Current issue

• 2021 Vol.37 No.9 Published:25 March 2021

  Low Temperature Stress at Soybean Flowering Stage: Effect on Sucrose Metabolism of Leaves and Yield Zhao Jingjing, Zhou Nong, Zheng Dianfeng 2021, 37 (9):  1-8.  DOI: 10.11924/j.issn.1000-6850.casb2020-0240 Abstract + ( 456 )   HTML ( 9 )   PDF ( 1338KB )   ( 68 ) To study the effect of low temperature stress on the yield formation of soybean at flowering stage, ‘Kenfeng 16’ (chilling tolerant variety) and ‘Hefeng 50’ (chilling sensitive variety) were used as research materials, the sucrose content and metabolic enzyme activities were determined with pot experiment. The yield was measured at maturity stage. The results showed that plant height and yield were significantly reduced in both soybean varieties, and the height of bottom pods was increased. With the low temperature treatment prolonging, the production reduction was gradually increased. Compared with the control (H-CK and K-CK), the yield of ‘Hefeng 50’ was significantly decreased by 10.29%-30.88%, and that of ‘Kenfeng 16’ was significantly decreased by 9.58%-24.22%. The production reduction of chilling sensitive variety was higher than that of chilling tolerant variety. Starch and sucrose content declined and fructose content increased in leaves with the low temperature treatment prolonging. The activities of acid invertase, neutral invertase and sucrose synthase were improved, and the activity of sucrose phosphate synthase was inhibited by low temperature stress. The above indicators showed opposite trends in both soybean varieties during recovery period (1-4 days in natural environment after 4 days of low temperature treatment). The catabolism pathway of sucrose was accelerated, and the synthesis pathway of sucrose was inhibited, and finally sucrose content in leaves was drastically reduced when soybeans were exposed to low temperature stress during the flowering period, and the damage could not be restored within 4 days under natural environment. This is not conducive to the formation of soybean yield, and could be regarded as one of the important factors of soybean yield reduction caused by low temperature stress.

  Nitrogen, Phosphorus, and Potassium in Adlay: Uptake, Distribution and Utilization Characteristics Li Xiangdong, Dai Yi, Pan Hong, Lu Xiujuan, Wei Xinyuan, Shi Ming, Su Yue 2021, 37 (9):  9-15.  DOI: 10.11924/j.issn.1000-6850.casb2020-0280 Abstract + ( 583 )   HTML ( 7 )   PDF ( 1253KB )   ( 42 ) To provide a theoretical basis for scientific application of fertilizer and yield improvement, four adlay lines were used as materials in the field experiment in 2018—2019. The absorption, distribution and utilization of nitrogen (N), phosphorus (P) and potassium (K) were analyzed at different growth stages. The results showed that the total biomass dry weights of the four adlay lines ranged from 20.5 t/hm2 to 24.7 t/hm2. The biomass dry weights of the above-ground parts were 18.4-22.6 t/hm2, but the grain outputs were relatively low, which was 1969.2-3109.1 kg/hm2. N, P, K absorption and accumulation increased during heading to maturing period; nitrogen element was accumulated mainly in leaf and stem tissues in heading and flowering period, while grains had more N accumulation than other plant parts, and P, K were mainly accumulated in stems. The total absorption amounts of N, P, K were 183.93 kg/hm2, 62.57 kg/hm2and 320.56 kg/hm2 in average, respectively, with a ratio of N: P: K=2.94: 1: 5.12. In addition, the N, P, K use efficiency for grain output and harvest indices were relatively low, and the N, P, K requirement per 100 kg grain was 5.6-7.3 kg, 1.7-2.4 kg and 8.0-15.0 kg, respectively. It is concluded that the biomass is large in the four adlay lines with robust dry matter accumulation, but the N, P, K using and distribution efficiency for grain output are relatively low, indicating that there is still potential for improving the adlay yield.

  Chromosome Ploidy Analysis and Interspecific Hybridization of Abelmoschus manihot Yin Guo, Lu Zhengying, Sun Lu, Zhang Yanbo, Li Shiyun 2021, 37 (9):  16-21.  DOI: 10.11924/j.issn.1000-6850.casb2020-0205 Abstract + ( 412 )   HTML ( 4 )   PDF ( 2481KB )   ( 39 ) To study the chromosome ploidy of ‘Abelmoschus manihot No.3’, using the new root tip of ‘Abelmoschus manihot No.3’ as material, the chromosome ploidy analysis was carried out by conventional squash method. The results showed that ‘Abelmoschus manihot No.3’ was diploid with 66 chromosomes, and the karyotype formula was K (2n)=2x=66. The hybrid F1 could be obtained by crossing ‘Abelmoschus manihot No.3’ and allotetraploid upland cotton ‘Han 818’ with 52 chromosomes. The results showed that the hybrid F1 could be obtained from the cross combination with ‘Abelmoschus manihot No.3’ as female parent. The PCR amplification results showed that the hybrid contained parental specific bands. The hybrid could develop normally, but the pollen was abortive and could not bear. All the young bolls of the hybrid combinations with ‘Abelmoschus manihot No.3’ as male parent fell off, and no hybrid was obtained. The results of squash showed that there were 59 chromosomes in the new root tip of F1 hybrid, which further confirmed that F1 hybrid was obtained by crossing parents. This study revealed for the first time the genetic regularity of chromosome ploidy and intergeneric hybridization in this species, which could provide a theoretical basis for further study on cytogenetics of Abelmoschus manihot .

  Cloning and Expression Analysis of EgNIP5;1 Gene in Oil Palm Under Boron Deficiency Jin Longfei, Yin Xinxing, Feng Meili, Zhou Lixia, Cao Hongxing 2021, 37 (9):  22-27.  DOI: 10.11924/j.issn.1000-6850.casb2020-0265 Abstract + ( 581 )   HTML ( 5 )   PDF ( 1335KB )   ( 29 ) This research aims to investigate the mechanism of boron transportation in oil palm and lay a theoretical foundation for the subsequent screening of boron efficient varieties. According to the sequence of AtNIP5;1 which is functional verified, we cloned the full-length sequence of boron transport channel protein gene EgNIP5;1. The gene structure, sequence characteristics, phylogenetic relationships, transmembrane domain and expression pattern were analyzed. The length of open reading frame of EgNIP5;1 was 894 bp, which coded a protein of 297 amino acids. EgNIP5;1 had highly conserved NPS, NPV and Ar/R motifs. EgNIP5;1 contained 4 extrons and 3 introns, and 5 transmembrane structures. Phylogenetic analysis showed that EgNIP5;1 was closely related to TcNIP5 of cacao. Real-time fluorescence quantitative PCR analysis showed that EgNIP5;1 was mainly expressed in roots of oil palm, and the expression ofEgNIP5;1 was induced by boron deficiency. The expression of EgNIP5;1 reached the maximum level at 48 h after boron deficiency treatment, which was 8.2 times of the control. This research suggests that EgNIP5;1 is possibly involved in the response to boron deficiency and plays an important role in boron absorption of oil palm.

  Effect of Nutrient Solution pH on Nitrate-N and Ammonium-N Uptake of Rosa roxburghii Seedlings Wang Mengliu, Fan Weiguo, Guan Jiyuan, Gong Fangfang, He Chunli 2021, 37 (9):  28-34.  DOI: 10.11924/j.issn.1000-6850.casb2020-0286 Abstract + ( 541 )   HTML ( 6 )   PDF ( 1303KB )   ( 35 ) The effects of different nutrient solution pH conditions on the absorption characteristics of different nitrogen forms in Rosa roxburghii were studied, aiming to provide guidance for rational fertilizer in the cultivation of R. roxburghii on soil with different pH conditions. Taking R. roxburghii ‘Guinong 5’ seedlings as materials, using the method of nutrient solution culture and ion depletion, six treatments with nutrient solution pH 4, 5, 6, 7, 8, 9 were set up under the application of nitrate and ammonium nitrogen respectively, the absorption kinetics parameters of NO3 -, NH4+ in R. roxburghii seedlings were determined, and the plant height, dry weight biomass, nitrogen content and nitrogen uptake of the R. roxburghii seedlings were measured, the correlation between nutrient solution pH change and absorption kinetic parameters of NO3 -, NH4 and the correlation between nutrient solution pH change and plant height, dry weight biomass, nitrogen content and nitrogen uptake of R. roxburghii seedlings were analyzed. The results showed that the absorption pattern of nitrate nitrogen, ammonium nitrogen and total nitrogen followed the Michaelis-Menten kinetics equation. The nutrient solution pH change affected the absorption of NO3- and NH4+ in the roots of R. roxburghii. When the nutrient solution pH change increased from 4 to 9 and nitrate nitrogen was applied, the maximum absorption rate (Imax) of the root of NO3 -, the root and NO3- affinities, the rate (α) in the roots of the NO3- flow into the roots, plant height, dry weight biomass, nitrogen content and nitrogen uptake of R. roxburghii seedling decreased with the increase of pH, there was a significant negative correlation between the nutrient solution pH change and the above indexes. The above indexes of R. roxburghii seedling of NH4 + increased with the increase of pH under the condition of ammonium nitrogen application, and there was a significant positive correlation between nutrient solution pH change and the above indexes. Acidic condition is beneficial to the nitrate uptake of R. roxburghii seedlings, while the increase of the pH of the nutrient solution is not beneficial for R. roxburghii seedlings to absorb nitrate. Alkaline condition is beneficial to the ammonium uptake of R. roxburghii seedlings, while acidic condition is unfavorable for R. roxburghii seedlings to absorb ammonium nitrogen.

  Low Temperature Storage: Effect on the Physiological and Developmental Change of Strawberry Ramets Yu Hongmei, Yuan Huazhao, Guan Ling, Chen Xiaodong, Tang Shanyuan, Wang Qinglian, Zhao Mizhen 2021, 37 (9):  35-41.  DOI: 10.11924/j.issn.1000-6850.casb2020-0200 Abstract + ( 643 )   HTML ( 9 )   PDF ( 1285KB )   ( 59 ) To establish a safe cold storage system for strawberry ramets, the strawberry variety ‘Ning Yu’ was used as material. The effects of low temperature on the physiological indexes such as the contents of chlorophyll, SOD, POD, MDA, soluble sugar, proline and endogenous hormones, phenological phase and yield were measured. The results showed that under the low temperature, the contents of chlorophyll a, chlorophyll b and soluble sugar, the ratio of chlorophyll a/b, SOD activity and the soluble sugar were decreased, however POD activity was increased. After the treatment of 21 days, the decreased range of chlorophyll a content was 0.28 mg/g, SOD was decreased by 46.5%, while POD was increased by 428.73%. The content of proline was increased quickly on the 3 rd day of treatment, and then decreased gradually. MDA content showed a descending trend as a whole. GA3 and IAA were decreased first and then increased, but the content of ABA was increased rapidly first and then decreased, reaching valley and peak respectively at the 8th day of the treatment. In addition, within 8 days of low temperature storage, the phenological phase of strawberry was ahead of schedule, and the early-period yield was increased. In summary, under the storage condition of 5℃ low temperature, the strawberry ramets can be safely stored for 8 days, and early-mature and stable production could be achieved.

  Zinc Chitooligosaccharide: Effects on Disease Control, Fruit Quality and Yield of Greenhouse Tomato Yu Fenghui, Cheng Daoquan, Wang Xiangchuan, Zhou Qian, Wu Wenlei, Zhang Qian, Yang Chuanlun, Han Lixia, Wu Lei, Liu Haiyu, Xu Zeping 2021, 37 (9):  42-48.  DOI: 10.11924/j.issn.1000-6850.casb2020-0256 Abstract + ( 571 )   HTML ( 8 )   PDF ( 1519KB )   ( 49 ) To investigate the effect of zinc chitooligosaccharide (zinc-COS) on the disease control, fruit quality and yield of greenhouse tomato, the common plant pathogens and greenhouse tomato were used as research subjects. The antimicrobial activity of zinc-COS and its effect on disease control, plant growth, fruit quality and yield of tomato were determined by antimicrobial test and field experiments. The results showed that in the antimicrobial test, zinc-COS had a good inhibitory effect on various pathogens such as Pseudomonas syringae pv. lachrymans, Ralstonia solanacearum, FusaHum graminearum Sehw, Rhizoctonia solani Kühn, Fusarium oxysporum f. sp. Vesinfectum, etc., and the MIC values were significantly lower than that of conventional chemical bactericides. In the field experiments, compared with the control group under normal greenhouse management, the spraying of zinc-COS could significantly reduce and alleviate the occurrence of tomato plant diseases, and significantly promote the growth of tomato plant height and stem diameter, with relative increments of 17.11% and 53.89%. Moreover, the contents of soluble solid, solid acid ratio, reducing sugar, vitamin C and zinc in tomato fruit were increased by 5.88%, 11.90%, 27.88%, 51.60% and 87.91%, respectively. And the total acid content was reduced by 5.38%. Meanwhile, the total yield and yield of first-class fruit were increased by 23.35% and 30.73%, and there was no second-class fruit and inferior fruit. It can be seen that zinc-COS has a broad bacteriostasis spectrum, and better disease prevention, growth promotion, quality improvement and yield-increasing effects. Hence, zinc-COS has the dual-purpose of biological bactericide and fertilizer, and a certain value of development and application in agricultural production.

  Different Combinations of Fertilizer and Water: Effects on Plant Growth and Nutrient Absorption of Pepper Gao Wenrui, Wang Xin, Li Decui, Sun Yanjun, Han Bing, Fan Xiaoxue, Xu Gang 2021, 37 (9):  49-56.  DOI: 10.11924/j.issn.1000-6850.casb2020-0263 Abstract + ( 526 )   HTML ( 9 )   PDF ( 1486KB )   ( 78 ) The study aims to investigate the effects of different combinations of fertilizer and water on the growth and nutrient absorption of pepper. Pepper variety ‘Sujiao 5’ was used as the test material. By studying the effects of different water and fertilizer combinations on plant growth and nutrient absorption, the optimal water and fertilizer management techniques for pepper organic substrate cultivation were proposed. The results show that the growth of pepper plants is the most vigorous when N application amount is 0.88 g, P2O5 application amount is 0.40 g, K2O application amount is 3.31 g and the water content is 63.53%. When N application amount is 0.88 g, P2O5 application amount is 0.40 g, K2O application amount is 22.23 g and the water content is 63.53%, the plant stem diameter is the largest. Combined with the previous research results of water and fertilizer coupling on yield, it is suggested that N 0.88 g, P2O5 0.40 g, K2O 3.31 g should be added to each plant in the base fertilizer in pepper substrate cultivation production, and the water content of substrate should be controlled to 63.53%. Nitrogen fertilizer is the most absorbed in pepper seedling stage, followed by potassium fertilizer and phosphorus fertilizer. From flowering stage to early fruiting stage, potassium fertilizer is the most absorbed, followed by nitrogen fertilizer and phosphorus fertilizer. Increasing the water content of substrate and reducing the total amount of fertilizer can increase plant height, stem diameter and plant dry and fresh weight to a certain extent. The results could provide a theoretical foundation for further study on accurate management of fertilizer and water in pepper organic substrate cultivation.

  The Plastic Film Source Reduction Technology: Feasible Path Discussion Zhao Jijun, Yu Xianfeng, Zhang Xucheng 2021, 37 (9):  57-63.  DOI: 10.11924/j.issn.1000-6850.casb2020-0238 Abstract + ( 552 )   HTML ( 6 )   PDF ( 1148KB )   ( 170 ) In order to effectively reduce plastic film input and alleviate plastic film residue, the present domestic application status of agricultural plastic film is analyzed, and the feasible path of plastic film source reduction technology is discussed in this study. It is pointed out that the plastic film has the characteristics of “large mulching areas, and wide application to regions and crops”, and the plastic film residue has the characteristics of “time limit accumulation, regional difference, and distribution variation”. It is considered that five types of technologies have certain feasibility in plastic film reduction, such as reusing of old film, replacement with biodegradable plastic film, replacement with straw mulching, application of super absorbent polymer, and optimization of farming cultivation pattern, but the technologies need to be further studied and improved. It is suggested that a comprehensive application system should be constructed by integrating reduction technologies, products and patterns, which is the future development path of plastic film source reduction technology.

  Increasing Transplanting Density and Reducing Nitrogen Fertilizer: Effect on Nitrogen Loss and Nitrogen Use Efficiency in Paddy Field Gu Xuejia, Wang Yufeng, Sun Yang, Zhou Xuequan, Zeng Yuan, Wang Jun, Si Yang 2021, 37 (9):  64-70.  DOI: 10.11924/j.issn.1000-6850.casb2020-0273 Abstract + ( 504 )   HTML ( 10 )   PDF ( 1252KB )   ( 44 ) This study aims to lay a foundation for the prevention and control of nitrogen and phosphorus loss in paddy field. The plot experiments were conducted to investigate the effects of different treatments of increasing transplanting density and reducing nitrogen fertilizer on the nitrogen loss by surface runoff, nitrogen utilization efficiency of rice, and soil nitrogen balance. The results show that the total nitrogen loss is significantly reduced due to the decreasing of nitrogen application and the increasing of seedling number. The nitrogen loss before transplanting accounts for more than 60% of the whole growth period. The total nitrogen loss of the conventional treatment (T2) is the highest, reaching 11.80 kg/hm2, and those of T3-T6 treatments are reduced by 13.42%-53.52% compared with T2. The agronomic efficiencies of nitrogen fertilizer of T3-T6 treatment increase by 2.86%-28.99% and nitrogen partial productivity increases by 3.40%-24.98% compared with T2. The nitrogen surplus decreases with the decreasing of nitrogen application amount and the increasing of seedling number. The nitrogen surplus of T2 to T6 is 20.55 kg/hm2, 15.23 kg/hm2, 16.10 kg/hm2, 6.33 kg/hm2, -10.62 kg/hm2, respectively. Therefore, properly increasing seedling density and decreasing nitrogen input could reduce nitrogen loss, improve nitrogen use efficiency and guarantee soil nitrogen balance.

  Yield Effect of Sweet Corn and Characteristics of Farmland Nitrogen and Phosphorus Runoff Losses Under Reduced Fertilizer Rate Guo Qiuping, Liang Shan, Kan Yujing, Huang Bangyu, Lei Zexiang, Li Yongsheng, Du Jianjun 2021, 37 (9):  71-78.  DOI: 10.11924/j.issn.1000-6850.casb2020-0278 Abstract + ( 484 )   HTML ( 10 )   PDF ( 1328KB )   ( 67 ) Starting from the source of farmland non-point source pollution, the yield effect of sweet corn (Zea mays) and nitrogen and phosphorus runoff losses from farmland under reduced fertilizer rate were studied, and the measures for fertilizer reduction and controlling the losses of nitrogen and phosphorus from sweet corn farmland were explored. Field experiments were conducted with treatments: (1) no fertilizer (CK); (2) conventional fertilization (CF); (3) formula fertilizer (FF); (4) FF + organic fertilizer (OFFF); (5) FF + biochar (BFF); (6) FF + controlled-release urea (CRUFF); (7) FF + controlled release BB fertilizer (UCRF). The results showed that under the condition of reducing nitrogen fertilizer by 20%, there was no significant difference between the treatments of CF and FF, BFF, CRUFF, but the difference between the treatments of OFFF and UCRF (P<0.05) were significant. The yield of sweet corn of OFFF and UCRF increased by 17.8% and 16.8% respectively compared with that of CF. During the growth period of sweet corn, the total nitrogen concentration of runoff showed a gradual downward trend, and the total amount of CF nitrogen loss was the largest, reached 3.54 kg/hm2. The total amount of nitrogen loss in farmland was significantly reduced under the condition of reduced fertilization rate, with a decrease of 18.4%-45.5%, of which CRUFF was the most significant, followed by UCRF, OFFF and BFF. Under reduced fertilizer rate, the total phosphorus loss of OFFF, FF and UCRF were significantly reduced (P<0.05), with the decrease rate of 46.7%-60.0%, of which OFFF was the most significant. The concentration of nitrogen and phosphorus in shallow groundwater could reflect the nitrogen and phosphorus leakage of farmland to a certain extent. The nitrogen and phosphorus concentration of shallow groundwater of CF during the growth period of sweet corn was the highest of 45.85 and 4.10 mg/L, respectively, while the total nitrogen concentration of CRUFF was 22.79 mg/L, which was 50.3% lower than that of CF. The highest phosphorus concentration was 2.73 mg/L, which was 33.4% lower than that of CF. The nitrogen in the shallow groundwater was mainly in the form of ammonium nitrogen. Compared with traditional fertilization, formula fertilizer (21.2-6.36-18.42) aiming to reduce nitrogen by 20% and its combining application with controlled-release urea, controlled-release bulk blending fertilizer and organic fertilizer respectively could not only achieve high yield, but also effectively prevent and control the losses of nitrogen and phosphorus from farmland, reducing the risk of non-point source pollution.

  Classification and Evaluation of Cultivated Land Quality in Luohe City Li Zhifang, Shen Xinlei, Wang Rui 2021, 37 (9):  79-84.  DOI: 10.11924/j.issn.1000-6850.casb2020-0254 Abstract + ( 589 )   HTML ( 7 )   PDF ( 1387KB )   ( 62 ) To analyze the quantitative characteristics, spatial distribution and limiting factors of different types of cultivated land in Luohe City, Henan Province, and put forward specific protection measures, a comprehensive evaluation system with 17 selected indexes was constructed. By means of analytic hierarchy process and membership function method, the weight value and membership degree of each index were studied. The authors calculated the comprehensive indexes and grades according to natural breakpoint method. The results showed that: (1) the quality of cultivated land decreased from northeast to southwest in Luohe City, among which the quality of cultivated land in Linying County, Yancheng District, Yuanhui District and most of Zhaoling District was relatively high, and the quality of cultivated land in southwest Wuyang County and northern Zhaoling District was relatively poor; (2) the proportion of superior land, higher land, middle land and lower land in Luohe City was 12.48%, 39.28%, 38.58% and 9.67%, respectively, and the quality level of cultivated land needs to be further improved; (3) according to the main restrictive factors such as soil nutrient status, farmland infrastructure construction and soil barrier factors, the corresponding improvement measures were implemented. This study provides effective references for strengthening cultivated land quality construction and enhancing agricultural production capacity in Luohe City.

  The Improvement and Utilization of Bare Saline-alkali Soil in the Songnen Plain by Sand-covering Hu Juan, Zhou Daowei, Guan Shengchao, Zhang Dan 2021, 37 (9):  85-94.  DOI: 10.11924/j.issn.1000-6850.casb2020-0272 Abstract + ( 625 )   HTML ( 8 )   PDF ( 1413KB )   ( 47 ) The improvement and utilization of bare saline-alkali soil in the Songnen Plain were studied by different thickness of sand-covering and planting corps or forages. Two years results showed that SWC, pH and EC in sandy soil layer were significantly lower than that of saline-alkali soil layer, and increased with sandy soil depth. SWC, pH and EC in the same sandy soil layer decreased with the increase of sand-covering thickness. EC of surface saline-alkali soil was reduced from 621 μS/cm to 389-594 μS/cm under different sand-covering thickness treatments. The yield of maize with sand-covering of 30 cm in 2013 was 51.1% higher than that of 2012, and was 32.29% higher than that of sand-covering of 20 cm (P<0.05) and 8.9% lower than that of sand-covering of 40 cm (P>0.05), respectively. The yield and total root biomass of alfalfa with sand-covering of 30 cm in 2013 was 2.04 times and 3.65 times that of 2012, respectively. The yield of alfalfa with sand-covering of 30 cm was not significantly different from that of sand-covering of 20 cm and sand-covering of 40 cm, but the total root biomass of alfalfa increased by 55.9% and 106.3%, respectively. EC of alfalfa in sandy soil layer was decreased by 23.1% and 43.5% in 2012 and 2013 respectively under the sand-covering of 30 cm. Therefore, sand-covering has some improvement effects on saline-alkali soil, and planting maize and alfalfa under sand-covering of 30 cm has remarkable effects on yields.

  Sn-hsc70 Gene in Sipunculus nudus: Cloning and Expression Analysis Huang Jianqiang, Wei Wenlu, Zhong Ruzhuo, Zhang Jiawei, Yang Chuangye, Wang Qingheng 2021, 37 (9):  95-102.  DOI: 10.11924/j.issn.1000-6850.casb2020-0268 Abstract + ( 423 )   HTML ( 9 )   PDF ( 3888KB )   ( 35 ) The purpose is to explore the role of heat shock protein 70 (Hsc70) from Sipunculus nudus in the process of oogenesis, and to accumulate basic data for understanding the molecular mechanism of S. nudus oocyte development. With S. nudus as the samples, the full-length cDNA of Sn-hsc70 gene was obtained with the method of RACE technology. According to the bioinformatics analysis, Sn-hsc70 held the full-length of 2508 bp and encoded 656 amino acids; Sn-Hsc70 protein was a hydrophilic protein with molecular weight of 71.65 kDa. The conserved sequence, nuclear localization sequence, cytoplasmic localization sequence, continuous repeating tetrapeptide sequence, advanced structure, phylogenetic tree and domain of the protein were also analyzed. RT-PCR results showed that the expression level of Sn-hsc70 was significantly different in various stages of oocyte development (P <0.05) and showed a single peak. During the development of coelomic fluid (O1-O4), the expression of Sn-hsc70 increased rapidly, especially in the vigorous synthesis stage and mature stage of yolk (O3-O4). The expression of Sn-hsc70 was significantly down-regulated after leaving the coelomic fluid (O5-O6). The study indicates that Sn-hsc70 might play an important role in the accumulation of yolk, which is related to the weakening of oocyte transcription and protein synthesis.

  Pyruvate Decarboxylase (Pdc6) Gene Cloning and Bioinformatics Analysis in Saccharomyces cerevisiae Wang Changli, Liao Wei, Ye Guangbin, Ge Jingping, Liu Lei, Ma Yujian, Huang Xia, Bin Xiaoyun 2021, 37 (9):  103-108.  DOI: 10.11924/j.issn.1000-6850.casb2020-0296 Abstract + ( 488 )   HTML ( 11 )   PDF ( 1643KB )   ( 33 ) The aims are to study the structure and function of pyruvate decarboxylase (Pdc6) in Saccharomyces cerevisiae, and clone pdc6 gene in S. cerevisiae H5. A pair of 20 bp primers was designed by Primer5.0 software. The pdc6 gene was cloned using the genomic DNA of S. cerevisiae H5 as template, and the cloned sequence was subsequently verified and analyzed by bioinformatics method. The results show that the sequence length is 1692 bp with a completely open reading frame (ORF) without deletion. Besides, the Pdc6 protein contains 563 amino acid residues and the number of acidic amino acid is almost the same as that of the basic amino acid residues. The theoretical isoelectric point of Pdc6 is 5.8 and the maximum hydrophobicity is 2.32. Subcellular localization predicts that it is located in extracellular matrix and belongs to acidic protein, and the spatial structure model is predicted. This study shows that the structure of Pdc6 protein is similar to the Pdc1 protein and the Pdc5 protein. The bioinformatically analysis of the gene sequence of pyruvate decarboxylase (Pdc6) encoded by S. cerevisiae H5 can provide a theoretical basis for the subsequent study of gene sequence selection for single gene knockout.

  Development of Rhizobium Based on Web of Science Wu Wenyan, Cheng Zhichao, Li Mengsha, Sui Xin, Zeng Xiannan 2021, 37 (9):  109-117.  DOI: 10.11924/j.issn.1000-6850.casb20200300191 Abstract + ( 722 )   HTML ( 14 )   PDF ( 1413KB )   ( 58 ) The study aims to conduct a dynamic analysis on the research hotspots of rhizobium at home and abroad from 2000 to 2019, summarize the dynamic research development direction of rhizobium, and provide reference for the researchers in rhizobium-studying area. The articles in Web of Science database from 2000 to 2019 were used as data source. The relative analysis was conducted with bibliometric analysis and VOS viewer software. The results showed that the number of rhizobium articles was generally increased from 2000 to 2019. The United States, France and China were the top three countries that published relevant articles. Spanish Consejo Superior de Investigaciones Cientificas published the most papers in the world. The main journals in this field included International Journal of Systematic and Evolutionary Microbiology, Molecular Plant Microbe Interactions, Applied and Environmental Microbiology. The most cited author was Young, ND, of University of Minnesota. In conclusion, the rhizobium research of China is in the developing process. In the future, in order to accelerate the development of relevant scientific research, it is necessary to further identify the research hotspots related to rhizobium, establish a stable sharing resource relationship, and enrich and strictly inspect the rhizobium resources database (RRDB), so as to promote the depth of rhizobium research.

  Establishment of Gas Chromatography for the Determination of Fatty Acids in Soybean Zan Guangmin, Zhang Ling, Zhang Yanrui, Sheng Yinghua, Zhou Kai, Wang Xianzhi 2021, 37 (9):  118-124.  DOI: 10.11924/j.issn.1000-6850.casb2020-0250 Abstract + ( 547 )   HTML ( 11 )   PDF ( 1234KB )   ( 56 ) The objective of this study is to establish a rapid and efficient method for determining fatty acids in soybean, and provide certain references for the genetic improvement and food quality inspection of fatty acids in soybean. In this study, sixteen soybean varieties were used as materials to optimize the extraction of fatty acids by methylation method. The fatty acids determination conditions by gas chromatography were optimized, and the determination methods of fatty acids with internal and external standard were established. The results show that the optimal treatment temperature is 50℃ and the optimal processing time is 35 min for the methyl esterification extraction of fatty acids. The results of the internal and external standard methods based on Thermo Fisher gas chromatography have high consistency, and the internal standard method shows relatively high efficiency and low price. The methods established in this study could meet the requirements of high sensitivity, simple and rapid processing, and good linear, and thus could be applied to the rapid and accurate determination and quality improvement of fatty acids in soybean.

  The Immunomodulatory Effect of Auricularia curicula Lectin on RAW264.7 Cells Fang Jiamin, Ma Chengyao, Zhang Yanlong 2021, 37 (9):  125-130.  DOI: 10.11924/j.issn.1000-6850.casb2020-0228 Abstract + ( 405 )   HTML ( 15 )   PDF ( 1406KB )   ( 24 ) The paper aims to solve the problem of the release of IL-6, IL-1β, TNF-α, NO and the immune regulation effect of Auricularia auricula lectin on RAW246.7 cells. The A. auricula lectin was separated and purified by 40% (NH4)2SO4 precipitation method, and accompanied by the detection of coagulation activity and amino acid composition, the crude product of A. auricula lectin was obtained. Through the AKTA protein purification system, pure A. auricula lectin was obtained. The molecular weight of the lectin was analyzed by using SDS-PAGE electrophoresis. The Griess method was used to detect the secretion of NO by macrophage RAW264.7. ELISA was used to detect the release of IL-6, IL-1β and TNF-α. The results showed that the molecular weight of the A. auricula lectin was about 20 kDa. Through detection, it was found that A. auricula lectin could promote the secretion of cytokines IL-6, IL-1β and TNF-α by macrophage RAW264.7, and it showed a dose dependent and immunomodulatory effect.

  Gastrodia elata Polysaccharide from Shaanxi by Ultrasound-assisted Hot Water Extraction: Process Optimization and Antioxidant Activity Zhang Shuangqi, Liu Lin, He Nianwu, Zhao Ying 2021, 37 (9):  131-136.  DOI: 10.11924/j.issn.1000-6850.casb2020-0235 Abstract + ( 413 )   HTML ( 9 )   PDF ( 1329KB )   ( 36 ) The aim of this study is to optimize the extraction process of polysaccharide of Gastrodia elata and to analyze its antioxidant activity. In this study, Gastrodia elata in Shanluo City was used as material, the technology of ultrasonic assisted hot water extraction for polysaccharide of Gastrodia elata was optimized by orthogonal test, and the scavenging ability of DPPH free radical and hydroxyl free radical was determined and the antioxidant activity was analyzed. The optimum extraction condition was: 65℃ for 45 min with a solvent-to-solid ratio of 40:1 g/mL. The polysaccharide yield of Gastrodia elata was 32.83 mg/g under the condition. The ability of polysaccharides in Gastrodia elata to scavenge DPPH and hydroxyl radicals was improved with the increase of concentration, indicating that polysaccharides in Gastrodia elata had excellent scavenging effect on DPPH and hydroxyl radicals within a certain range. When the concentration was 3.5 mg/mL, the DPPH scavenging rate of Gastrodia elata polysaccharide reached 40.52% and hydroxyl radical was up to 36.52%. Polysaccharides from Gastrodia elata exhibit the potential to be developed into antioxidants.

  Dynamic Change of Protease Activity and Protein Content in ‘Two Stews and One Stop’ Flue-curing of Flue-cured Tobacco Pan Hong, Long Qingxiang, Lin Xiaoqi, Liu jie, Ai Fuqing 2021, 37 (9):  137-141.  DOI: 10.11924/j.issn.1000-6850.casb2020-0293 Abstract + ( 353 )   HTML ( 14 )   PDF ( 1044KB )   ( 35 ) The study aims to investigate the difference of the dynamic changes of protease activity and protein content of flue-cured tobacco between the ‘two stews and one stop’ curing and the conventional curing process. The results showed that protease activities presented a ‘double-peak curve’ of up-down-up-down in both the two curing processes, and the first peak occurred in the yellowing period with higher enzyme activity and the second peak occurred in the color fixing period. The protein content showed a downward trend, rapidly declined in the yellowing period, slowly declined in the fixation period, and had little change in the dry gluten period. The yellowing period was the main degradation period of protein, and the degradation range was above 80%. For the two curing methods, the enzyme activities of the two peaks were 208.5 and 199.26 U/mg respectively in ‘two stews and one stop’ curing process, which were 19.46 and 30.63 U/mg higher than those in the control, and the average enzyme activity in the peak interval was higher, the duration was longer, and the peak appeared later than those of the control. The degradation range of protein was greater in ‘two stews and one stop’ curing, and the degradation range during the yellowing period accounted for 89.3% of the total degradation range, 8.5 percentages more than that in the control, and the protein content of flue-cured tobacco was lower. The research results indicates that the activity and duration of tobacco leaf protease can be improved by ‘two stews and one stop’ curing method, which is more conducive to protein degradation and could reduce the protein content of the flue-cured tobacco leaf.

  The Control of Citrus Blue Mold: A Review Xu Mingyu, Du Chunmei 2021, 37 (9):  142-148.  DOI: 10.11924/j.issn.1000-6850.casb2020-0340 Abstract + ( 800 )   HTML ( 24 )   PDF ( 1254KB )   ( 156 ) Citrus blue mold is a major postharvest disease of citrus in the storage and transportation engineering, which can result in huge economic losses. It is mainly caused by Penicillium italicum and P. digitatum. In order to effectively prevent and control the occurrence and development of Citrus blue mold, and provide a scientific basis for the transportation and preservation of Citrus, in this paper, the main technical means and preparations of physical, chemical and biological control of Citrus blue mold were summarized, the advantages and disadvantages of different control methods were analyzed, and the follow-up research direction and strategy on controlling Citrus blue mold were put forward. It is pointed out that further studying the pathogenesis of Citrus blue mold, exploring the prevention and control mechanism of biogenic preparations on Citrus blue mold, and promoting the combination of biological control method and physical or chemical control method, could lay a foundation for the development of new drugs and establish an integrated control management strategy.

  A New Herbicide Flurochloridone in Potato Field on Qinghai Plateau: Application and Safety Li Wei 2021, 37 (9):  149-154.  DOI: 10.11924/j.issn.1000-6850.casb2020-0246 Abstract + ( 805 )   HTML ( 12 )   PDF ( 1254KB )   ( 83 ) To explore the safety application technology of the new herbicide flurochloridone in potato field on Qinghai Plateau, the potato variety ‘Qingshu 9’ was used as material, pesticide registration field efficacy trials and potato quality analysis were conducted, and the best dosage, application mode and quality index data of flurochloridone were measured. The results show that the effective dose of flurochloridone in potato field is recommended to be 350-650 g a.i./hm 2, the best application time is after sowing and before seedling, usually at 15-20 d after sowing. The best application mode is to seal the soil. The comprehensive control effect of Flurochloridone on monocotyledonous and dicotyledonous weeds could be more than 80%, and the yield could be increased by more than 10.15%, and it had no effect on the important parameters of the content of starch, Vc and reducing sugar and the dry matter quality. Therefore, Flurochloridone can be popularized as the main herbicide in potato fields on Qinghai Plateau and potato growing areas in northwest China.

  Secondary Metabolites Extracted from Three Plant Species: Antibacterial Effects on Six Strains of Fusarium Wilt Wei Qianqian, Zheng Ruirui, Chen Yunkun, Hu Chunyan, Feng Xue, Cao Hui 2021, 37 (9):  155-159.  DOI: 10.11924/j.issn.1000-6850.casb2020-0383 Abstract + ( 615 )   HTML ( 9 )   PDF ( 1348KB )   ( 58 ) Fusarium wilt, one of the most threatening soil-borne diseases of agriculture, affects the yield and quality of many crops seriously. The purposes of this study are to explore and develop the environmental friendly plant resources with effective and strong inhibition of fusarium wilt, and to provide a theoretical basis for the research of plant-derived fungicides. The extracts of Syzygium aromaticum, Glycyrrhiza uralensis and Stellera chamaejasme were used as materials, and the antifungal activities against six kinds of fusarium wilt fungi were determined by mycelial growth rate method. The results demonstrated that the three kinds of plant extract could all inhibit the six kinds of fungi at 2 mg/mL, the antifungal rate was above 44.5% after 96 h. S. aromaticum showed the highest inhibition activity with EC50 value ranged in 0.1473-0.3785 mg/mL; the EC50 value of G. uralensis and S. chamaejasme was 0.1866-2.6262 mg/mL and 0.6281-3.1703 mg/mL, respectively. The results show that the extract of S. aromaticum, G. uralensis and S. chamaejasme have better antifungal activity against the six kinds of fungi, and could be explored as the new botanical pesticide against fusarium wilt.

  The Status and Path of Modern Agriculture Development: Taking Shanghe County in Shandong Province as an Example Bai Tonghao, Gao Ruize, Zhan Ying, Li Jianwei, Ma Zhijun, Rui Yukui 2021, 37 (9):  160-164.  DOI: 10.11924/j.issn.1000-6850.casb2020-0314 Abstract + ( 567 )   HTML ( 12 )   PDF ( 1060KB )   ( 97 ) To study the current situation of modern agriculture development in some regions of China, the modern agriculture development in Shanghe County and Sunji Town under its jurisdiction was analyzed by using the methods of example analysis and path analysis. The results show that Shanghe County has reached the initial level in the development of agricultural modernization, but there are still some problems. Taking into account the actual situation of Shanghe County and the policies of Shandong Province, countermeasures such as accelerating the development of industrial integration, supporting advantageous industries, insisting on the leading of science and innovation, comprehensively deepening reform and promoting agricultural industrialization are proposed. In the process of agricultural modernization, we should pay attention not only to modernization, but also to the unique local culture in the vast rural areas, and give full play to local advantages, in order to realize the development and integration of industries and promote the process of agricultural modernization.