Current issue

• 2020 Vol.36 No.29 Published:15 October 2020

  The Improvement of Ideal Plant Type of Rice: A Review Ma Mengying, Gong Wenjing, Kang Xuemeng, Duan Haiyan 2020, 36 (29):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb20190900610 Abstract + ( 811 )   HTML ( 23 )   PDF ( 1139KB )   ( 310 ) Rice yield has been stagnant in recent years, and the construction and optimization of the ideal plant type can create new possibilities for the improvement of rice yield. To strengthen the research on the breeding of rice ideal plant type, the classical models of five kinds of rice ideal plant types are summarized, and the morphological characteristics of root, stem, leaf, and panicle of rice are analyzed. This paper lists the related genes and their regulatory networks found at home and abroad in recent years which affect rice plant types, and puts forward future development trends in rice breeding.

  Low-Temperature Germination of Rice Seeds: Research Progress Quan Ruilan, Fu Ding, Ma Hanyun, Huo Erwei, Shen Guanghui, Guo Guiying, Wang Qinglin 2020, 36 (29):  7-14.  DOI: 10.11924/j.issn.1000-6850.casb20200300238 Abstract + ( 559 )   HTML ( 12 )   PDF ( 1168KB )   ( 112 ) The poor germination of rice varieties at low temperature limits the development of direct seeding rice. In order to promote the development of low-temperature resistant rice breeding and cultivate new rice varieties with low-temperature germination ability suitable for direct seeding, this paper outlined the evaluation methods of low-temperature germination ability of rice seeds and summarized the changes of cell membrane properties, reactive oxygen metabolism, energy supply, hormone content and other related physiological metabolism of low-temperature germination in rice. The molecular regulation mechanism of rice seed germination at low temperature was also generalized, including ABA-dependent signal transduction and ABA-independent signal transduction, at the same time, the genetic studies of QTL mapping and genome-wide association analysis (GWAS) related to low-temperature germination in rice were reviewed. On this basis, the existing problems in current research on low-temperature germination of rice were analyzed and suggestions were proposed, aiming to provide a reference for the research on rice low-temperature germination and the cultivation of new varieties.

  Simulation of Light Response Curve of Spring Wheat in Semi-arid Rainfed Area Under Drought Stress Yang Yang, Ma Yihao, Wang Runyuan, Qi Yue, Zhang Kai 2020, 36 (29):  15-24.  DOI: 10.11924/j.issn.1000-6850.casb20190800546 Abstract + ( 457 )   HTML ( 5 )   PDF ( 1360KB )   ( 62 ) To reveal the adaptability of drought stress in semi-arid rainfed areas to spring wheat light response model, through the analysis and comparison of four kinds of light response curve models, the applicability of drought stress to the spring wheat light response model was discussed. The results showed that continuous drought stress significantly reduced the net photosynthetic rate of spring wheat leaves, and the rehydration in the late stage of reproductive growth caused the over-compensation effect of T1 and T2 treatment. The fitting results of the light response parameters under each model showed that the maximum net photosynthetic rate had the best simulation effect in the exponential model, the light compensation point had the best fitting effect in the right angle hyperbolic correction model, and the dark breathing rate had the best fitting effect in the exponential model. The right angle hyperbolic correction model in the four models had the best simulation results. In summary, drought stress significantly reduced the photosynthetic capacity of spring wheat leaves and decreased the photosynthetic activity of wheat mesophyll cells, however, the hydration in the late stage of stress caused the photosynthetic capacity of T1 and T2 treated wheat leaves to recover, and the overcompensation effect appeared.

  Changes of Flag Leaf Photosynthetic Characteristics After Heading: Effect on Yield of Winter Wheat Li Longhua, Zhao Pengtao, Zhang Yaowen, Zhao Xiaoguang, Zhai Zhouping, Hou Junli, Shang Yi, Luo Honglian 2020, 36 (29):  22-31.  DOI: 10.11924/j.issn.1000-6850.casb20200300173 Abstract + ( 516 )   HTML ( 4 )   PDF ( 1372KB )   ( 66 ) To explore the differences of photosynthetic characteristics among different wheat varieties and the relationship between photosynthesis and economic yield, four different winter wheat varieties were selected to determine their photosynthetic characteristics in six growth periods. Results showed that: the change tendency and degree of six photosynthetic characteristic indexes of wheat flag leaf with the development process were basically the same, but the values and change degrees of photosynthetic characteristics of different varieties in different development periods were different. Six photosynthetic characteristic indexes were positively correlated with grain yield respectively. The order of the correlation degree was as following: green leaf area > stomatal conductance > intercellular CO2 concentration > net photosynthetic rate > chlorophyll content > transpiration rate. The order of correlation between photosynthetic characteristics and grain yield in different growth stages was middle grain filling stage > early grain filling stage >post grain filling stage >flowering stage> heading stage > end grain filling stage. It was the basis of increasing wheat yield to maintain and improve the green leaf area, chlorophyll content, net photosynthetic rate, stomatal conductance and intercellular CO2 of flag leaf from flowering stage to post filling stage. Therefore, it is of reference value and guiding significance to determine and compare the photosynthetic characteristics of germplasm resources in wheat breeding with high light efficiency.

  Yield per Plant and Main Agronomic Characters of Chinese Cabbage: Relationship Analysis Lai Jia, Huang Ling, Wei Shugu, Dai Shundong, Sheng Yuzhen, Zhan Qianfang, Ye Pengsheng 2020, 36 (29):  32-36.  DOI: 10.11924/j.issn.1000-6850.casb20200300213 Abstract + ( 651 )   HTML ( 7 )   PDF ( 1103KB )   ( 97 ) To reveal the effect of main agronomic characters on the yield per plant of Chinese cabbage, 16 new varieties were used as materials, and the correlation analysis, partial correlation analysis, multiple stepwise regression analysis and path analysis were conducted to analyze yield per plant and 8 agronomic characters. The results showed that the variation coefficient of the maximum leaf petiole length was the largest, followed by yield per plant. The maximum leaf width had an extremely significant and positive correlation with the yield per plant, while the plant width was significantly and positively correlated with the yield per plant. The partial correlation analysis showed that the yield per plant was positively correlated with all the 8 agronomic characters, among which the leaf number and the maximum leaf width were extremely and significantly correlated with the yield per plant, while the partial correlation coefficients between other characters and yield per plant were the maximum leaf petiole thickness and the plant width in order. The multiple stepwise regression analysis indicated that Y (yield per plant) = -1480.847 + 31.562X5 (the maximum leaf width) + 26.028X3 (the number of leaves) + 13.425X2 (the plant width) + 429.535X8 (the maximum leaf petiole thickness) was the optimal regression equation for yield per plant character, whose coefficient of determination R2 was 0.930. The direct path coefficients of the 8 agronomic characters to the yield per plant were all positive, and the top 4 characters were in the order of the maximum leaf width > the number of leaves > the maximum leaf petiole thickness > the plant width. Therefore, in the high yield breeding practice of Chinese cabbage, it is necessary to focus on the selection of the characters of the maximum leaf width and leaf number, and the maximum leaf petiole thickness and plant width should also be considered.

  Total RNA Extraction of Rice Seeds: Quality Discussion Xie Yuelan, Cui Huan, Wang Changlong, Chen Zhiqiang, Xiao Wuming 2020, 36 (29):  37-46.  DOI: 10.11924/j.issn.1000-6850.casb20190900635 Abstract + ( 625 )   HTML ( 11 )   PDF ( 4235KB )   ( 161 ) Total RNA isolation from rice seeds plays an important role in the molecular genetic basic experiments of rice. However, it is difficult to obtain high-quality rice seed RNA, which hinders the construction of cDNA library, RNA Seq and gene expression analysis. In order to explore the relevant impact factors of total RNA isolation from rice seeds and find the appropriate isolation methods, this study compared three different isolation methods, including Trizol method, GeneMark Kit Method and Adlaid kit method, different consumable treatment methods, grinding methods and other different factors to improve the effect of total RNA isolation from rice seeds. Different tests results showed that the Aidlad Polysaccharide Extraction Kit isolated total RNA from rice seeds with complete 28S, 18S bands, low degradation and high purity. Among the different consumables treatment methods, the total RNA isolated by the proteinase K-treated consumables degraded less than the other two methods. Besides, the 28S and 18S bands were clearer and more complete, and the total RNA had the highest quality and the best effect. In the grinding methods, the liquid nitrogen freeze-grinding method could inhibit the degradation of RNA by RNase effectively. In this study, the analysis and improvement of the relative factors of rice seed RNA isolation process lays a certain technical foundation for promoting the molecular experiment of rice seed as the research object.

  Plant E3 Ubiquitin Ligase and Abiotic Stress: Research Progress Wang Shuang, Li Haiying 2020, 36 (29):  47-53.  DOI: 10.11924/j.issn.1000-6850.casb2020-0053 Abstract + ( 538 )   HTML ( 12 )   PDF ( 1477KB )   ( 199 ) To have an in-depth understanding of the mechanism of plant E3 ubiquitin ligase in response to abiotic stress, the authors reviewed recent studies on the involvement of E3 in abiotic stress in Arabidopsis, rice, wheat and other plants. The pathways and types of E3 ubiquitin ligase are introduced, and the relevant research progress of E3 ubiquitin ligase in response to abiotic stress in plants is summarized. In view of the research status, the authors pointed out the research problems of functional redundant E3 and the problem of using high-throughput technology to find the target protein, aiming to provide a theoretical basis for improving the E3 ubiquitin ligase involved in abiotic stress regulation mechanism.

  Bioinformatics and Expression Analysis of MYB Gene Family Based on Transcriptome of Cold-acclimated Mirabilis himalaica Callus Liu Jiajia, She Lulu, Lan Xiaozhong, Lu Yaning, Yang Jiahui, Liu Huan, Lu Cunfu, Chen Yuzhen 2020, 36 (29):  54-61.  DOI: 10.11924/j.issn.1000-6850.casb2020-0104 Abstract + ( 298 )   HTML ( 4 )   PDF ( 2081KB )   ( 70 ) The paper aims to get insight into the MYB genes in Mirabilis himalaica. We used bioinformatics methods to screen the MYB genes from Mirabilis himalaica callus transcriptome data. The MYB protein sequences were identified by PlantTFDB 3.0 and BLASTP. At the same time, conserved domain was analyzed by using Web Logo 3.0 for those R2R3-MYB transcription factors with the largest proportion. Phylogenetic tree analysis was conducted by using Web MEGA 7.0 for all MhMYB. The expression levels of MhMYB under cold acclimation were analyzed by Mev. The results showed that 34 MYB genes were identified in Mirabilis himalaica, 30 of them belonged to R2R3-MYB, 2 of them belonged to 1R-MYB and 2 of them belonged to 3R-MYB. The subcellular localization prediction showed that MhMYB proteins were mostly localized in nucleus. The MhMYB proteins were divided into 15 subfamilies according to the classification method of Arabidopsis family. The homologous genes involved in flavonoids biosynthesis mainly belonged to the S2, S7 and S20 subfamilies. Gene expression analysis indicated that the expression level of MhMYB6, MhMYB15, MhMYB62 genes were up-regulated during cold-acclimation. Co-expression analysis showed that MhMYB6, MhMYB15 and MhMYB62 played a certain role in the regulation of flavonoids synthesis. This study shows that MhMYB genes play an important regulatory role in flavonoids biosynthesis and provides basic information for further exploration of the function of MhMYB genes.

  Chemical Composition and Antimicrobial Activity of the Essential Oil of Artemisia Sieversiana in Ningxia Zhang Chen, Wang Wencui, Bai Lu, Shi Shulian, Yao Lei 2020, 36 (29):  62-68.  DOI: 10.11924/j.issn.1000-6850.casb20190900663 Abstract + ( 671 )   HTML ( 4 )   PDF ( 1290KB )   ( 88 ) To explore the chemical composition, antibacterial function and safety of the essential oil of Artemisia sieversiana Ehrhart ex Willd. in Ningxia, steam distillation was adopted to extract the essential oil, gas chromatography-mass spectrometry (GC-MS) was adopted for component analysis. The inhibition zone diameter of three strains was determined by filter paper method, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. CCK-8 method was used to detect the toxic effects of Artemisia sieversiana essential oil on skin cells. The results showed that the main components of Ningxia Artemisia sieversiana essential oil were chamazulene (29.61%), camphor (4.80%), eucalyptol (4.32%), methyl isocostate (4.02%). The minimum inhibitory concentration for Pseudomonas aeruginosa and Escherichia coli was 0.0781 μg/mL, the minimum bactericidal concentration was 0.3125 μg/mL. The MIC of Staphylococcus aureus was 0.0195 μg/mL, the MBC was 0.078125 μg/mL. When the concentration of essential oil was less than 100 μg/mL, there was no toxicity to keratinocytes (HaCaT) and skin fibroblasts (NHSF). In summary, the essential oil of Artemisia sieversiana in Ningxia has strong antibacterial activity and high safety. The above results can provide a theoretical basis for the development of essential oil of Artemisia sieversiana, and science and technology support for local poverty alleviation.

  Effects on 2,3-butanediol Production of Saccharomyces cerevisiae: gpd2 Gene Knockout by CRISPR/Cas9 Technology Liu Lei, Li Na, Jiang Xueyong, Sun Jian, Lv Yuze, Ge Jingping 2020, 36 (29):  69-77.  DOI: 10.11924/j.issn.1000-6850.casb2020-0127 Abstract + ( 525 )   HTML ( 13 )   PDF ( 1788KB )   ( 94 ) This study aims at using CRISPR/Cas9 gene editing technology to knock out the glycerol-3-phosphate dehydrogenase gene (gpd2) in Saccharomyces cerevisiae, and investigating its effect on 2,3-butanediol production. Designing donor and guide RNA (gRNA) based on glycerol-3-phosphate dehydrogenase gene (gpd2) of S. cerevisiae W5, and linking the knockout vector could express Cas9 protein to the gRNA fragment, then the recombinant plasmid and donor DNA fragment were transformed into S. cerevisiae W5 cells. The gpd2 gene knocked-out strain was obtained through phenotypic screening and PCR validation, indicating that the gpd2 gene was successfully knocked out. Compared with the original strain, the gpd2 gene knocked-out strain increased ethanol production by 24.65%, and decreased glycerol production by 22.01% and 2,3-butanediol production by 10.60%. The production of 2,3-butanediol did not increase by knocking out the gpd2 gene, probably because that gradually accumulated NADH was preferentially oxidized by a large amount of alcohol dehydrogenase in the cell, and affected the production of ethanol rather than the synthesis of 2,3-butanediol. In this study, a suitable gene knockout system is constructed for S. cerevisiae, which has practical reference for further exploring the relationship between other metabolites of S. cerevisiae synthesis and 2,3-butanediol synthesis.

  Mannanase Production by Lactobacillus casei HDS-01: Condition Study Zhang Xin, Wang Yao, Jiang Jing, Zhao Dan 2020, 36 (29):  78-86.  DOI: 10.11924/j.issn.1000-6850.casb20190900618 Abstract + ( 556 )   HTML ( 6 )   PDF ( 1415KB )   ( 37 ) The purpose of this research is to increase the mannanase production of Lactobacillus casei HDS-01 isolated from the fermentation liquid of pickled Chinese cabbage and lay a foundation for the separation, purification and industrial production of mannanase. The single factor experiment was carried out by setting different medium components and fermentation conditions based on MRS. Mannanase activity and L.casei HDS-01 growth were measured by DNS method and flat colony counting method, respectively. The results showed that the optimum condition for mannanase production by L. casei HDS-01 is: 0.8% pectin as optimum carbon source, 0.2% yeast extract and ammonium nitrate as optimum nitrogen source, 0.2% ammonium citrate, 0.1% dipotassium hydrogenphosphate and 0.9% sodium acetate as inorganic salts; 100 mL /250 mL liquid loading, 7% inoculation, 37℃ culture temperature and initial pH value of 5.5. Under the optimal condition, after 36 h of shaking at a speed of 140 r/min, the enzyme activity could reach 72.7±0.30 U/mL, which is 6.51 times higher than that before optimization.

  The Purification Effect on Polycyclic Aromatic Hydrocarbons of Post-harvest Vigna unguiculata by Purifying Liquid Wu Guifen, Qiao Shuangyu, Long Minghua 2020, 36 (29):  87-92.  DOI: 10.11924/j.issn.1000-6850.casb20190900681 Abstract + ( 387 )   HTML ( 4 )   PDF ( 1375KB )   ( 32 ) To reduce PAHs in vegetables, Vigna unguiculata was used as a material, and different concentrations of detergent, salt, rice wine, rice vinegar, vegetable oil and water were used to dip the pods of V. unguiculata. The PAHs of V. unguiculata were detected by HPLC-MS to screen the optimum purification method of PAHs in V. unguiculata. The removal effect of rice wine and rice vinegar on the PAHs of V. unguiculata was basically the same. In the rice wine and the rice vinegar treatment group, ∑PAHs decreased by 68.92% and 73.88%, respectively. ∑PAHs was the total concentration of 16 polycyclic aromatic hydrocarbons monitored with priority by the United States Environmental Protection Agency. Rice wine and rice vinegar had a remarkable removal effect on naphthalene, diphenyl(a,h) anthracene and hydrazine(1,2,3-c,d) pyrene, etc. Water washing could effectively reduce the content of hydrazine (1,2,3-c,d) pyrene in V. unguiculata, but increase the content of phenanthrene. Salt treatment could increase the ∑PAHs by 77.15%, by increasing the 2 and 3 ring of PAHs accumulation in V. unguiculata. Although the vegetable oil treatment could reduce the content of individual PAHs, but it introduced other PAHs and increased the ∑PAHs. The results of toxicity equivalent calculation showed that rice wine could effectively reduce the PAHs toxicity in V. unguiculata, so could the salt treatment. The rice wine and rice vinegar could effectively reduce the ∑PAHs and dibenzo (a,h) anthracene, as well as their toxic equivalent in V. unguiculata.

  Effects of Rice Husk Biochar and Zeolite on Phosphorus Availability in Latosolic Red Soil and Fluvo-aquic Soil Zhu Jing, Bai Yuchao, Wang Zongkang, Zhang Xinming 2020, 36 (29):  93-99.  DOI: 10.11924/j.issn.1000-6850.casb2020-0101 Abstract + ( 304 )   HTML ( 5 )   PDF ( 1342KB )   ( 52 ) In this paper, the effects of rice husk biochar and zeolite addition on P availability of mixed fertilizer in latosolic red soil and fluvo-aquic soil were studied, in order to use rice husk biochar and zeolite to improve the availability of P fertilizer in soil, slow down the P fixation and improve the P utilization rate of P fertilizer. The effect of the addition amounts and combined ratios of rice husk biochar and zeolite in mixed fertilizer on P availability in soil were studied by laboratory culture experiments and field plot experiments, and P fertilizer use ratio in tomato was studied. The results showed that the addition amounts and combined ratios of rice husk biochar and zeolite had significant effects on the latosolic red soil available phosphorus content, and the available phosphorus content displayed significant interaction between addition amounts and combined ratios. The addition amount was the dominant factor that affected the latosolic red soil available P content. The combined ratios of rice husk biochar and zeolite had significant effect on the fluvo-aquic soil available P content, and they were the dominant factor on the latosolic red soil available P content. Compared with CK, the utilization ratio of P in tomato increased (31.05%-76.46%) with the mixed fertilizer added rice husk biochar and zeolite (5%-10%), P fertilizer use ration in tomato increased in the treatment of rice husk biochar and zeolite combined addition. The addition of rice husk biochar and zeolite could improve the P efficiency of the mixed fertilizer in the soil. The findings could have a positive effect on reducing the application of phosphate fertilizer and improving its utilization rate.

  Fertilizers’ Effect on Plug Seedlings Quality of Sunflower: Based on Principal Component Analysis Ji Hongting, Wang Yong, Zeng Yannan, Cheng Rundong, Wang Qingnan, Zhao Hejuan 2020, 36 (29):  100-106.  DOI: 10.11924/j.issn.1000-6850.casb20190900671 Abstract + ( 454 )   HTML ( 9 )   PDF ( 1432KB )   ( 57 ) This study aims to investigate the effects of different fertilizers on plug seedlings’ growth, and to select the suitable fertilizer type and healthy index for sunflower plug seedlings. The ornamental sunflower ‘Summer Breeze’ was used as material. The principal component analysis is used to comprehensively evaluate the effects of different fertilizers on plug seedling quality of sunflower. The results show that application of Huaduoduo fertilizer with high percentage of nitrogen and potassium could improve the leaf chlorophyll content, plant height and stem diameter, and increase assimilate accumulation of sunflower plug seedling compared with other fertilizer treatments. Application of potassium sulfate compound fertilizer could benefit root growth and root assimilate accumulation of sunflower plug seedling. Compared with other fertilizer treatments, the leaf chlorophyll content, plant height, stem diameter, dry weight per plant, fresh weight per plant, shoot dry weight and shoot fresh weight under Huaduoduo fertilizer with high percentage of nitrogen and potassium increase on average by 15.6%, 10.0%, 6.6%, 15.1%, 11.4%, 16.6%, 13.8%, respectively. The root dry weight, root fresh weight and main root length under potassium sulfate compound fertilizer increase on average by 13.3%, 35.0%, 4.9%, respectively. The efficiency of the four fertilizers is in order as follows: Huaduoduo fertilizer with high percentage of nitrogen and potassium>potassium sulfate compound fertilizer>controlled-release fertilizer> Huaduoduo No. 1. In conclusion, Huaduoduo fertilizer with high percentage of nitrogen and potassium is preferred for sunflower plug seedlings. The stem diameter/plant height ×fresh weight per plant ×100 could be used as the healthy index of sunflower plug seedlings.

  Temporal-spatio Variation Characteristics of Early Rice Heat Injury in Guangxi: 1958 - 2018 Tan Mengxiang, He Yan, Wang Ying, Ou Zhaorong, Huang Rongcheng 2020, 36 (29):  107-113.  DOI: 10.11924/j.issn.1000-6850.casb20190900685 Abstract + ( 242 )   HTML ( 5 )   PDF ( 3828KB )   ( 63 ) To master the variation characteristics of heat injury of early rice in Guangxi, and provide decision-making support for rice cultivation and damage prevention, based on the meteorological data of 89 meteorological observatories and the corresponding geographic information data in Guangxi from 1958 to 2018, we analyzed the change characteristics of the time and spatial distribution of heat injury of early rice by GIS technology, M-K abrupt change analysis and Morlet wavelet analysis. The results showed that: (1) the incidence of heat injury of early rice in Guangxi showed an increasing trend from 1958 to 2018, the 1990s was a trough, while the 2010s was a period of high incidence;(2) the occurrence of heat injury of early rice in Guangxi increased sharply in 2009, except serious heat injury, there was an abrupt change in the occurrence of both mild and moderate heat injury;(3) the occurrence frequency of heat injury had a significant periodic change of about 18 years and 32 years, it was expected that heat injury would still be in a high incidence season for early rice in Guangxi after the year of 2018; (4) heat injury areas of early rice in Guangxi were mainly distributed in the valleys of Zuojiang River and Youjiang River, Guizhong Basin and Xijiang River - Xunjiang River - Yujiang River Basin. The occurrence frequency of heat injury in coastal areas was less than that in inland areas. The conclusions above could have important practical significance for realizing high, stable and optimal yield of rice.

  ‘Hongyang’ Kiwifruit Ulcer Disease and Temperature and Humidity Meteorological Condition in Western Guizhou Chi Zaixiang, Chen Yun, Hu Qiuling, Wang Bei, Xiao Jun, Li Xiuya 2020, 36 (29):  114-125.  DOI: 10.11924/j.issn.1000-6850.casb20190800576 Abstract + ( 472 )   HTML ( 4 )   PDF ( 1458KB )   ( 90 ) To study the effect of temperature and humidity change on the occurrence of ‘Hongyang’ kiwifruit ulcer disease, based on monitoring data of ulcer disease from March to April in 2013 to 2018 of 5 test areas in Houchang, Miluo, Shaomi of Shuicheng County, Langdai of Liuzhi Special Zone and Pugu of Panzhou City, and the observation data of temperature, humidity and days of persistent rainfall in the same period, we used mathematical statistics to analyze the relationship of the occurrence and the prevalence of ulcer disease of ‘Hongyang’ kiwifruit with temperature, humidity and days of persistent rainfall. The results showed that the temperature and humidity condition for the starting time of ‘Hongyang’ kiwifruit ulcer disease was precipitation weather (daily precipitation ≥0.1 mm) for 4 days or more, the average daily temperature≤15.0℃ and the average daily relative humidity≥80%, in addition, after the occurrence of the disease, the low temperature, overcast and rain and high humidity maintained for 1 day or more. The climate condition for the prevalence of the disease was precipitation weather (daily precipitation ≥ 0.1 mm) for 4 days or more, the daily average temperature ≤18.0℃ and the daily average relative humidity ≥ 80%, in addition, after the prevalence of the disease, the low temperature, overcast and rain and high humidity maintained for 1 day or more. In conclusion, the occurrence and prevalence of ‘Hongyang’ kiwifruit ulcer disease has a good response to the change of temperature and humidity in Guizhou Province.

  Spatial and Temporal Characteristics of Spring Droughts in Shanxi He Peng, Xu Lishuai, Bi Rutian, Zhao Qingkang 2020, 36 (29):  126-131.  DOI: 10.11924/j.issn.1000-6850.casb20190800579 Abstract + ( 471 )   HTML ( 5 )   PDF ( 2298KB )   ( 152 ) Based on the drought monitoring results of TVDI in spring from 2007 to 2018, the spatial and temporal characteristics of spring droughts in Shanxi Province and the influencing factors were analyzed by trend analysis, skewness coefficient and structural similarity. The results showed that (1) affected by the spatial distribution of water resources (precipitation, surface water and ground water), the trend of TVDI decreased in southwest Shanxi from 2007 to 2018, which indicated that the probability of spring drought decreased, the trend of TVDI increased in northeast Shanxi and spring drought became serious; (2) the skewness coefficient of TVDI varied from -1 to -1.7 from 2007 to 2018 and was negatively correlated to cumulative precipitation on the time scale, moreover, precipitation at non water stress sensitive stages could not alleviate the drought caused by water shortage at the water stress sensitive stages, as the sensitivity of water stress was different at different growth stages; (3) with the increase of terrain complexity and the difference in soil types (ventilation porosity and water retention capacity), the SSIM of TVDI decreased, which indicated that the spatial difference increased, and vice versa.

  Determination of 5 Kinds of Pesticide Residues in Tea by HPLC Ding Yi, Li Rongyu, Liu Shijiang, Zhao Qijun 2020, 36 (29):  132-138.  DOI: 10.11924/j.issn.1000-6850.casb19010113 Abstract + ( 632 )   HTML ( 7 )   PDF ( 1537KB )   ( 122 ) To provide technical support for green tea production, HPLC method for determining 5 kinds of pesticide residues in tea samples was established. After soaking in water, the samples were extracted by V (n-hexane): V(acetone)=5:1, then extracted by ethylacetate, purified by floriferous silica and activated carbon column. High performance liquid chromatography (HPLC) was used to determine the pesticides of lambda-cyhalothrin, cypermethrin, bifenthrin, thiamethoxam and imidacloprid in the samples. The results showed that there was a good linear relationship between the chromatographic peak area and the concentration of the 5 pesticides in the range of 0.1-10.0 mg/L. The correlation coefficients were higher than 0.9994. The average recovery rate at three spiked levels of 0.1, 0.5 and 1 mg/L ranged from 85% to 95%, with the relative standard deviation (RSDs) from 0.55% to 2.5% in the blank tea samples. The method could meet the requirements of pesticide residue analysis test and has a high sensitivity.

  Application of Heat Pump Technology in Greenhouse Wang Qiang, Yang Yuyao, Xia Liru, Bao Encai, Cao Kai, Wu Delin, Cao Qingsui 2020, 36 (29):  139-144.  DOI: 10.11924/j.issn.1000-6850.casb20190900632 Abstract + ( 514 )   HTML ( 4 )   PDF ( 999KB )   ( 67 ) To explore the application prospect of heat pump technology in sustainable agricultural development, the heat pump development status, its working principle as well as application in various kinds of greenhouses were analyzed, and the application of heat pump in greenhouse in recent 20 years was reviewed. The results show that the application of heat pump in the greenhouse has geographical and environmental limitations in a certain degree, and the compound heat pump could break this limitation through mutual learning. Therefore, it is necessary to take compound heat pump as the key research object in the future to make heat pump more widely applied in greenhouse. As a new energy-saving, efficient and environmental protection technology, heat pump system is favored by the public, and has a good application prospect.

  Research Hotspots and Trends of Wetland Soil Microbiology Based on Bibliometric Analysis Cheng Zhichao, Wang Wenhao, Sui Xin, Zeng Xiannan 2020, 36 (29):  145-152.  DOI: 10.11924/j.issn.1000-6850.casb2020-0056 Abstract + ( 400 )   HTML ( 5 )   PDF ( 1793KB )   ( 62 ) Wetland plays an irreplaceable role in regional ecosystem, and is the result of a long-term interaction between regional ecological and environmental factors, it is important for maintaining the ecological balance. Based on the Web of Science database and the China National Knowledge Infrastructure (CNKI) database, we analyzed the bibliographic information to gain a high-frequency word co-word matrix, obtained co-occurrence view by using Ucinet and Net draw software, and studied the clustering of keywords, in order to discover wetland soil microbial research trends and hotspots. The results show that: (1) the number of publications about wetland soil microorganisms has basically increased year by year, and has entered a rapid growth stage since 2015; (2) the research contents of wetland soil microorganisms in China and abroad are quite different, foreign countries pay more attention to strengthening wetland protection and ecological restoration of degraded wetlands, while domestic researchers mainly focus on wetland soil microbial diversity and microbial functions; (3) keywords in co-occurrence network visualization, such as Wetland, Phytoremediation and Microbes, and soil microorganisms, soil enzyme activity and microbial biomass carbon, have become the focus of current research to some extent; (4) foreign countries mainly use wetland ecosystems whose habitats have been damaged as research objects, and the research scale is large, involving regions, countries and even the global level; domestic research is carried out on wetland reserves. In the future, it is expected that further research could be conducted in the field of wetland soil microorganism research and environmental protection theory and method.

  Influencing Factors of Grain Production Fluctuation in Hunan Province: Analysis and Prediction Yang Fanyu, Liu Liming, Yuan Chengcheng 2020, 36 (29):  153-160.  DOI: 10.11924/j.issn.1000-6850.casb20190900631 Abstract + ( 359 )   HTML ( 3 )   PDF ( 1269KB )   ( 80 ) The aim is to provide a theoretical basis for predicting the prospect of grain production, improving the efficiency of grain production and ensuring food security. Using the statistical data of Hunan Province, the grey relational analysis method was used to screen the highly relevant influencing factors and a GM (1, N) prediction model was established to predict the grain production. The most influential factors related to the grain production of Hunan in 2008-2017 are the sowing area of grain crops and the total power of agricultural machinery. The scientific and technological factors are the main factors that affect the grain production, followed by natural and social factors. In 2018-2027, the grain production of Hunan has less fluctuation, and the total power of agricultural machinery and the fiscal agricultural expenditure have a greater impact. The total power of agricultural machinery has an important influence on grain production in the past and next ten years, and it is increasingly dominant. To maintain the level of production, it is necessary to attach great importance to the level of agricultural mechanization and steadily increase the sowing area of grain crops.

  Models of Waste Resources Utilization and Operation of “Ecological Bridge” Project in Pinggu of Beijing Shi Shengwei, Yang Tingting, Wu Yueyang, Li Haoyang, Zhuo Xiuqiong, Duan Bihua 2020, 36 (29):  161-164.  DOI: 10.11924/j.issn.1000-6850.casb20191100889 Abstract + ( 765 )   HTML ( 8 )   PDF ( 979KB )   ( 122 ) The “Ecological Bridge” Project is consisted of enhancing the utilization of waste resources and comprehensive management of rural ecological environment in Pinggu District of Beijing. The authors analyzed the characteristics of waste resources utilization and the operation model of “Ecological Bridge” Project. The “Ecological Bridge” Project focuses on waste materials of peach branches and establishes a series of ecological cycle models through composting organic fertilizer, cultivating edible fungi, and making cultivation substrate and land surface covering materials. The operation model of the “Ecological Bridge” Project provides an ecological linkage between investment and financing platform, which could coordinate the use and the investment through establishing effective measures for financial funds management. This operation model could stimulate the incentives for enterprises to invest in rural environmental governance, and ensure the full support of local farmers. Through the project, the environmental quality has been effectively improved, the reform of the investment and financing mechanism for rural ecological environment construction has been promoted, and the comprehensive management level of the rural ecological environment has been enhanced. Therefore, the “Ecological Bridge” Project is a good case of rural environmental governance in China.