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Table of Content

    15 January 2021, Volume 23 Issue 1
    Change Law and Trend of Grain Production in China Since the Founding of the People's Republic of China
    WANG Yongchun1, LI Jing2, WANG Xiudong3*
    2021, 23(1):  1-11.  DOI: 10.13304/j.nykjdb.2020.0935
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    This paper analyzed the change law of grain production and put forward the development trend. Since the founding of new China from 1949, the grain production has increased in fluctuations and the yield per unit played an important role in it.  The variety structure has been continuously optimized according to market demand, and the main production area has been moving northward, and Heilongjiang has become a veritable Beidacang. The grain function has also changed from only satisfying food to feed industrial materials, and then to the international market method. The macro-management policy of food has changed from the tight management and control during the period of shortage to the tightly balanced management and control of the gradual marketization, and then to the strategic response to the international market. The grain production faces many problems and challenges such as resource shortage, low enthusiasm for growing grain, increased consumption and improved quality standards, and the rise of international protectionism. In  future, the strategic security status of grain production will further rise, the efficiency of resource utilization will gradually increase, the production of staple grains will develop steadily, the varieties of minor cereals will be diversified, and technology will remain the decisive factor for grain production in the future. Some suggestions to improve the level of food security in China were put forward, which included increasing the enthusiasm of farmers and local governments to grow grain, encouraging educated young people to go to the rural areas, improving the quality of farmers, encouraging enterprises to invest in the grain industry, and strengthening research, development and application of science and technology, and promoting green development of grain production.
    Current Status, Problems and Countermeasures of Algae Industry Development in China
    LI Han, QING Ping, ZHANG Xiaoheng*, KUANG Yiting
    2021, 23(1):  12-20.  DOI: 10.13304/j.nykjdb.2019.0896
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    China is a big country in algae production, consumption and trade. As an important part of national strategic industry, algae industry is facing many new opportunities for development as well as many problems to be solved urgently. This paper firstly sorted out the current situation of algae cultivation, processing, trade and consumption in China, and then analyzed the demand characteristics of consumers in depth according to the survey data. The results showed that: the yield and area of algae culture in China were on the rise, and the yield of each species was uneven. At the same time, algae processing products were increasingly rich, trade advantages were obvious, but the income of algae practitioners was low. Although consumers had a low level of understanding of algae products, they did not reject them. The packaging and brand construction of algae products were poor. Nutrition and safety were the main reasons for consumers to eat algae products. Based on this, this paper pointed out the main problems and contradictions existing in the development process of algae in China. Finally, taking the supply-side reform as the main line, this paper expounded the countermeasures and suggestions to revitalize the algae industry from the aspects of policy, science and technology, market, consumer culture, labor force, production organization structure and trade.
    Physiological Response  and Expression  of Genes Encoding Ascorbate-glutathione Synthesis Enzymes  to Cu 2+ Stress  in Wheat
    ZHENG Yongxing, LI Gezi*, KANG Guozhang*
    2021, 23(1):  21-29.  DOI: 10.13304/j.nykjdb.2019.0617
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    Ascorbate-glutathione (ASA-GSH) cycle plays an important role in plant response to different stresses. In this study, plants of wheat cultivar ‘Bainong 207’ was used and treated by different Cu 2+ concentrations (0.05、0.10、0.50、1.00 mmol·L-1) to investigate the roles of ASA-GSH under copper stress. Physiological indexes and expression levels of four key enzymes genes in ASA-GSH cycle were determined in wheat plants. Results indicated that the parameters of growth, such as plant height, root length and fresh weight were gradually decreased with the increase of Cu 2+ concentration, while contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), ASA and GSH were increased under different Cu 2+ concentrations treatments. Furthermore, the expression levels of APX (ascorbate peroxidase), DHAR (dehydroascorbate reductase), MDHAR (monodehydroascorbate reductase), and GR (glutathione reductase) in ASA-GSH cycle, had been determined by quantitative real-time PCR (qPCR). Expression trends of APX were the same in leaves and roots, which  increased at Cu 2+ concentration of 0.05 and 0.10 mmol·L-1 and decreased at Cu 2+ concentration of 0.50 and 1.00 mmol·L-1, respectively. Expression trends of DHAR and GR were similar, which  increased at Cu2+ concentration of 0.05 and 0.10 mmol·L-1 and decreased at 0.50 and 1.00 mmol·L-1 in leaves; while their expression levels increased along with the increasing of Cu 2+ concentration in roots. Expression levels of MDHAR were similar to DHAR and GR in leaves, and similar to APX in roots. It was demonstrated that these four genes were significantly induced in roots and leaves by Cu 2+ stress. To sum up, ASA-GSH might play an important role in response to Cu 2+ stress in wheat, which was closely related to the changes of ASA and GSH contents and the differential expression of ASA-GSH cycle related enzyme genes.
    Physiological and Biochemical Responses of Sweet Sorghum to Cadmium Stress and Its Cadmium Accumulation
    HAO Zhenggang, ZHAO Huijun, WEI Yuqing*, ZENG Zhouqi, WANG Zhiheng
    2021, 23(1):  30-42.  DOI: 10.13304/j.nykjdb.2019.0260
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    In order to clarify the effects of cadmium stress on physiological and biochemical indexes of sweet sorghum and the characteristics of cadmium enrichment, Liaotian 1 and 5 different concentrations of cadmium solution (0, 50, 100, 200, 300 μmol·L-1))were used to simulate the stress environment. The growth index, antioxidant enzyme activity, isoenzyme, photosynthetic parameters, fluorescence parameters, light response curve and cadmium enrichment rate of seedlings under stress were measured and analyzed. The results showed that:① The cadmium stress significantly decreased the fresh weight, plant height, shoot and shoot dry weight of sweet sorghum.② With the increase of stress concentration, superoxide dismutase (SOD) increased first and then decreased, peroxidase (POD) activity increased significantly, catalase (CAT) activity decreased significantly, and ascorbate peroxidase (APX) became lower first, then increase and then lower. In the early stage of stress, multiple bands of SOD and POD zymograms were deepened with the increase of stress concentration, and new S2,P2 bands appeared, while no new bands appeared in CAT and APX zymograms.③ Leaf chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr), leaf primary light energy conversion efficiency (Fv/Fm), photosynthetic electron transport quantum efficiency (φPSⅡ), photochemistry quenching coefficient (qP), maximum net photosynthetic rate (Pmax), apparent quantum efficiency(Q), dark respiration rate (Rd), light saturation point (LSP) decreased significantly, and intercellular CO2 concentration (Ci), non the photochemical quenching coefficient (NPQ) and the light compensation point (LCP) increased. ④ With the increase of stress concentration, the cadmium concentration in the aboveground and underground parts increased, while the enrichment rates of aboveground, underground and single plant decreased. Therefore, cadmium stress reduced biomass by inhibiting photosynthesis of sweet sorghum. Sweet sorghum maintained its normal cell metabolism by regulating the gene expression of its antioxidant enzymes. The low concentration of cadmium stress was beneficial to enrichment of cadmium in sweet sorghum, and the high concentration of cadmium stress caused sweet sorghum irreversible damage, and the biomass reduced, resulting in a decrease in the enrichment rate of cadmium in sweet sorghum.
    Coupling Effects of Stress-resistant Substances and Osmotic Regulators on Tomato Yield and Water Use Efficiency and Its Possible Mechanism
    LI Yanmei1, ZHOU Yawen2, ZHANG Lin1, LIAO Shangqiang1*, SUN Yanxin1*
    2021, 23(1):  43-50.  DOI: 10.13304/j.nykjdb.2019.0333
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    In order to explore the potential of application of anti-stress regulation technology in greenhouse tomato production, “Xinyu” variety was selected as  test material, and two kinds of anti-stress substances (calcium dihydrogen phosphate and potassium silicate) and two kinds of osmotic  regulator (proline and betaine) during the growth period were applied to study the coupling effects of anti-stress substances and osmotic regulators on water use efficiency, nutritional and physiological characteristics, and yield of tomato. The results showed that, spraying calcium dihydrogen phosphate, and calcium dihydrogen phosphate+proline had the best application effect, which increased yield by 14% and 10%, respectively, and water use efficiency increased by 8 and 6 kg·m-3, respectively. The spray of silicon suspension increased yield by 3.5%. Calcium dihydrogen phosphate and betaine is far less than calcium dihydrogen phosphate and proline in terms of regulation effect. Single application of proline or betaine reduced tomato yield and water use efficiency, the negative effect of betaine was more obvious than proline applied at the same concentration. There were significant interaction on the effect of anti-stress substances and osmotic substance on tomato yield and water utilization, and the contribution of each factor is as much as: osmotic regulators > anti-stress substances > osmotic regulators × anti-stress substances. According to the comprehensive analysis, spraying calcium dihydrogen phosphate and calcium dihydrogen phosphate + proline by three times, with the compound concentration of 1.5 g·L-1 and dosage of 1 020 L·hm-2 can achieve ideal regulatory effect.
    Study on in vitro Cultivation of Lilium orential ‘Sorbonne’
    JIA Mingliang, FANG Hefang, LI Tongjian, WEN Feng, HAN Xingjie, JIN Hongguang, XU Lingling, LIAO Liang*
    2021, 23(1):  51-57.  DOI: 10.13304/j.nykjdb.2019.0818
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    As the main market fresh cut lily variety, Lilium orential ‘Sorbonne’ has great market potential. In order to meet the market demand, flower organs were used as initial materials to study the callus induction, cluster bud proliferation and rooting culture of L. orential ‘Sorbonne’ in vitro culture. The results showed that ovary was the appropriate initial explant for callus induction, and the lower part of leaf or bulb was the appropriate explant for further propagation. The suitable medium for callus induction was MS+ 2.0 mg·L-1 2,4-D+0.2 mg·L-1 6-BA+30 g·L-1 sucrose+6.5 g·L-1 agar, pH 5.8. Cluster bud proliferation medium was MS+ l.0 mg·L-1 6-BA + 0.l mg·L-1 NAA +30 g·L-1 sucrose+6.5 g·L-1 agar, pH 5.8. Rooting culture medium was MS+0.5 mg·L-1 NAA+30 g·L-1 sucrose+6.5 g·L-1 agar, pH 5.8. The results provided a basis for further improving the in vitro culture system of L. orential ‘Sorbonne’ and for large-scale production of high-quality seed bulbs.
    Effects of Cadmium with Different Concentrations on Seeding Growth and Auxin-related Gene Expression of Tobacco
    LUO Yong1, JIAO Guizhen1, LIU Shengbo2*, WEI Yuewei1, SHAO Huifang1, JIA Hongfang1*
    2021, 23(1):  58-65.  DOI: 10.13304/j.nykjdb.2019.0366
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    In order to explore the effect of cadmium stress on tobacco growth and its regulation mechanism, DR5∷GUS Yunyan 87 transgenic homozygous strain was used as  material in this study. Five cadmium concentrations of 0, 5, 10, 20, 40 μmol·L-1 were set up by nutrient solution hydroponics. The biomass, chlorophyll, antioxidant capacity, cadmium content, auxin distribution and content and auxin-related gene expression of tobacco seedlings treated with different concentrations of cadmium were studied. The results indicated that with the increase of cadmium level, the cadmium content in tobacco seedlings increased significantly, and the toxic effect of cadmium stress on tobacco seedlings increased gradually. Compared with the control, the biomass of  tobacco seedlings decreased significantly by 73.1%,  chlorophyll content decreased by 75.5%, and the auxin content of the aboveground and lower parts decreased significantly by 59.6% and 84.5%, respectively, and the relative expression levels of the related genes NtYUCCA4, NtYUCCA6, NtYUCCA8, NtYUCCA9, NtPIN1a, NtPIN1c, NtPIN4 and NtPIN9 were significantly decreased, and the MDA content was significantly increased under the cadmium stress of 40 μmol·L-1. The decreased expression level of the synthesis of auxin NtYUCCA gene family and the auxin polar transport protein NtPINs gene family might be an important reason for the inhibition of tobacco seedling growth under cadmium stress.
    Application Progress of Microfluidic Technology to Solve the Problem of Polyspermy in Porcine IVF
    LIU Qianqiu, CHEN Qiang, LEI Anmin*
    2021, 23(1):  66-72.  DOI: 10.13304/j.nykjdb.2019.0546
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    With the advantages of automation, high sensitivity and precision, microfluidic technology have been used to control complex and precise biological experiments, to ensure real-time and accurate acquisition of experimental phenomena. In this paper, the applications of microfluidic devices in IVM(in vitro maturation), IVF(in vitro fertilization) and IVC(in vitro culture) of mammalian oocytes were reviewed, and the applications of microfluidic technology in mammalian embryology research were also summarized. At the same time, this paper proposed to apply the microfluidic technology to the IVF of porcine, aiming to solve and overcome the multiple spermatozoa in the IVF of porcine, and to provide a feasible solution for improving the IVF of porcine. At the same time, it provided new ideas for the optimization and improvement of human medical assisted reproductive technology.
    Decomposition Characteristics of Corn Stover by Microbial Consortium PLC-8 with Lignocellulose-degradation at Low Temperature
    YANG Mengya1, YAN Feifan1, YAN Meichao1, WANG He1, PIAO Renzhe1, CUI Zongjun2, ZHAO Hongyan1*
    2021, 23(1):  73-81.  DOI: 10.13304/j.nykjdb.2019.0841
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    In order to improve the decomposition efficiency of corn stover in cold northeast region and break through the bottleneck of low temperature, this study explored decomposition effect and microbial diversity of microbial consortium PLC-8 of degradating corn stover at low temperature, evaluated the decomposition effect of corn stover through indicators such as pH, weight loss of corn stover, lignocellulose content, enzyme activity, and organic acid content. Denaturing gel electrophoresis (DGGE) and high-throughput sequencing were used to research its microbial diversity. The results indicated that the pH droped and then rose to the  initial value;after 30 d, the weight-loss ratio of corn straw reached 43.65%; the content of hemicellulose, cellulose and lignin decreased by 61.13%, 40.91% and 14.25%, respectively. Cellulase activity increased and then decreased, the filter paper enzyme and β-glucosidase activities were at 20 d, which were 0.054 and 0.025 U·mL-1, respectively. The highest endonuclease and exonuclease activities were at 15 d, which were 0.032 and 0.030 U·mL-1, respectively. Xylanase activity gradually increased with the decomposition of corn stover. The highest values of formic acid and acetic acid were at  20 and 15 d, respectively. Microbial community analysis showed that PLC-8 was composed of bacteria and fungi and had decomposition stability. The dominant bacterial strains at the genus level were Chryseobacterium, Brevundimonas, Acinetobacter, and the dominant strain of fungi was Hypocreales.
    Analysis of Information Extraction and Dynamic Change of Salt Pan Based on Landsat TM/OLI Image in Shouguang City
    CHEN Simeng1,2, YU Xinyang2*, JIANG Guanghui1, CHEN Weifeng2*
    2021, 23(1):  82-88.  DOI: 10.13304/j.nykjdb.2019.0329
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    Shouguang city is an important salt  production base of sea salt in China,which needs typical data to analyze and manage the significant changes in volume and distribution pattern. Landsat TM/OLI remote sensing platform was used as data source combined with expert knowledge to supervise classification and processing of four remote sensing images in 1989, 1995, 2005 and 2015 in Shouguang city of Shandong province. Based on the dynamic changes in the past 30 years, salt pan area and driving forces affecting the change were analyzed by using land-use change matrix method. The results showed that: the accuracy of land use classification results in the study area was higher than 85%, and the Kappa coefficient was greater than 0.80. The area of salt pan in Shouguang city increased by 19 503.72 hm2 in the past 30 years, with an annual growth rate of 3.68%, showing a trend of decreasing after the increasing. From 1985 to 1995, the area of salt pan increased rapidly, with an  annual growth rate of 12.13%; the annual growth rate dropped sharply from 1995 to 2005, only 1.35%; the area of salt pan showed negative growth during 2005—2015, with an annual growth rate of 1.63%. During the study period, the increased salt pans were mainly from intertidal zone, coastal waters and grassland, while the decreased salt pans were mainly reclaimed for cultivated land and construction land. The results could provide data and basis for the scientific management and utilization of coastal salt pan, the reclamation of the waste salt field and the restoration of wetlands in Shouguang city and even in Shandong province.
    Wheat LAI Estimation in Main Growth Period Based on UAV Images
    ZHOU Kai1, ZHOU Tong1, DING Feng2, DING Dawei2, WU Wei1, YAO Zhaosheng1, LIU Tao1, HUO Zhongyang1, SUN Chengming1*
    2021, 23(1):  89-97.  DOI: 10.13304/j.nykjdb.2019.0515
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    Crop LAI is one of the important indicators to characterize the growth status of crops. In order to monitor wheat LAI rapidly and nondestructively, 3 densities and 4 nitrogen fertilizer treatments were set in this study to form different wheat growth groups, and field images were acquired by RGB camera mounted by UAV, and LAI was measured by synchronous sampling. The 9 color characteristic indexes constructed by R, G and B were selected to conduct correlation analysis with the measured LAI during the overwintering stage, returning green stage, jointing stage, flowering stage and grouting stage of wheat growth. The results showed that, at the early stage of wheat growth (overwintering stage, and returning green stage), the correlation between color index and LAI was weak, while at the late growth stage (jointing stage, flowering stage, and grouting stage), the correlation between all color indexes and LAI reached extremely significant level. The model of maximal R2 in the commonly used exponential, linear, logarithmic, polynomial and power function models was selected as the final estimation model to estimate wheat LAI in three periods: jointing, flowering and grouting stages. The estimation models were verified to be reliable and accurate by the measured LAI. These results provided a new means for rapid measurement of LAI in crop fields.
    Parameter Optimization Design of Apple Seedling Stubble Cutter Based on Virtual Orthogonal Test
    YANG Zhen1,2, YANG Xin1*, YANG Xiaobin1, WANG Pengfei1, LI Jianping1, LIU Hongjie1, LI Xuejun1
    2021, 23(1):  98-106.  DOI: 10.13304/j.nykjdb.2019.0359
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    In order to obtain the physical characteristics of rootstock  and analyze the cutting principle of the cutting device of flat stubble machine, based on ANSYS LS-DYNA software, the finite element model of apple stock cutting device was established to study the relationship between working parameters and blade parameters during apple seedling cutting. Cutting force and cutting power were taken as indicators. Optimization results of Design Expert dynamic response software were adopted. When the cutting speed was 4 200 r·min-1, the forward speed was 1 km·h-1 and the number of teeth was 100, the cutting power of a single group was 1.801 kW, which provided the basis for apple seedling flat stubble cutting device. In the trial production of apple seedling stubble machine, the qualified rate in the field test was higher than 95%, meeting the agronomic requirements of flat stubble. This research of apple seedling flat stubble cutting device was of great significance to realize the mechanization of apple seedling flat stubble.
    Development Trend of Ramie Mechanized Production Technology Based on Patent Analysis of IncoPat
    XIANG Wei, MA Lan, LIU Jiajie, DENG Xin, LONG Chaohai, WEN Qinghua, LIU Chunjie, LYU Jiangnan*
    2021, 23(1):  107-118.  DOI: 10.13304/j.nykjdb.2019.0430
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    To clarify the research progress of mechanized ramie production technology and equipment, this paper used the IncoPat patent data analysis platform to mine and analyze the development trend of ramie mechanized production technology, regional analysis, key technical fields, patent innovation institutions and main inventors by using patent data. Visualization methods were used to demonstrate innovation situation, research and development trend of this technology field. The results showed that: the mechanized ramie production technology was in the period of rapid development, and its patent applications were mainly concentrated in China. Research direction of this paper was focused on decorticating technology, textile material and degumming technology. Ramie fiber stripping treatment and mechanized ramie planting and harvesting were the focuses and hotspots in this field. This paper revealed the role of intellectual property development to promote scientific research, put forward the importance of the research on ramie planting and production technology with the integration of agricultural machinery and techniques, strengthen the development of technology and equipment of ramie combine harvesting and peeling, strengthen the innovative research on the physical degumming technology of ramie fiber, which promoted the rapid development of mechanized ramie production technology in China.
    Research Progress on Hyperthermophilic Composting and Its Resource and Harmlessness
    LIU Zile1, BAI Lin1*, HU Hongwen2
    2021, 23(1):  119-127.  DOI: 10.13304/j.nykjdb.2019.0352
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    Hyperthermophilic composting is a new technology in recent years, which can accelerate the decomposition of organic matter and shorten the decomposition time. The advantages and disadvantages of the hyperthermophilic composting process were reviewed in this paper. In addition, research progress on hyperthermophilic composting and its resource and harmlessness were summarized, in which enhanced the degradation rate of organic matter and the nitrogen retention rate, improved the problem of low degradation of antibiotic resistance genes, and passivated heavy metals in certain extent. The shortcomings existed in the current research were discussed and advices were given, which aimed at optimizing the hyperthermophilic composting process and providing theoretical guidance of practical application.
    Effect of Wood Biochar on the Methane Production Performance of Anaerobic Fermentation
    XIAO Shengling1, JING Yong1,2, FENG Jing2, SHEN Ruixia2*, ZHAO Lixin2, WANG Quanliang1, ZHANG Ying2
    2021, 23(1):  128-135.  DOI: 10.13304/j.nykjdb.2020.0014
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    To explore wood biochar on the influence of anaerobic fermentation, corn stalk and cow dung were used as fermentation substrate, and shrub biochar, poplar biochar and mixed sawdust biochar were used as additives. By changing the key factors such as biochar type, particle size and ash content, batch anaerobic fermentation was studied. The results showed that: biochar had an important effect on anaerobic fermentation system, and the smaller the particle size of biochar, the stronger the gas production capacity. Among them, the addition of poplar biochar had the greatest impact on the anaerobic fermentation system, which not only increased the cumulative production of methane (4.9%), maximum methane daily production rate (15.0%) and hydrolysis rate (15.6%) of the anaerobic fermentation system, but also shortened the fermentation lag phase.  In addition, the ash content of poplar biochar also had an important effect on anaerobic fermentation. When the ash content was 2.6 g·L-1, it had the greatest impact on the anaerobic fermentation system. While improved the buffer capacity of the anaerobic fermentation system and the maximum methane production rate (14.4%), the  lag phase (11.8%) was also shortened. The higher or lower ash content was not conducive to the production of methane in the system.
    Influences of the Interaction between Nitrogen Fertilizer Application Rate and Transpanting Density on Kenjing 7 Rice Quality
    LAN Yuchen1, GUO Xiaohong1*, LI Meng 2, ZHAO Yang3, LI Xiaolei3, JIANG Hongfang1, WANG Heying1, XU Lingqi1, ZHANG Xiaoning1, LYU Yandong1
    2021, 23(1):  136-145.  DOI: 10.13304/j.nykjdb.2019.0673
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    In order to investigate the effect of nitrogen application rate and transplanting density on rice quality under the field conditions, this paper adopted the split-plot experiment using a cold land Japonica rice Kenjing 7 as experimental material.  The nitrogen application rate (N) was used as the main plot (pure nitrogen was 0, 90, 120, 150, 180 kg·hm-2, respectively) and the transplanting density (M) was used as the split block (20.2×104, 25.1×104, 33.3×104 hills·hm-2, respectively). The results showed that: the effect of transplanting density on the processing quality of Kenjing 7 reached extremely significant level, as the transplanting density increased, the processing quality gradually increased. When the transplanting density was 33.3×104 hills·hm-2, it was beneficial to improve the processing quality of the Kenjing 7. The interaction between nitrogen application rate and transplanting density had a significant effect on the appearance quality of Kenjing 7. When the nitrogen application rate was 180 kg·hm-2 and the transplanting density was 20.2×104 hills·hm-2, it was beneficial to improve the appearance quality. The effect of nitrogen application rate on the nutritional quality and taste score of Kenjing 7 reached an extremely significant level. With the increase of nitrogen application rate, the nutritional quality gradually increased, and the taste quality gradually decreased. When the nitrogen application rate was 180 kg·hm-2 and the transplanting density was 20.2×104 hills·hm-2, it was beneficial to improve the nutritional quality of the Kenjing 7 but the taste quality of Kenjing 7 was reduced. In summary, the appearance quality and nutritional quality of Kenjing 7 were comparatively excellent under the treatment with 180 kg·hm-2 of pure nitrogen and 20.2×104 hills·hm-2 of transplanting density (N4M1).
    Impact of Rice-Ratoon Rice-Rapeseed/Green Manure Rotation Cropping System and Nitrogen Application on Yield and Grain-Filling Properties of Rice
    TIAN Guisheng, WANG Zhibin, LI Xiaokun*, ZHU Dandan, ZHANG Jianglin, LIU Qiuxia
    2021, 23(1):  146-153.  DOI: 10.13304/j.nykjdb.2019.0327
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    In order to  investigate the effect of nitrogen (N) application on rice yield and grain filling characteristics under the rotations of rice-ratoon rice-rapeseed (R-R-R) and/or green manure (R-R-G), this paper conducted field experiment during the period of 2015—2017 in Wuxue city, Hubei province. Four treatments were: N application of 0, 0 and 0 kg·hm-2 under the R-R-R rotation (T1); N application of 165, 120 and 180 kg·hm-2 under the R-R-R rotation (T2); N application of 165, 120 and 180 kg·hm-2 under the R-R-G rotation (T3); and N application of 165, 120  and 0 kg·hm-2  under the rotation of rice-ratoon rice-fallow (T4), respectively. The changes of rice yield and yield components under different treatments were studied, and the Richards equation was used to fit the strong and weak grain filling process of rice. The results showed that: ① Yields of the first-season rice and ratoon rice in 2015—2017 were T3>T2>T4>T1. Compared with T4, the yield of first-season rice and ratoon rice under T2 increased by 8.4% and 14.4%, 22.2% and 17.7% respectively in 2016—2017, and T3 increased by 12.7% and 17.9%, 251% and 244%, respectively. Compared with T1, the yield of first-season rice and ratoon rice under T2 in 2015—2017 increased by 35.1% and 22.0%, 36.4% and 30.3%, 65.1% and 65.6%, respectively. ②Under rice-ratoon rice-rapeseed/green manure rotation cropping system and nitrogen application conditions, the grain-filling characteristics of the first-season rice and ratoon rice were consistent in 2017. Compared with T4, T2 and T3 could increase the initial potential of strong grain and the dry matter quality of weak grain at the maximum grain filling rate. Compared with T1, T2 prolonged the active period of grain filling and increased effective grain filling time of first-season rice and ratoon rice, respectively. Therefore, the grain weight and yield of first-season rice and ratoon rice were increased.
    Effects of Different Drip Irrigation on the Growth and Quality of Wine Grapes in Hongsibu District
    WANG Dong1, CAO Yuanbei2, JI Yaofang3, FU Yuliang3*
    2021, 23(1):  154-161.  DOI: 10.13304/j.nykjdb.2019.0783
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    In order to find the best drip irrigation mode suitable for the wine vineyards in Hongsibao area, this paper took 6 a wine grape ‘Cabernet Sauvignon’ as the test material, and used drip irrigation as the irrigation method to design 5 different irrigation water gradients: 1 500 m3·hm-2 (T1), 2 250 m3·hm-2 (T2), 3 000 m3·hm-2 (T3), 3 750 m3·hm-2 (T4), and 4 500 m3·hm-2 (T5). The effects of different drip irrigation on the growth, photosynthetic rate, water use efficiency, yield and quality of wine grape plants were analyzed. The results showed that: T4 treatment (3 750 m3·hm-2) had the most significant effect on growth of new shoot length and plant height, the best nutrient absorption, and significantly increased the relative chlorophyll content (SPAD) and vegetation difference index (NDVI) of wine grape during the flowering and expansion stages, the dry matter accumulation of fresh leaves was the largest, the water use efficiency was the most significant (42.69%), and the yield per plant was the highest (2.24 kg). When the drip irrigation exceeded 3 750 m3·hm-2, it caused a certain amount of yield reduction. In addition, tannin content decreased first and then increased with the increasing of drip irrigation, anthocyanin content increased first and then decreased with the increase of drip irrigation, and there was a significant positive correlation between total phenolic content in grape skins and drip irrigation. Under T4 treatment, the contents of soluble solid (19.87%), titrable acid (0.72%) and soluble sugar (19.44%) in wine grapes were all at relatively appropriate levels, with relatively high glycolic acid, high tannin (3051 mg·g-1), the highest total phenol content (10.65 mg·g-1), and the best grape quality, which was the optimal drip irrigation mode in this experiment.
    Influences of Organic Mulching on Soil Nutrient and Microbial Diversity of Panax notoginseng (Burk.) F. H. Chen
    LIU Qian1,2, LI Jichao1, ZUO Yingmei1, YANG Tianmei1, YANG Meiquan1, ZHANG Jinyu1*
    2021, 23(1):  162-175.  DOI: 10.13304/j.nykjdb.2019.0291
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    The effects of organic mulching on soil nutrient change, microbial richness and diversity of Panax notoginseng were studied in order to provide theoretical basis and support cultivation techniques for P. notoginseng mulching planting. A completely random block plot experiment was performed to cover the soil surface of P. notoginseng seeds with organic mulch. It was conducted with five treatments including Artemisia annua mulching(HHH),  Tagetes erecta L. mulching(WSJ), Fagopyrum dibotrys mulching(JQM), pine needle  mulching(SZ), and no mulching (CK). Soil samples were collected after 10 months of growth. Soil nutrient content and microbial diversity were determined by chemical analysis and high-throughput sequencing. The results showed that: ① the organic matters of treatment HHH and SZ were significantly higher than that of CK, the total nitrogen and hydrolytic nitrogen content of treatment HHH was significantly higher than that of CK, and the available phosphorus and potassium contents of treatment SZ were significantly higher than that of CK after 10 months. ② There was a strong positive correlation between total nitrogen content and hydrolytic nitrogen. ③ 27 phylum and 64 classes and 131 orders and 263 families and 444 genus were obtained by sequencing the 16S rDNA of bacteria, Proteobacteria, Actinobacteria, and Bacteroidetes were the main dominant phylum. Acidibacter, Gennmtimonas, and Flavobacterium were the main dominant genus. The bacterial richness and diversity of treatment WSJ, JQM, and SZ were higher than those of CK, while those of treatment HHH were lower than those of CK. ④ There were differences in community structure and diversity of soil fungi. 12 phylums, 40 classes, 115 orders, 246 families, 510 genera were obtained by sequencing the ITS region of fungi. Ascomycota, Basidiomycota, Zygomycota were the main dominant phylum. Conocybe, Fusarium, Mortierella and Trichoderma were the main dominant genus. The richness and diversity of fungal community in mulching treatment were lower than that in non-mulching treatment. A. annua and pine needle mulching provided nutrients of soil,and organic mulching improved the ability of P. notoginseng to fight against pathogenic bacteria, and mulching pine needle had some effect on reducing the occurrence of P. notoginseng root rot and solving the obstacle of P. notoginseng continuous cropping.
    Effects of Biochar Application for Four Consecutive Years on Microbial Community Structure of Tobacco Cinnamon Soil
    YIN Quanyu1, LIU Jianhao1, LIU Guoshun1, YANG Xinling2, LI Xiaofu2, ZHANG Yulan1, LI Yang1,YE Hongchao3*
    2021, 23(1):  176-185.  DOI: 10.13304/j.nykjdb.2019.0505
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    To study the effects of biochar application on soil bacteria, fungal diversity and community structure for many years in cinnamon soil, and to understand the relationship between the changes and soil physical and chemical properties,three biochar dosage treatments (1.5, 15, 45 t·hm-2 biochar with additional 30 kg·hm-2 pure nitrogen to each treatment) were designed. The results showed that: ① biochar significantly increased available phosphorus, available potassium, organic matter, pH and water content in all treatments, and significantly reduced soil volume. ② There was no significant effect of the application of biochar on OTU number and alpha diversity index of fine and fungi, but PCA analysis showed that biochar treatment significantly changed the structure of fine and fungi communities. ③ The 15 t·hm-2 biochar treatment significantly affected the relative abundance of dominant microflora of fine and fungi, increased the relative abundance of Proteus, Actinomycetes, Curvularia and Ascomycetes, and reduced the relative abundance of Acidobacteria and Bacteroides. ④ Analysis of fine and fungal communities and environmental factors showed that the total soil nitrogen and ammonium nitrogen were significantly correlated with bacterial community structure (P<0.01), and soil ammonium nitrogen, available potassium, soil bulk density were significantly correlated with fungal community structure distribution (P<0.05). These results suggested that continuous application of biochar changed the structure of soil fine and fungal communities, of which 15 t·hm-2 biochar treatment had the most significant effect on dominant soil microflora. At the same time, the change of soil physical and chemical properties after the use of biochar had a significant correlation with the distribution of soil fine and fungal communities. This study  provided data support for biochar to improve microbial diversity and community structure of cinnamon soil.
    Study on the Collecting Method of Heterotrophic Chlorella Cells
    HUANG Weiwei1, BI Shenglei2, YANG Di3, LIU Yu1, XIN Nahui1, LI Yuyuan1, ZHANG Naiqun1*
    2021, 23(1):  186-193.  DOI: 10.13304/j.nykjdb.2019.0992
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    The small volume of heterotrophic Chlorella and the complex components of fermentation broth make it difficult in algae cell harvesting and high recovery cost. In this study, five flocculant  of ferric chloride, aluminum sulfate, chitosan, polyacrylamide and mold  were compared, single factor test and response surface analysis were used to optimize the process conditions of collecting heterotrophic Chlorella by ferric chloride flocculation method, and a quadratic regression model was obtained. The optimal variables were the dosage of ferric chloride 2.0 g·L-1, agitation rate 150 r·min-1, agitation time 20 min. Under this condition, the recovery rate reached 95.3%, and the collection cost was 0.07 yuan·kg-1. The recovery rate was high and the recovery cost was low, which laid the foundation for the industrialization application.
    Effects of Intermittent Feeding Mode on Feed, Growth and Digestive Enzyme Activities of Sea Cucumber, Apostichopus japonicus Selenka
    HAN Sha1, HU Wei1, LI Chenglin1*, ZHAO Bin1, YAO Linlin1, WANG Qi1, SUN Yongjun2*, JU Wenming2
    2021, 23(1):  194-200.  DOI: 10.13304/j.nykjdb.2020.0323
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    In order to investigate the effects of feeding mode on growth, feed and digestive enzyme activities of sea cucumber, Apostichopus japonicus Selenka, the continuous feeding of 1 d·time-1 was used as the control group, and the intermittent feeding mode of 2 d·time-1 was used, with 125%, 150%, 175% and 200% of the normal feeding amount (100%). The sea cucumber individuals with an average body weight of (3.41±0.05) g were fed for 30 d under different feeding patterns, and the feeding, growth and digestive enzyme activities of sea cucumber were detected. The results showed that the intermittent feeding mode could significantly affect the growth of sea cucumber, and the specific growth rate of sea cucumber increased with the increase of feeding level, but there was no significant difference with the control group. The weight gain rate of sea cucumber was positively correlated with the feeding level, and it was the best in 200% group, which was significantly higher than that in control group (P < 0.05). With the increase of feeding level, the feeding rate of sea cucumber gradually increased, while the feed conversion rate showed a trend of first decreasing and then increasing. The feeding rate of sea cucumber with 200% intermittent feeding was significantly higher than that with 100% continuous feeding, but there was no significant difference between the feed conversion rate of sea cucumber with 200% and 125% intermittent feeding and that with 100% continuous feeding. Intermittent feeding mode had a significant effect on protease activity of sea cucumber. The protease activity of 125% and 150% groups decreased significantly (P<0.05), while there was no significant difference between 175% and 200% groups and the control group (P>0.05), but the feeding mode had no significant effect on amylase activity. It was demonstrated that the intermittent feeding mode of 2 d·time -1 and the feeding level of 175%~200% could meet the normal feeding needs of sea cucumber and effectively promote its growth, based on its performance and feed conversion and utilization.