Current issue

• 2022 Vol.38 No.29 Published:15 October 2022

  Rice Germination and Seedling Growth: Responses to the Regulation of Exogenous Substances WANG Jingdong, HUI Jian, BAI Haibo, MA Sishuang, LI Shuhua 2022, 38 (29):  1-7.  DOI: 10.11924/j.issn.1000-6850.casb2021-0449 Abstract + ( 180 )   HTML ( 6 )   PDF ( 1395KB )   ( 75 ) To clarify the morphological indexes of rice seeds during germination stage, including simple vigor index, radicle and seedling height, and their response to exogenous NaCl, IAA and CaCl2, salt-sensitive and salt-tolerant rice varieties were used as materials in this study. The germination dish method was adopted, and data were analyzed by single factor LSD multiple comparison. The results showed that under the stress of 0.1 mol/L NaCl, the simple vigor index, number of radicles, radicle length and plant height of 4 materials were lower than those of CK by 21.9%-76.5%, 20.0%-40.9%, 14.6%-55.9%, and 23.9%-36.2%, respectively. All of these indexes showed significant differences. Under salt stress, adding IAA could increase the simple vigor index of the two salt-sensitive materials by 2.6% and 13.3%, while adding CaCl2 could increase the simple vigor index of salt-sensitive materials by 9.6%-24.8%. The radicle length and plant height of salt sensitive materials were increased by 7.1%-49.0% and 14.7%-20.9%. With the CaCl2+ IAA compound treatment, the simple vigor index, number of radicles and plant height were increased by 6.9%-94.6%, 2.1%-21.2% and 9.9%-20.3%, respectively. In conclusion, the response of rice germination and seedling growth to exogenous substances is related to genotype and morphological indexes. Under salt stress, the response degree of the three indexes to exogenous CaCl2 is higher than that to IAA treatment. Furthermore, CaCl2+IAA compound treatment could effectively offset the inhibition of salt injury on rice growth.

  QTL of Kernel Yield of Maize and Its Components’ Traits: Research Progress XIE Wen, HUO Chuan, PENG Chaoying, HUO Shiping 2022, 38 (29):  8-15.  DOI: 10.11924/j.issn.1000-6850.casb2021-0912 Abstract + ( 163 )   HTML ( 4 )   PDF ( 1102KB )   ( 63 ) In order to promote the application of molecular marker-assisted selection in maize breeding, the research progress of QTL of kernel yield of maize and its components’ traits in recent 30 years was summed up. The results showed that there were 5-9 QTLs for kernel yield, and they were mainly distributed on chromosome 1, 2, 5, 6, 7, 8 and 9. There were 3-6 QTLs for the kernel row number, kernel number per row and 100-kernel weight, and they were mainly distributed on chromosome 1, 2, 3, 4, 5, 6, 7 and 8. These QTLs were distributed in clusters on several main chromosomes and formed QTL enrichment regions, and they could explain about 25% of the phenotypic variation in traits. QTLs of most traits mainly manifested as additive, dominant, partial dominant or superdominant effects, and QTLs of some traits showed genetic × environment interaction. It indicated that QTLs of kernel yield and its components’ traits had common chromosomal carriers, the breeding selection should be carried out in multiple environments and with large number of samples, and those QTLs that could be expressed stably in different environments were more suitable for breeding selection. The QTL study on ear number per plant, plant traits and stress resistance should be strengthened.

  Different Row Spacing and Reducing Nitrogen Application in Soybean-Maize Intercropping Under Mechanization: Effects on Crop Yield and Photosynthetic Characteristics of Soybean ZHU Xixia, ZHENG Yuzhen, WANG Haihong, HUANG Bao, PING Xishuan, LIU Tianxue, ZHAO Xia, LI Yuzhen 2022, 38 (29):  16-21.  DOI: 10.11924/j.issn.1000-6850.casb2022-0411 Abstract + ( 192 )   HTML ( 2 )   PDF ( 1294KB )   ( 50 ) The population yield and photosynthetic characteristics of soybean under different maize-soybean intercropping modes of field mechanization were studied, to provide a theoretical basis for selecting suitable row spacing configuration and reducing nitrogen application for maize-soybean intercropping in Henan Province. The row ratio and fertilizer reduction were set as two factors, and maize monoculture and soybean monoculture were used as control. Two row ratios were set as 2:4 intercropping of maize and soybean (2/4J) and 4:4 intercropping of maize and soybean (4/4J). The treatment of reducing nitrogen application reduced the nitrogen rate of the above row ratios by 20 % (2/4N, 4/4N). The effects of row spacing and nitrogen fertilizer reduction on crop yield, soybean LAI, dry matter weight, SPAD value and leaf photosynthetic rate were studied. The results of the two years’ experiment showed that the yield of 2/4J, 4/4J, 2/4N and 4/4N treatments were lower than those of monoculture, and LAI, dry matter weight, SPAD value and leaf photosynthetic rate were significantly lower than those of monoculture. However, compared nitrogen reduction with no nitrogen reduction, except LAI, there was no significant difference of dry matter weight, leaf photosynthetic rate (Pn) and SPAD value. In summary, in row spacing configuration and fertilization of maize-soybean intercropping mode in Henan Province, 2/4N treatment of maize-soybean intercropping with row ratio of 2:4 and nitrogen reduction of 20% can increase the accumulation of photosynthetic products, so as to improve soybean yield and intercropping efficiency.

  Correlation Analysis of Agronomic and Nutrient Quality Characters of Millet in Northern Shanxi LI Yongquan, JIN Yun, LI Jiayue, SUN Xueliang, CHEN Shujun 2022, 38 (29):  22-30.  DOI: 10.11924/j.issn.1000-6850.casb2021-1037 Abstract + ( 249 )   HTML ( 3 )   PDF ( 1194KB )   ( 31 ) In order to explore the adaptability of the introduced millet varieties planted in Guangling County, a spring millet producing area of northern Shanxi Province, a two-year planting experiment was carried out in Baituan Xibu village of Zuotuan Township of Guangling County with ‘Jingu 21’, ‘Jingu 59’, ‘Datong 45’, ‘Xingu 4’ and ‘8311’ as experimental millet varieties and ‘Dabaigu’ as control, the differences and correlations of main agronomic and nutritional quality characters were analyzed. The results showed that the growth period of ‘Jingu 59’ and ‘Jingu 21’ was 146 d and 139 d respectively, which belonged to late-maturing varieties of spring sowing, and the growth period of ‘8311’ was 120 d, which was the shortest. The yield of ‘Jingu 59’ was the highest in 2019 (6483.11 kg/hm2) and 2020 (6707.80 kg/hm2), which increased by 13.44% and 15.15%, respectively, compared with that of the control ‘Dabaigu’. The yield of ‘Jingu 21’ was slightly higher than that of the control. The plant height and spike width of ‘Jingu 21’ and ‘Jingu 59’ were relatively large, so were the spike length of ‘Datong 45’, ‘Jingu 21’ and ‘Jingu 59’. The spike weight and spike grain weight of ‘Jingu 59’, ‘Jingu 21’ and ‘Datong 45’ were significantly higher than those of other varieties. The highest 1000-grain weight was found in ‘Datong 45’ and ‘Xingu 4’, which was significantly different from that of other varieties. The protein content of ‘Jingu 21’ was the highest in 2019 and 2020 (13.03% and 11.23%) among the varieties, followed by that of ‘Jingu 59’, significantly different from that of other varieties. The fat content of ‘Jingu 59’ was the highest, which was 3.47% and 5.13% in 2019 and 2020, respectively, while the content of carbohydrate and starch in ‘8311’ were the highest. The study demonstrated that yield, spike width, flag leaf width, spike weight, spike grain weight, 1000-grain weight and the contents of protein, fat and dietary fiber had large variation coefficient. Yield was extremely significantly and positively correlated with plant height, spike width, spike weight, spike grain weight and 1000-grain weight, significantly and positively correlated with flag leaf width and fat content, and significantly and negatively correlated with carbohydrate and starch content. These characters had a great impact on millet yield, and there were also significant or extremely significant correlations among the characters. Through comprehensive analysis of the agronomic and nutritional quality characters of the introduced millet varieties, the agronomic characters of ‘Jingu 21’ and ‘Jingu 59’ are prominent, and the yield and the content of main nutrients are higher than those of the control. The two varieties can adapt to the ecological environment of Zuotuan Township of Guangling County, and are feasible to be popularized locally.

  Response Mechanism of Crops to Drought Stress and Measures for Improving Drought Resistance of Crops: Research Progress WANG Shuo, JIA Xiaoqian, HE Lu, LI Haoran, WANG Hongguang, HE Jianning, LI Dongxiao, FANG Qin, LI Ruiqi 2022, 38 (29):  31-44.  DOI: 10.11924/j.issn.1000-6850.casb2021-1042 Abstract + ( 257 )   HTML ( 7 )   PDF ( 1268KB )   ( 71 ) Drought is one of the most important abiotic stresses affecting the growth and yield of crops. The risk of crops suffering from drought stress is increasing under climate change. In order to cope with drought, crops show a series of resistance mechanisms, including the changes of morphological characteristics, and physiological and biochemical characteristics (antioxidant enzyme, osmotic regulation substances, and endogenous hormone), which play an important role in improving the resistance of crops under drought conditions. This paper summarized the response mechanism of crops to drought stress and introduced the measures to improve the drought resistance ability of crops, including: (1) selecting drought-resistance cultivars to promote the absorption of deep soil water; (2) soil mulching, which could reduce soil evaporation and increase soil water content; (3) water-saving irrigation techniques, such as micro-sprinkler irrigation and drip irrigation, which could precisely control the irrigation application and increase irrigation frequency; in addition, partial root-zone irrigation could reduce luxurious transpiration and soil evaporation by regulating stomatal closure; (4) anti-transpirants, which could inhibit excessive transpiration of water by forming ultrathin transparent protective film on the surface of crop branches and leaves; (5) plant growth regulators, which could enhance crop drought resistance by regulating plant physiological metabolism; (6) nano-fertilizers, which could promote plant growth and development by changing physiological and biochemical reactions of crops and enhance drought resistance of crops; (7) biochar, which is beneficial to soil aeration and water retention, and could improve soil physical properties and soil water retention capacity. In order to provide a theoretical basis and technical reference for coping with drought stress, this paper systematically discussed the action mechanism, application prospect and existing problems of the above 7 measures.

  PEG Simulated Drought Stress: Effects on Morphological Indices of Drought-tolerant and Drought-sensitive Sugar Beet Germplasms SHI Yang, YIN Xilong, LI Wangsheng, XING Wang 2022, 38 (29):  45-51.  DOI: 10.11924/j.issn.1000-6850.casb2022-0298 Abstract + ( 188 )   HTML ( 5 )   PDF ( 1277KB )   ( 32 ) In order to provide a theoretical basis for the selection of drought-tolerant sugar beet germplasm and the research on sugar beet stress tolerance, the effects of different levels of drought stress on the growth of sugar beet seedlings were discussed. In this study, two drought-tolerant types of BGRC16137 (V1) and Ian 1 (V2) and two drought-sensitive types 92011/1-6/1 (V3) and 7412/823-3 (V4) were used as materials, and drought was simulated with PEG and the effect of drought stress on sugar beet was studied by significance test of difference and stepwise regression analysis. As the degree of drought stress increased, the aboveground and underground indices of seedlings and the relative leaf water content of the four sugar beet germplasms all showed significant decrease, and the root-shoot ratio gradually increased. Under various concentrations of drought stress, the drought-tolerant V1 and V2 germplasms showed lower decrease in leaf fresh weight, leaf dry weight, leaf saturated fresh weight, root length and root fresh weight than the drought-sensitive V3 and V4 germplasms. Under severe drought stress, the relative leaf water content of the drought-sensitive V3 and V4 germplasms decreased by 37.33% and 43.90%, respectively, compared with that of the control, while the relative leaf water content of the drought-tolerant V1 and V2 germplasms only decreased by 14.94% and 20.45%, respectively. The results suggested that the drought-tolerant sugar beet germplasms can adapt to drought stress by increasing leaf fresh weight, leaf dry weight, leaf saturated fresh weight, root length, root fresh weight and the relative leaf water content.

  Complete Genome Sequence of Pectobacterium carotovorum Strain ZX67: An Plant Pathogen of Amorphophallus konjac Soft Rot Disease XIA Tao, LI Mengfei, ZHANG Wen, CHEN Xueying, SHI Yinlian, WANG Hongying, LI Gang, ZHU Wei 2022, 38 (29):  52-60.  DOI: 10.11924/j.issn.1000-6850.casb2022-0224 Abstract + ( 172 )   HTML ( 4 )   PDF ( 1445KB )   ( 28 ) Strain ZX67 belonging to Pectobacterium carotovorum subsp. carotovorum is the pathogen of konjac soft rot disease. In order to further understand the characteristics of the pathogen and effectively control and prevent konjac soft rot disease, the whole genome of the strain was sequenced and analyzed. The results showed that its total genome length was 4,909,724 bp and GC-content was 51.27%. It contained 4,977 coding genes, and the sequence accounted for 85.25% of the total genome. The predicted non-coding RNA (ncRNA) mainly included tRNA (74), rRNA (22) and sRNA (100). There were 10 gene islands, and 6 transposons. Two prophages were predicted, the average length of each prophage was 26,258 bp. Five CRISPR sequences were predicted, with the average length of each sequence of 621 bp. In the coding genes, the pectate lyases and other enzymes related to degradation of host plant cells were analyzed. There were five protein secretory systems related to the infected plants. The results provided a new and comprehensive idea for further understanding the characteristics of the pathogen, and studying its prevention and control measures.

  Typing Methods of Bacillus cereus: Research Progress MENG Qinglei, ZHANG Yuliang, ZHAO Donghui, JIA Weijuan, HE Yunjiang, CHI Shanshan, CHEN Yunjiao, WANG Xueli 2022, 38 (29):  61-66.  DOI: 10.11924/j.issn.1000-6850.casb2021-1029 Abstract + ( 246 )   HTML ( 5 )   PDF ( 1169KB )   ( 45 ) Bacillus cereus is an opportunistic pathogen which can cause food poisoning, and it is widely distributed in nature. The pathogenic strain and Bacillus anthracis have similar toxins, and the strains that cause poisoning are divided into two categories of vomiting and diarrhea. The study on Bacillus cereus typing has important implications for the tracing and the epidemiological investigation. At present, the popular methods for typing this bacterium are traditional typing methods and molecular typing methods. The traditional typing methods include phage typing, biochemical typing, etc.; and the molecular typing methods include repetitive-element PCR, amplified fragment length polymorphism, whole genome sequencing and so on. This paper took the Bacillus cereus as the test object, reviewed and expounded all the typing methods and the advantages and disadvantages of them, with the aim of providing reference for prevention and control of bacterial disease caused by this bacterium.

  Short-term Response of Photosynthesis and Chlorophyll Fluorescence Characteristics of Fir Seedlings to Nitrogen Deposition ZHAO Jiaojiao, AI Jianguo 2022, 38 (29):  67-73.  DOI: 10.11924/j.issn.1000-6850.casb2021-1035 Abstract + ( 169 )   HTML ( 3 )   PDF ( 1240KB )   ( 20 ) To explore the change law of the photosynthesis and chlorophyll fluorescence characteristics of fir seedlings under simulated nitrogen deposition condition, the short-term response of fir seedlings to nitrogen deposition in different seasons was discussed from the perspective of photosynthesis physiology. The fir seedlings were selected as experimental subjects, and the nitrogen deposition experiment was simulated with four treatment levels of the control (N0), low nitrogen (N30:30 kg/(hm2.a)), medium nitrogen (N60:60 kg/(hm2.a)), and high nitrogen(N90:90 kg/(hm2.a)). The results showed that after adding nitrogen, the net photosynthesis rate (Pn), initial fluorescence yield (F0), maximum fluorescence yield (Fm), maximum PSII light energy conversion efficiency (Fv/Fm) and PSII potential activity (Fv/F0) were significantly reduced, while water utilization rate (Wue) increased significantly (P<0.05). With the increase of nitrogen deposition level, stomatal conductance (Gs) and transpiration rate (Tr) showed a tendency of increase first and then decrease, and the water use efficiency showed a trend of first decrease then increase. With the medium and high nitrogen treatment, Fv/Fm and Fv/F0 values were significantly reduced (P<0.05). In winter, the net photosynthesis rate was significantly and positively correlated with stomatal conductance, transpiration rate and intercellular CO2 concentration (P<0.01); and in spring, the net photosynthesis rate was significantly and positively correlated with stomatal conductance and transpiration rate (P<0.01), and negatively correlated with intercellular CO2 concentration. After the accumulation of nitrogen deposition reached a certain threshold, the water loss was increased, which reduced the water utilization efficiency of the plant. In winter, the net photosynthesis rate was mainly affected by the stomatal limit, heat dissipation increased, and the PSII reaction center showed photo-suppression phenomenon; when it turned to spring, the excessive accumulation of nitrogen deposition destroyed the photosynthesis structure of seedlings, resulting in an increase in the concentration of carbon dioxide between cells and a decrease in the net photosynthesis rate. Then the non-stomatal limits became the main reason for the impact on the net photosynthesis rate. The medium nitrogen treatment could reduce the potential activity of PSII in chlorophyll, and the photosynthetic electron transfer capacity of the photoreaction center decreases, resulting in the decrease of photosynthesis efficiency.

  Research Progress of Fraxinus mandshurica SUN Bin, WANG Fang, YANG Yuchun, WANG Jun, LU Zhimin, DONG Guangzhi, SHI Wanling 2022, 38 (29):  74-79.  DOI: 10.11924/j.issn.1000-6850.casb2021-1002 Abstract + ( 162 )   HTML ( 6 )   PDF ( 1083KB )   ( 41 ) Fraxinus mandshurica is an important timber species in China, as well as one of the major afforestation species in northeast China. In order to have a comprehensive understanding of this species, the physiology, ecology, genetic improvement and breeding techniques of F. mandshurica were reviewed and discussed. It is suggested that the future research on F. mandshurica should focus on the following aspects: the cultivation of large diameter timbers of F. mandshurica, the somatic embryogenesis of F. mandshurica, the application of F. mandshurica as landscape tree species, and the development and application of its medicinal value. The research direction is also discussed in the study, aiming to provide certain reference for subsequent research on F. mandshurica.

  Study on Germination Characteristics and Dormancy Breaking Methods of Tilia amurensis Seeds WANG Yinhua, KONG Yuguang, LI Qinghua, WU Dejun, YAN Liping, XU Tao, LU Yizeng, ZHAI Guofeng 2022, 38 (29):  80-85.  DOI: 10.11924/j.issn.1000-6850.casb2021-1015 Abstract + ( 152 )   HTML ( 4 )   PDF ( 1790KB )   ( 32 ) In order to find out the cause of Tilia amurensis seed dormancy and a method to quickly relieve the dormancy, the seed coat permeability, seed germination characteristics and dormancy release methods of Tilia amurensis pure seeds were studied. The permeability test results showed that: when treated with concentrated H2SO4, the permeability and water absorption of Tilia amurensis seeds increased significantly. The experiment of seed germination characteristics showed that the complete seed germination rate of Tilia amurensis was 0. After removing the seed coat, the germination rate of seeds with intact endosperm, partially removed endosperm (root tip was not exposed), cap-stripped endosperm with exposed root tip, and in vitro embryos was 4.0%, 23.3%, 84.7%, and 100%, respectively. The results show that Tilia amurensis seeds have dormancy, but their seed embryos do not have dormancy. The dormancy is caused by extraembryonic factors, and endosperm (especially endosperm cap) is the main cause of seed dormancy of Tilia amurensis. The test results of seed dormancy breaking method show that the dormancy of Tilia amurensis seeds can be quickly relieved by being treated with concentrated H2SO4 for 15 min + soaking in 500 mg/L GA3 solution for 12 h + at low temperature stratification for 30 d, reaching a germination rate of 92.0%. In conclusion, the seed coat of Tilia amurensis seeds has a certain permeability barrier, but the endosperm cap is the main reason for its dormancy. The comprehensive treatment method of concentrated H2SO4 treatment + GA3 soaking + low temperature stratification can relieve the dormancy of Tilia amurensis seeds within 30 days.

  Chlorophyll Fluorescence Characteristics of Lilium spp. Cultivars Under Natural High Temperature CHEN Minmin, NIE Gongping, LI Xin, ZHOU Lin, YANG Liuyan, ZHANG Yongchun 2022, 38 (29):  86-95.  DOI: 10.11924/j.issn.1000-6850.casb2021-0920 Abstract + ( 183 )   HTML ( 4 )   PDF ( 2222KB )   ( 29 ) A study on the response of chlorophyll fluorescence parameters of different Lilium spp. cultivars to natural high temperature was carried out to analyze the important indicators reflecting the characteristics of chlorophyll fluorescence, establish a suitable method for evaluating the high temperature response of Lilium spp. cultivars, and select sensitive and insensitive cultivars to natural high temperature. 66 Lilium spp. cultivars were selected as experimental materials, and the Fv/Fm values of functional leaves were measured under natural high temperature in Shanghai. The fuzzy membership function analysis method and the sample optimal segmentation clustering method were adopted to evaluate the heat tolerance. Under natural high temperature conditions, the chlorophyll fluorescence characteristic parameters including Fo, Fm, Fv/Fo, Fv/Fm, PIABS, DIo/CSo and φEo in leaves were determined by rapid fluorescence detector. Then, we compared the sensitivity of different Lilium spp. cultivars. Results showed that the Fv/Fm values of the 66 cultivars were all influenced by natural high temperature. The sample optimal segmentation clustering method was used to classify the 66 cultivars into five grades. 25 cultivars, including ‘Souvenir’, ‘Merlet’, ‘Conca D'Or’, ‘Sunny Martinique’, ‘Methone’ and so on, belonged to grade I, which were not sensitive to high temperature and had strong adaptability. 19 cultivars, including ‘Zambesi’, ‘Triumphator’, ‘Nashville’, ‘Brindisi’, ‘Tresor’, etc., belonged to grade V, which were more sensitive to high temperature and had poor adaptability. This study screened and identified sensitive and insensitive Lilium spp. cultivars to high temperature, which could provide reference for further research on heat-resistant mechanism of Lilium spp. and breeding heat-resistant cultivars.

  Responses of Photosynthetic Parameters and Yield of Winter Wheat at Filling Stage to Soil High Humidity and Drought Change REN Sanxue, QI Yue, TIAN Xiaoli, ZHAO Huarong 2022, 38 (29):  96-102.  DOI: 10.11924/j.issn.1000-6850.casb2021-1134 Abstract + ( 210 )   HTML ( 6 )   PDF ( 1204KB )   ( 96 ) To study the influencing mechanism of soil moisture on photosynthetic parameters and yield change of winter wheat, an experiment was conducted with 4 treatments of soil high humidity (W1), moderate drought (W2), severe drought (W3) and control (CK) using artificially controlled irrigation in the rainproof shed, to study the effects of soil moisture change on the photosynthetic parameters and yield of winter wheat at the filling stage. The results showed that: the net photosynthetic rate, transpiration rate and stomatal conductance of winter wheat during the filling stage decreased with the decrease of soil moisture. The intercellular CO2 concentration of W3 was similar to that of CK, and the main reason for the decrease of photosynthesis was non-stomatal restriction. The effectively utilized light intensity range of winter wheat leaf of W1 was expanded, while the effectively utilized light intensity range by leaves was narrowed due to soil drought stress. Night respiration of leaves under soil high humidity and drought stress were both increased. Drought stress reduced photosynthesis during the day, enhanced night respiration, and consumed more nutrients. ‘One decrease and one increase’ was the physiological reason for the grain collapse and low yield. High soil moisture and drought could affect the source-sink matching of dry matter transport and accumulation in winter wheat grains during grain filling stage. The green organs of the leaves under high humidity treatment dominated the transport of photosynthetic products, and the dry matter transport and contribution rates of the vegetative organs before flowering became smaller. Under drought stress, the photosynthetic products of green organs such as leaves were less, and the dry matter transported by grains was reduced. However, the dry matter transport and contribution rates of the vegetative organs before anthesis were increased relatively. The harvest index of soil high humidity was basically similar to that of the control, while the harvest index of the drought treatment was obviously smaller than that of the control.

  Effects of Organic Fertilizer on Crop Quality, Soil Fertility and Environment: Research Progress CHAO Ying, FU Gangfeng, YAN Xianghui, HANG Zhongqiao, YANG Quangang, WANG Hui, PAN Hong, LOU Yanhong, ZHUGE Yuping 2022, 38 (29):  103-107.  DOI: 10.11924/j.issn.1000-6850.casb2021-0631 Abstract + ( 604 )   HTML ( 13 )   PDF ( 1055KB )   ( 68 ) The substitution of chemical fertilizers by organic fertilizers is an effective strategy to reduce the amount and increase the efficiency of chemical fertilizer. It also significantly stimulates crop yield and soil fertility. However, it is worth noting that the substitution of chemical fertilizers by organic fertilizers could contribute to greenhouse gas emissions and pollution loading in soil environment. This paper reviewed the effects of organic fertilizer application on crop quality, soil amelioration, greenhouse gas emissions and agricultural non-point source pollution. Besides, we summarized current research of organic fertilizer application and put forward proposals for further studying the organic fertilizer application. Firstly, constantly optimizing the fermentation process to improve the quality of organic fertilizer is of overarching importance. Secondly, it is suggested to strengthen the quality trait evaluation in assessing the application effect of organic fertilizer, and take full advantage of long-term positioning observation and modern monitoring means to improve the soil fertility monitoring level and accomplish the comprehensive environmental effect evaluation. These suggestions aim at providing guidance for rational and efficient application of organic fertilizers, and for sustainable utilization of soil and water resources.

  Spatial Distribution and Formation of Phosphorus in Typical Land-use Soils in Karst Agricultural Areas YANG Miao, TIAN Yongzhu, HAN Zhiwei, LUO Guangfei, ZHAO Ran, TIAN Yutong, XIAO Han 2022, 38 (29):  108-117.  DOI: 10.11924/j.issn.1000-6850.casb2021-0903 Abstract + ( 206 )   HTML ( 6 )   PDF ( 1937KB )   ( 30 ) A study on the spatial distribution, migration characteristics and influencing factors of phosphorus in vertical and horizontal soil under different land use types in karst agricultural areas was carried out. A total of 56 samples were collected from 9 soil profiles under typical land use types (grassland, riverside, paddy field, dry land, etc.) around Kaizhang reservoir, and the water content, pH, organic matter, exchangeable acid, total phosphorus, available phosphorus and inorganic phosphorus of each soil profile were determined. The results demonstrated that the total phosphorus content and available phosphorus content were measured to be over a wide range of 420.73-1669.53 mg/kg and 2.50-64.14 mg/kg, respectively, and the soil phosphorus activation coefficient was in the range of 0.34%-5.96%. It was found that available phosphorus content in the surface soil of agricultural land was more than 15 mg/kg, which was correlated with the overuse and waste of phosphate fertilizer. Meanwhile, the risk of phosphorus leaching downward into underground water was found in the surface soil of dry land in the agricultural area behind the dam (the average content of available phosphorus was 64.14 mg/kg). The soil inorganic phosphorus forms in paddy field and dry land were mainly Fe-P and Al-P, and in grassland and riverside were mainly Fe-P and O-P. The results indicated that soil pH was significantly and negatively correlated with available phosphorus, Fe-P and Al-P, and soil organic matter was significantly and positively correlated with total phosphorus, available phosphorus, Al-P, and Fe-P. It is concluded that the soil phosphorus content of agricultural area is generally higher than that of non-agricultural area because of different phosphorous distributions in different land use types. The study clarifies the spatial distribution of phosphorus and its forms in karst agricultural areas, which could provide a basis for the prevention and control of agricultural non-point source pollution caused by phosphorus.

  The Quality Grade and Nutrient Characteristics of Cultivated Land in Pingchuan District PAN Xue, CAI Liqun, DONG Bo, NIE Guangyun 2022, 38 (29):  118-128.  DOI: 10.11924/j.issn.1000-6850.casb2021-1074 Abstract + ( 216 )   HTML ( 3 )   PDF ( 3117KB )   ( 30 ) The study aims to comprehensively and timely grasp the cultivated land quality grade, nutrient spatial distribution characteristics and nutrient content difference of different soil types in Pingchuan District of Baiyin City, Gansu Province, and provide an effective basis for rational planting and fertilization in the future. According to the national standard of Cultivated Land Quality Grade, the cultivated land resource management information system at county scale was used to analyze the cultivated land quality grade, nutrient spatial distribution and nutrient content difference of different soil types in Pingchuan. The results showed that the cultivated land quality in Pingchuan belonged to grade five to ten, without cultivated land of grade one, two, three and four. The cultivated land of grade seven had an area of 13543.35 hm2, accounting for 34.51% of the total cultivated land area in Pingchuan. The overall nutrient level of the cultivated land in Pingchuan was low, and the cultivated land with low soil organic matter content and total nitrogen content showed a bipolar distribution. The cultivated land with low content of available phosphorus was concentrated, and the cultivated land distribution of other grades was scattered. The cultivated land with high available potassium content was concentrated in the villages and towns in southern Pingchuan; and the nutrient contents of deep cultivated lime-calcium soil were overall high among the six soil types in Pingchuan, and the coefficient of variation was the lowest.

  Phenological Change Characteristics of Stipa Grass at Flowering Stage on Alpine Grassland and Their Influencing Factors LOU Zhongshan 2022, 38 (29):  129-134.  DOI: 10.11924/j.issn.1000-6850.casb2022-0375 Abstract + ( 170 )   HTML ( 4 )   PDF ( 1354KB )   ( 70 ) Based on the phenological data of Stip sareptana var. krylovii flowering stage on alpine grassland and contemporaneous meteorological data observed by Xinghai County Meteorological Bureau in Sanjiangyuan region from 1999 to 2021, this paper analyzed the change trend of the Stip sareptana var. krylovii flowering stage on alpine grassland, to find out the main meteorological factors influencing the flowering time and build the forecast model by using the regression analysis method. The results showed that: (1) the average temperature was stable during flowering stage of Stip sareptana var. krylovii on alpine grassland of Xinghai County from 1999 to 2021, but precipitation increased significantly; (2) the flowering stage of Stip sareptana var. krylovii showed no significant delay trend from 1999 to 2021, and the flowering time of herbage varied greatly from year to year, the difference between the earliest and the latest was 26 days; (3) correlation analysis showed that, the average temperature and average maximum temperature in the first ten days and the last ten days of April were significantly negatively correlated with the flowering time, the average maximum temperature and sunshine duration in the first ten days of May were significantly positively correlated with the flowering time, and the average minimum temperature in late April was very significantly negatively correlated with the flowering time of herbage; (4) the regression analysis showed that for every 1.0℃ increase (or decrease) of the average minimum temperature in late April, the flowering time of herbage was correspondingly earlier (or delayed) by 2.1 days.

  Meteorological Indexes and Forecast of Autumn Osmanthus Blooming Period in Chengdu ZHAO Guiqiong, DENG Ruijie, CHEN Zhilong, CAI Xinming, CHEN Le 2022, 38 (29):  135-139.  DOI: 10.11924/j.issn.1000-6850.casb2022-0586 Abstract + ( 201 )   HTML ( 2 )   PDF ( 1269KB )   ( 43 ) To develop refined meteorological services for autumn Osmanthus in Chengdu, and establish a meteorological forecast model, this research used mathematical statistics to study the relationship between the pre-flowering period and flowering period of Osmanthus and the meteorological factors, and established the prediction model of the initial flowering period of Osmanthus in combination with the Osmanthus growth characteristics based on the phenological observation of Osmanthus and meteorological data in Chengdu from 2004 to 2016. The results showed that: with abundant rainfall before flowering, when the sliding average temperature on the 5th day passed 23℃, Osmanthus entered the first flowering period in 3-6 days. During the flowering period, there was an alternation of sun and rain with the daily average temperature ranging from 20℃ to 24℃. The number of rainy days, precipitation and sunlight were the main meteorological factors influencing the duration of flowering period. The initial flowering period of Osmanthus was positively correlated with the highest temperature in late February, sunshine duration in late February and rainy days in late July, but negatively correlated with rainfall in late October and rainy days in late May. The prediction model of the flowering period of Osmanthus in Chengdu had a high historical fitting rate and a good forecast effect, which could predict the flowering time 20 days in advance. The study could be used for the medium and long term forecast of the early flowering period of Osmanthus and provide accurate meteorological service for the appreciation of Osmanthus in Chengdu.

  Overexpression Vector Construction and Tissue Expression Analysis of HMOX1 Gene in Hezuo Pigs LI Jianrong, WANG Wei, LUO Dingguo, MA Xiaoxia, XU Meiling, GUN Shuangbao, YANG Qiaoli 2022, 38 (29):  140-145.  DOI: 10.11924/j.issn.1000-6850.casb2021-0808 Abstract + ( 155 )   HTML ( 2 )   PDF ( 1444KB )   ( 23 ) In order to construct an overexpression vector of HMOX1 gene in Hezuo pigs and analyze its tissue expression characteristics, the complete CDS region sequences of HMOX1 gene were obtained by PCR amplification, and then were inserted into pcDNA3.1 (+) blank vector to construct pcDNA3.1-HMOX1 overexpression vector. At the same time, the expression of HMOX1 gene in the heart, liver, spleen, lung, kidney, stomach, duodenum and longissimus dorsi muscle of Hezuo pigs were detected by real-time quantitative PCR. The results showed that the completed CDS region of 924 bp of HMOX1 gene was successfully amplified and identified by double enzyme digestion and sequencing, which was successfully linked to the pcDNA3.1(+) overexpression vector. Results of tissue expression analysis showed that HMOX1 gene expression was the highest in Hezuo pig spleen tissue, followed by liver, lung, kidney and heart, and the lowest was in duodenum. These results can provide reference for further research on the function of HMOX1 gene in the process of adaptation of Hezuo pigs to high altitude and hypoxia.

  The Research Status and Prospect of Strengthening Cultivation of Parents of Two Indigenous Freshwater Fish CHEN Duhuang, LIN Ershu, XUE Lingzhan, HU Zhenxi, CHEN Zhi, FAN Haiping, WU Bin 2022, 38 (29):  146-151.  DOI: 10.11924/j.issn.1000-6850.casb2021-1027 Abstract + ( 189 )   HTML ( 2 )   PDF ( 1139KB )   ( 31 ) Opsariichthys bidens and Acrossocheilius hemispinus are two kinds of indigenous freshwater fish in Fujian Province. They have good market foundation, development potential and broad promotion prospects. However, in the process of large-scale artificial breeding, it is found that the parent fish of the two indigenous freshwater fish have common problems such as slow gonadal development, poor synchronization, low amount of eggs and poor egg quality, which seriously affect the industrialization process of the two fish varieties. The strengthening cultivation of parent fish is beneficial to improve fish reproductive performance in order to obtain a large number of high-quality fish fry, so the strengthening cultivation of parent fish is particularly important. At present, the study of strengthening cultivation of parent fish has become an important, complex and extensive research topic. This paper expounds on the research status of strengthening cultivation of parent fish of the two indigenous freshwater fish from the aspects of parent fish strengthening concept, strengthening methods (nutritional strengthening and environmental stimulation) and parent fish conservation scheme. This paper also analyzes the current problems and shortcomings in the cultivation, and puts forward corresponding suggestions, so as to promote the high-quality development of Opsariichthys bidens and Acrossocheilius hemispinus.

  Automatic Extraction of Individual Tree in Forest Land Based on UAV Remote Sensing Images: Taking Danxia Mountain Wetland Reserve as an Example CHEN Bin 2022, 38 (29):  152-158.  DOI: 10.11924/j.issn.1000-6850.casb2021-1025 Abstract + ( 183 )   HTML ( 3 )   PDF ( 11329KB )   ( 36 ) UAV technology can be used to quickly acquire high resolution remote sensing images of forest nature reserve. In forestry resource investigation and monitoring, UAV images have more advantages than traditional satellite images. This study took Danxia Mountain Wetland Nature Reserve as the research object and proposed an automatic extraction method of individual forest tree based on UAV images. A multi-scale segmentation algorithm for UAV remote sensing image was adopted. Then, through constructing the characteristic information model of forest land, the automatic extraction of individual tree in artificial forest land in the study area was realized. The results showed that the proposed method had high feasibility in automatic extraction of artificial forest land in Danxia Mountain Wetland Nature Reserve. The Kappa coefficient was 0.979, and the overall accuracy of classification extraction reached 98.40%, which could meet the needs of artificial forest land extraction. This method can eliminate the human intervention and prior knowledge before the classification of artificial forest land, greatly improve the efficiency of UAV images in the investigation and monitoring of forest land resources, and provide a new way for accurate forest survey.

  Price Evaluation Method of Farmland Contract Right Based on Separating Rural Land Rights YANG Jianbo, WANG Li, GUO Jiawei, LI Wei 2022, 38 (29):  159-164.  DOI: 10.11924/j.issn.1000-6850.casb2021-1047 Abstract + ( 175 )   HTML ( 1 )   PDF ( 1180KB )   ( 21 ) Under the background of China’s urban and rural development, ‘separating rural land rights’ (separation of ownership rights; contractors’ rights and land management rights), an innovation theory of China’s farmland system in the new period, provides the opportunity for the reform of land property rights, and the connotation and value composition and price assessment of the farmland contract right is worth in-depth study, which can not only provide a basis for agricultural land circulation, but also be used as the key to natural resource asset value accounting. Starting from the policy evolution of ‘separating rural land rights’, this paper reinterprets the connotation and value composition of the contract right, and discusses the application of Income Approach and Superposition to evaluate the benchmark land price of the contract right on the premise of analyzing the factors affecting the value. The research got three results. (1) The farmland contract right refers to the right to contract collective property obtained according to the collective membership. The identity right has obvious characteristics, including subject specificity, property income, benefit disposal and effective possession. (2) The collective membership right has four characteristics of identity, equality, commonality and constraint, and the main form of the membership right can be the rural household or the individual of the collective economic organization or the combination of the two. (3) According to the value of production usufruct right and the composition of social security value of farmland contract right, the two methods of Income Approach and Superposition are adopted to evaluate the right price of ownership. When determining the social security value, the social security cost value in the comprehensive land price of the expropriated area can be used to quantify. On the premise of protecting farmers’ land rights and interests, this study is expected to provide useful reference for the comprehensive and orderly development of agricultural land quality price assessment and value accounting.