosphatase (ACP) and alkaline phosphatase (AKP) in the experimental groups were not significantly different from the control group; the expression of Mx in spleen of fish fed with 250 mg·kg -1 PNS was significantly higher than that of control; the expression of Mx in spleen of fish fed with 50 mg·kg -1 PNS and in head-kidney of fish fed with 10 mg·kg-1 PNS were higher than that of control, but not significantly; the expression of TNF-α in all the exprimental groups were lower than that of control, but not significantly; the expression of IL-10 and MHCⅡ-α in all the exprimental groups were not significantly different from the control. The mortalities of the exprimental fish challenged with P. plecoglossicida were not significantly different from the control. It was indicated that feeding diets containing 10-250 mg·kg -1 PNS for 14 d did not improve the immunity of large yellow croaker Figures and Tables | References | Related Articles | Metrics

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Establishment and application of multiplex PCR-capillary electrophoresis for 7 swine diseases TU Teng, YIN Qingqing, ZHANG Pengfei, WANG Yin, YANG Zexiao, YAO Xueping, LUO Yan 2021, 33(4):  618-631.  DOI: 10.3969/j.issn.1004-1524.2021.04.07 Abstract ( 1099 )   HTML ( 28 )   PDF (4737KB) ( 1680 )   The aim of this study was to develop a multiple PCR assay on a basis of capillary electrophoresis for simultaneous detection of seven pathogens of swine infectious diseases, including Streptococcus suis(SS), Classical swine fever virus(CSFV), Japanese encephalitis virus(JEV), Porcine reproductive and respiratory syndrome virus(PRRSV), Haemophilus parasuis(HPS), Porcine rotavirus(PoRV), Salmonella(SE). Firstly the conservative sequences of the 7 reference pathogens were analyzed to design 7 pairs of specific primers. Subsequently, the specific chimeric primers were obtained by adding universal primer sequences in 5' end of each specific primer. Gradient PCR amplification was adopted to optimize annealing temperature. The primer concentrations were optimized by orthogonal test. The sensitivity test was performed by using serially diluted standards (10 7-10-1 copies·μL-1). Cross reactivity test was performed by using random mixed templates that orginate from cDNA or DNA of these 7 pathogens. Specificity test was performed by detection of some other common pathogens, including PEDV, TGEV, ASFV plasmid, E. coli. Repeatability test was performed by using serially diluted standards as templates to be amplified triplicates. The results indicated that the optimum annealing temperature was 58.3 ℃. Detection limit of this assay was 10 3 copies·μL-1, when 7 positive results were visible from identical lane. With a variety of control samples, the results of positive samples showed specificity peak in contrast of the negative results of all the negative control samples. In addition, neither cross reactivity nor unspecific amplification were detected within these 7 kinds of random mixed templates. the differences among triplicate experiments were small and low. The test results of the 63 clinical samples were exactly the same with the results obtained by national standards. As is indicated in the results, it is an effective toll applied to differential diagnosis rapidly for clinical samples and epidemiological investigation. Figures and Tables | References | Related Articles | Metrics

Horticultural Science

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Analysis of correlation between inflorescence stem strength and melatonin content of herbaceous peony SHI Wenbo, GAO Tianxiang, HU Yunyu, XU Cong, TAO Jun, ZHAO Daqiu 2021, 33(4):  632-639.  DOI: 10.3969/j.issn.1004-1524.2021.04.08 Abstract ( 1775 )   HTML ( 84 )   PDF (2739KB) ( 1777 )   The straightness of inflorescence stem is an important index affecting the cut flower quality of herbaceous peony (Paeonia lactiflora Pall.), and the stem strength is a physical standard to measure the stem straightness. To investigate the relationship between inflorescence stem strength and melatonin content of P. lactiflora, in this paper, two groups of P. lactiflora cultivars with high and low inflorescence stem strengths were used to measure the stem strength, morphology indexes, photosynthetic characteristics, lignin and melatonin contents. The results showed that the stem diameter, stem weight, photosynthetic capacities, lignin contents and melatonin contents of the P. lactiflora cultivars with high stem strength were significantly higher than those with low stem strength. Besides, correlation analysis showed that the inflorescence stem strength was positively correlated with melatonin content, and both of them were significantly positively correlated with lignin content. The results indicated that melatonin may indirectly affecting inflorescence stem strength by regulating lignin synthesis in P. lactiflora, which laid a theoretical foundation for the regulation of P. lactiflora inflorescence stem strength. Figures and Tables | References | Related Articles | Metrics

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Principal component analysis and cluster analysis for evaluating free amino acids of 16 pepper materials ZHANG Ting, LIU Huiqin, GUO Qinwei, LI Chaosen, ZHANG Xinhui, XIANG Xiaomin, ZHAO Dongfeng, WAN Hongjian 2021, 33(4):  640-650.  DOI: 10.3969/j.issn.1004-1524.2021.04.09 Abstract ( 1122 )   HTML ( 1745260552 )   PDF (1052KB) ( 2142 )   In order to analyze the differences in the comprehensive quality of free amino acids in 16 different peppers, the free amino acids (FAAs) were determined by liquid chromatography-tandem mass spectrometry, and the systematic evaluation were performed by principal component analysis (PCA) and cluster analysis. The results showed that 16-17 kinds of FAAs were detected in all kinds of peppers, and the total content ranged from 10.57 to 25.68 mg·g-1. There were significant differences in the contents of free amino acids (FAA), but no obvious difference in species in the 16 cultivars of peppers, among which the highest contents of total free amino acids, essential amino acids, limiting amino acids were observed in the cultivar D1, D4 had the highest content of taste-active amino acids. Three principal components (F1, F2, F3) were extracted by PCA, which contributed cumulatively to 83.501% of the total variance. The comprehensive evaluation model was established as F=0.775F1+0.126F2+0.0969F3. The comprehensive scores of D4, D1 and D2 were ranked as the top three. Cluster analysis was used to divide these daylily cultivars into 3 groups, and the results were consistent with the PCA, which reflected the distinction among different germplasms of peppers. Figures and Tables | References | Related Articles | Metrics

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Image perception of scenic villages based on visitor-employed photography method: a case study on Yueliangqiao Village ZHANG Jianguo, LIN Jianan, CHEN Jing 2021, 33(4):  651-660.  DOI: 10.3969/j.issn.1004-1524.2021.04.10 Abstract ( 605 )   HTML ( 37 )   PDF (1223KB) ( 1667 )   The construction of beautiful villages in Zhejiang Province has entered the era of “Wancun scenic spots”. As one of the first 3A level scenic villages in Zhejiang Province, understanding tourists’ perception of the tourism image of Yueliangqiao Village can provide certain reference for the construction and development of it in the future. In this paper, the visitor-employed photography (VEP) method was used to study the image perception of tourists in Yueliangqiao Village. The results showed that the volunteers paid the highest attention to the rural residential buildings and residential buildings, and paid more attention to the intuitive feelings, rural environment, moon theme and plants; the volunteers’ evaluation of scenic villages was mainly positive perception, but there was still a small part of negative perception; there was a little deviation between the content of volunteers’ attention and the content to be present; the service of reception and explanation in scenic villages was not perfect. Therefore, some suggestions were put forward, such as systematically displaying the tourist attractions, emphasizing the theme of “Tianmu Yuexiang”, improving the team reception and explanation service, so as to provide reference for the sustainable management and development of the scenic villages in the future. Figures and Tables | References | Related Articles | Metrics

Plant Protection

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Identification of causal agent and dynamics survey of celery stalk basal rot and screening of fungicides WANG Guorong, FENG Xiaoxiao, WU Huiming, CAO Tingting, LI Qian, ZHENG Yongli 2021, 33(4):  661-669.  DOI: 10.3969/j.issn.1004-1524.2021.04.11 Abstract ( 1323 )   HTML ( 72 )   PDF (4694KB) ( 1757 )   In order to characterize the causal agent and occurrence of celery stalk basal rot in Hangzhou, Zhejiang province and effective fungicides, the dynamic survey of celery stalk rot in field was investigated in 2017-2018, the pathogen was isolated and identified by tissue separation, morphological and phylogenetic analysis and its pathogenicity was determined by mycelial suspension inoculation, the inhibition of 29 common fungicides were determined by mycelial growth rate method, and field control experiment were conducted as well. The results showed that frequent occurrence of celery stalk basal rot was during June to September. Fusarium oxysporum was the pathogenic fungus that caused celery stalk basal rot. In vitro screening test showed that thiophanate-methyl and tebuconazoles fungicides had the best inhibitory effect on mycelial growth of pathogenic F. oxysporum, and field application of 75% trifloxystrobin·tebuconazole WDG and 70% thiophanate-methyl WP had better control effect on celery stalk basal rot. Figures and Tables | References | Related Articles | Metrics

Environmental Science

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Effect of drip fertigation with organic liquid fertilizer on soil environment, fruit yield, quality, and economic benefits of citrus cv. beni madonna XI Hui, LI Guolei, TAO An’an, GU Pin, HAN Dongdao, LI Na, CHEN Xijing 2021, 33(4):  670-677.  DOI: 10.3969/j.issn.1004-1524.2021.04.12 Abstract ( 1565 )   HTML ( 66 )   PDF (835KB) ( 1791 )   Based on the nutritional requirement, the organic liquid fertilizer made from biogas, rotting citrus and chemical fertilizers, was drip fertigated to test its effect on soil fertility, fruit yield and economic income of citrus cv. beni madonna. Four treatments were set: CK, no fertilization; F1, traditional fertilization (spread application, N 480 kg·hm-2, P2O5 480 kg·hm-2, K2O 480 kg·hm-2); F2, balanced chemical fertilization (N 480 kg·hm-2, P2O5 180 kg·hm-2, K2O 540 kg·hm-2, drip fertigation); F3, organic liquid fertilization (N 400 kg·hm-2, P2O5 120 kg·hm-2, K2O 380 kg·hm-2, drip fertigation). The results showed that fertilization could enhance soil fertility, increase citrus fruit yield and economic income, but would decrease soil pH and soil organic matter content. Compared with F1 and F2 treatments, it achieved higher soil pH, and increased economic income by 6.73%-25.39% under F3 treatment. Besides, there was no significant difference on fruit quality within treatments. Although drip fertigation with organic liquid fertilizer could reduce fertilizer input, improve soil fertility, elevate soil pH, and increase the fruit yield and economic income, addition of other organic fertilizers should be well considered. Figures and Tables | References | Related Articles | Metrics

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Effects of staw-derived biochar on ammonia volatilization in tropical soil-rice system WU Peicong, ZHANG Peng, SHAN Ying, ZOU Ganghua, DING Zheli, ZHU Zhiqiang, ZHAO Fengliang 2021, 33(4):  678-687.  DOI: 10.3969/j.issn.1004-1524.2021.04.13 Abstract ( 1376 )   HTML ( 724992 )   PDF (1020KB) ( 2090 )   Ammonia volatilization is one of the main pathways of nitrogen loss in rice field. As a practical agronomic measure to improve soil quality and agricultural sustainability, the application of straw-derived biochar may effectively reduce ammonia volatilization emission. In this study, six treatments including no nitrogen fertilization (ON), only chemical fertilizer (CT), biochar (BI), biochar+chemical fertilizer (CBI), straw (ST) and straw+chemical fertilizer (CST) were set up in the soil column experiment to study the effects of direct returning and carbonized returning of rice straw on ammonia volatilization in tropical soil-rice system. The results showed that compared with straw direct returning to the field, biochar application reduced ammonia volatilization flux and accumulated ammonia volatilization amount in the rice field. Compared with CT, CBI treatment resulted in a 4.1% reduction in accumulated ammonia volatilization amount, mainly due to biochar’s unique physic-chemical properties, which decreased the concentration of soil ammonium nitrogen (NH4+-N) through adsorption. Therefore, application of straw-derived biochar is an effective way to control ammonia volatilization and to reduce agricultural non-point source pollution in tropical soil-rice system. Figures and Tables | References | Related Articles | Metrics

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Effects of integrated rice-redclaw crayfish farming system on soil nutrients, carbon pool and rice quality LI Baoxian, WANG Baojun, HUAI Yan, SHEN Yaqiang, ZHANG Hongmei, CHENG Wangda 2021, 33(4):  688-696.  DOI: 10.3969/j.issn.1004-1524.2021.04.14 Abstract ( 2073 )   HTML ( 1140885278 )   PDF (1035KB) ( 2115 )   The integrated rice-shrimp farming systems has been greatly developed in recent years. Redclaw crayfish, a type of valuable freshwater economic shrimps, has a broad development prospect. The study of soil nutrients, carbon pool and rice quality in the integrated rice-redclaw crayfish farming system is of great significance for fertilization management and regulation of the soil nutrient cycling and balancing. In this study, the field experiment was conducted to study the dynamic changes of soil nutrients and carbon pool and rice quality under the integrated rice-redclaw crayfish farming system and rice monoculture pattern. Results showed that the contents of soil ammonia nitrogen and soil available phosphorus significantly (P<0.05) increased by 24.16% and 48.10% under integrated rice-redclaw crayfish farming system during the whole growth period. The contents of soil nitrate nitrogen, available potassium, easy oxidation of organic carbon, dissolved organic carbon and microbial organic carbon was reduced by 1.00%, 16.40%, 3.93%, 16.59% and 52.80%, respectively, compared with the rice monoculture pattern. In terms of rice yield and quality, the rice-redclaw crayfish farming system could reduce yield, but the chalkiness of rice could be reduced, and the rice quality was better than that of rice monoculture pattern. In conclusion, under the experimental conditions, the integrated rice-redclaw crayfish farming system could increase soil ammonia nitrogen and available phosphorus content, reduce the content of active carbon pool in the rice field. Besides, the integrated rice-redclaw crayfish farming system could reduce the chalkiness of rice and improve the rice quality. Figures and Tables | References | Related Articles | Metrics

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Effect of ammonium polyphosphate on phosphorus adsorption and desorption in laterite and calcareous soil YANG Yibin, CHEN Xiaojuan, DENG Lansheng, LIN Jingjing, CHENG Fengxian, HU Kewei, ZHANG Chenglin, TU Panfeng 2021, 33(4):  697-703.  DOI: 10.3969/j.issn.1004-1524.2021.04.15 Abstract ( 591 )   HTML ( 19 )   PDF (694KB) ( 1864 )   In the present study, the soil culture experiments were conducted to study the adsorption and desorption behaviors of ammonium polyphosphate (APP) and monoammonium phosphate (MAP) in calcareous soil and laterite, to provide theoretical reference for the evaluation of phosphorus availability. Six treatments were introduced in this work according to the materials used: APP1 (mainly high polymer), APP2 (mainly oligomeric), APP3 (mainly low, medium, and high polymer), MAP, A-M (APP3 and MAP mixed with the ratio of 1∶1 based on the content of P2O5), and CK (blank control). All the treatments set the same rate of nitrogen and phosphorus except CK. After 50 days of soil cultivation, the adsorption and desorption characteristics of phosphorus were measured. The results showed that the equations of Langmuir, Freundlich, and Temkin could well fit the adsorption characteristics of soil phosphorus in different soils, and the Freundlich equation had the best fitting effect with a correlation coefficient of 0.86-0.98. In calcareous soil (except CK), the soil with APP1 had the strongest adsorption capacity, while the soil with A-M had the weakest adsorption capacity, the largest phosphorus desorption, and the highest phosphorus desorption rate. In laterite (except CK), the soil with APP1 showed the strongest adsorption capacity, and the soil with APP2 showed the weakest adsorption, the largest phosphorus desorption, and the highest phosphorus desorption rate. The results indicated that the application of MAP with APP with uniform polymerization degree distribution and high aggregate content could reduce the adsorption of phosphorus in calcareous soil to improve the availability of phosphorus. While APP with low polymerization degree could lower the adsorption of phosphorus by laterite, and maintain the balance of phosphorus. Figures and Tables | References | Related Articles | Metrics

Food Science

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Effects of different gas composition storage on physiological changes and quality of Dog-head jujube fruit FENG Luoluo, GAO Haiyan, ZHANG Runguang, YAN Xinpeng, ZHANG Yani, HAN Qiqi, ZHANG Youlin 2021, 33(4):  704-713.  DOI: 10.3969/j.issn.1004-1524.2021.04.16 Abstract ( 835 )   HTML ( 40 )   PDF (2438KB) ( 1950 )   The effects of different gas composition storage on physiological changes and quality of Dog-head jujube fruit were studied. Shaanxi Yan’an Dog-head jujube was selected as the material to investigate the respiration type, and the storage effect of different gas ratios on the content of sugar, acid, vitamin C (VC) and the activity of main enzymes. The sensory evaluation was carried out after the storage. Results showed that Dog-head jujube was non-climacteric fruit. The ratio of 10%O2+90%N2 gas could slow down the decreasing rate of fruit hardness and titratable acid content, maintain the content of reducing sugar and VC, inhibit the activities of polygalacturonase (PG), peroxidase (POD) and polyphenol oxidase (PPO), and enhance catalase (CAT) activity. The fresh fruit was stored under the condition of low temperature of -1~0 ℃, relative humidity of 90%~95% and gas ratio of 10% O2+90% N2 for 80 d. After storage, the good fruit rate was 88.6%, freshness index was 0.59, and sensory evaluation quality was good. Figures and Tables | References | Related Articles | Metrics

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Identification of functional effects of bovine whey protein based on odor information of mouse feces LONG Ming, ZHANG Peng, LIU Yuanlin, BAI Xiaoqin, ZHANG Fumei, TIAN Xiaojing, CAO Hong, ZHOU Xueyan, MA Zhongren, LUO Li, SONG Li, Nurul Izza NORDIN 2021, 33(4):  714-723.  DOI: 10.3969/j.issn.1004-1524.2021.04.17 Abstract ( 707 )   HTML ( 13 )   PDF (2035KB) ( 1750 )   In order to establish a new method for nondestructive evaluation of bovine whey protein function based on odor information, the gas sensor array of electronic nose (E-nose) was used to track the flavor of fecal samples of mice affected by bovine whey. The results showed that compared with the NS group, the superoxide dismutase (SOD) activity in the serum of the bovine whey protein test group was increased, and the malondialdehyde (MDA) content was significantly decreased. The bovine whey protein has antioxidant capacity in the mouse serum. The electronic nose experiment showed that the effects of sample weight, headspace generation time, headspace generation volume and flow rate carrier gas on the response signal of the sensor were studied by one-way ANOVA. It was found that the response of E-nose sensors was affected by sample weight, headspace generation time, headspace generation volume and flow rate carrier gas significantly, except for S5. The experiment condition for E-nose was optimized as followed: 1 sample, 10 min of headspace generation time, 150 mL of headspace generation volume and 200 mL·min-1 of carrier gas flow rate. To distinguish the difference of doses of bovine whey protein and control group, principle component analysis (PCA) and canonical discriminant analysis (CDA) could discriminate the samples of different groups, and could distinguish the fecal samples of mice of different cycle groups with different gavage doses. For the prediction of the weight, the multiple linear regression analysis (MLR) was employed, and effect predictive model was built for weight (R2=0.122 7), the effect was acceptable. The typical correlation analysis results showed that the odor information of electronic stool had an excellent correlation with its physiological indicators, and the correlation was strong. Based on the odor of fecal samples of mice, it’s possible to distinguish the effect of bovine whey protein treatment with the controls, providing an idea for the non-invasive evaluation of functional food in vivo. Figures and Tables | References | Related Articles | Metrics

Biosystems Engineering

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Design and experiment of small-sized potato harvester suitable for hilly and mountainous areas WANG Haiyi, ZHANG Zhaoguo, IBRAHIM Issa, XIE Kaiting, Wael EL-KOLALY, CAO Qinzhou 2021, 33(4):  724-738.  DOI: 10.3969/j.issn.1004-1524.2021.04.18 Abstract ( 688 )   HTML ( 23 )   PDF (7171KB) ( 1774 )   In view of the problems of low applicability, low exposure rate, high damaged rate, serious skin breakage, and low mechanical harvest level in imported potato harvester model operations, a small-sized potato harvester suitable for hilly and mountainous areas was designed, which mainly included three-point suspension device, excavating device, exciting separating screen, multi-stage vibration adjusting device, excavating adjusting device, gearbox, transmission device, etc. The parameter determination and type selection design of excavating device and lifting and separating device were carried out according to the specific operation requirements. The excavating shovel was a second-order shovel with an arc transition surface, which enhanced the performance of soil crushing and shearing, and improved soil guiding ability. The resistance model and kinematics model of the excavating device during work were established, and the finite element analysis was performed on the excavating device. Analysis showed that the maximum strain of the excavating shovel was 5.05×10-8 m·m-1, the maximum stress was 9 327.7 Pa, and the maximum deformation was 2.98×10-4 mm. The kinematic model of the potato lifting process was established to analyze the movement forms of the potato-soil mixture, and the quadratic orthogonal rotation combination test was designed with calculated parameter. Based on the response surface analysis of each test index, the main factors affecting exposure rate were operating speed and slope angle of screen surface; the main factors affecting damaged rate were operating speed and slope angle of screen surface; the main factors affecting the breakage rate were the penetration angle and the slope angle of screen surface. The field test showed that, when the operating speed was 1.05 mm·s-1, the penetration angle was 17°, and the slope angle of screen surface was 15°, the exposture rate was 96.7%, the damaged rate was 1.3%, and the skin breakage rate was 1.5%, which were better than the national standard, and met potato harvesting operation requirements. Figures and Tables | References | Related Articles | Metrics

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Design and experiment on scoop hole-wheel precision seed-metering device for rice LIU Jun, ZHU Dequan1, YU Congyang, XUE Kang, ZHANG Shun, LIAO Juan 2021, 33(4):  739-752.  DOI: 10.3969/j.issn.1004-1524.2021.04.19 Abstract ( 939 )   HTML ( 21 )   PDF (4669KB) ( 1889 )   In order to solve the problems of poor seed filling performance and low precision in high-speed seeding process, a scoop-hole-wheel precision seed-metering device for rice was designed. A scoop was used to disturb the seed layer to increase the fluidity between rice seeds and enhance the performance of seed filling. The basic structure and working principle of the seed metering device were expounded, the structural parameters of key components such as seeding wheel, scoop, hole, seed protection guard were determined, and the mechanical model of the seed-metering process was established. The numerical simulation experiments based on discrete element method were carried out by using Gangyou 898 as the research object. Taking rotation speed and hole inclination of seeding wheel as the experimental factors, single-factor experiments, comparative experiments and orthogonal rotation combined experiments with two factors and five level were carried out. The regression model between experimental factors and seeding performance index was established. The influence regulation of experimental factors on the seeding performance was analyzed by the response surface method, and the best combination of parameters was determined through the multi-objective optimization method. The optimization results showed that the seeding performance of seed-metering device was the best when rotation speed of the seeding wheel is 25.94 r·min-1 and hole inclination of the seeding wheel was 34.75°, and seeding qualified rate, replay rate and missing rate were 87.55%, 9.79%, and 2.66%, respectively. In order to verify the reliability of the simulation results and the adaptability of the seed-metering device, rice seeds of three varieties of Fengliangyou 3948, Gangyou 898 and Gangyou 3551 were used as test materials to perform the bench tests and field tests. The test results showed that the results of bench tests were basically consistent with the simulation results, and seeding qualified rates of Fengliangyou 3948, Gangyou 898 and Gangyou 3551 were 84.40%, 84.53% and 83.74%, respectively, their sowing qualified rates of field test were 81.34%, 82.13% and 80.67%, respectively. Sowing performance of three varieties rice seeds all met the requirements for precision sowing of rice. This research results could provide reference for structure optimization and performance improvement of the scoop hole-wheel precision seed-metering device for rice. Figures and Tables | References | Related Articles | Metrics

Agricultural Economy and Development

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Spatio-temporal evolution characteristics of cultivated land use transition in Zhejiang Province MIAO Miao, ZE Hanlu, WU Yonghua 2021, 33(4):  753-760.  DOI: 10.3969/j.issn.1004-1524.2021.04.20 Abstract ( 752 )   HTML ( 172166 )   PDF (9637KB) ( 2052 )   Based on the land use data of Zhejiang in 2000, 2010 and 2020, geo-information tupu model regarding cultivated land use transition was constructed, and the spatio-temporal evolution characteristics of cultivated land use transition in Zhejiang Province were revealed by using ArcGIS 10.6 software. It was shown that the cultivated land use transition in Zhejiang mainly consisted of forestland occupation and supplementation, as well as transition to construction land, with a C-shaped spatial agglomeration, and presented remarkable characteristics of east-occupation-west-supplementation, and the spatial distribution changed from Hangjiahu plain, Hangshaoyong region and Yongwen coastal economic belt to the basin hilly region. The amount and separation degree of cultivated land use transition increased, and the occupation area was greater than the supplementation area, yet the gap narrowed. The cultivated land use transition mainly happened in the period of 2010-2020. The forestland was the main source for cultivated land supplementation, and the occupation of cultivated land by construction land was a major concern. In view of this, it was suggested that the stock should be revitalized, the increment should be promoted, and the variables should be tackled. What’s more, the allocation of cultivated land resources should be optimized and the justice of land use should be ensured to finally realize the bidirectional balance of cultivated land supplementation and construction land safeguard, as well as the coordination of trinity system, which consists of ecological protection, food security and development space. Figures and Tables | References | Related Articles | Metrics

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Impact of rural industrial convergence on farmers’ income growth: an empirical study based on spatial effect and threshold effect WANG Liying, DING Shuyu, LIU Houping 2021, 33(4):  761-776.  DOI: 10.3969/j.issn.1004-1524.2021.04.21 Abstract ( 810 )   HTML ( 24 )   PDF (1573KB) ( 1886 )   The impact of rural industrial convergence on farmers’ income growth is a focus both in theory and practice. Based on the data of 30 provinces (autonomous regions, municipalities) in China (Hongkong, Macao, Taiwan, Tibet not excluded), the spatial and threshold effects of the impact of rural industrial convergence on farmers’ income were empirically analyzed by using spatial measurement models and threshold models in this study. It is shown that the level of rural industrial convergence in China has the characteristics of “east high and west low”, and it has positive correlation with space. From the regional perspective with single province (autonomous region, municipality) as study unit, the level of rural industrial convergence has a positive effect on farmers’ income in the region, yet it has no spatial spillover effect within regions. The level of rural industrial convergence has a positive effect on the proportion of net business income in disposable income in the region, yet it has a negative spatial spillover effect within regions. The level of rural industrial convergence has a negative effect on the proportion of wage income in disposable income both in the region and within regions. Under different operation scales, the level of rural industrial convergence has a threshold effect on farmers’ income. Therefore, to promote the convergence of rural industry and to increase farmers’ income, it is necessary to raise the level of rural industrial convergence, strengthen the links within regional convergence activities, exert the demonstration effect of successes, promote moderate scale operation, and realize the optimal allocation of factor resources. Figures and Tables | References | Related Articles | Metrics