Current issue

• 2019 Vol.35 No.29 Published:14 October 2019

  The Main Agronomic Characters of the New Wheat Variety‘Pingmai 189’: Adaptability Analysis 2019, 35 (29):  1-7.  DOI: 10.11924/j.issn.1000-6850.casb18090128 Abstract + ( 1484 )   PDF ( 1316KB )   ( 188 ) To assess the environmental adaptability, stress resistance and high yield of the new wheat variety ‘Pingmai 189’, the yield, effective spike number, grain number per spike, 1000-grain weight, the maximum tiller number, spike forming rate, plant height, black embryo rate of‘Pingmai 189’in different areas of Henan were investigated and analyzed with traditional seed cupping method. Results showed that‘Pingmai189’had better adaptability and stability in many agronomic characters, such as, effective spike number, grain number per spike, 1000-grain weight, the maximum tiller number, spike forming rate, plant height, black embryo rate and other related characters. In addition, the drought resistance index of‘Pingmai189’was 0.921 and its drought resistance level reached the third level in 2015, and that of 2016 was 0.800, which belongs to the fourth level, the comprehensive performance of drought resistance was better. The disease resistance of ‘Pingmai189’to stripe rust and sheath blight was medium in 2015 and 2016. The comprehensive analysis show that‘Pingmai 189’has better wide adaptability and stability in main agronomic characters, and is suitable for planting in Henan and its bordering areas.

  Correlation and Cluster Analysis of Agronomic Characters of 35 Wheat Varieties 2019, 35 (29):  8-13.  DOI: 10.11924/j.issn.1000-6850.casb18050078 Abstract + ( 794 )   PDF ( 1235KB )   ( 441 ) The aim is to provide a basis for genetic improvement of wheat. 35 wheat varieties were used as materials. 7 agronomic characters, such as yield, stem length, grain number per spike and so on were investigated with correlation analysis, multiple comparison analysis and cluster analysis. The influence factors of yield were discussed. Correlation analysis showed that the correlation coefficient between yield and effective panicles per unit area and grain number per spike was 0.685 and 0.439, respectively, reaching a very significant level. The correlation coefficient of yield and the basic seedlings per unit area was 0.368, which also reached a very significant level. Multiple comparison analysis results showed that the correlation coefficient of yield and basic seedlings per unit area, the highest stem tillers, effective spikes per unit area, stem length, grain number per spike and 1000-grain weight was 435.2742857, 358.8485714, 413.7485714, 371.8142857, 419.8914286, 406.7571429, respectively, and they all reached a significant level. The results of cluster analysis showed that the 35 wheat varieties were divided into 7 groups. The basic seedlings per unit area, stem length and grain numbers per spike are the most important factors that restricting the yield, and the study provides a theoretical basis for breeding, hybridization and tissue culture selection of high-yield wheat.

  Sowing Date and Planting Density: Effect on Yield Formation of Winter Wheat Cultivar‘XinMai29’ 2019, 35 (29):  14-19.  DOI: 10.11924/j.issn.1000-6850.casb18050043 Abstract + ( 595 )   PDF ( 1261KB )   ( 165 ) To screen out the suitable combination of sowing date and planting density of winter wheat, and adapt to the environment change of increaing accumulative temperature before winter, taking‘Xinmai 29’as the object, a field experiment with split plot design was conducted at Huixian City in the northern Henan Province during 2016-2017. The main plots were three sowing dates of October 12th, 18th and 24th, and the split plots were three planting densities of 210×104, 300×104 and 390×104 seedlings/hm2. The effects of different sowing dates and planting densities on yield and yield components of‘Xinmai 29’were explored. The results showed that, the grain volume weight of October 12th sowing was significantly lower than those of the other two sowing dates. The average grain volume weight also increased with the increasing planting density. All three yield components (the number of spike, grain number per spike and 1000-grain weight) of wheat was significantly influenced by the sowing date. However, the impact of sowing date on grain yield was not significant. There were significant difference levels for yield, the number of spike and grain number per spike with planting density. The interaction effect between sowing date and planting density had significant difference for grain yield and spike number per area. October 12th was the best sowing date with the suitable density of 300×104 seedlings/hm2. The suitable sowing date for the yield potential of‘Xinmai29’was October 12th to 18th, and the corresponding suitable planting density of basic seedlings was 300×104-390×104/hm2.

  Biochar Affects Seed Germination and Root Morphological Characteristics of Maize 2019, 35 (29):  20-24.  DOI: 10.11924/j.issn.1000-6850.casb18050137 Abstract + ( 586 )   PDF ( 1564KB )   ( 265 ) In order to define the effects of biochar on the seed germination and seedling growth, maize was used as experimental material for germination culture experiment. The seeds were cultured in light culture under the control, bamboo leaf biochar, tobacco stalk biochar and wheat straw biochar treatment. The germination potential, germination rate, germination index, and root morphology of the seedlings were measured respectively. Results showed that biochar had no significant effect on maize seed germination, but had significant inhibitory effect on the root development of maize seedlings. The inhibition rates of bamboo leaf, tobacco stalk and wheat straw biochar to maize root length were 14.4%, 59.7% and 37.3% respectively. This experiment can be initially concluded that: under the conditions of biochar, the sensitivity of maize seed germination is less than the root elongation of seedlings; and the root inhibition rate can be used as a good test method for the assessment of phytotoxicity of biochar.

  Maize Drought in Northeast China: Meteorological Service Index System and Its Applicability 2019, 35 (29):  25-31.  DOI: 10.11924/j.issn.1000-6850.casb18050111 Abstract + ( 564 )   PDF ( 1301KB )   ( 313 ) In order to enhance the professional capacity of drought monitoring, prediction, assessment and prevention of agricultural and meteorological sectors in maize production, we summarized 7 kinds of maize drought indexes suitable for northeast China, including sliding precipitation, soil moisture in 10-day period, soil rainfall gain and loss rate in 10-day period, soil moisture in different growth periods, water deficit index at various development stages, and plant morphological indicators, and pointed out the applicability characteristics of different indexes and applied the indexes in the risk zoning of maize arid climate in northeast China. Finally, we discussed the problems that should be highlighted in the construction and use of maize drought indexes, indicated that crop drought index should have distinct agricultural meteorological significance, clear mechanism, suitable spatial and temporal scale, suitable business application, and the indexes confusion and blind spatial and temporal average should be avoided.

  Physiological Indexes of Maize Inbred Lines: The Relationship with Drought Resistance and Recovery Capacity 2019, 35 (29):  32-40.  DOI: 10.11924/j.issn.1000-6850.casb20190400073 Abstract + ( 614 )   PDF ( 1501KB )   ( 125 ) To evaluate the drought resistance of different maize inbred lines, the relationship between physiological indicators and drought resistance, recovery capacity and comprehensive drought resistance was explored. 19 inbred lines were used as materials under moderate drought and re-watering of seedling by potted weighing and controlling water method. The responses of biomass, chlorophyll content, carotenoid content, Fv/ Fm, proline content and antioxidant enzyme to drought and re-watering were determined. The analysis found that the inbred lines‘Zheng 8713’,‘Zheng 63 ’and‘Chang 7-2’had stronger drought resistance, recovery capacity and comprehensive drought resistance. The drought resistance of inbred lines‘Zheng C112’,‘Zheng 718’and‘Zheng 6722’was weak, but their recovery capacity and comprehensive drought resistance were strong. Inbred lines‘Zheng 3733’,’Zheng E846’and‘Zheng 36’had weak recovery capacity, but drought resistance and comprehensive drought resistance were strong. At the same time, there was a significant correlation between carotenoids and drought resistance (P=0.503*). The relationship between POD antioxidant enzymes and recovery ability was significant (P=0.421*), Fv/Fm and comprehensive drought resistance was significant (P=-0.456*). There were significant differences between chlorophyll content and drought resistance (P=0.468*) and comprehensive drought resistance (P=0.407*). The above results provide excellent germplasm resources for breeding drought-tolerant varieties, and guidance for the screening and identification of drought resistance, recovery capacity and comprehensive drought resistance of maize.

  Continuous Water Stress at Key Growth Stages of Spring Maize: Effects on Soil Moisture Dynamics and Yield 2019, 35 (29):  41-46.  DOI: 10.11924/j.issn.1000-6850.casb20190400009 Abstract + ( 570 )   PDF ( 1438KB )   ( 123 ) To investigate the effects of water stress at key growth stages on soil moisture dynamics and yield of spring maize, water stress simulation experiment in critical growth period was carried out in Wuwei, a typical arid area. The experiment set up CK (control treatment with sufficient water supply during the whole growth period), T1 (continuous drought during the jointing period until the end of the growth period), and T2 (continuous drought during the tasseling period until the end of the growth period). The results showed that under the influence of water stress, the soil temperature of 0-20 cm and 0-40 cm in T1 and T2 drought treatment was higher than that of CK treatment, and the soil temperature of T2 treatment was higher than that of T1 treatment. After the seven-leaf stage, the soil moisture content of the drought treatment section varied greatly. By the milky stage, the water storage capacity of T1 and T2 treatments decreased by 72% and 57%, respectively. The water stress during the key growth period mainly affected the final yield by affecting the vegetative growth and reproductive growth of spring maize. The T1 and T2 drought treatment yields decreased by 66.4% and 54.2%, respectively, and the yield level WUE decreased by 23.4% and 13.1%, respectively. The research results can provide a basis for the quantitative assessment of the drought in the key growth period of spring maize, and provide ideas for the determination of the ecosystem response threshold.

  Screening of Salt-tolerant Hybrid and Conventional Foxtail Millet 2019, 35 (29):  47-51.  DOI: 10.11924/j.issn.1000-6850.casb18080020 Abstract + ( 547 )   PDF ( 1230KB )   ( 358 ) To select salt-tolerant foxtail millet varieties, the seeds and seedlings of 27 common varieties from Shanxi, Shaanxi, Hebei were treated. The germination rates in different salt concentrations were investigated, and the relative salt damage rates were measured. The salt damage index at seedling stage was measured according to the identification method of salt tolerance at seedling stage of“Millet Germplasm Resources Description Standard and Data Standard”. The results showed that under 0 mmol/L and 150 mmol/L salt stress, there was little difference in the germination period of different varieties. However, under 200 mmol/L salt stress, the difference was obvious. At 200 mmol/L salt solution,‘Zhang zagu No.3’reached the salt tolerance standard of grade 3, and‘Zhang zagu DH3’reached the salt tolerance standard of grade 5. The results of salt tolerance identification at seedling stage showed that‘Zhang zagu No.3’reached the salt tolerance standard of grade 3, and‘Zhang zagu DH3’reached the salt tolerance standard of grade 7. The results of seedling emergence and growth showed that with the increase of the salt concentration, the seedling rate decreased gradually, and the growth height of seedlings also decreased gradually. For the individual with non- salttolerant parents, the salt tolerance could be significantly enhanced by hybridization. The results indicate that the salinity concentration of soil more than 0.3%, is not suitable for the normal growth of foxtail millet, and the mild saline-alkali land with a salt concentration of less than 0.3% is the key area for breeding salt-tolerant millet varieties.

  Biodegradable Film Mulching Affects the Physical and Chemical Properties of Soil, the Growth and Yield of Cotton Field-seeded After Barley (Rape) Harvest 2019, 35 (29):  52-56.  DOI: 10.11924/j.issn.1000-6850.casb18050037 Abstract + ( 429 )   PDF ( 1421KB )   ( 80 ) Field experiments were carried out in cotton field-seeded after barley (rape) to explore the effects of film mulching on biomass accumulation and yield in 2016 and the effects of film mulching on soil physical and chemical properties, biomass accumulation and yield in 2017. Four treatments, including planting without mulching (CK), planting with polyethylene film mulching(PM) and two kinds of biodegradable film mulching(AM and BM), with three replicates were conducted. The results showed that the mean soil water content and soil temperature in 0~20 cm soil layer increased in all mulching treatments compared with that in CK. The soil available N, P and K increased with highest value in the treatment of PM and BM at cotton seedling and budding stage respectively. The soil organic content increased in the treatment of BM and decreased in PM and AM compared with that in CK. The soil enzyme activities of urease, invertase, catalase, and neutral phosphatase decreased at seedling stage but increased at budding stage with higher value in the treatment of PM and BM respectively. The biomass accumulation initiated and terminated earlier in all film mulching treatments than that in CK. The maximum biomass and its maximum speed increased with optimized characteristics in the treatment of BM. Yield and yield ratio before frost was higher in film mulching treatments, especially in BM, than that in CK. In sum, biodegradable film mulching can promote seedling growth due to the improvement of soil physical and chemical properties, which may contribute to improving yield and the yield ratio before frost.

  Differential Analysis of Yield Formation and Quality of Fresh-edible Sweetpotato Varieties with Different Yield Levels 2019, 35 (29):  57-62.  DOI: 10.11924/j.issn.1000-6850.casb18080025 Abstract + ( 532 )   PDF ( 1430KB )   ( 132 ) To investigate the difference of growth, yield formation and quality of fresh- edible sweetpotato varieties with different yield levels, and provide references for breeding, two fresh-edible sweetpotato varieties with different yield levels‘Taishu No.14’and‘Yanshu No.25’were used as materials. The stem and leaf growth, root expansion rate, yield and quality at harvest stage were determined, and the variation was analyzed. The results showed that: the stem diameter, vine length, stem and leaf fresh weight, and leaf area per plant of ‘Taishu No.14’were higher than those of‘Yanshu No.25’. The underground part growth of‘Yanshu No.25’ was earlier than that of‘Taishu No.14’, while the growth rate of the underground part of‘Taishu No.14’at the later growth stage was faster than that of‘Yanshu No.25’. 80 days after planting, the weight per storage root and the storage root weight per plant of‘Taishu No.14’were significantly higher than those of‘Yanshu No.25’; marketing tuber ratio of‘Yanshu No.25’was higher than that of‘Taishu No.14’, storage root yield of‘Taishu No.14’was higher and dry matter yield was lower than that of‘Yanshu No.25’. The dry matter ratio, starch ratio and soluble sugar content of‘Taishu No.14’were significantly lower than that of‘Yanshu No.25’, β- carotene content was significantly higher and taste grade was lower than that of‘Yanshu No.25’. The stem and leaf function period of‘Taishu No.14’was longer than that of‘Yanshu No.25’, which made‘Taishu No.14’ have greater high- yield potential, and the quality and taste of‘Yanshu No.25’were superior to those of ‘Taishu No.14’

  Fertilization Model of Nitrogen, Phosphorous and Potassium: Based on Yield and Quality Index of Sugar Beet 2019, 35 (29):  63-69.  DOI: 10.11924/j.issn.1000-6850.casb18050134 Abstract + ( 630 )   PDF ( 1402KB )   ( 123 ) To explore the optimal fertilization model of nitrogen, phosphorus and potassium for high yield and good quality of sugar beet, we took sugar beet as the research object and adopted the field regression experiment, to study the relationship between N, P and K factors in sugar beet cultivation and yield and quality of sugar beet, determine the weight of each quality index (brix, K, Na, a-N) and yield by Analytic Hierarchy Process (AHP), and evaluate the yield and quality of all kinds of sugar beet by membership function, and preliminarily establish and optimize the regression equation of N, P, K factors and the comprehensive quality index of sugar beet. The results showed that: the suitable N, P, K application amount was 68.89-88.61 kg/hm2, 47.94-92.06 kg/hm2, 54.34-100.66 kg/hm2 by optimal fertilization of N, P and K based on sugar beet quality and yield index; the NPK fertilizer ratio was 1.13:1:1.11, which was an appropriate fit value in a specific area and should be adjusted according to the basic fertility of soil in the cultivated area.

  Populus tomentosa Hybrid with High Cold Resistance: In vitro Culture and Vitrification Seedlings Research 2019, 35 (29):  70-75.  DOI: 10.11924/j.issn.1000-6850.casb18050017 Abstract + ( 508 )   PDF ( 1634KB )   ( 126 ) To apply the good resources of Populus tomentosa in the north of north latitude 41°, and provide high quality seedlings for the construction of ecological protection forest in northern China, the shoots from branch water culture of‘Mengshu No.1’(P. tomentosa hybrid with high cold resistance) were used as explants, the best disinfectant and sterilization time were screened. The stem segments propagation of aseptic seedlings, leaf blade differentiation, rooting culture and vitrified seedling culture were conducted. The shoots were sterilized in 0.10% HgCl for 5 minutes, the disinfectant effect was the best. The pollution rate of explants was 15.60%, and the germination rate was 77.70%. The best proliferation medium of stem segments was MS+ 0.20 mg/L 6-BA+0.05 mg/L NAA, and the average number of differentiation bud was 4.21. The best induction medium of root was 1/2 MS+0.50 mg/L IBA+0.20 mg/L NAA, and the rooting rate was 93.90%. Vitrification seedlings restored best in the medium MS+0.2 mg/L 6-BA + 0.05 mg/L NAA + 30 g/L sucrose+8 g/L AGAR, and the restoration rate was 82.38%. The establishment of in vitro micropropagation system for‘Mengshu No.1’ lays a foundation of somatic polyploid breeding for P. tomentosa, landscaping and ecological construction in northwest China

  Changlin Series of Camellia oleifera Abel.: Introduction Performance and Evaluation 2019, 35 (29):  76-79.  DOI: 10.11924/j.issn.1000-6850.casb18070056 Abstract + ( 681 )   PDF ( 1274KB )   ( 119 ) The paper aims to provide reference for selecting superior varieties of Camellia oleifera for Changshan and west Zhejiang by evaluating the introduction performance of Changlin series in Changshan. We introduced 6 fine varieties of Camellia oleifera from Changlin series in 2010 and analyzed the tree growth, yield and fruit traits. The results showed that: there were differences in tree growth, fruit traits and yield between the 6 fine varieties; the crown of‘changlin 23’,‘changlin 166’and‘changlin 3’was relatively large; while the yield per crown of‘changlin 4’,‘changlin 40’,‘changlin 53’and‘changlin 23’was over 1 kg/m2 and the oil content of kernel of‘changlin 23’and‘changlin 40’was over 44%. In conclusion,‘changlin 4’,‘changlin 40’, ‘changlin 53’and‘changlin 23’have better performance in the experiment and could be given priority for the development of Camellia oleifera in Changshan.

  Application of Near-infrared Spectroscopy in Tea: Research Progress 2019, 35 (29):  80-84.  DOI: 10.11924/j.issn.1000-6850.casb18050109 Abstract + ( 505 )   PDF ( 1124KB )   ( 159 ) To analyze the quality of tea quickly, this paper describes the research progress of near-infrared spectroscopy in tea briefly, including qualitative analysis and quantitative analysis. The qualitative analysis is mainly applied in tea identification, origin identification, grade evaluation, tea beverage identification, etc. In terms of quantitative analysis, the main application of near-infrared spectroscopy is the quick measurement of the content of chemical constituents in tea. The study points out the problems in the application of nearinfrared spectroscopy in tea, and predicts the technology in tea quality control, online monitoring, substance testing, etc., aiming to provide a reference for the broader application of near-infrared spectroscopy in the improvement of tea quality.

  Aquatic Economic Plants Cultivated in Biogas Slurry with Different Hydraulic Loads 2019, 35 (29):  85-89.  DOI: 10.11924/j.issn.1000-6850.casb18080119 Abstract + ( 515 )   PDF ( 1329KB )   ( 69 ) In this research, we cultivated aquatic water spinach under different hydraulic loads of biogas slurry by using the inlet and outlet water dynamic system, and analyzed the purifying effect of biogas slurry and the growth of aquatic water spinach. The results showed that the purifying effect of biogas slurry was the best when the hydraulic load was between 1.1×10-2 and 1.7×10-2 m3/(m2·d), and the removal efficiency of COD, NH4+-N and TP was more than 60%. At the same time, the heavy metals concentration in the edible parts of aquatic water spinach was lower than that stipulated by the Standard of Green Food Aquatic Vegetables (NY/T 1405- 2015). Therefore, aquatic water spinach cultivated under reasonable hydraulic load would effective purifying of waste water from pig farm, and could be used as edible vegetables and green fodder whose safety of food was guaranteed, and recycle some of the nitrogen and phosphorus in biogas slurry to achieve certain economic benefits.

  Urban Land Use in Lanzhou: Performance Evaluation and Analysis of Obstacles Mechanism 2019, 35 (29):  90-96.  DOI: 10.11924/j.issn.1000-6850.casb18050141 Abstract + ( 546 )   PDF ( 1509KB )   ( 163 ) The paper aims to explore the dynamic changes of land use performance and the mechanism of obstacle factors in Lanzhou. We took the entropy weight method and optimized TOPSIS method to evaluate the land use performance of Lanzhou with the evaluation index system from 4 levels (input level, utilization degree, benefit and ecological sustainability), then used the obstacle degree model and SPSS correlation test to judge the obstacle factors and analyzed the mechanism. The results show that: the land use performance of Lanzhou has increased year by year, and the performance value increased from 0.192 to 0.707 from 2006- 2015, achieving a transition from low performance to good performance; the obstacle degree of land use level and benefit have decreased year by year, while the obstacle degree of land input and ecological sustainability have increased year by year, in the long run, the degree of land use is still the primary factor affecting the overall performance of land use in Lanzhou. Therefore, it is suggest to raise the construction land area per capita, to control the population density rationally, to develop a three-dimensional model, to adjust the land use structure scientifically, and to optimize the overall resource.

  Intensive Use Level of Construction Land in Ningxia: Spatial Differentiation Characteristics Based on Spatial Autocorrelation 2019, 35 (29):  97-102.  DOI: 10.11924/j.issn.1000-6850.casb18060056 Abstract + ( 498 )   PDF ( 1586KB )   ( 317 ) Abstract: The purpose of this study is to find out the status level of intensive use of construction land in 22 counties of Ningxia, summarize the spatial distribution characteristics, analyze the problems in land use, and to provide scientific evidence for further improving land management and scientifically formulating targeted management policies. Based on the county scale, this study used multi-factor comprehensive evaluation method to evaluate the intensive use of construction land in 22 counties of Ningxia, and used spatial autocorrelation analysis method to analyze the spatial differentiation of construction land. This study revealed that the spatial differentiation of intensive use of construction land in Ningxia were obvious. Only five counties got more than 80 points, and the land use was highly intensive. The state of intensive use of construction land in Ningxia showed a gradual decline from north to south: The hotspots were concentrated in the northern part of Ningxia; the sub-hotspots were located in the periphery of the hotspots; the sub-cold spots were scattered and scattered; the cold spots were distributed in the central and southern counties. The conclusion of this study is that the intensive use level of construction land in Ningxia is not high and the spatial distribution is extremely unbalanced. It shows strong spatial correlation and obvious spatial agglomeration characteristics. In the future, the northern and southern counties of Ningxia will have to formulate differentiated land management policies based on their own realities. The northern counties with better economic development are mainly to excavate the potential of stock land and improve efficiency of new land; the southern counties are mainly to promote rapid economic and social development and improve land use efficiency.

  Fungi from Forest Litters of the Greater Khingan Mountains and Their Secondary Metabolites’Activities 李泽宇,,邱天艺 and 2019, 35 (29):  103-108.  DOI: 10.11924/j.issn.1000-6850.casb19040008 Abstract + ( 687 )   PDF ( 1395KB )   ( 278 ) This study aims to obtain the new fungal resources with activities from forest litters of the Greater Khingan Mountains. A particle method was used to isolate cultivable fungi from forest litters. The fungal sequences of internal transcribed spacer were used for the molecular identification of isolated fungi. Two methods were used for the fermentation of novel fungi and the preparation of secondary metabolic extracts. A double-layer-plate drug diffusion assay and a DPPH radical scavenging assay by thin layer chromatography were used to test activities of crude extracts, respectively. The result of molecular identification showed that 40 fungi were isolated and cultured, and they belonged to 35 genera and 38 taxa, of which 6 fungi were suspected as new fungal species. 2 crude extracts from 2 fungal strains showed the antibacterial activities. In particular, the strain LB0026 of Parapyenchaeta genus had stronger activity against a gram-positive bacterium and no significant activity against a tested gram-negative bacterium. In addition, other 2 crude extracts from 2 fungal strains showed the DPPH free radical scavenging activity. There were 2 and 3 antioxidant compounds in these 2 crude extracts, respectively. In the forest litters of the Greater Khingan Mountains, there are rich kinds of cultivable fungi, of which 4 strains of new fungi have obvious antibacterial or antioxidant activities and they are worthy of further study.

  Changes and Extreme Characteristics of Cold Wave in Langfang Under Climate Warming 2019, 35 (29):  109-115.  DOI: 10.11924/j.issn.1000-6850.casb18120086 Abstract + ( 551 )   PDF ( 1279KB )   ( 152 ) To reveal the influence of cold wave change and extreme weather on agriculture, the variation and extreme characteristics of cold wave weather in Langfang were analyzed by the linear trend analysis, mathematical statistics and synoptic climatology analysis using the data of cold wave, temperature, precipitation, gale, blowing sand and ground temperature from 1964 to 2017. The results indicated that: (1) The cold wave weather mainly occurred from October to December and from January to April, and was most frequent in October, with the change of years, the number of cold wave days decreased obviously, but it did not reduce obviously in March and October, the beginning and the last day of the cold wave were ahead of schedule, and the last day was obviously earlier; (2) The maximum cold wave days were under the minimum temperature standard in 48 h, while the least were those under the average temperature standard in 24 h, the number of strong cold wave and the extra strong cold wave days showed a decreasing trend with the time went on, but the statistics of strong cold wave days under the standard of 48 h average temperature and the lowest

  Analysis of Atmospheric Circulation Characteristics of the Abnormal Cold Winter in Hainan and Its Application in Cold Winter Forecast 2019, 35 (29):  116-122.  DOI: 10.11924/j.issn.1000-6850.casb18040019 Abstract + ( 564 )   PDF ( 1882KB )   ( 115 ) [Objective][Method]There is no winter throughout the year in Hainan island. The abnormal cold winter often have adverse effect to the tropical fruit, rubber trees and other agricultural and tourism. Using the monthly mean temperature observation data from Hainan province Nearly 40 years and the NCEP/NCAR reanalysis datasets of 1977-2017 and NOAA ERSST date and Nino3.4 index and AO index and 74 circulation index from National Climate Center, this paper study the atmospheric circulation characteristics of the cold winter and its application in the trend forecast of cold winter temperature. [Result]The results show that: The temperature of winter over Hainan has the interannual characteristic. In recent years, the cold winter appeared 12 years and happened frequently. During the cold winter, the cold high pressure in low level and the East Asian winter monsoon strengthen. The ENSO and AO index can be used in the cold winter forecast. [Conclusion]The collective effect of cold phase of ENSO index and positive phase of AO index is beneficial to lead to low temperature over Hainan and then causing the cold winter. In addition,the accuracy of the regression forecast equation established by the atmospheric circulation index can be well used in the cold winter temperature trend forecast.

  Characteristics of Continuous Rainstorm in Loess Plateau Areas 赵玉娟 2019, 35 (29):  123-128.  DOI: 10.11924/j.issn.1000-6850.casb18030043 Abstract + ( 552 )   PDF ( 2052KB )   ( 114 ) This paper aims to study the causes and characteristics of the continuous rainstorm in Qingyang area of Gansu, and provide references for the severe rainstorm forecast and early warning in this area. The continuous rainstorm process in Qingyang from 17 to 22 August 2017 is analyzed by conventional meteorological data and diagnostic analysis technology. The results showed that: (1) the precipitation duration of the continuous rainstorm in earlier stage is short, intensity is large, distribution is uneven, and outburst is obvious. The medium duration is long, scope is wide, local precipitation intensity is strong, accumulative precipitation is large; In the later period, it has a long duration, wide range, uniform distribution and large accumulative precipitation. (2) low layer uplifting of low level jet and high-jet suction caused the development and maintenance of the rainstorm. (3) the mesoscale cloud cluster is active, with high degree of organization and long duration. (4) in the early stage, atmosphere is in a state of extreme high energy instability, and in the middle period, the energy of unstable energy decreases, and in the later stage, unstable energy decreases sharply. (5) specific humidity increase obviously in the early stage, jump value reached 4g/kg,and larger than the later period, the strong southerly airflow in the low layer of the atmosphere formed a strong upward draft of the synoptic scale..

  The Application of Stable isotope in plant secondary metabolism: A review 雷玉娟 and 2019, 35 (29):  129-133.  DOI: 10.11924/j.issn.1000-6850.casb18110067 Abstract + ( 731 )   PDF ( 1078KB )   ( 186 ) The secondary metabolism of plants is the result of the interaction between plants and the environment in the long process of evolution. The secondary metabolites products play an important physiological role in many aspects of plant life activities, and are also an important source of drugs, spices and industrial materials. Early studies of secondary metabolic pathways in plants have been carried out mainly through radioisotope tracer technology. This paper reviews the discovery, physicochemical properties, the principle and the application progress of stable isotope as tracer in plant secondary metabolic study. The application of stable isotope tracer technique to the modification of known secondary metabolic pathways of plants and the study of unknown metabolic pathways are analyzed. Besides, the direction and prospect of the stable isotope tracer technology in future study on plant secondary metabolic pathway is also presented.

  Stabilization Treatment of Wheat Germ 2019, 35 (29):  134-142.  DOI: 10.11924/j.issn.1000-6850.casb18050165 Abstract + ( 548 )   PDF ( 1518KB )   ( 143 ) Using three different treatment methods to study the stabilization of wheat germ, we aim to provide a basis for the comprehensive development and utilization of wheat germ. In this experiment, fresh wheat germ was used as raw material to study three methods (baking, microwave and synthesis of atmospheric steam and microwave) enhancing the stabilization of wheat germ, and the effects on moisture content, color, smell, taste, lipase and lipoxygenase activity of wheat germ were studied. The best condition under each of the three stabilization treatment methods was obtained. The results showed that the best processing condition for baking treatment was under 250℃ for 4 min, the best condition for microwave treatment was under 640 W for 4 min, and the best condition for atmospheric steam plus microwave was under atmospheric steam for 5 min plus 800 W microwave for 4 min. Then, the wheat germ was stabilized under the optimal condition of the three treatment methods and subject to an accelerated storage stability test in a constant temperature incubator at 50℃. Taking AV and POV as evaluation indexes, the best treatment method was atmospheric steam plus microwave, after this treatment, the vacuum packed wheat germ could be safely stored for 8 months at room temperature (20℃), and there was only little difference of the basic nutrient composition of the wheat germ before and after the treatment.

  Optimization of Extraction Process of Polysaccharide of Phellinus igniarius Mycelium and Analysis of Its Antioxidant Activity in vitro 2019, 35 (29):  143-150.  DOI: 10.11924/j.issn.1000-6850.casb18080057 Abstract + ( 573 )   PDF ( 1526KB )   ( 117 ) To study extraction process of polysaccharide from Phellinus igniarius mycelium and its antioxidant activity in vitro, according to hot water extraction and based on the single factor experiments, the extraction condition of polysaccharide from Phellinus igniarius was optimized using orthogonal test and its antioxidant activity in vitro was primarily evaluated by ABTS+. and DPPH. free radical scavenging ability. The results showed that the optimal extraction conditions were determined as follows: extraction time 2.5 hours, extraction temperature 60 ℃, number of extraction 3 times and liquid-to-solid ratio of 14 times. Under these conditions, the average extraction yield was 4.97%. The result of antioxidant activity in vitro experiments showed that the highest scavenging ability of polysaccharides against ABTS+. and DPPH. was 73.54% and 88.83% respectively. The optimization extraction process of polysaccharide from Phellinus igniarius Mycelium was reasonable and feasible, and it had stronger antioxidant activity and had a potential exploited value in functional foods and medicines.

  Study on Agricultural Science and Technology Exchanges and Cooperation Between China and Kenya 2019, 35 (29):  151-158.  DOI: 10.11924/j.issn.1000-6850.casb18110070 Abstract + ( 853 )   PDF ( 1262KB )   ( 210 ) From 1963 to now, the agricultural science and technology exchanges and cooperation between China and Kenya has experienced a transition from unidirectional free aid to mutually beneficial cooperation, and many achievements have been made in aspects of the introduction and promotion of Chinese excellent agricultural crops and export of cultivation management technology systems, scientific cooperation research, agricultural science and technology talent training, biodiversity conservation, and expansion of agricultural products markets, with four major contents of agricultural science and technology cooperation demonstration and germplasm resources utilization, China"s agricultural high-tech popularization in Kenya, short-term technical training courses setting in agriculture, and agricultural talent cultivation with high degree, through high-level government visits, China-Africa Agricultural Cooperation Forum, agricultural investment and seminars, experts and international students exchange, universities and scientific research institutions support and other ways. However, it still face many challenges of insufficient preliminary researches and investment, limited paths, contents and effectiveness, as well as language, cultural and history issues, China and Kenya need to cope with that by initiating long-term planning programme, establishing high-level coordination mechanisms, strengthening basic investigation, expanding cooperation channels and contents, increasing agricultural investment, improving fiscal and taxation support systems, and continuing to attach importance to personnel training and persisting in green cooperation and sustainable development.

  Comprehensive Evaluation of Ecological Security of Urban Agriculture in the Pearl River Delta Based on PSR Model 2019, 35 (29):  159-164.  DOI: 10.11924/j.issn.1000-6850.casb18040077 Abstract + ( 483 )   PDF ( 1262KB )   ( 486 ) With the acceleration of industrialization, urbanization and modernization, the binding force of urban resources and environment is continuously increasing, and the ecological security of urban agriculture is worth paying attention to. Based on the PSR model, this paper constructs the evaluation index system of urban agriculture ecological security in Pearl River Delta, and comprehensive evaluation for urban agriculture ecological security in Pearl River Delta and analysis of related obstacle factors has been carried out by applying the comprehensive index method, the entropy value method and obstacle degree model. The results showed that: from 2006 to 2015, the comprehensive index of urban agriculture ecological security in Pearl River Delta has been gradually improved. The urban agriculture ecological pressure of Shenzhen and Zhongshan is larger, the urban agriculture ecological status of Dongguan is relatively poor, and the urban agriculture ecological response of Zhaoqing and Jiangmen is relatively weak. The indexes of urbanization rate, cultivated land per capita etc. became major obstacle factors to the ecological security of urban agriculture. The Pearl River Delta region should vigorously strengthen the protection of cultivated land resources, continue to promote the urban ecological environment and agricultural non-point source pollution control, so as to ensure the stable development of urban agriculture ecological security.