Table of Content

15 April 2021, Volume 23 Issue 4

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Spatial Distribution of Agricultural Research Talents in China and Its Impact on Agricultural High-quality Development

XUE Pengfei1, LIU Shuang1, LIN Qingning2*

2021, 23(4):  1-10.  DOI: 10.13304/j.nykjdb.2021.0020

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Talent is the key for the improvement of independent innovation capability and an important driving force  for agricultural high-quality development. Based on the data of agricultural  research talents in China, using spatial statistics and local autocorrelation analysis methods, this paper explored their spatial distribution and convergence, and built a regression model on the basis to test the impact of spatial distribution of agricultural  research talents on agricultural high-quality development, and explored the influence path. The results showed as follows: ① the spatial distribution of agricultural  research talents in China showed a relatively unbalanced and typical characteristic  with a pattern of dense in the east and sparse in the northwest. Beijing, Shandong and Guangdong were high-level clusters of agricultural  research talents. ② The distribution of agricultural  research talents showed a certain spatial autocorrelation. The cold spots of agricultural  research talents were concentrated in western regions such as Gansu and Qinghai, without obvious hot spots. In terms of academic qualifications, the hot spots for doctoral talents included Shanghai, Jiangsu, Beijing, and Tianjin, while the cold spots were mainly concentrated in the western region; the hot spots for masters talents included Jiangsu, Shanghai and Anhui, and the cold spots were concentrated in the western region; and undergraduate agricultural research talents had not shown obvious changes in cold and hot spots. ③ The agglomeration of all agricultural  research talents, doctor talents and master talents didnt show a trend of backward regions catching up with leading regions, but undergraduate agricultural  research talents had a trend of backward regions catching up with leading regions. ④ Agricultural research talents had a significant promotion  on the high-quality development of agriculture in the region, and this promotion effect was realized based on the path that the spatial distribution of agricultural research talents drives the local technological progress level. Above results provided  references for training talents and introducing, which had important practical significance for promoting the high-quality development of agriculture.

Reform of the Supply System of Public Resources Governance in China——Taking Agricultural Biological Genetic Resources as an Example

ZOU Wannong, SONG Min*

2021, 23(4):  11-19.  DOI: 10.13304/j.nykjdb.2019.0770

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The genetic resources are indispensable and strategic in modern biotechnology research and development. In recent years, Chinas genetic resources in agriculture are faced with biodiversity degradation, biological piracy, breeding materials shortage, low level of genetic resources development and other practical problems. The publicity, scarcity, non-exclusiveness and utility integration of public resources determine the demand of real-time diversification system in public resources governance. If the society lacks flexible and efficient institutional change mechanism, the resulting shortage effective system will lead to the "commons tragedy" in public resources governance. With the help of the theoretical structure of institutional supply, and taking agricultural biological genetic resources as the object, this paper analyzed the status quo and problems of the system supply of public resources management in our country, and explored the causes of the problems, and put forward the countermeasure suggestions of perfecting the mechanism of institutional change.


Discussion on Good Laboratory Practice （GLP） in the #br# Safety Management of Agricultural GMOs in China

LI Wenlong1, XU Junfeng2, XU Linjie1, SUN Zhuojing1, LI Lu1, SONG Guiwen1*

2021, 23(4):  20-26.  DOI: 10.13304/j.nykjdb.2020.0437

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Good laboratory practice (GLP) as a test quality management system, has been widely used in non-clinical trial safety evaluation of medicine, veterinary drug and foods all over the world. At the same time, GLP has also been used in the field of management of genetically modified organisms (GMOs) by many developed countries. In this paper, the concept and basic elements of GLP were introduced, and its main characteristics such as ensuring the authenticity and traceability of safety evaluation data were analyzed. In addition, combining with the characteristics of GLP and the development requirements of agricultural GMOs, this paper analyzed the necessity and feasibility of GLP in the safety management of agricultural GMOs from the aspects of improving the data quality of safety evaluation of GMOs and ensuring the scientific nature of safety evaluation of GMOs. Based on above, five suggestions were put forward, including formulating GMOs GLP regulations, building the GLP laboratories, organizing training and research, accelerating GLP application, and promoting international cooperation, so as to provide reference for the safety management, research and development, and industry development of GMOs.

Research Progress of Plant microRNAs in Drought Stress Response

ZHANG Haoyang, JIN Yinan, SUN Yanxin, LI Ziwei, GUO Xiaoheng, XU Zicheng*

2021, 23(4):  27-36.  DOI: 10.13304/j.nykjdb.2020.0354

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Drought is a common and recurring climate feature that seriously affects crop production. microRNAs (miRNAs) are a class of small molecular non-coding RNAs with the length of 18~24 nt. Transcribed miRNAs regulate gene expression and participate in plant growth and development. This paper focused on the discovery, synthesis and mechanism of miRNAs, the species and target genes of miRNAs in response to drought stress, and the mechanism of miRNAs in response to drought stress. It was pointed out that microRNAs were species-dependent and tissue-specific in plant response to drought stress, and were affected by drought stress conditions. It was also found that the current plant microRNAs in drought stress response of the study was the mechanism of action of miRNAs in drought stress and its target gene regulatory network was unclear. The research prospects for the future, such as exploring miRNAs regulate gene regulation of cis component characteristics, and the target genes of plant drought stress response function and network of the interaction between the key factors, and the construction of plant drought resistance microRNAs repository was discussed, in order to promote the application of miRNAs in  plant resistance to drought stress.

Identification and Expression Analysis Under Abiotic Stress of GRF Gene Family in Sorghum

CUI Jianghui§, YANG Puyuan§, CHANG Jinhua*

2021, 23(4):  37-46.  DOI: 10.13304/j.nykjdb.2020.0278

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Growth regulation factor (GRF) is a type of special transcription factor in plants, which plays an important role in plant hormone regulation, growth and development, stress response. This paper screened and identified the GRF gene family members of sorghum, obtained 8 GRF genes, and then analyzed their conservative protein domain and gene structure, function promoter elements, evolutionary relationship and collinearity. The results showed 8 GRF genes were conserved in structure in sorghum. The analysis of function promoter elements revealed these genes had drought, low temperature and jasmonate response elements etc, indicating these genes participate in the response to biotic and abiotic stress. A candidate gene (SORBI_3002G297800) for salt tolerance and a gene (SORBI_3006G203400) for hormone stress  were screened through transcriptome expression analysis of salt stress and uniconazole treatment. The results provided important reference for further studing the function of these genes in sorghum.

Difference Analysis of Morphology, Structure and Physiological Characteristics in Roots of Grapevines with Different Cold Resistance

SUN Yan, HAN Bin, YUAN Junwei, LIU Changjiang, LI Minmin, YIN Yonggang, JIA Nan, GUO Zijuan, ZHAO Shengjian*

2021, 23(4):  47-57.  DOI: 10.13304/j.nykjdb.2019.0966

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To screen and evaluate suitable cold-resistance indexes, this paper studied the differences of morphology, structure and physiological characteristics in roots of grapevines with different cold resistance, and analyzed the roots of grapevines with high cold resistance (‘Zuoshanyi’ and ‘Beta’), moderate cold resistance (‘Shanhe 2’, ‘5BB’, ‘SO4’ and ‘1103P’), and low cold resistance (‘Muscat Hamburg’ and ‘Red Globe’), and compared the angel, anatomical structure, water content and the texture of root, etc.. The results showed that: the ratio of cortex thickness (RCT), vessel density (VDY), vessel diameter (VDR), size of ray cells (SRC), free water content (FWC) and free water content/ bound water content (F/B) in roots of ‘Zuoshanyi’ and ‘Beta’ were all significantly smaller than those in roots of other grapevines, respectively. But also the tissue cells were arranged more densely in roots of ‘Zuoshanyi’ and ‘Beta’ than that in roots of other grapevines. The cross cutting hardness (CCH), cross cutting total work (CCTW), longitudinal cutting hardness (LCH) and longitudinal cutting total work (LCTW) of roots in ‘Zuoshanyi’ and ‘Beta’ were all significantly higher than those in ‘Muscat Hamburg’ and ‘Red Globe’ (P<0.05), respectively. In conclusion, the grapevines with high cold resistance had the characteristics,such as compact structure, low free water content, low ratio of F/B, high hardness and high total work. And CCTW of root could be a good index for easily and accurately identifying the cold resistance of grapevines. And these results  provided scientific basis and technical support for identification, breeding and cultivation of cold resistant grape cultivars.

Effect of Drought Stress on Endogenous Hormone Content of Gardenia jasminoides Ellis

WANG Deyun1,2, LIU Peipei1, CHEN Yunting1, XU Yueying1, ZHOU Li1, LUO Guangming1*

2021, 23(4):  58-63.  DOI: 10.13304/j.nykjdb.2019.0784

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In order to study the change of endogenous hormones content of Gardenia jasminoides Ellis in response to drought stress, this paper measured the content of four kinds of endogenous hormones of Gardenia jasminoides Ellis leaves every 5 d by simulating light, moderate and severe drought stress with 5%, 10% and 20% polyethylene glycol (PEG-6000) . The results showed that: compared with normal treatment, with the extension of drought stress time, the content of abscisic acid (ABA) increased gradually in Gardenia jasminoides Ellis leaf under light and moderate drought stress, the contents of ABA increased first and then decreased under severe drought stress, the contents of indoleacetic acid (IAA) and gibberellic acid (GA) increased first and then decreased, the contents of zeatin riboside (ZR) had a trend of high-low-high. The values of IAA/ABA and GA/ABA decreased gradually, the values of ZR/ABA, IAA/GA, IAA/ZR and GA/ZR fluctuated differently. Comprehensive analysis showed that Gardenia jasminoides Ellis would response to drought by adjusting the content and proportion of endogenous hormones after drought stress.

Screening of Cellulose-degrading Bacteria from Bactrian Camel and Their Degradation Effect on Distillers Grains

LI Guowei1, HE Jing1, GUO Kunjie1, JIRIMUTU1,2*

2021, 23(4):  64-75.  DOI: 10.13304/j.nykjdb.2019.1036

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As the main animal species in desert and semi-desert areas, camels have unique physiological functions after long-term natural selection. However, there were few studies on bactrian camel intestinal cellulose-degrading bacteria. In order to explore the bacteria with cellulose degradation ability in Bactrian camel feces, CMC-Na plate method was used for primary screening, then they were separated and purified, and the cellulase activity was detected by DNS method. According to the size of transparent ring and cellulase activity, the strain with strong cellulose degradation ability was screened out. The screened strains were identified by morphological observation, physiological and biochemical characteristics and 16S rRNA sequencing analysis. The conditions of inoculum amount, initial pH, culture temperature and fermentation time were optimized by single factor, and response surface optimization was further adopted on the basis of single factor. The optimized bacteria solution was inoculated into distillers grains, and the degradation effect of bacteria solution on distillers grains on the 7, 14 and 21 d were studied. The results showed that the screened strain YT5-1-1 had strong cellulose degradation ability, and it was identified as Enterobacter xiangfangensis. The optimum enzyme production conditions of YT5-1-1 were as follows: inoculum amount 2.6%, initial pH 4.5, culture temperature 30 ℃, fermentation time 43 h, and the maximum predicted activity of CMCase was 1.819 IU·mL^-1. Strain YT5-1-1 had no effect on pH change during distillers grains fermentation, and could maintain higher dry matter content, which would significantly reduce neutral detergent fiber content and acid detergent fiber content in distillers grains. At the end of fermentation, the degradation rates of hemicellulose and degradation of cellulose values for the YT5-1-1 group were 4.18% and 3.46% higher than those of the blank group, respectively.

Maize Growth Promotion and Nitrogen-fixing Rates by Inoculation with Wild-type and Ammonium-excreting Mutant of Pseudomonas stutzeri

YANG Hua1, LI Jiang2, ZHANG Wei1, ZHOU Zhengfu1, YAN Yongliang1, GUO Jia3, LIU Xiangguo3, HAO Dongyun3, LIN Min1, KE Xiubin1*

2021, 23(4):  76-84.  DOI: 10.13304/j.nykjdb.2020.0211

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Compared to symbiotic nitrogen fixation in legumes, associative nitrogen fixation is widely existed in the rhizosphere of non-leguminous food crops such as rice and maize, which potentially plays major role in reducing the use of synthetic nitrogen fertilizer in agriculture and increasing plant yield. Pseudomonas stutzeri A1501,  a model associative/endotrophic nitrogen-fixing bacterium, was isolated from the rhizosphere of rice. Inoculation with wild-type A1501 could promote the growth of rice and maize plants. In order to further elucidate the relationship between the biological nitrogen fixation (BNF) in rhizosphere and the plant-growth promotion, an efficient associative nitrogen fixation system consist of excretion-ammonium mutant strain (1568/pVA3) and transgenic nitrogen efficient maize genotype was constructed, and used for the evaluation of promoting effect and BNF quantification under greenhouse condition. After 60 d, inoculation of two maize genotypes (transgenic nitrogen efficient maize and the control) with 1568/pVA3 and wild-type A1501 all significantly increased the plant biomass of aboveground and underground, compared with the control without inoculation. However, in all the conditions assayed, transgenic nitrogen efficient maize inoculated with 1568/pVA3 or wild-type strains showed no significant difference between plant biomass and the control genotype. In the efficient associative nitrogen fixation system,  the biomass of the transgenic nitrogen efficient maize inoculated with 1568/pVA3 significantly increased by 25.5%, compared with the N fertilization treatment control, 39% total N content compared with the control without inoculation. According to the estimation by 15N-isotopic dilution method, individual maize plant could obtain  N 0.8 g·plant^-1 from BNF. Meanwhile,  the biomass of the transgenic nitrogen efficient maize inoculated with wild-type A1501 significantly increased by 24.8%, compared with the N fertilization treatment control. Accordingly, individual maize plant could obtain  N 0.64 g·plant^-1 from BNF. Therefore, the efficient associative nitrogen fixation system used in this study contained transgenic nitrogen efficient maize genotype and associative diazotrophs especially the excretion-ammonium engineering bacteria performed better in terms of nitrogen fixation rate and plant biomass. It was estimated that 23% synthetic fertilizer could be reduced in this efficient associative nitrogen fixation system, against than 7.5% in the control system.

Enzymatic Properties of an Acidic Trehalase TreA from Bispora sp. MEY-1#br#

JIANG Xiao, TU Tao, WANG Kun, TONG Lige, LUO Huiying*

2021, 23(4):  85-92.  DOI: 10.13304/j.nykjdb.2020.0452

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As a biocatalystase, acid trehalase is widely used in biological industry. It is very important to exploit new acid trehalase with excellent enzymatic properties. In this study, an acid trehalase gene (TreA) from Bispora sp. MEY-1 was successfully cloned and expressed in Pichia pastoris GS115. The enzymatic properties of purified trehalase TreA were identified. The optimum pH was 4.0, and the relative activity maintained over 60% under the range of pH 2.2~5.0. The relative activity of purified enzyme was more than 88% after treated for 1 h under pH 1.0~4.0, which exhibited the good acid stability. The optimum temperature of purified enzyme was 60 ℃, which was enzyme with medium-high temperature resistance. The specific activity of purified enzyme was 1 913 U·mg^-1, and its Km and Vmax were 0.67 mg·mL^-1 and 119 μmol·min^-1·mg^-1, respectively. Moreover, the effects of different mental ions or chemical reagents, and the protease resistances on the purified enzyme activity were also evaluated.

Application Status and Problems of Disinfection Technology in Prevention and Control of African Swine Fever

WANG Wei1,2, LUO Yuzi1, ZHANG Li1, MA Jifei2*, QIU Huaji1*

2021, 23(4):  93-102.  DOI: 10.13304/j.nykjdb.2020.0625

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African swine fever (ASF) is an acute hemorrhagic infectious disease of domestic pigs and wild boar caused by African swine fever virus (ASFV). The World Organization for Animal Health (OIE) lists it as a notifiable animal disease. As there is no effective vaccine against ASF currently, quarantine, culling and strict biosecurity measures are mainly adopted to prevent and control the disease in China. Disinfection is an important means of biosecurity against ASF. At present, there are various inactivation methods for ASFV, but the inactivation effect needs to be further tested. Current ASF etiological diagnostic techniques cannot determine the infectivity of a sample and therefore cannot accurately evaluate the efficacy of a disinfectant against the pathogen. This review summarized the main ASFV disinfection techniques and their mechanisms, killing effect, advantages and disadvantages, and analyzed the problems existing in disinfection technologies and the limitations of the current detection techniques, and further the potential techniques for differential detection of infectious ASFV were discussed to provide references for innovation and improvement of ASFV diagnostic technology and effective control of ASF.

Control Conditions and Effects of Plant Protection Unmanned Aerial Vehicle (UAV) on Diseases and Insect Pests of Rice#br#

FU Rongtao, CHEN Cheng, WANG Jian, CHEN Xuejuan, LU Daihua*

2021, 23(4):  103-109.  DOI: 10.13304/j.nykjdb.2019.0682

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In order to explore the control conditions and effects of plant protection UAV on diseases and insect pests of rice, the influences of planting drone flight height, flight speed, additives on the characteristics of pesticide droplets, and the control efficacy of two different application methods on rice sheath blight, rice false smut, and rice stem borer were studied in this paper. The results showed that the sedimentation density (22.3 drop·cm^-2) was the largest  when the planting drone was 2 m away from the canopy and the flight speed was 3 m·s^-1, and the droplet sedimentation density in different parts of the rice canopy were different: upper > middle > lower. Despite that droplet density reduced from 20.3 to 16.4 drop·cm^-2  after adding adjuvant for aviation plant protection, the wetted area of pesticide solution increased by 76.4%, while droplet diameter and droplet spraying coverage increased from 256.3 μm, 5.56% to 327.5 μm, 9.82%. At rice booting stage, under condition of the same reagent combination, the control effects of spraying chemical pesticides and biological agents on rice sheath blight were 86.20% and 8320%, respectively, which was significantly better than that of traditional artificial electric sprayers. Meanwhile, the control effects on rice false smut and rice stem borer were 86.51%, 84.01% and 89.32%, 81.47%, respectively, and the control effects of the two spraying methods were not significantly different. The results indicated that the control effects of plant protection UAV on diseases and insect pests of rice were significant under optimum flight altitude and flight speed, and it was valuable for popularization and large-scale application.

Development of Microbial Seed Coating Agents and Their Effects on the Growth of Maize Seedlings

ZHOU Maochao1,2, HUANG Yanna2, DUAN Saifei1,2, SHU Shiyuan1,2, TANG Xueming2*

2021, 23(4):  110-118.  DOI: 10.13304/j.nykjdb.2019.0988

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Corn stalk rot is a soil borne disease commonly coourring in corn production areas of the world, and it is also one of the main diseases in corn production areas of China. In order to screen suitable antagonistic bacteria of corn stalk rot pathogen and study the effect of seed coating agent on corn growth, the antagonistic strains of corn stalk rot pathogen were screened by plate confrontation test, and the strains with potential to promote corn seed growth were further screened by measuring two physiological indexes of iron carrier and indoleacetic acid, and the screened strains were used as the activity of microbial seed coating agent. The effects of different proportion of film-forming agent on seed germination, seedling growth and strain activity of maize were studied. In this study, 5 strains of bacteria and 1 strain of Trichoderma were found to inhibit the pathogen of corn stalk rot by plate confrontation test. By further physiological indexes, 6 strains of Bacillus with potential to promote the growth of corn seeds and the ability to produce IAA and iron carriers were obtained. TXM-1 (Bacillus velezensis) and TXM-2 (Bacillus amyloliquefaciens) were selected as the active components of biological seed coating agents based on the functions of bacteria inhibition and the growth promotion. The germinating test of corn seed showed that BSCA-1 and BSCA-2 had the functions of antagonizing pathogen and promoting the growth of corn seedling. Their formulations were as follows: TXM-1 and TXM-2 as active components, sodium alginate and polyvinyl alcohol as film-forming agents, bentonite and benzophenone as additives, respectively. The best mixing ratio of the two film formers was 1∶9, which could not only promote the growth of corn, but also delay the decline rate of the activity of the film formers. The results showed that the biological seed coating agent based on two kinds of Bacillus could not only antagonize the pathogen of corn stalk rot, but also promote the growth of corn seedling, which revealed its potential to replace the chemical seed coating agent in corn planting.

Correlation Analysis of Rice Taste Quality Characteristics and Their Relationship with Leaf Photosynthesis

YIN Chunyuan, WANG Shuyu*, LIU Hemei, SUN Jianquan, HU Xiuming, WANG Hele, TIAN Fanghui, MA Chaoyang, ZHANG Xu, ZHANG Ruiping

2021, 23(4):  119-127.  DOI: 10.13304/j.nykjdb.2020.0218

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In order to identify the quality characteristics of high quality rice varieties and its relationship with leaf photosynthesis，breed and screen new rice varieties with good taste, eight high-quality rice varieties along the Yellow River rice area in Henan province were used as experimental materials under field cultivation. This study measured and analyzed rice amylose content, protein content, processing quality characteristics (brown rice rate, milled rice rate, head rice rate) and appearance quality characteristics (chalky grain rate and chalkiness), and measured the photosynthetic rate of sword leaf in the grain-filling stage. The results showed that the brown rice rate, milled rice rate and head rice rate of eight excellent rice varieties were higher, the coefficient of variation among the varieties was lower. The chalky grain rate and chalkiness varied among rice varieties, and their coefficients of variation among the varieties were 39.73% and 36.49%, respectively. The coefficients of variation of amylose content, protein content and taste value affecting taste qualities of rice were relatively small, less than 5%. The correlation analysis showed that the protein content had a significant left-biased parabolic relationship with the food taste value（r=0.827*）, the straight-chain starch content had a very significant negative correlation with taste value (r=-0.905**). The grain thickness of brown rice had a significant open-down parabolic relationship with the taste value（r=0.747*）. The appearance quality, protein content and taste value were negatively correlated with leaf photosynthetic rate in the middle and late grain filling stage, but positively correlated with amylose content. These results showed that the lower the content of protein and amylose, the better taste quality of rice. The taste quality became better with the increase of grain thickness in a certain range, but decreased with the grain thickness of brown rice exceeding more than 2.1 mm. Increasing the photosynthetic rate of rice leaves in the middle and late grain filling stage could help to improve the appearance and nutritional quality of rice, while the increase of  amylase content led to the reduction of rice taste value. Therefore, the high photosynthetic efficiency of rice leaves had some certain selection pressure in the quality rice breeding. It was of great significance for improving taste quality of rice by reasonably regulating the photosynthetic rate of leaves in the middle and late grain filling stage.

Quality Evaluation and Analysis of Main Cultivated Litchi in Lingnan Region

ZHENG Jinjin1,2, LIU Shuai1, CHEN Yan1*, ZHANG Xin1,2, YANG Hui1, LIU Xiangxiang1, WANG Fuhua1,2*

2021, 23(4):  128-136.  DOI: 10.13304/j.nykjdb.2019.1112

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To explore the nutritional quality characteristics and differences of litchi in different producing areas in Lingnan region, this paper collected eight litchi cultivars from six main producing areas (Haikou, Maoming, Zhanjiang, Guangzhou, Huizhou and Shanwei) , and measured single fruit weight, edible rate, Vc, reducing sugar, sucrose, total acid, soluble solids and sugar acid ratio to compare the differences of litchi quality of different cultivar from different producing areas. The results showed that: different cultivars of litchi had their own advantages in individual quality indicator. Among the eight litchi cultivars, Ziniangxi litchi and Nuomici litichi had the highest single fruit weight and edible rate, respectively, Feizixiao litchi had the highest Vc and reducing sugar, while Guiwei litchi had the highest content of sucrose and soluble solids. The quality indexes were correlative. The eight quality indexes were integrated into three principal components by principal component analysis, and Feizixiao litchi got the highest score. The quality indexes of the same litchi cultivar from different producing areas were also different. For Feizixiao litchi, the contents of single fruit weight, Vc, reducing sugar, sucrose and soluble solid were not significantly different among three main producing areas (Haikou, Huizhou and Maoming), but the edible rate and sugar acid ratio of Feizixiao litchi from Haikou was significantly higher than that from Zhanjiang. The edible rate, Vc and total acid content of Guiwei litchi from Guangzhou were significantly higher than that from Maoming. The contents of single fruit weight, Vc and sucrose of Nuomici from Huizhou were the highest among the three main producing areas. All cultivars from three producing areas were divided into three categories by cluster analysis, and the same cultivars among different producing areas were in one cluster. The results provided scientific basis for the cultivar screening of fresh litchi and planting structure adjustment.

Study on the Intercepting and Blocking Sand Effect of 200 MWp Photovoltaic Array in Kubuqi Desert

JIA Ruiting, MENG Zhongju*, DANG Xiaohong, TANG Guodong, SHI Tao

2021, 23(4):  137-144.  DOI: 10.13304/j.nykjdb.2020.0586

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In order to explore wind and sand resistance effect of photovoltaic array in sand region, this paper took the 200 MWp photovoltaic power station in Kubuqi dessert as research object, setting observation point A at the upwind edge in the array, observation point B at downwind edge and CK at upwind flows the sand outside array, and the variation of wind speed and sediment transport were measured concurrently through HOBO small mobile weather station and stepped sand collector. The results showed that: ① The roughness of observation point A and B had been increased than the shifting sandy land, and the average wind speed of each observed altitude decreased. At 0.2 m height, the wind speed had the largest reduction value (27.76%, 29.83%), and the wind speed reduction value decreased with the increase of height, and the corresponding height wind speed reduction values were shown as observation point A < observation point B. ②The sand transport rate of observation point A and observation point B were 65.07% and 47.79% of the shifting sandy land ( 2.72 g·min-1·cm-1). Therefore, the existence of photovoltaic array had a significant interception effect on wind speed and sand transport, which weakened the near-surface sand activities. The research results could provide data support for the assessment of the impact of large-scale photovoltaic power stations on sand environment in desert areas.

Effects of Silicon Fertilizer on Lodging Resistance of Kenjing 7 Under Different Tillage Modes

WANG Wenyu, WAN Siyu, ZHANG Xuesong, WANG Xu, LI Jiashuo, ZHENG Guiping*

2021, 23(4):  145-153.  DOI: 10.13304/j.nykjdb.2020.0073

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Taking the rice variety Kenjing 7 as material, using the field community experiment method, this paper set 4 silicon fertilizer consumption: D1 (0 mL·hm^-2), D2 (150 mL·hm^-2), D3 (375 mL·hm^-2) and D4 (600 mL·hm^-2) under two tillage modes (ridge cropping and heisaku ), and studied the differences in lodging resistance and main physical traits of plant height, height of gravity center, first internode of base (N1), second internode (N2), third internode (N3) and fourth internode (N4), and analyzed the correlation between lodging index, breaking-resistance strength and main physical traits of stem. The results showed that: under the two tillage modes, with appropriate silicon fertilizer treatment, rice plant height and height of gravity center decreased; internode length of N1 and N2 shortened, internode length of N3 and N4 elongated; internode roughness, unit internode dry weight, stem wall thickness, bending force and bending moment increased; lodging index decreased, and lodging resistance ability enhanced. Both tillage modes had the lowest lodging index at D3, the internode lodging indexes of N1,N2,N3 and N4 treated by D3 under ridge cropping decreased by 15.35%, 5.18%, 5.89% and 10.61%,respectively, compared with D1; the internode lodging indexes of N1, N2, N3 and N4 treated by D3 under heisaku decreased by 12.20%,6.59%,6.29% and 8.70%,respectively, compared with D1. The lodging index was negatively correlated with internode diameter, dry weight of unit internode and stem wall thickness, and positively correlated with plant height and height of gravity center. The internode breaking-resistant strength was positively correlated with internode diameter, dry weight of unit internode and stem wall thickness, but negatively correlated with height of gravity center. Under different tillage modes, the breaking-resistant strength and lodging resistance of rice increased with appropriate silicon fertilizer dosage. In this study, the lodging resistance of rice was the best when silicon fertilizer dosage was 375 mL·hm^-2.

Influences of Spraying Selenium Fertilizer on Leaves on Agronomic Characters and Selenium Content of Different Genotypes of Foxtail Millet

YUE Linqi, GUO Jiahui, BAI Xionghui, SHI Weiping, GUO Pingyi*, GUO Jie*

2021, 23(4):  154-163.  DOI: 10.13304/j.nykjdb.2020.0915

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Na₂SeO₃ was sprayed on the leaves of different genotypes of foxtail millet materials to explore the difference of selenium sensitivity of foxtail millet germplasm resources. Taking 31 cultivars and landraces as materials, by spraying 110 g·hm^-2 Na2SeO3 at heading stage with water  as control, this paper compared agrological properties and selenium content changes of different varieties after selenium treatment. The results showed that selenium application could significantly (P<0.05) increase the panicle diameter, spike weight and spike grain weight of foxtail millet, and extremely significantly (P<0.01) decrease the plant height and stem diameter. The results of cluster analysis showed that the 31 germplasm resources of millet could be divided into 4 groups, among which the first group was selenium-sensitive material with Sanbianlian, the second group was selenium-resistant material with Changsui 7, the third group included Wawuli, 95 jian 5, Xia 2, and others were the fouth group. The results of principal component analysis showed that the cumulative contribution rate of the first four principal components was 76.11%, and the main load factors were spike weight, spike grain weight, panicle length, selenium content, spike number and thousand grain weight. Those results provided a theoretical basis for the screening of selenium-rich foxtail millet materials and a reference for the breeding of selenium-rich foxtail millet.

Impact of Nitrogen and Calcium Application on Growth and Physiological Characteristics of Peanut in Flowering Stage

YI Miao1,2§, WANG Jianguo2§, YIN Jin1, GUO Feng2, ZHANG Jialei2, TANG Zhaohui2, LI Xinguo2,3*, WAN Shubo2,3*

2021, 23(4):  164-172.  DOI: 10.13304/j.nykjdb.2019.0954

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In order to explore the effect of reducing nitrogen fertilizer application on peanut, pot experiment was carried out, in which the main local cultivars were selected in Huang-huai-hai region in Northern Region and red soil upland region in Southern Region. Peanut cultivar ‘Huayu 25’ was selected as the material in Northern Region, and 6 treatments were set up, including 0 kg·hm^-2 N（T0）, 157.5 kg·hm^-2 N（T1）, 157.5 kg·hm^-2 N+ 450 kg·hm^-2 CaO (T2), 450 kg·hm^-2 CaO (T3), 67.5 kg·hm^-2 N + 450 kg·hm^-2 CaO as base fertilizer+ 45 kg·hm^-2 N at anthesis stage (T4), 67.5 kg·hm^-2 N as base fertilizer + 45 kg·hm^-2 N + 450 kg·hm^-2 CaO at anthesis stage (T5). In Southern Region, Peanut cultivar ‘Xianghua 2008’ was selected as research material, and 4 treatments were set up, including 0 kg·hm^-2 N (S0), 157.5 kg·hm^-2 N (S1), 157.5 kg·hm^-2 N+568 kg·hm^-2 CaO (S2), 112.5 kg·hm^-2 N (S3), 112.5 kg·hm^-2 N+568 kg·hm^-2 CaO(S4). The effects of different treatments on dry matter accumulation, leaf SPAD value, carbon and nitrogen metabolic enzyme activity, root nodules and yield components of peanut were investigated. The results showed that T4 treatment significantly increased the number and fresh weight of nodules at pod setting stage, increased chlorophyll relative content and dry matter accumulation at late growth stage, promoted the activities of carbon and nitrogen enzymes in leaves, and increased the peanut yield by 4.5%, compared to T1 treatment. Compared with T1 treatment, T2 treatment significantly promoted dry matter accumulation and increased peanut yield by 10.8%. The yield of T4 treatment was increased by 22.8% than T5 treatment. Meanwhile, total dry matter accumulation per plant and yield of S2 treatment were increased by 15.6% and 29.8% than those of S1 treatment, respectively. Compared with S1 treatment, the yield of S4 was increased by 27.7%. It was suggested that the effect of calcium fertilizer on yield increasing was more obvious than that of nitrogen fertilizer reduction, and the effect of calcium fertilizer as base fertilizer was better. Therefore,  calcium fertilizer was an effective measure for increasing peanut yield in peanut producing areas of Huang-huai-hai in Northern China and upland red soil in Southern China. It could be used as an important cultivation method to ensure peanut production stability accompanying the reduction of nitrogen fertilizer application.

Effects of Nitrogen Application on Diurnal Variation of Photosynthesis and Yield of Two Lycium Species

MA Xingdong1, GUO Yehong1*, DU Tao2, LI Meiying3, XU Yingjie1, CHEN Xiaowei1, YAN Zongbang1, YANG Shaojie1, FENG Jinglu1

2021, 23(4):  173-182.  DOI: 10.13304/j.nykjdb.2019.0893

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In order to clarify the effect of nitrogen application on diurnal variation of photosynthesis and yield of Lycium species, Lycium ruthenicum and Lycium barbarum were selected and 5 nitrogen application treatments including 0(CK), 50(F1), 100(F2), 150(F3) and 200 (F4)g·plant^-1 were set up. The net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 concentration (Ci), instantaneous water use effiency (WUE), stomatal limitation (Ls) and yield of L. ruthenicum and L. barbarum transplanted to arid areas in Wuwei City, Gansu Province were studied. And the best nitrogen application amount was fitted from the perspective of photosynthesis increasing yield. The results showed that nitrogen application could increase Pn, Tr, Gs, WUE and yield of L. ruthenicum and L. barbarum in different time periods of 1 d, reduce Ci and Ls of the two Lycium species, thus increase their photosynthesis. The effect of nitrogen application on photosynthetic parameters of L. ruthenicum was more significant than that of L. barbarum. The daily average net photosynthetic rate (PnA) and yield of L. ruthenicum in F3 treatment were the highest, with 9.842 μmol·m^-2·s^-1 and 173.621 g, respectively. PnA of L. barbarum in F3 treatment was the highest, which was 11.616 μmol·m^-2·s^-1; its yield in F3 treatment was the highest, which was 205.264 g·plant^-1. Therefore, nitrogen application with 150 g·plant^-1 was beneficial to increase photosynthesis of L. ruthenicum and L. barbarum, thus could obtain the maximum yield.

Influences of Nitrogen Application on Nitrogen Metabolism Enzymes Activities, Yield and Quality of Tomato in Composite Sand Culture

LIU Qianjie, CHENG Yunxia, JIA Kai, SHI Zhenyu, ZHANG Jing, WEI Shaowei, WU Hui*

2021, 23(4):  183-191.  DOI: 10.13304/j.nykjdb.2019.1016

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In order to explore the optimal nitrogen application amount and its physiological functions on promoting high yield and high quality of composite sand cultured tomatoes, tomato variety of ‘Maofen 812’ was used as the experimental material, five nitrogen application treatments with 0 (N0), 143 (N1), 285 (N2), 428 (N3) and 571(N4) kg·hm-2  were set up. The effects of different nitrogen application treatments on the activities of nitrate reductase (NR) and glutamine synthase (GS) in tomato leaves, as well the fruit quality and yield of tomato were analyzed. The results showed that appropriate amount of nitrogen fertilizer was helpful to increase the activities of nitrogen metabolism enzymes in tomato leaves, thus improve fruit quality and yield. Compared with N0 treatment, the NR and GS activities of N3 treatment were increased by 42.79% and 182.93%, respectively. The vitamin C content, soluble protein content, soluble sugar content, soluble solids content and yield of N3 were increased by 70.90%, 6667%, 25.00%, 27.25% and 58.38% than those of N0 treatment, respectively. Principal component analysis, membership function method and comprehensive evaluation showed that the comprehensive ranking of different treatments was N3 > N4 > N2 > N1 > N0. Therefore, 428 kg·hm-2 was recommended as the fertilization standard for the cultivation of compound sand-cultured tomatoes, which provided theoretical basis for nitrogen fertilizer management of compound sand culture tomato.

Study on Changes of Carbohydrate and Its Related Enzyme Activities during Drying of Cigar with Different Maturities

LIU Boyuan1, ZHAO Songchao1, LI Yifan2, HE Fan3, YANG Weili4, ZHAO Mingqin1*

2021, 23(4):  192-201.  DOI: 10.13304/j.nykjdb.2019.0411

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In order to understand the influence of different maturities on the quality of cigar tobacco leaves, with cigar variety ‘H382’ as material,  a field experiment was conducted to study the differences of carbohydrate content and its related enzymes activities among different maturities cigar leaves, as well the quality of flue-cured cigar leaves with different maturities treatments, including Unripe, Ripe and Overripe. The results showed that water loss rate and moisture content of cigar leaves during air drying in Ripe treatment were suitable for ripening and harvesting, thus promoting the transformation of internal substances. The starch content in Ripen leaves was the lowest among three maturities leaves, thus suggested their starch degradation was relative fast and thorough. Meanwhile the contents of total sugar and reducing sugar were relatively higher, and the activities of amylase and starch phosphatase were all the highest in Ripe leaves. The main chemical components of the air-cured cigar leaves scored the highest  in Ripe treatment. The present research provided theoretical basis for cigar tobacco leaf harvesting in Wuzhishan, Hainan province.