Current issue

• 2021 Vol.37 No.13 Published:05 May 2021

  Effects of Successive Years of Rice-duck Co-cultivation on Soil Properties, Rice Yield and Quality in Paddy Field Ji Li, Shao Wenqi, Chen Fuping, Dong Qingjun, Zhang Ankang 2021, 37 (13):  1-7.  DOI: 10.11924/j.issn.1000-6850.casb2020-0455 Abstract + ( 361 )   HTML ( 5 )   PDF ( 1382KB )   ( 47 ) To explore the influence of large-scale rice-duck co-cultivation for successive years on paddy soil properties, and rice yield and quality, two treatments were set up for 10 consecutive years (2010 to 2019) of large-scale rice-duck co-cultivation and conventional high-yield rice cultivation. The indexes of soil nutrient content, rice yield structure, rice quality, heavy metal content and pesticide residues in paddy fields were tested for comparison. The results showed that compared with conventional rice cultivation, the soil bulk density decreased by 5.65% after years of rice-duck co-cultivation, and the contents of organic matter, total nitrogen, available phosphorus and available potassium in 0-10 cm topsoil increased by 8.71%, 14.29%, 9.68% and 8.34%, respectively, which improved the fertility of paddy soil. The number of grains per panicle, the seed setting rate and the 1000-grain weight of the rice-duck co-cultivation increased by 11.3%, 2.9% and 3.2%, respectively, which was beneficial to the formation of large panicles, but the reduction of effective panicles reduced rice yield by 16.4%. The rate of brown rice and milled rice increased by 4.8% and 3.6%, respectively, the chalky grain rate and chalkiness degree decreased significantly, and the protein content increased by 7.5%. At the same time, the amylose content and hard gel consistency were not significantly different from those of conventional field and the overall rice quality was improved. In the two treatments, the contents of heavy metal elements in the soil and the contents of heavy metal elements and pesticide residues in rice all meet the green standards. Therefore, rice-duck co-cultivation for successive years could improve soil properties, soil fertility and rice quality, but the reduction of effective panicle can significantly reduce rice yield.

  Effects of Rice Field Fertilizer Reduction on Wheat Straw Decomposition Xin Caiyun, Wang Yu, Zhao Qinglei, Ma Hui 2021, 37 (13):  8-13.  DOI: 10.11924/j.issn.1000-6850.casb2020-0405 Abstract + ( 215 )   HTML ( 5 )   PDF ( 1218KB )   ( 35 ) The cumulative release rate and average release rate of straw residues, nitrogen, phosphorus, potassium and cellulosic carbohydrates during the decomposition of wheat straw were investigated under the condition of the same amount of fertilizer reduction in rice field. Total nitrogen was determined by H2SO4-H2O2 digestion-distillation method, total phosphorus by molybdenum-antimony anticolorimetry, total potassium by flame photometric method, cellulose, hemicellulose and lignin by colorimetric method. The residual rate, cumulative release rate and average release rate of straw were calculated, and the decay dynamics of straw were fitted with modified Olson exponential decay model. The results showed that fertilization could promote the decomposition of wheat straw in the rice field and reduce the residual rate of straw. Meanwhile, the modified Olson exponential decay model was used to simulate the decomposition process of straw. It was shown that the theoretical prediction time of 50% straw decomposition under CK and F50 treatment was shortened by 22 days and 12 days respectively compared with CK0 treatment. The theoretical prediction time of 95% straw decomposition under CK and F50 treatment was reduced by 95 days and 59 days compared with CK0 treatment, respectively. Fertilizer application could promote the cumulative carbohydrates release rate and the average release rate of straw nitrogen, phosphorus, potassium and fiber, in which, the fertilizer reduction had the least effect on the cumulative release rate of potassium, the average release rate of NPK nutrients was relatively quick in the early stage, cellulose, hemicellulose and lignin had longer release period. In rice-wheat rotation system, fertilizer application could promote the cumulative and average release rate of N, P, K and cellulose carbohydrate of wheat straw, and the study could provide theoretical support for fertilizer utilization of wheat straw.

  Regulatory Effects of Nitrogen Fertilizer and Separate Roots on the Interspecific Relationship and Intercropping Dominance in Oilseed Flax/Soybean Intercropping System Ruan Wenhao, Gao Yuhong, Wu Bing, Yan Bin, Wang Yifan, Cui Zhengjun, Zhao Bangqing, Cao Zhi 2021, 37 (13):  14-21.  DOI: 10.11924/j.issn.1000-6850.casb2020-0510 Abstract + ( 309 )   HTML ( 7 )   PDF ( 1393KB )   ( 30 ) The paper aims to optimize the interspecific relationship of intercropping crops by rational using nitrogen fertilizer and root separation model technology, for further exerting interspecific advantages. The pot experiment was adopted to study the effects on advantages and disadvantages, and interspecific competitiveness under different nitrogen fertilization modes including no nitrogen application(N0) and 15N 80 mg/kg (N80) and different root systems including completely separated(T1), root system no separation(T2) and root system separated by nylon net(T3) in oilseed flax/soybean intercropping system. The results showed that the dry matter accumulation of oilseed flax had no significant difference among different treatments. The dry matter accumulation of soybean in whole growth period under the treatment of N80 was significantly higher than that of N0 treatment. The effective pod number per plant, seed number per pod, 1000-grain weight and grain yield of oilseed flax under N80T2 treatment were the highest. Among them, the grain yield was 41.94%-137.84% higher than that of other treatments. The nodule number of soybean was N0>N80. The pod number per plant, the seed number per pod and the 100-grain weight were the highest under N80T2 treatment. The grain yield of N80T3 treatment was the highest and 4.33%-13.99% higher than that of other treatments, and its difference with N80T2 treatment was significant. The land equivalent ratio of all treatments was greater than 2, and it was the maximum under N80T2 treatment. The interspecific competitiveness under the T2 treatment showed that oilseed flax was stronger than soybean (AF>0, CRF>1), but it was the opposite under T3 treatment (AF<0, CRF<1). The results indicate that the application of 15N 80 mg/kg and non-separation of roots in oilseed flax/soybean intercropping system is beneficial to coordinate the inter-specific relationship between oilseed flax and soybean, and it can promote the crop grain yield.

  Response of Growth, Photosynthesis and Chlorophyll Fluorescence of Cotton to Drought Stress Yang Mingfeng, Wang Jinmei, Ji Chunrong, Liu Yong, Bai Shujun 2021, 37 (13):  22-28.  DOI: 10.11924/j.issn.1000-6850.casb2020-0388 Abstract + ( 316 )   HTML ( 5 )   PDF ( 1416KB )   ( 47 ) To study the effects of drought stress on growth, photosynthesis and chlorophyll fluorescence of cotton, an experiment was conducted with 3 treatments: severe drought, mild drought and CK. Up-land cotton cultivar ‘Xinluzao 57’ was taken as the material and grown in soil moisture test site, and indicators including the development stages, LAI, biomass, seed cotton yield, water potential, photosynthesis and chlorophyll fluorescence were determined under different drought degrees. The results showed that: LAI, photosynthetic matter accumulation, seed cotton yield, net photosynthesis (Pn), transpiration rate (Tr), stomatal conductance (Gs), the maximal photochemical efficiency of PSⅡ in the dark (Fv/Fm), actual photochemical efficiency of PSⅡ in the light (Yield) and photochemical quenching coefficient (qP) presented downward trends along with the prolonging of the drought stress. Water potential increased at the early time, and then decreased, while non-photochemical quenching coefficient (qN) showed an increasing trend. Significant difference was found among Pn, Tr and Gs in drought treatment and CK (P＜0.05). Significant difference was also found between severe drought treatment and CK for Yield, qP and qN after 15 days of drought stress. Pn, Tr, Gs, Yield, qP and qN could be considered as indicators in cotton leaves, while Pn, Tr, Gs were more sensitive.

  Effects of Truncation Measures on the Phenotypic Characters and Nutrient Elements of Seed Harvesting Trees in Seed Orchard of Robinia pseudoacacia Han Chao, Bi Wei, Duan An’an, Wu Hongzhu, Sun Yuhan, Su Lizhuo, Yang Zhiheng, Niu Dongsheng, Wang Hongsheng, Liu Jiaping, Han Peiyao, Liu Xiaodi, Li Yun 2021, 37 (13):  29-34.  DOI: 10.11924/j.issn.1000-6850.casb2020-0330 Abstract + ( 202 )   HTML ( 4 )   PDF ( 1365KB )   ( 24 ) With the increasing of tree age, there are problems in the seed trees of Robinia pseudoacaia seed orchard, such as high fruit position, difficult seed collection, low seed production rate and weak tree body. In view of these problems, the trunk of seed trees were truncated and dwarfed to explore the effect of trunk truncating measures and the changing law of nutrient elements. Taking the seed trees in two experimental bases of R. pseudoacacia seed orchard as the research object, three truncating height treatments (0.8, 1.0 and 1.2 m) were conducted respectively in 2016 and 2017, and phenotypic investigation and nutrient content analysis were conducted in 2018. The results showed that the branch length and inflorescence amount of the seed trees with three cutting height in Linghai base were significantly better than those of the non-truncating trees. In the comparative experiment, it was found that the branch length and inflorescence number of the seed trees were the best when the truncating height was 1.0 m; the determination of 10 nutrient elements showed that different truncating height had significant promoting effect on the absorption of both P and Mg element. The results of the research on R. pseudoacacia seed orchard in Jixian base showed that truncating trunk seed trees in 2017 and 2016 were superior to that of non-truncating seed trees, and the cutting measures could significantly improve the length and base diameter of the current-year-branches, and the amount and weight of compound leaves; the trunk truncating trees were conducive to Mg element absorption in 2017. These results could provide a basis for dwarf cultivation and nutrient balance of tree body in the seed orchard of R. pseudoacacia in the future.

  The Degradation Efficiency of Trametes hirsuta 27-1 Laccase on Phenolic Acids Zhou Xin, Miao Xiaolei, Yu Xuejun 2021, 37 (13):  35-41.  DOI: 10.11924/j.issn.1000-6850.casb2020-0770 Abstract + ( 307 )   HTML ( 5 )   PDF ( 1560KB )   ( 27 ) The study aims to investigate the degradation efficiency of phenolic acid compounds by Trametes hirsuta 27-1 laccase so as to provide a basis for the degradation of phenolic acids in bamboo forest. Ultra-high performance liquid chromatography was used. By measuring the change of phenolic acid content after bacterial solution treatment, we explored the degradation properties of 10 kinds of phenolic acid compounds by Trametes hirsuta 27-1 laccase. The results show that laccase could completely degrade vanillic acid, caffeic acid and sinapic acid; the degradation effect of syringic acid, ferulic acid and gentian acid are general and the degradation rate is about 50%; the degradation effect of protocatechuic acid is poor, the degradation rate could be 35%, and coumaric acid, p-hydroxybenzoic acid and chlorogenic acid could not be degraded. By studying the efficacy of Trametes hirsuta 27-1 laccase in the degradation of syringic acid under different conditions, it is found that, under the condition of pH 5, temperature of 30℃ and the initial concentration of syringic acid less than 100 mg/L, the strain could have high degradation ability of syringic acid. After ABTS solution is added to the degradation system as a mediator, the degradation effect is much better. At a concentration of 0.5 mmol/L, the degradation rate could reach 100%. In conclusion, the laccase produced by Trametes hirsuta 27-1 has good degradation efficiency on phenolic acids.

  The Regulatory Mechanism of Polycyclic Aromatic Hydrocarbon in Vegetables Wu Guifen, Long Minghua, Qiao Shuangyu 2021, 37 (13):  42-48.  DOI: 10.11924/j.issn.1000-6850.casb2020-0363 Abstract + ( 313 )   HTML ( 4 )   PDF ( 1518KB )   ( 33 ) The paper aims to reveal the self-regulation mechanism of PAHs in vegetables and provide certain references for reducing the harm of PAHs in vegetables to human body. Lactuca sativa var. capitata, Brassica juncea, Benincasa hispida, Cucurbita moschata, Psophocarpus tetragonolobus and Vigna unguiculata were selected as the test materials. The interaction between PAHs and protein, fat, VA, VB1, VC, VE, Ca2+, Fe2+, Na+ and K+ were studied to find out the key substances causing the change of PAHs content. The types and contents of PAHs in different types of vegetables are different, as well as the contents of nutrients. The order of the PAHs types in vegetables is: leaves> melons> beans. Protein, VE, VB1 and Fe2+ have synergistic inhibitory effects on benzo(a)pyrene, while VA and Ca2+ have direct or indirect inhibitory effects on acenaphthylene, acenaphthene, phenanthrene, fluorene, chrysene, benzo(k)fluoranthene, pyrene and benzo(g,h,i)perylene, while Na+could promote the absorption or accumulation of benzo(k)fluoranthene, fluorene and benzo(g,h,i)perylene in vegetables. Nutrients in vegetables have a certain regulatory effect on PAHs, especially vitamins with strong antioxidant properties, which play a significant role in reducing PAHs in vegetables.

  Comparison on Morphological and Quality Traits of Different Broccoli Cultivars Yu Hui, Wang Tingting, Zhang Pu, Huang Ying, Yu Tengrong, Cao Xue 2021, 37 (13):  49-55.  DOI: 10.11924/j.issn.1000-6850.casb2020-0311 Abstract + ( 299 )   HTML ( 5 )   PDF ( 1402KB )   ( 32 ) To select the broccoli cultivars with excellent morphological and quality traits, and provide material basis for the quality improvement, 19 domestic broccoli cultivars commonly used were taken as materials, and the morphological and quality indexes of flower head were determined, including quality, diameter, stem diameter, shape, size, color, chlorophyll, water, soluble protein, total soluble sugar and vitamin C. The results showed that the morphological and quality traits of these broccoli cultivars had significant differences, and most cultivars were relatively circular in shape and dark green in color. The diameter of flower head of ‘Saliao 55’ was the largest (18.50 cm); while the stem diameter of ‘Lvguan 308’ was the largest (3.97 cm). Both the quality and the water content of ‘Lvguan 90’ were the highest (286.82 g and 79.62% respectively). The shape of ‘Yilv’ was circular and its color was grey green, and the content of chlorophyll, total soluble sugar and vitamin C were all the highest (2.35 mg/g, 9.71% and 29.17 mg/100 g respectively), but the soluble protein content was the lowest (10.28 mg/g). The shape of ‘Biqing’ was relatively circular and its color was light green, and it had the highest level of soluble protein (11.32 mg/g) and the lowest level of chlorophyll and water content (1.31 mg/g and 47.13% respectively). It is found by the comprehensive comparison that three cultivars including ‘Lvguan 90’, ‘Biqing’ and ‘Yilv’ are of outstanding quality traits which could be used for further genetic improvement of broccoli.

  GC-MS Analysis of Volatile Components in Flowers of Four Kinds of Fragrant Dendrobium Species Cao Hua, Xu Feng, Lu Lin, Ji Yulu, Chen Xiang, Zhang Baoqiong, Li Han 2021, 37 (13):  56-62.  DOI: 10.11924/j.issn.1000-6850.casb2020-0381 Abstract + ( 414 )   HTML ( 5 )   PDF ( 1493KB )   ( 38 ) The aim is to analyze the volatile components of Dendrobium fragrans flowers by solid phase microextraction combined with gas chromatography-mass spectrometry (SPME/GC-MS). The volatile components and their corresponding contents of Dendrobium aphyllum, D. nobile, D. candidum and D. loddigesii were determined by SPME/GC-MS. 80 volatile components were identified from four Dendrobium species. The common volatile components of the four species were trans-α-ocimene and β-myrcene. Among them, the main volatile components of D. aphyllum were 2-ethylhexyl acetate and trans-α-ocimene, with relative content of 45.86% and 37.3%, respectively; that of D. nobile was β-caryophyllene, with the highest relative content of 20.7%; the main volatile components of D. candidum were α-pinene, limonene and cineole, with relative content of 31.49%, 14.6% and 13.6%, respectively; the main volatile component of D. loddigesii was 2-ethylhexyl acetate, the relative content was 83.21%. The volatile components and relative contents of different kinds of Dendrobium flowers were different. These main volatile components play a decisive role in the fragrance of different Dendrobium flowers.

  Introduction Adaptability and Stress Resistance of Hibiscus syriacus: Research Progress Feng Xiaolu, Chen Junqiang, You Jie, Dou Xiao, Dong Zhangkai 2021, 37 (13):  63-68.  DOI: 10.11924/j.issn.1000-6850.casb2020-0134 Abstract + ( 392 )   HTML ( 6 )   PDF ( 1112KB )   ( 35 ) This article summarizes the biological characteristics, application value, variety classification, breeding technology of Hibiscus syriacus, and the research status of its introduction adaptability and stress resistance. It is considered that H. syriacus is a garden plant with edible, medicinal, and economic value, as well as garden application and ecological value. In the future, in-depth research should be carried out on the introduction and domestication of H. syriacus, variety breeding, physiological and biochemical research, molecular biology, garden application, etc., making full use of local hibiscus resources while introducing foreign H. syriacus varieties, to cultivate new cultivars which could well adapt to the market.

  Garden Application of Groundcover Plants in China: Research Progress Luo Yuanyuan, Deng Kangxin, Liu Xiangyan, Zhang Yuqing, Guo Wensi, Wang Ke 2021, 37 (13):  69-76.  DOI: 10.11924/j.issn.1000-6850.casb2020-0269 Abstract + ( 489 )   HTML ( 15 )   PDF ( 1343KB )   ( 44 ) This paper reviewed relevant domestic literature from 2001 to 2019, teased out the concepts, classification and research trends of groundcover plants, and summarized related research progress of the variety resources, application principles and forms, and application evaluation of groundcover plants in landscape application. On this basis, it is proposed that in the research on the application of groundcover plants in gardens in China, the ecological value and landscape value of groundcover plants should be strengthened, the application quality of groundcovers in gardens should be highlighted, especially the application safety, and a resource bank of native herbaceous groundcover plants should be established.

  Response of Herbage to Climate Change in Qinghai Han Youxiang, Liu Caihong, Li Guoshan 2021, 37 (13):  77-83.  DOI: 10.11924/j.issn.1000-6850.20190700423 Abstract + ( 354 )   HTML ( 6 )   PDF ( 1349KB )   ( 46 ) Based on linear trend analysis and correlation analysis, we studied the height, coverage, yield, turning green period and yellow withering period of herbage and the influencing factors of climate change on herbage in Qinghai. The results show that the height and coverage of forages increase at different rates from July to August, the herbage production increases at different rates in June and July. The herbage production presents a decreasing trend in August. The rejuvenation period is advanced at a rate of -0.65 d/10 a. The yellow withering period is delayed at the rate of 0.15 d/10 a. The growth period of herbage is prolonged. In Banma, Gande, Jiuzhi, Maqên, Haiyan, Qingshuihe, Tianjun and Tongde, the growing period of herbage is extended, and in other areas, the growing season is shortened. Winter temperature, temperature in late June and wind speed in August are the main factors influencing herbage in the Tuotuo River area. Evaporation in September, the minimum air temperature in autumn and the accumulated temperature in June ≥10℃ are the main factors affecting herbage in Gande area. The air temperature, the ground temperature of 0cm in February and the accumulated temperature of ≥0℃ in September are the main factors affecting the forage in Tianjun area.

  The Climatic Regionalization of Cherry Planting Based on GIS in Wulian County Zhu Xiuhong 2021, 37 (13):  84-88.  DOI: 10.11924/j.issn.1000-6850.casb2020-0207 Abstract + ( 277 )   HTML ( 5 )   PDF ( 1954KB )   ( 61 ) Cherries have become a key fruit development object in the southeast mountainous region of Shandong, and the establishment of cherry planting divisions can provide support for fruit farmers to managing cherry orchards. The meteorological conditions such as dormancy, flowering, young fruit, fruit development and maturity were analyzed respectively. The factors were standardized using the maximum value standardization and range standardization methods, and the cherry comprehensive regionalization map of Wulian County was compiled through GIS technology. The results show that the suitability of cherry planting in Wulian County has a decreasing trend from southeast to northwest. The suitable areas for cherry planting in Wulian County are mainly distributed in Jietou, Kouguan, Chaohe and Hubu in the southeast. The sub-suitable areas are mainly distributed in Xumeng, Hongning, Songbai, Shichang and other parts of the central and northern regions. The unsuitable areas are mainly distributed in Li Town, Gaoze, Wanghu and Zhongzhi. Meteorological, topographic and soil factors are comprehensively considered, and most areas of the county are suitable for cherry planting. Therefore, cherry planting has a relatively wide regional and strong suitability in Wulian County.

  Model Construction of the Relationship Between the Yield of Lycium barbarum and Meteorological Condition in Qaidam Area Lei Yuhong, Wang Fake, Xu Xuelian, Hou Yue, Yan Liangdong, Li Chunhui, Liang Zhiyong 2021, 37 (13):  89-93.  DOI: 10.11924/j.issn.1000-6850.casb2020-0420 Abstract + ( 276 )   HTML ( 5 )   PDF ( 1256KB )   ( 206 ) In Qaidam Lycium barbarum producing area, the developmental phase, precipitation and sunshine in stations of Golmud and Nuomuhong were selected, and the effect of meteorological factors in different developmental phases on yield was studied by stepwise regression and probability statistics. The results showed that: (1) Lycium barbarum yield was positively correlated with daily average temperature in flowering stage of Laoyan branch, the highest temperature and accumulated temperature in spring branch growth stage, the lowest temperature in fructescence of Laoyan branch, temperature daily range in summer fruit formation and maturity stage and total sunshine hours of spring branch growth and autumn branch flowering stage; (2) the yield of Lycium barbarum was negatively correlated with the precipitation in the flowering stage of Laoyan branch, fruit formation stage of Laoyan branch, growth stage of spring branch, summer fruit maturity stage, autumn branch flowering stage and autumn fruit maturity stage; (3) the results of regression analysis between key meteorological factors and Lycium barbarum yield showed that the multiple correlation coefficient of the equation was 0.9705, according to built model, the results of previous yield and practical yield in 2019 had little absolute error and relative error, and high forecast accuracy, fully indicating that the selected 5 meteorological elements could accurately forecast the production of Lycium barbarum, which could be applied in practical forecast.

  Analyzing and Zoning of Eco-climate Suitability of Late-maturing Citrus in Sichuan Wang Xun, Xiong Bo, Li Qiquan, Liao Ling, Deng Honghong, Deng Qunxian, Yu Dong, Zhu Jin, Wang Zhihui 2021, 37 (13):  94-101.  DOI: 10.11924/j.issn.1000-6850.casb2020-0679 Abstract + ( 343 )   HTML ( 7 )   PDF ( 2063KB )   ( 77 ) From the climate data of 145 meteorological stations in Sichuan from 1981 to 2010, combing with the climate characteristics of the late-maturing citrus growing regions and the citrus tree status, the critical influencing factors on late-maturing citrus were analyzed. Eight environmental variables, including annual mean temperature, ≥10℃ accumulated temperature, frost-free period, July mean temperature, January mean temperature, sunshine hours, precipitation and altitude, were confirmed to be the climatic regionalization indices for Sichuan late-maturing citrus. Using GIS spatial interpolation, the climate elements and zoning index weight were calculated. Two meteorological disasters of late-maturing citrus during the growth period, such as the winter freezing injury and disaster elevated temperatures, were selected to conduct further zoning. The results show that the most suitable region of late-maturing citrus in Sichuan is with the altitude ranging from 400-700 m, and with gentle terrain slopes. The tolerable altitude for late-maturing citrus could be as low as 150-250 m and as high as 900-1200 m. The plateau and mountainous regions with the altitude more than 1200 m are unsuitable for late-maturing citrus growing.

  Pathogen Identification and Biological Control of Gray Mold on Postharvest Tomato Shen Yan, He Pengbo, He Pengfei, Wu Yixin, Kong Baohua, Li Xingyu, Shahzad Munir, He Yueqiu 2021, 37 (13):  102-107.  DOI: 10.11924/j.issn.1000-6850.casb2020-0798 Abstract + ( 464 )   HTML ( 7 )   PDF ( 1978KB )   ( 52 ) In order to explore the biological control of gray mold caused by Botrytis cinerea on postharvest tomato, strain FQ-2 was isolated from tomato fruit by the Koch’s postulate, and the pathogen was identified based on its morphology and rDNA-ITS sequence. Bacillus amyloliquefaciens B9601-Y2 (Y2), an endophyte of wheat and B. velezensis DJB5 (DJB5), an endophyte of Dendrobium thyrsiflorum were used for biological control of the disease. By analyses, FQ-2 was identified as Botrytis cinerea, Y2 and DJB5 had good preventive and therapeutic effects on gray mold of tomato. Y2 with 1×107cfu/mL and DJB5 with 1×108cfu/mL had 88.10% and 73.47% of prevention effects, respectively, after 10 days when they were inoculated following FQ-2 in the same day. In the curing experiment, on the day of inoculation of B. cinerea, Y2 with 1×108cfu/mL and DJB5 with 1×107cfu/mL had 68.56% and 78.74% of curing effect, respectively, after 10 days when they were inoculated following FQ-2 in the same day. These results are of great significance to the postharvest biological control of tomato gray mold.

  Effect of Chinese Herbal Compound Antibacterial Agent on the Disease Control and Yield and Quality of Radix Pseudostellariae in Continuous Cropping Field Wang Ruoyan, Hua Cui, Tan Longyan, Wang Daoping, Zhang Zhong, Wu Yuejun 2021, 37 (13):  108-114.  DOI: 10.11924/j.issn.1000-6850.casb2020-0549 Abstract + ( 330 )   HTML ( 4 )   PDF ( 1363KB )   ( 35 ) The aim of this study is to investigate the effect of Chinese herbal compound bacteriostatic agent on field disease control and yield and quality of radix pseudostellariae in continuous cropping field. Two-year continuous cropping plots of radix pseudostellariae were used, and the effect of different treatments was investigated through complete block plot experiment. The disease incidence of radix pseudostellariae treated with bacteriostatic agent No. 1 decreased by 82.2% (P<0.01), the disease index decreased by 14.7 times, the control effect was 93.0% (P<0.01), the yield increased by 43% (P<0.05), and the total polysaccharide increased by 51%. The combined effect of No. 1 bacteriostatic agent and No. 1 antiviral agent was 99.4% (P<0.01), the combined effect of this combination with chemical agents was up to 99.5% (P<0.01). The yield of the two treatments was twice as high as that of the control. When bacteriostatic agent No. 1 was combined with antiviral agent No. 1, the content of total polysaccharide and cyclic peptide B increased by 15% and 12% respectively, and the content of cyclic peptide B also increased by 12% with the application of bacteriostatic agent No. 1 alone. In conclusion, Chinese herbal compound bacteriostatic agent No. 1 has significant effect on the prevention and treatment of virus disease and the improvement of yield and quality of radix pseudostellariae.

  Suitability Evaluation and Taste Characteristics of Yuhua Tea Processed by Different Tea Varieties Ai Zeyi, Mu Bing, Li Song, Tang Jun, Wan Qing, Li Ronglin, Yang Yiyang 2021, 37 (13):  115-121.  DOI: 10.11924/j.issn.1000-6850.casb2020-0327 Abstract + ( 357 )   HTML ( 4 )   PDF ( 1415KB )   ( 45 ) The paper aims to identify and screen suitable varieties or resources for Yuhua tea, so as to provide technical support for the introduction of superior varieties of tea plants and the improvement of the quality of Yuhua tea. Agronomic traits including amino acids, tea polyphenols, water extract, caffeine, phenol-ammonia ratio, appearance, liquor color, aroma, taste and leaf bottom of six main tea varieties in Nanjing were compared. The suitability evaluation and taste characteristics of tea varieties for Yuhua tea were studied by biochemical analysis and sensory evaluation. Sensory evaluation results show that ‘Longjing 43’ has the highest score of aroma, taste and liquor color, and the total quality score is in the order of ‘Longjing 43’> ‘Suchazao’> ‘Yingshuang’> ‘Zhenong 117’/‘Xicha 5’> ‘Wuniuzao’. The analysis of quality components show that different tea varieties have little effect on the content of water extractable substances and caffeine in Yuhua tea, but great effect on the composition of amino acids, catechins and the contents of tea polyphenols and gallic acid. The total amount of tea polyphenols in ‘Longjing 43’ is significantly higher than that of the other five varieties, and its content of gallic acid (GA), catechin (C), epigallocatechin gallate (EGCG), ester catechins and total catechins also rank the highest. The taste characteristics of Yuhua tea are mainly determined by catechins with bitter taste. Neither L-theanine nor L-glutamic acid, the two umami amino acids in tea soup, could reach the umami threshold, while concentration of GA is much higher than the threshold (0.034 mg/mL). It is supposed that GA is one of the key factors for the umami taste in Yuhua tea. In addition, ‘Longjing 43’ with the highest content of tea polyphenols also shows the strongest DPPH free radical scavenging activity, and its IC50 is only 26.65 μg/mL, showing a strong antioxidant activity. In conclusion, ‘Longjing 43’ has certain advantages for processing Yuhua tea, and the study could provide technical reference for the introduction of superior varieties of tea plants and the improvement of the quality of Yuhua tea.

  Effects on the Biosythesis of Isofraxidin in Fermenfed Acanthopanax senticosus by Endophytic Fungus Wan Lu, Yan Jiajia, Zheng Chunying 2021, 37 (13):  122-126.  DOI: 10.11924/j.issn.1000-6850.casb2020-0378 Abstract + ( 255 )   HTML ( 4 )   PDF ( 1470KB )   ( 29 ) Endophytic fungi were used to ferment Acanthopanax senticosus to increase the contents of isofraxidin, then, isofraxidin was separated and purified. With isofraxidin as reference substance, four endophytic fungi were chosen to ferment A. senticosus, and the target strain which had the ability of improving the contents of isofraxidin was selected by HPLC. Meanwhile, isofraxidin was separated and purified by silica gel column chromatography method from the fermented A. senticosus, and the target strain was identified by its morphology characters and the ITS rDNA sequence homology. Isofraxidin in fermented A. senticosus by AJ14 was increased significantly which was separated and purified by silica gel column chromatography, and endophytic fungus AJ14 was identified as Aspergillus ochraceus. Fermented A. senticosus using endophytic fungi could biotransform isofraxidin directly, and this lays the foundation for the production of isofraxidin by microbial fermentation.

  Application of Eutectic Solvent Extraction of Baicalin and Its Compound Preservation Solution in Fresh Meat Wei Xiaxia, Zhang Xiaohu, Zheng Yan 2021, 37 (13):  127-134.  DOI: 10.11924/j.issn.1000-6850.casb2020-0214 Abstract + ( 205 )   HTML ( 5 )   PDF ( 2204KB )   ( 67 ) Taking Scutellaria baicalensis as the research object, microwave-assisted eutectic solvent was used to extract the effective antibacterial component baicalin. The effects of 9 different properties of DESs on the extraction rate of baicalin were investigated, and DES-1 was determined as the optimal extraction solvent. On the basis of single factor experiment, using response surface method analysis, the highest yield of baicalin was 66.99 mg/g at extraction time of 16 min, liquid-solid ratio of 20:1(mL:g), and extraction temperature of 85℃. The compound preservation solution was prepared with baicalin, and its fresh-keeping effect was evaluated by measuring the physical and chemical indicators of fresh meat. The results show that the compound preservation solution containing baicalin can effectively reduce the decreasing rate of pH and the increasing rate of peroxide value and volatile base nitrogen. It can effectively inhibit the fat oxidation and protein decomposition of fresh meat, and as the concentration of baicalin increases, the preservation effect of fresh meat is getting better. The study can be used as a technical reference for baicalin in meat storage and preservation.

  Single Tree Detection Method in Natural Environment: Based on Improved Faster-RCNN Network Zhang Yutang, Xie Xiaochun 2021, 37 (13):  135-146.  DOI: 10.11924/j.issn.1000-6850.casb2020-0362 Abstract + ( 495 )   HTML ( 4 )   PDF ( 4770KB )   ( 125 ) To study the single tree detection technology in the process of intelligent industrialization and precise management of fruit forests, this paper collected high spatial resolution remote sensing data of navel orange orchards in southern Jiangxi Province, and used K-means clustering analysis anchor (anchor points) to improve network parameters; proposed an improved network structure Des Faster-RCNN network to ensure the multiplexing and fusion of shallow features during the process of network convolution extracted features; added transfer learning in the training process to achieve fine-tuning. The robustness of detected small targets and densely adhered targets was enhanced. The experimental results showed that the detection accuracy of the Des Faster-RCNN network was improved by adding K-means on the test set was 97.68%, the recall rate was 97.99%, and the F1 value was 0.9783, increased by 8.01%, 8.14% and 0.081, respectively, compared with the those of Faster-RCNN network. And compared with other detection frameworks and traditional fruit forest detection research methods, the detection accuracy was improved by about 10%. The average detection time of a single image was about 0.138 s. In conclusion, the Des Faster-RCNN network improved by adding K-means proposed in this paper can adapt to the detection task of small and dense targets in complex environments, and obtain higher detection accuracy and robustness.

  Research Status of Sugar Beet Based on CiteSpace Bibliometric Analysis Wang Gang, Lu Zhengyu, Hao Wangsen, Geng Gui 2021, 37 (13):  147-152.  DOI: 10.11924/j.issn.1000-6850.casb2020-0669 Abstract + ( 365 )   HTML ( 4 )   PDF ( 1537KB )   ( 24 ) The research used the CiteSpace document visualization analysis tool to visually analyze 406 articles in CNKI from 2015 to 2020 and 1549 articles in WOS (including 150 articles of Chinese scholars), aiming to accurately understand the current status of China’s sugar beet research and its future development trend. The results show that Germany and the United States have developed rapidly in the field of sugar beet research and have great influence, while China’s research in this field has an obvious gap compared with the leading countries. China’s basic research on sugar beet is mainly concentrated in universities and scientific research institutes in its three main sugar beet producing areas (northeast, northwest, and north China), and the involvement of enterprises is relatively low. The subjects involved in sugar beet research include agricultural science, life science, ecological environment and material chemistry, among which, the agricultural science research is relatively practical and active, and the influence of material science research is relatively high. It is supposed that in the future, affected by the development of modern agriculture and interdisciplinary, the field of sugar beet research will receive more attention. Among the keyword visualization results, the most frequent words are sugar beet, yield, root rot, sugar content, photosynthetic characteristics, etc. In the past five years, domestic sugar beet research has mainly focused on agricultural science to solve key problems in sugar beet production, such as sugar beet planting yield, germplasm resource research and development, sugar beet adaptation to environmental stress, and sugar beet plant protection.

  Knowledge Map of the Research on Air Negative (Oxygen) Ions Xie Ziyang, Jiang Lan, Zhu Jing, Li Changshun, Deng Huiying, Liu Jinfu, He Zhongsheng 2021, 37 (13):  153-160.  DOI: 10.11924/j.issn.1000-6850.casb2020-0334 Abstract + ( 438 )   HTML ( 5 )   PDF ( 1570KB )   ( 46 ) The study aims to provide a reference for the future research on negative air (oxygen) ions by summarizing its research progress and frontier topics. Based on the Web of Science core database with ‘air negative oxygen ion’ as the search object, we got the literature on air negative (oxygen) ion from 2002 to 2019, and studied its development history in the 18 years through the knowledge graph. The results show that the Web of Science database includes 285 relevant documents in 2002-2019, with an average annual growth rate of 7.08% and a collaboration index of 4.54. There are many highly productive authors and highly cited articles, and articles from journals with high impact factors and with high citation counts are more likely to be cited by other authors. The major disciplines of the air negative (oxygen) ion source journals are physics, engineering technology, and chemistry, with 12 articles published in Journal of Physics D: Applied Physics, which is the largest number. Related high-frequency keywords from air negative (oxygen) ion articles are mainly about oxygen, air, performance, nitrogen, discharge, plasma and so on, the application of new energy and materials (e.g., plasma, batteries, graphene) is a hot topic in recent years. The Chinese authors have relatively a large number of published articles, citations and collaboration with authors from abroad, but their number of citations per article is relatively low. There are differences in the research field between Chinese and foreign authors. In China, the main focus is on the relationship between air negative (oxygen) ions and forest therapy and environmental factors, while in foreign countries, the application of air negative (oxygen) ions in chemistry, industry and medical treatment is the main research focus.

  The Way out for the Development of the New Agricultural Management Entities Zhang Xiao, Kuang Zongren, Sun Zhe 2021, 37 (13):  161-164.  DOI: 10.11924/j.issn.1000-6850.casb2020-0257 Abstract + ( 270 )   HTML ( 3 )   PDF ( 1146KB )   ( 62 ) Through literature research and data analysis, this paper studies the problems faced by the new agricultural management entities, aiming to provide ideas for solving the development dilemma. The research shows that in the process of development, the new agricultural management entities are faced with problems such as human resource shortage and waste, unstable management right, difficulty in cooperation and slow progress in starting up the business. The paper argues that to break the development barriers, we should distinguish existing new agricultural management entities and future new agricultural management entities, promote land transfer with the concept of urban and rural integration to create a suitable environment for the growth of new agricultural management entities, pay more attention to innovation and entrepreneurship and solve development problems through entrepreneurship.