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    2024,43(2):1-9 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.001
    Abstract:
    The transformation and upgrading of freshwater fisheries is of great significance for promoting consumption upgrading and achieving high-quality sustainable development of industry. Based on the analysis of the prominent problems faced by the transformation and upgrading of freshwater fisheries and the needs of engineering science and technology in China, this paper puts forward the specific overall ideas, the promotion paths, the main tasks and the main goals for the transformation and upgrading of freshwater fisheries. And through systematic research, the key research points of engineering science and technology innovation are put forward, such as green and efficient breeding, excellent species breeding technology and equipment, precise feeding and efficient feed utilization technology, water environment control technology under different breeding modes, efficient green technology and equipment for tailwater treatment, multi-information intelligent stereoscopic sensing technology and equipment, freshwater product fishing and high-quality freshness preservation, storage and transportation technology in cold chain logistics and equipment for aquaculture product primary processing, to provide the decision-making reference for comprehensively promoting the mechanization, establishment, and intelligence level of freshwater fishery in our country.
    2024,43(2):10-21 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.002
    [Abstract] (27) [HTML] (42) [PDF 1.35 M] (110)
    Abstract:
    Owing to the properties of low concentration and high toxicity,emerging contaminants (ECs) have become one of the major threats to water safety.Biochar has attracted extensive attention in the removal of ECs from aquatic environment due to its easy accessibility and high treatment efficiency.In order to promote the application of biochar in the removal of ECs,in this paper the pollution status of ECs ,the properties of biochar,and the research and application of biochar in the removal of ECs in aquatic environment were reviewed.The research progress of removal of ECS by biochar as absorbents,advanced oxidation catalysts and microbial immobilization carriers was summarized,and the prospect was put forward.
    2024,43(2):22-29 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.003
    [Abstract] (21) [HTML] (19) [PDF 2.18 M] (102)
    Abstract:
    To accurately design the inlet structure of the factory circular recirculating aquaculture tank, based on the computational fluid dynamics technology, fluent software was used to establish a numerical model to simulate the flow field distribution characteristics of the inlet pipe in the pond under different inlet angles θ, inlet diameter ratio d/r, and inlet height h in this study. The average velocity vavg and uniformity coefficient U were used as the evaluation indexes, and the inlet structure was optimized and analyzed. On the basis of physical experiments that the numerical model can better simulate the flow field characteristics in the aquaculture pond, the effects of different inlet structures on the flow field were simulated. The results showed that under the same conditions, the maximum vavg was achieved at θ=40° and the U difference between water layers was minimized; the larger vavg and U was achieved at d/r=0.1 and the U difference between water layers was minimized; the larger vavg was achieved at h=100~400 mm and the U difference between water layers was smallest at h=100 mm. It was shown that the flow field characteristics in the pond were in an optimal state when the inlet angle θ=40°, inlet angle d/r=0.1 and the inlet height h=100 mm.
    2024,43(2):30-39 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.004
    Abstract:
    To investigate the growth characteristics and patterns of largemouth bass (Micropterus salmoides) during pond cultivation, various growth parameters including length, total length, snout length, eye diameter, head length, caudal peduncle length, head height, body height, caudal peduncle height, body width, and body mass were measured from individuals ranging from (16.3±4.9) g to (424.9±27.2) g.The correlations among these growth parameters were analyzed, and the predictive models for body mass were constructed using support vector regression (SVR), radial basis function neural network (RBF), and random forest regression (RF).The best-fit model was determined by comparing the predicted values with the actual measured values.Optimal growth models were also developed for each growth parameter using model-fitting approach.The results revealed a highly significant correlation between body mass and growth parameters.The SVR-based predictive model exhibited the highest accuracy, with a coefficient of determination (R2) of 0.996, a root mean square error (RMSE) of 9.004, and a mean absolute error (MAE) of 6.598.A power function relationship was observed between body mass and body length, with an equation of W=0.0127×L3.224 and a R2 of 0.977.The Logistic models were the best for total length, body length, snout length, and head length.Von Bertalanffy models were the best models for head height, body height, eye diameter, and body width, while Gompertz models were most suitable for body mass, caudal peduncle length, and caudal peduncle height.The condition factor of largemouth bass fluctuated from 2.26% to 2.93% during the cultivation period.These findings suggest that growth models and body mass predictive models can be utilized to understand the growth process of largemouth bass under pond-cultured conditions.Accurate feeding based on these models can lead to optimal cultivation outcomes.
    2024,43(2):40-46 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.005
    [Abstract] (22) [HTML] (18) [PDF 1.13 M] (109)
    Abstract:
    Aquaculture of captive-pond mode has higher sewage treatment efficiency and breeding density, which is due to the benefit of frequent removals of aquaculture waste in the captive tank. However, dissolved oxygen in high density aquaculture water is a concern for farmers. When the water temperature is high in summer, air aeration is inefficient, and the bubble-based aeration method cannot meet the requirements of oxygen supply. Gas-liquid mixed pump has a great performance on increasing dissolved oxygen in sewage aeration treatment. To explore whether gas-liquid mixed pump is suitable for the oxygen enhancement in the captive-pond mode, it is necessary to explore the optimal process parameters through experiments. In this study, the performances of the pump were tested under different water temperatures, outlet pressures and gas-water volume ratios, and the field tests were carried out in the pond captive tank (diameter 4 m, height 2 m, aquaculture water volume 20 m3). The results showed that, under the conditions of outlet pressure of 0.25 MPa and gas-water volume ratio of 0.01 to 0.05, the dissolved oxygen in outlet water was inversely proportional to the water temperature (5.6 ℃, 13.5 ℃ and 30.3 ℃), and the dissolved oxygen varied from 47.93 mg/L to 20.60 mg/L. The oxygen absorption efficiency was inversely proportional to the gas-liquid volume ratio, and the oxygen absorption efficiency varied from 91% to 33.7%. The dynamic efficiency was proportional to volumetric gas-liquid ratio and varied from 22.32 kg/(kW·h) to 55.12 kg/(kW·h). Field test showed that, under the condition of fish oxygen consumption density of about 13.19 to16.49 kg/m3 , when the pump’s working power was about 3 kW, the dissolved oxygen of each captive tank can reach 11 mg/L in the daytime and keep above 8 mg/L at night. The fluctuation of dissolved oxygen in the captive tank was within 0.2 mg/L, and the uniformity was good. The pump system is simple in structure and can work efficiently under high water temperature conditions.
    2024,43(2):47-55 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.006
    [Abstract] (22) [HTML] (17) [PDF 1.44 M] (120)
    Abstract:
    In order to explore the optimal control range of water depth for Vallisneria natans type aquiculture, based on the natural distribution water depth of V. natans in the pond, four light intensity gradient groups, including 5% (L1), 15% (L2), 25% (L3), and 35% (L4) of the full sunlight intensity (L1 was the suitable light intensity group, L2, L3, and L4 were the strong light groups), were set up, corresponding to the underwater depth of 1.0-1.1, 0.6-0.8, 0.4-0.6, and 0.3-0.4 times the transparency of the pond, respectively, to study the growth, antioxidant, and purification ability of V. natans under natural light period and intensity. The results showed that under natural light period, the total biomass of V. natans increased significantly with the increase of light intensity (5%-35% full sunlight range), and the maximum leaf length appeared in L2 group. The content of malondialdehyde (MDA) and superoxide dismutase (SOD) activity in L2, L3, and L4 groups were significantly lower than those in L1 group; the content of dissolved oxygen (DO) and pH values in water in L3 and L4 groups were significantly higher than those in L1 group, while the chlorophyll a (Chl a) content was opposite. The concentrations of ammonium nitrogen (NH4+-N) and nitrite nitrogen (NO2--N) in each group rapidly decreased to lower levels (<0.30, <0.02 mg/L) within 3 and 2 weeks, respectively; except for group L1, the concentrations of nitrate nitrogen (NO3--N) and total nitrogen (TN) in other groups continued to decrease at different rates with time until the end of the experiment (<2.50, <3.00 mg/L), which was negatively correlated with light intensity to a certain extent. The activities of glutamate synthase (Fd-GOGAT) and alkaline phosphatase (AKP) in L3 and L4 groups were significantly higher than those in L1 and L2 groups, and the removal rates of orthophosphate (PO43--P) and total phosphorus (TP) in each group were more than 80%, showing good removal effects. Research has shown that the water level for V. natans type aquiculture should be controlled within a range of about 0.3 to 0.6 times transparency above V. natans.
    2024,43(2):56-63 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.007
    Abstract:
    Filter media filtration can effectively reduce the content of suspended solids and other harmful substances in fish culture tailwater and is often used as a primary treatment technology for aquaculture tailwater. In order to investigate the effect of filter media filtration for pond captive tailwater treatment, this study used volcanic rock, activated carbon and zeolite as the filter media materials, and carried out pond captive tailwater treatment experiments with filter media type, filter media size and filter media thickness as the test factors, and total suspended solid (TSS) removal efficiency, ammonia nitrogen (NH4+-N) removal efficiency and chemical oxygen demand (COD) removal efficiency as the test indexes. The results showed that all three filter media could remove TSS and COD in the tailwater, and all could reduce the concentration of NH4+-N in the tailwater to a certain extent, and among the three filter media, the treatment effect of activated carbon was better than the other two, and the smaller the particle size or the larger the thickness of the filter media, the better the effect of the activated carbon in treating the tailwater. The results of the orthogonal test based on the single-factor test showed that the best overall treatment effect of the filtration device was achieved when the filter media was activated carbon, the particle size was 0.5-2 mm, and the thickness of the filter media was 80 cm. Under these conditions, the removal efficiencys of TSS, COD and NH4+-N were 83.86%, 49.78% and 29.89%, respectively. The study showed that the filter media filtration has good effect on the removal of TSS and COD, but the NH4+-N removal effect is not satisfactory. Therefore, in the treatment of captive tailwater, media filtration can be used as a primary treatment process for captive tailwater, but further purification of tailwater is needed for ammonia nitrogen by means of biofilter, artificial wetland or bioreactor.
    2024,43(2):64-74 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.008
    Abstract:
    Neuronic acid (NA) is an ultra-long chain monounsaturated fatty acid,a core component of the myelin sheath of brain nerve fibers,with functions including repairing damaged brain nerve fibers and promoting regeneration of nerve cell.Therefore,more and more studies are focusing on NA.At present,NA mainly relies on extraction from natural species,which is difficult to meet market needs and limits its further development and application.In recent years,with the development of genetic engineering and synthetic biology,constructing NA metabolic pathways in existing species through multi-gene strategies can economically and sustainably obtain NA to meet the needs of fields such as nutrition,pharmaceuticals,and chemical industries.This article reviewed the biological functions,biological sources,and synthetic pathways of NA.The advantages and disadvantages of genetic engineering production of NA chassis were compared.The influencing factors of producing NA-rich seed oil using cruciferous oil crops as the chassis were further explored.It will provide some ideas and strategies for regulating NA production and obtaining renewable NA resources in the future through transgenic technology and molecular breeding.
    2024,43(2):75-84 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.009
    [Abstract] (15) [HTML] (22) [PDF 2.33 M] (108)
    Abstract:
    Rice is one of the important food crops.Lodging during the production of rice is a common phenomenon that can have a significant impact on the yield and quality of rice.Therefore,developing rice varieties with lodging-resistance is one of the main goals of rice breeding.524 rice germplasm resources were used to further mine the genes that control lodging resistance in rice.Genome-wide association analysis (GWAS) was used to identify the locus qRLG7 that is significantly associated with lodging resistance.The candidate genes regulating lodging resistance in rice were determined by analyzing the expression level and the association of candidate gene.CRISPR-Cas9 technology was used to construct mutant families of two candidate genes on the basis of analyzing the expression characteristics and natural variations of candidate genes in the promoter region.The lodging resistance of mutant families was examined.The results showed that the expression levels of two tandemly arrayed genes (LOC_Os07g37220 and LOC_Os07g37230),both encoding inositol-1-monophosphatase (IMP),were significantly higher than that of the other candidate genes in the internode at 5 cm away from the bottom of culm.The expression levels of the two IMP genes in the highly lodging resistant germplasms were significantly higher than that in the highly lodging-prone germplasms.The SNPs in the promoter regions of the two genes were significantly associated with culm diameter at 5 cm from the bottom (CD5).The significant SNPs of candidate genes were mainly divided into two haplotypes,and the CD5 values of the two haplotypes were significantly different.The activity of the promoters of two genes had significant differences between the two haplotypes as well.The mutants of the two candidate genes had significantly reduced culm-breaking resistance,culm thickness,culm diameter,plant height,and panicle weight compared to the wild-type rice.It is indicated that the candidate gene LOC_ Os07g37220 and LOC_ Os07g37230 has a certain lodging resistance.It will provide reference for further mining and characterizing genes for the genetic improvement of lodging resistance in rice.
    2024,43(2):85-92 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.010
    Abstract:
    The phenotype identification, microscopic observation of endosperm cells, determining the content of storage substance in endosperm, and map-based cloning of a defective maize kernel mutant named as empty pericarp35 (emp35) were conducted to study its physiological function in the development of maize kernel and map the Emp35 gene. The results showed that the development of emp35 kernels was slow and significantly smaller than that of the wild-type kernels during the same period of development, resulted in the shrunken and empty pericarp kernels. The development of embryo and endosperm in the emp35 was severely delayed, and the mitochondrial structure in endosperm cells was abnormal. The accumulation of starch and protein in the emp35 was reduced. The seeds in the F2 population segregated in a ratio of 3 wild type to 1 empty pericarp, indicating that the defective kernel phenotype is controlled by a single recessive nuclear gene. The Emp35 gene was mapped at the interval between 127.90 Mb and 163.36 Mb on the chromosome 8 of maize with a bulked segregant analysis (BSA). Four InDel markers were developed within this interval, and Emp35 gene was finely mapped at the interval between 139 571 117-146 176 858.
    2024,43(2):93-98 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.011
    Abstract:
    Water is the lifeline and the largest bottleneck for the sustainable development in Xinjiang. Agriculture is the largest water consumer in Xinjiang, accounting for more than 90% of the total socioeconomic water consumption, and the proportion of agricultural water consumption in southern Xinjiang is even higher. The key to water-saving potential in Xinjiang lies in agriculture, and agricultural water saving is the fundamental way to solve the sustainable development of economy and society in Xinjiang. The development of agricultural water-saving in the irrigation areas of Xinjiang was reviewed to improve the agricultural water use efficiency and promote the high-quality development of agriculture in Xinjiang. The current status and existing problems of developing agricultural water-saving were analyzed. The countermeasures and suggestions including vigorously developing water-adapted agriculture, increasing the construction of high-efficient water-saving projects, continuously promoting salt reduction and water saving, strengthening the construction of digitalized irrigation areas, promoting water-saving publicity and training, and improving service system for agricultural water-saving were put forward based on the Central Government’s new positioning and requirements of the country for the development of agriculture in Xinjiang in the new era. It will provide strong support for promoting the sustainable development of modern agriculture and ensuring the national security of grain and cotton production in Xinjiang.
    2024,43(2):99-108 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.012
    Abstract:
    One functional fungus strain was isolated and screened from plant rhizosphere soil with high background value of 50.187 mg/kg selenium (Se) and 50.311 mg/kg cadmium (Cd) using selective culture medium to solve the problem of co-accumulation of selenium and cadmium in crops.The fungus strain obtained was identified as Fusarium redolens.The changes in available selenium and cadmium in soil,as well as the content of Se and Cd in edible parts of plants were determined with soil simulation experiments and pot experiments.Evaluate The effects of fungus on selenium uptake and cadmium reduction based on the enrichment of selenium/cadmium and the transport coefficients.The results of soil simulation experiments showed that the rate of active selenium was positively correlated with culture time after the fungus was inoculated,while the rate of cadmium immobilization was opposite.The rate of active selenium reached its peak on the 5th day,at 60.9%.The rate of cadmium immobilization was highest at 41.2% on the third day and lowest at 27.3% on the fifth day.The results of the pot experiments showed that adding 108 cfu/mL of fungi significantly reduced the soil pH by 0.35 units compared to the control.There was no adverse effect on the growth of the seedlings of Cardamine violifolia,with an average plant height,root length,and biomass of 7.4 cm,9.6 cm,and 2.9 g,respectively,all higher than that of the control.The content of available selenium in the soil significantly increased,with the highest rate of active selenium reaching 24.8%,while the content of available cadmium significantly decreased,with the rate of cadmium immobilization of 24.7%.The content of total selenium in the above ground and underground parts of Cardamine violifolia increased by 25.6% and 36.8%,respectively,while the content of total cadmium in the above ground and underground parts of Cardamine violifolia decreased by 32.7% and 11.6%,respectively.It is indicated that fungi have the ability to activate selenium and immobilize cadmium in natural soil with high background value of selenium and cadmium,and the best effect is achieved when adding a concentration of 108 cfu/mL,which helps to enrich selenium and reduce cadmium in Cardamine violifolia.
    2024,43(2):109-113 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.013
    Abstract:
    为探求抑制香菇镉富集的方法,开发镉污染防控技术,设置实验室菌丝培养和大棚袋式栽培2个阶段试验,分析培养条件及外源添加物对香菇菌丝及子实体中镉含量的影响。结果显示,在温度10~30 ℃范围内随着培养温度升高,菌丝镉含量呈现先上升后平稳的趋势;在pH 4~8范围内随着培养基pH值升高,菌丝镉含量呈现先上升后下降的趋势;在含镉的液体培养基中分别添加5 mmol/L Ca(NO32、KNO3和 Mg(NO32,发现Mg2+能明显抑制菌丝对镉的富集;随着香菇子实体发育成熟,镉含量逐渐降低,不同部位镉含量呈现菌褶>菌盖>菌柄;在培养料中分别添加硫酸镁、硫酸锌、活性炭和沸石,发现添加50 mg/kg硫酸镁、60 mg/kg硝酸锌和2.5%活性炭,能使子实体镉含量下降42.8%、46.9%和50.3%。上述研究表明,培养条件和外源添加物对香菇菌丝体和子实体镉含量具有一定的影响,可通过外源添加物抑制香菇对镉的富集作用。
    2024,43(2):114-122 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.014
    Abstract:
    The daily observation data set of the National Meteorological Station of China from 1991 to 2020 and the urban green space area data of China in 2020 were used to analyze the effects of extreme climate on major urban gardens in China with the percentile method and GIS spatial analysis technology to study the risks of urban gardens suffering from extreme climate under the background of global climate changes. The results showed that the high-risk areas affected by extreme low temperatures were located in the northern and high-altitude areas of China. High risk areas of extreme high temperature generally occurred in eastern cities with rapid urbanization. The high-risk areas of heavy precipitation were basically consistent with the distribution of rainfall belts in China, mainly located in central and southern China, with average precipitation of above 30 mm. Shigatse and Naqu in Tibet, and the northern and eastern coastal areas of China are high risk areas of gales. Urban green space in the Yunnan-Guizhou Plateau, the middle and lower reaches of the Yangtze River, parts of North and Northeast China are vulnerable to extreme drought. Designing urban gardens in the future needs to combine the characteristics of local extreme climate, improve tree species and planting structures, and enhance the adaptability of ecological systems such as landscape architecture to climate changes.
    2024,43(2):123-133 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.015
    Abstract:
    A method suitable for identifying and classifying pepper diseases was designed to achieve precise recognition and classification of pepper diseases in complex environments including background clutter or interference.Six common diseases in the growth process of peppers were used to expand the dataset with data augmentation methods.An improved MaxViT-DF model was proposed based on MaxViT.The ordinary convolution in the MaxViT model was replaced with deformable convolution to enable the model to extract features closer to the recognition target in complex environments.A feature fusion module was introduced when applying attention to the MaxViT model to improve the model’s global perception ability.The results showed that the improved MaxViT-DF model had an identification and classification accuracy of 98.10%,and the classification accuracy for six common pepper diseases was higher than 95%.The improved model had significant advantages in convergence speed and classification accuracy compared with models including ResNet-34,EfficientNetv2,and VGG-16.It is indicated that the MaxViT-DF model can effectively identify and classify common diseases in different types of peppers.
    2024,43(2):134-143 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.016
    Abstract:
    Accurately identifying pests and diseases in citrus can be used to timely reduce the economic losses.A common method for detecting pests and diseases in citrus based on the improved YOLOv5s model was proposed to solve the problems that the existing models of detection cannot accurately identify multiple types of pests and diseases of citrus in the natural environment.The model was improved by introducing the ConvNeXtV2 model and constructing a CXV2 module to replace the C3 module of YOLOv5s, enhancing the diversity of extracted feature.The dynamic detection head DYHEAD was added to improve the processing ability of the model for different spatial scales and task targets.The CARAFE upsampling module was used to improve the efficiency of extracting feature.The results showed that the improved YOLOv5s-CDC had a mean recall rate and average precision of 81.6% and 87.3%,4.9 percentage points and 3.4 percentage points higher than that of the original model,respectively.Compared with the detection with other YOLO serial models in multiple scenarios,it had higher accuracy and stronger robustness.It is indicated that this method can be used for detecting the diseases and pests of citrus in complex natural environments.
    2024,43(2):144-153 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.017
    Abstract:
    The effects of genotypes and culture conditions on the microspore culture in mustard (Brassica juncea) were studied to establish an optimal system of the microspore culture and chromosome doubling in mustard.34 inbred lines of 8 different varieties of mustard were used to conduct the microspore culture.The effects of heat shock times,concentrations of activated carbon,and densities of microspore on the rate of microspore embryogenesis were analyzed.The results showed that genotypes had a significant impact on the success of microspore culture in mustard,with 11 out of 34 inbred lines successfully producing embryoids.There were significant differences in rates of producing embryo among different inbred lines,among which Brassica juncea var. megarrhiza Tsen et Lee had the highest rate of producing embryo,reaching 23.85 embryos/anther.The optimal conditions for producing microspores in mustard were 32 ℃ heat shock for 1-2 days,culture medium containing 3-5 g/L activated carbon,and the density being 1.5×105 to 2.0×105 microspores/mL.The results of chromosome doubling experiment showed that immersing the stem tips in 1 g/L colchicine solution for 1 hour had a high efficiency of chromosome doubling and low chimerism,which could be used to double the chromosomes in mustard.The results of chromosome doubling test showed that 1 g/L colchicine solution soaked in stem tip for 1 hour had high doubling efficiency and less mixed-ploidy formation,which could be used to double the chromosomes in mustard.
    2024,43(2):154-163 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.018
    Abstract:
    The three citrus pulp from Zigui navel orange,Yichang mandarin,and Ponkan tangerine was treated with six methods including refrigerator thawing,natural thawing,flowing water thawing,warm water thawing,ultrasonic thawing,and microwave thawing to study the effects of thawing methods on the quality characteristicsof the quick-frozen citrus pulp.The thawing time,loss rate of juice,conventional quality indexes,color,hardness,total phenolic content,antioxidant activity,and changes in sensory of quick-frozen citrus pulp were measured.The results showed that the effects of different thawing treatments on the quality of citrus pulp from Zigui navel orange,Yichang mandarin,and Ponkan tangerine were significantly different (P<0.05).The time of microwave thawing for Zigui navel orange,Yichang mandarin,and Ponkan tangerine was the shortest,being 0.82 min,0.89 min,and 0.81 min,respectively.The loss rate of juice in microwave thawing for Zigui navel orange,Yichang mandarin,and Ponkan tangerine was the lowest,being 0.25%,0.16%,and 0.15%,respectively.The conventional quality indexes of microwave and ultrasonic thawing were well preserved.The microwave thawing had the least effect on color with ΔE of 8.48,7.52, and 4.71,and the least loss of hardness with reductions of 36.1%,52.03%,and 36.48%,respectively.The content of total phenol and antioxidant activity in microwave thawing were relatively high,and the sensory profile was closest to that of fresh flesh samples.Compared to the other five thawing methods,microwave thawing can thaw the flesh within 1 minute,and effectively slow down the changes in color and the hardness loss of pulp,and better preserve the edible and nutritional qualities of the quick-frozen citrus pulp.
    2024,43(2):164-174 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.019
    Abstract:
    Aquaculture is one of the most important ways of providing aquatic products, and the aquafeeds, especially for carnivorous aquatic animals, requires large amounts of fishmeal. To date, fishmeal has been recognized as the best source of protein in aquafeeds in terms of nutritional quality. However, with overfishing, anthropogenic activities and extreme weather, the production of major fish species that provide fishmeal has been decreasing globally year by year, leading to fishmeal shortage and price increase, and thus there is an urgent need for the aquaculture industry to seek for high quality alternative protein sources to fishmeal in order to achieve its sustainable development. Aquaculture is one of the most important ways of providing aquatic products. The aquatic feeds especially for carnivorous aquatic animals require large amounts of fishmeal. To date, fishmeal has been recognized as the best sources of protein in aquatic feeds in terms of nutritional quality. However, the production of major fish species that provide fishmeal has been decreasing globally year by year with overfishing, anthropogenic activities and extreme weather, leading to the shortage of fishmeal and the increase of its price, and thus there is an urgent need to seek the alternative sources of protein with high quality as fishmeal to achieve the sustainable development of aquaculture industry. Black soldier fly (BSF, Hermetia illucens) is a saprophytic insect, and its larvae have characteristics including wide feeding habits, strong reproductive ability, and rich and balanced nutrients. It is considered as a highly potential and new sources of feed protein and has broad prospects of application in the production of aquatic animals. This article reviewed the main nutritional and bioactive components of BSF larvae, as well as progress on their application in feeds for different aquaculture species such as herbivorous, omnivorous, carnivorous, crustacean, and amphibian reptiles. The optimal amount of BSF larvae in different aquatic feeds was summarized. The feasibility of using BSF larvae as a sustainable source of protein in aquatic feeds was explored. The problems and challenges in its practical application were analyzed. It will provide a basis and reference for developing and utilizing black soldier fly and studying its mechanism in aquatic animals.
    2024,43(2):175-187 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.020
    Abstract:
    To find out the community structure of zoobenthos in five drinking water reservoirs including Guanyinge Reservoir, Baishi Reservoir, Chaihe Reservoir, Qinghe Reservoir, and Tanghe Reservoir, in Liaoning Province, and to estimate the potential fishery production according to the stock of zoobenthos, then to provide scientific guidance for the stocking and fishing of water conservation fisheries, seasonal surveys of the five reservoirs were carried out in 2019-2020. A total of 67 taxa, belonging to 3 phyla were identified. Among them, 39 species were chironomid larvae and 12 species were oligochaetes mainly Tubifex and Naididae. Only three species of mollusks were identified, including Radix swinhoei collected from Guanyinge Reservoir and Tanghe Reservoir, Bellamya purificata collected from Guanyinge Reservoir, and Cristaria plicata collected from Baishi Reservoir. The most species were detected in Tanghe Reservoir with 39 species, followed by 34 species in Guanyinge Reservoir, and the least in Baishi Reservoir with 23 species. The density was the highest in Baishi Reservoir with 1 546.89 ind/m2, followed by Guanyinge Reservoir with 658.33 ind/m2, and the lowest was Tanghe Reservoir with 481.92 ind/m2. The biomass was the highest in Baishi Reservoir with 7.76 g/m2, followed by Tanghe Reservoir with 5.68 g/m2, and the lowest was Qinghe Reservoir with 2.49 g/m2. The highest density of five reservoirs occurred in spring, summer and autumn, but the lowest values were all in summer. The biomass was higher in spring and winter, and lower in summer and autumn. The density and biomass of each reservoir was the highest in the still water zone. Only the highest density and biomass in Guanyinge Reservoir and biomass in Baishi Reservoir appeared in the transition zone. The density and biomass of Guanyinge Reservoir and Chaihe Reservoir were mainly composed of oligochaetes from the river zone to the front of the dam, while the reservoir entrance was dominated by chironomid larvae. The density and biomass of Qinghe Reservoir and Tanghe Reservoir were mainly composed of chironomid larvae from the reservoir entrance to the still water zone, while the front of the dam was dominated by oligochaetes. Baishi Reservoir was dominated by chironomid larvae from the reservoir entrance to transition zone, while the still water zone and the front of the dam were mainly composed of oligochaetes. The results of clustering and MDS ordination indicated that the communities of Guanyinge, Chaihe and Qinghe reservoirs were more similar. The communities of Baishi and Tanghe reservoirs were less similar and significantly different from those of Guanyinge, Chaihe and Qinghe reservoirs. Canonical correspondence analysis indicated that the density of zoobenthos were significantly correlated with the depth of water, total nitrogen, ammonia nitrogen, dissolved organic carbon and chlorophyll-a in five reservoirs. The species and composition of zoobenthos were obviously influenced by the contents of total nitrogen and ammonia nitrogen. The contents of total nitrogen and ammonia nitrogen in Tanghe Reservoir were the lowest, showing the most species and high dominance of chironomid larvae. The contents of total nitrogen and ammonia nitrogen in Baishi Reservoir were the highest, showing the least species and high dominance of tubificid worm. The fish production potential based on zoobenthos of Baishi Reservoir was the highest, followed by Tanghe Reservoir, and lowest in Qinghe Reservoir. Compared with previous surveys, the species numbers of five reservoirs increased, mainly due to the increase of chironomid larvae species. The trends of density and biomass were different from that of the number of species. The density and biomass of Guanyinge Reservoir decreased, while those of Qinghe and Tanghe Reservoirs increased. The density of Baishi Reservoir increased and the biomass decreased, while the density of Chaihe Reservoir decreased and the biomass increased. The stocking and fishing of demersal fish in five water source reservoirs should be managed in a targeted manner according to the characteristics of zoobenthos community structure.
    2024,43(2):188-196 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.021
    Abstract:
    In order to investigate the effects of dietary supplementation of yeast chromium and dihydropyridine on physiological and biochemical indices and HSP70 mRNA expression of periparturient dairy cows under heat stress, a total of 24 periparturient Holstein‐Friesian cows with similar body weights and parity were randomly assigned to three groups. Cows were housed at high ambient temperature-humidity index(above 68)for 40 d, and the effects of yeast chromium and dihydropyridine on the heat stress response of perinatal dairy cows were observed during the experimental period. The control group was fed with basal diet, the chromium yeast group was fed with basal diet plus chromium 1‰ and the amount of chromium yeast was 8 g/d, and the dihydropyridine group was fed with basal diet plus dihydropyridine and the amount of chromium yeast was 3 g/d. The results showed as follows: ① Compared with the control group, there was no significant difference in respiratory rate of periparturient dairy cows in chromium yeast group and dihydropyridine group (P>0.05). ② Compared with the control group, there was no significant difference in serum blood glucose and cholesterol in yeast chromium group and dihydropyridine group on the 7th day before delivery and the 3rd day after delivery (P>0.05). Compared with the control group, the content of serum triglyceride decreased significantly in dihydropyridine group on the 7th day before delivery (P<0.05). ③ Compared with the control group, there was no significant differences in serum Na+, K+ and Cl- concentrations in chromium yeast group and dihydropyridine group before and after delivery (P>0.05), and the concentrations of serum alkaline phosphatase and creatine kinase did not change significantly in the two experimental groups before and after delivery (P>0.05). ④ There was no significant difference in the expression of heat shock protein 70 mRNA in serum between chromium yeast group, dihydropyridine group and control group (P>0.05). In conclusion, dietary supplementation of 8 g/d yeast chromium with 1‰ chromium and 3 g/d dihydropyridine had no significant effects on physiological and biochemical indices and HSP70 mRNA expression of periparturient dairy cows under heat stress. These results indicated that supplementation of 8 g/d yeast chromium with 1‰ chromium and 3 g/d dihydropyridine had no significant effect on relieving heat stress of perinatal Holstein dairy cows.
    2024,43(2):197-204 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.022
    Abstract:
    The mouse blastocysts were used as a model to study the expression profiles of key genes in mice during the hatching and development of blastocyst and to further analyze the mechanism of pregnancy recognition. The transcriptome of blastocysts at different stages of the hatching process was analyzed. The expression levels of key genes were detected with qPCR. The expression patterns of key proteins were studied with immunofluorescence staining. The results of analyzing the transcriptome showed that the expression of differential genes exhibited two regulatory patterns during the hatching process of mouse blastocysts from expansion, hatching to the completion of hatching. The results of GO analysis and KEGG analysis on the set of genes in the regulatory pattern showed that they were involved in biological processes including immunity and inflammation, cell differentiation, and apoptosis, etc. The results of qPCR showed that the expression of key genes Ptgs1, Lyz2, Il-1α, Cfb and Ccl9 were up-regulated, while Cd36 was down-regulated during hatching of mouse blastocysts, which was consistent with the results of transcriptome analyses. The results of immunofluorescence staining showed that Plac1, Cdx2 and C3 were down-regulated, while Lyz2 and Il-1β were up-regulated during the hatching of mouse blastocysts. It is indicated that the expression of gene exhibits specific dynamics of differentiation and the expression of abnormal gene can lead to hatching at a standstill.
    2024,43(2):205-214 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.023
    Abstract:
    A vibration extrusion type water chestnut harvester was designed to solve the problems of high manual labor intensity, low operation efficiency, and difficulty in separating fruit and soil during dry harvesting of water chestnuts. The separated water chestnuts were scattered on the surface for easy manual picking by enhancing the effect of crushing the soil layer and improving the degree of fruit and soil separation. The key parameters affecting the separation performance were determined to be the amplitude of the vibration plate, the vibration frequency of the vibration plate, and the speed of the nail roller by analyzing the stress on the water chestnut soil block during the process of operation. The range of key parameter values was preliminarily determined according to the existing experience. Design-Expert 10.0 was used to design the CCD center combination test by using the amplitude of the vibration plate, the vibration frequency of the vibration plate, and the speed of the nail roller as the influencing factors, and the rate of soil fragmentation as the evaluation index. The results of simulating the RecurDyn-EDM coupling showed that there was a better crushing effect and the rate of soil fragmentation was 93.58% when the vibration frequency of the vibration extrusion plate, the vibration frequency of the vibration plate, and the speed of the nail roller was 33.04 mm, 6.63 Hz, and 336.72 r/min, respectively. The results of field verification test showed that the actual rate of soil fragmentation, the rate of water chestnut, and the damage rate was 93.54%, 80.33%, and 28.08%, respectively when the actual amplitude of vibration plate, vibration frequency and the speed of nail tooth was 32.41 mm, 6.5 Hz, and 330 r/min, respectively. It is indicated that the effect of crushing soil is good, and the fitting degree with the results of simulation is high.
    2024,43(2):215-226 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.024
    Abstract:
    A seedbed belt preparation device suitable for constructing rapeseed substrate block seedling transplanters was designed based on the large cavity of the boat type furrow opener and the characteristics of constructing a wide seedbed and a flat furrow bottom through the operation of the core ploughshare furrow opener, combined with the excessive connection of the similar ploughshare surface to solve the problems of poor stability of the furrow width, low flatness of the furrow bottom, and large soil disturbance, resulting in low seedling rate and high difficulty in soil covering operations in the operation of furrow opener device of rapeseed substrate block seedling transplanter. A mechanical model for the interaction between soil and preparation device was established. The main structural parameters for constructing a stable seedbed with a seedbed belt preparation device were determined. A four-factor and three-level quadratic orthogonal combination simulation test was conducted using EDEM and taking the operating speed, working depth, front-end width of the brush type surface,and edge angle of blade as factors, the soil disturbance amount and coefficient of variation of ditch width as evaluation indicators. The results of quadratic orthogonal combination test showed that the soil disturbance amount and the coefficient of variation of the ditch width was small when the working depth, the operating speed, the front-end width of the brush type surface and the edge angle of blade was 41 mm,0.52 m/s,40 mm,and 61°, respectively. The results of bench test under the optimal parameter combination showed that the soil disturbance amount was 13.01 cm2 and the coefficient of variation of the ditch width was 8.52%. The results of field comparative test showed that the seedling bed equipped with the preparation device installed on the transplanting unit increased the seedling rate of the substrate block by 2.09 percentage points, decreased the coefficient of variation of the ditch width by 13.3%, reduced soil disturbance by 20.9%, and increased the compactness of the ditch bottom by 28.7% compared to the boat type opener, meeting the requirements for the construction of the rapeseed substrate block seedling transplanter.
    2024,43(2):227-233 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.025
    Abstract:
    It is necessary to replenish water one by one for the mushroom sticks on the multi-layer mushroom rack during the process of mushroom production.A water injection machine for mushroom sticks on rack mainly composed of six parts including a clamping device,a water injection device,a lifting device,a rotating device,a driving device,and a positioning device was designed to solve the problems of high labor intensity,low efficiency,and inability to accurately control the amount of water injected by traditional manual water replenishment.The water injection unit is composed of a clamping device and a water injection device,the clamping and water injection for a total of 15 mushroom sticks on three layers can be completed simultaneously,and the water replenishing operation of multi-layer mushroom sticks can be realized under the driving of the lifting device.The water replenishing operation of the mushroom rack on the other side can be completed by the rotating device. According to theoretical calculation,the maximum holding force Fjmax of the clamping device is 4 750 N,and the minimum thrust Ftmin of the water injection device is 2 455 N.The rotating device needs to accelerate for 2 s before rotating at a uniform speed for 3.5 s.According to the structural design and theoretical calculation,this article developed a prototype of a water injection machine for mushroom sticks on rack,and conducted a prototype test.The results showed that the damage rate of the mushroom sticks after water replenishment was 0,with the average weight ratio of 84.8% and the average working efficiency of 230 pieces/h.The water injection machine adopts the method of replenishing water with mushroom sticks on rack,which improves the working efficiency and meets the requirements of replenishing water for mushroom sticks.It will provide a theoretical basis for the development of the water injection machine for mushroom sticks on rack.
    2024,43(2):234-246 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.026
    Abstract:
    A multi-sensor integrated positioning method for a rice transplanter supplemented with vision navigation system based on the GNSS/INS integrated positioning was proposed to improve the navigation effect of rice transplanter based on GNSS/INS integrated positioning when encountering the conditions of ambient occlusion, electromagnetic interference and sensor failure. Firstly, the improved Otsu method and the improved Hough transform algorithm were designed to extract the visual positioning information, and the relationship equation between the coordinate system of rice transplanter and camera was constructed to solve the position and pose values. Then, the federal Kalman filter algorithm with fault-tolerant function was used to fuse the visual positioning information with the positioning information output by GNSS and INS. Finally, tests were conducted in cement field and paddy field. Results showed that the accuracy of GNSS/INS/VNS combined positioning was similar to that of GNSS/INS integrated positioning in the open cement ground scene, but the average values of position error and heading error calculated by GNSS/INS/VNS combined positioning were 1.77 cm and 0.99°, respectively, which are 46.8% and 61.5% higher than those by GNSS/INS integrated positioning method. In paddy field experiment, the average values of lateral deviation and heading deviation of navigation system decreased by 45.7% and 67.9%, respectively after visual supplement, with the average values of lateral deviation of 1.97 cm and heading deviation of 0.49°. It is indicated that the multi-sensor integrated positioning method based on visual supplement can effectively reduce the positioning error and tracking deviation of navigation system, meeting the performance requirements of automatic driving operation of transplanter.
    2024,43(2):247-253 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.027
    Abstract:
    It is extremely important to obtain accurate information of soil moisture and understand the dynamic change pattern of soil moisture. A support vector machine algorithm(SVM) was introduced for fitting analysis and regression training optimization of ultrasonic velocity-soil moisture under four different treatments of alternating wet and dry, and a prediction model of the soil moisture based on ultrasonic velocity was constructed. The prediction model was used to estimate the water content of soil in farmland tillage layer with different moisture requirements. The results showed that the average relative error of verifying soil moisture in the field with the model constructed was about 1.5% compared with the traditional drying method. It is indicated that the prediction model for ultrasonic velocity-soil moisture based on SVM model can effectively describe the soil moisture in the area studied. It will provide reference for utilizing ultrasonic characteristics to achieve continuous monitoring of soil moisture in farmland.
    2024,43(2):254-263 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.028
    Abstract:
    The overset mesh model coupled with the VOF model in Fluent software was used to study the two-phase flow to deeply understand the spray coating process of preserved eggs and solve the problems of insufficient theoretical researches on the spray coating of preserved eggs. The liquid film wetting ratio during the coating process under different placement positions of preserved eggs was obtained. The changes of the aspect ratio of the droplets under different pipette parameters were analyzed. The optimal pipette parameters and working pressure for the removal of pendant droplets were selected by the Box- Behnken experiment using the variation index of film thickness as the response value. The results showed that the liquid film wetting ratio of the preserved eggs placed downward after spraying was 1 while the liquid film wetting ratio of the preserved eggs placed with the blunt end down after spraying was only 0.836. The optimal combination of straw parameters screened out was spacing of 14.50 mm, diameter of 12.09 mm, working pressure of 6.97 kPa, and predicted variation index of film thickness of 0.636. The experiments of simulation and the removal of pendant droplets using the air suction device were carried out under the optimal combination of straw parameters. The results showed that the relative error between the simulated value and the predicted value of the variation index of film thickness was 1.73%. The relative error between the observed value and the expected value of the variation index of film thickness was 7.55%, and the relative error between the observed value and the simulated value was 9.12%. Indicating that the coupling model in this study can be used for the simulation test of egg spray coating.
    2024,43(2):264-272 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.029
    Abstract:
    Near-infrared spectroscopy was used to qualitatively discriminate the adulteration in whole egg powder and to analyze the concentration of adulteration quantitatively. Six different pre-processing methods were used to pre-process the raw spectral data. The competitive adaptive reweighted sampling (CARS), successive projections algorithm (SPA) and combined CARS-SPA algorithms were used to filter the spectral data for characteristic wavelengths. Ensemble learning (EL) model was established to qualitatively discriminate the egg powder adulterated. The partial least squares regression (PLSR) model was established to quantitatively analyze the concentration of adulteration. The results showed that first order derivative was the best pre-processing method in qualitative discrimination. The CARS algorithm had the best effect of feature filtering. The EL model had an overall discrimination accuracy of 98.18% for adulterated samples, with the discrimination accuracy of differently adulterated samples of more than 97.78%.MSC was the best pretreatment method in quantitative analysis. CARS algorithm had the best effect of feature filtering. The prediction set correlation coefficient of PLSR adulteration concentration prediction models for one-component adulteration, two-component adulteration, three-component adulteration, and all adulterated samples adulteration was 0.958 5, 0.931 2, 0.945 6, and 0.955 8, respectively, with the root mean square error RMSEP of 4.689 1, 5.813 4, 4.604 1, and 3.802 9, respectively. It is indicated that the near-infrared spectroscopy can be used for detecting the adulteration in whole egg powder. It will provide a reference for regulatory agencies to detect adulteration in whole egg powder.
    2024,43(2):273-279 , DOI: 10.13300/j.cnki.hnlkxb.2024.02.030
    Abstract:
    Covalent attachment of ubiquitin onto lysine residues of the substrate requires the coordinated action of three classes of enzymes: the E1 ubiquitin-activating enzymes, the E2 ubiquitin-conjugating enzymes, and the E3 ubiquitin ligases. These ubiquitination-related proteins play a pivotal role in plant development and plant physiology.The APPBP1/UBA3 (E1), UBC12 (E2), Cullin1-Rbx1 (E3) and Nedd8 were used to reconstitute SCF E3 ligase activity in vitro to study protein ubiquitination in vitro. Ub (Ubiquitin) labeled with FITC-Cysteine green fluorescein was prepared. The ubiquitination system of SCF ubiquitin ligase in vitro was constructed. The self-ubiquitination modification of Cullin1 protein in SCF ubiquitin ligase was rapidly detected. The results showed that the autoubiquitination active reaction system of SCF E3 in vitro established has high operability and convenience.
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    Abstract:
    In this study, a model of necrotizing enteritis was established by infecting broilers with Clostridium perfringens type G, and the preventive effects of Bacillus subtilis compound microbial preparation on necrotizing enteritis of broilers were studied by adding different compound microbial preparation to feed. A total of 120 one-day-old 817 chicks were randomly divided into four treatment groups: Control group and necrotizing enteritis group were fed a basal diet, Prob1 group was fed a basal diet supplemented with 0.2% microbial agent 1, and Prob2 group was fed a basal diet supplemented with 0.2% microbial agent 2. On days 14 to 16, broilers in Prob1, Prob2 and NE groups produced Clostridium perfringens (CP) by continuous gavage. The test period was 23 days. The results showed as follows: the body weight of broilers in NE group was lower than that in Control group, and the body weight of Prob1 and Prob2 groups at the 17th and 23rd days of the experiment was significantly higher than that in NE group (P < 0.05). (2) The jejunal epithelial cells of broilers in NE group were necrotic and exfoliated, the villus was shorter, the crypt was deepened, and the villus length and the villus crypt ratio of broilers in NE group were significantly higher than those in NE group after the use of Bacillus subtilis compound microbial preparation (P < 0.05). The activities of T-SOD, T-AOC and AKP in jejunal mucosa of broilers in NE group were lower than those in Control group; On day 17, the T-AOC and AKP activities of jejunal mucosa of broilers in Prob1 and Prob2 groups were significantly higher than those in NE group (P < 0.05), and the T-SOD activity of jejunal mucosa of broilers in Prob1 group was significantly higher than that in NE group (P < 0.05). On day 23, the activities of T-SOD, T-AOC and AKP in jejunal mucosa of broilers in Prob1 and Prob2 groups were higher than those in NE group, and there were no significant differences (P > 0.05). The content of MDA in jejunal mucosa of broilers in NE group was higher than that in Control group, and the content of MDA in Prob1 and Prob2 groups was lower than that in NE group at the 17th and 23rd days (P > 0.05). The gene expressions of intestinal tight junction protein CLDN1 and ZO-2 in NE group were lower than those in Control group, and there were significant differences on day 17 of experiment (P < 0.05). On the 17th and 23rd day of the experiment, the gene expressions of intestinal tight junction protein CLDN1 and ZO-2 in Prob1 and Prob2 groups were higher than those in NE group (P > 0.05), and the gene expressions of ZO-1 in Prob1 and Prob2 groups were significantly higher than those in NE group (P < 0.05). The results showed that adding Bacillus subtilis compound microbial preparation to the diet could improve the growth and development of chickens with necrotizing enteritis, increase the antioxidant capacity and intestinal tight junction protein gene expression of broilers, and Bacillus subtilis compound microbial preparation 1 had a better preventive effect on chicken Necrotic enteritis
                                                                                                                   
    Abstract:
    To enhance the accuracy of mechanical harvesting of pineapples in regions with different maturity levels and ensure the quality of pineapples, a real-time pineapple ripeness detection method based on improved YOLOv8 is proposed. Addressing challenges such as small and densely packed targets and light obstruction in natural environments, this study replaces the common convolutions in the backbone and neck parts of the original YOLOv8 model with Depthwise Separable Convolutions (DSConv) to streamline model parameters. Additionally, a Convolutional Block Attention Module (CBAM) is introduced before feature fusion to prioritize important features, thereby improving the accuracy of target detection. The YOLOv8 network's original loss function, CIoU, is replaced with the EIoU loss function to expedite network convergence.Various ablation experiments are designed for different modules in the study, demonstrating the effectiveness of each improvement. The results show that the PmA of the improved model for pineapple maturity detection is 97.33%, which is 5.53, 7.91, 4.38 and 4.66 percentage points higher than that of Faster R-CNN, YOLOv4, YOLOv5 and YOLOv7, respectively. On the premise of ensuring the detection accuracy, the number of model parameters of the algorithm is only 16.8×106. The results show that the improved model improves the accuracy and inference speed of pineapple maturity recognition, and has stronger robustness.
                                                                                                                   
    Abstract:
    Cooking and eating quality is an important criterion for consumers to select rice. Starch, protein and lipid, as the three major components of rice, are closely related to the cooking and eating quality. In this paper, the composition and distribution, anabolic characteristics of three major substances in rice and their relationships with cooking and eating quality were reviewed. The effects of alternating wet and dry irrigation (AWD) on starch, protein, lipid and cooking and eating quality of rice were discussed. Problems such as the lack of studies on the influence of three major substances interaction on cooking and eating quality and the lack of in-depth studies on the regulation mechanism of AWD on cooking and eating quality were pointed out. It is recommended to further study the formation mechanisms of cooking and eating quality of rice based on the relationship between accumulation of three major substances and anabolism, and that the positively regulatory mechanisms of alternating wet and moderately dry irrigation (AWMD) on cooking and eating quality of rice. The purpose of this review is to provide theoretical basis and technical support for the improvement in rice taste.
                                                                                                                   
    Abstract:
    In order to optimize the fertilizer and drug application model of direct seeding winter rapeseed in karst mountainous areas of Guizhou Province, field experiments were carried out in 11 major winter rapeseed producing counties and urban areas of Guizhou Province for two consecutive years from 2018 to 2019 and 2019 to 2020 to study the effects of different fertilizer and pesticide mode (T1 Farmer’s fertilizer and pesticide mode,T2 Optimized fertilizer and pesticide mode,T3 Optimized fertilizer and pesticide mode without fertilizer,T4 Optimized fertilizer and pesticide mode without pesticide) on the yield and economic benefits of direct-sowing winter rapeseed,and to explore high-yield and high-efficiency fertilizer and pesticide techniques suitable for the current production of direct-sowing winter rapeseed in Guizhou karst mountains regions. The results showed that compared with T1,T2 reduced the total nutrient input by 19.9% and the pesticide input by 69.5%. As the winter rapeseed under T2 is direct seeding,its plant height,rootstock diameter,1 st branch,pod length,pod density,pods per plant,seeds per plant and 1000-seed weight were lower than those under T1,with a decrease of 18.7 cm, 0.43 cm, 1.0, 0.78 cm, 0.37/cm and 18.2 cm, 0.47 cm, 1.2, 0.84 cm, 0.37/cm, respectively. T2 has a population advantage, and compared to T1, the two-year harvest density of T2 significantly increased by 20.9×104 plants/hm2 and 20.4×104 plants/hm2, respectively. In two years,the yield of winter rapeseed under T2 was 2 224.4 kg/hm2 and 2 103.3 kg/hm2 respectively,which was 204.0 kg/hm2 and 74.3 kg/hm2 higher than that under T1. The efficiency of fertilizer agronomy and pesticide control of T2 were 2.20 kg/kg, 2.14 kg/kg and 141.82 kg/kg, 106.23 kg/kg,respectively,which were significantly higher than those of T1. The total output value and net benefit of T2 for winter rapeseed were 11 121.8 yuan/hm2,10 516.4 yuan/hm2 and 5286.8 yuan/hm2,4 681.4 yuan/hm2,respectively,which were 1 020.0 yuan/hm2,371.6 yuan/hm2,26 285.0 yuan/hm2 and 1 976.6 yuan/hm2 more than T1,realizing cost saving and income increase. In summary,the current optimized fertilizer and pesticide mode (T2) could meet the needs of the growth of direct-sowing winter rapeseed in Guizhou karst mountains regions,and can improve the yield,fertilizer and pesticide utilization efficiency and economic benefits of direct-sowing winter rapeseed. The current optimized cultivation pattern is recommended as the main pattern of direct-sowing winter rapeseed in Guizhou karst mountains regions.
                                                                                                                   
    Abstract:
    Using the self-made nylon net cages, the decomposition characteristics, nutrient release characteristics, and surface microstructure changes of rice straw under the disturbance of crayfish were simulated in a trenche for aquaculture about rice-crayfish model, with no crayfish as a control. The purpose was to identify the process and mechanism of crayfish participating in the decomposition of rice straw under continuous soaking conditions and provide scientific basis and technical support for improving the rice straw returning technology in the rice-crayfish model. The results showed that the average decomposition rate of rice straw in each stage showed a characteristic of fast-slow-fast-slow-fast regardless of whether there were crayfish involved. Before 150 days, there was no significant difference in the amount of decomposition, cumulative decomposition rate, and average decomposition rate of each stage between the treatment with crayfish and the treatment without crayfish. By 180 days and later, all indicators showed that the treatment with crayfish was significantly higher than the treatment without crayfish. By 210 days, the cumulative decomposition rate of rice straw in the treatment with crayfish reached 85.67%, 12.35 percentage points higher than the treatment without crayfish. The cumulative release rate of straw nutrients was K>P>N; After 150 days, the N cumulative release rate of the treatment with crayfish showed a higher trend than that of the treatment without crayfish, and after 180 days, the P cumulative release rate and total nutrient cumulative release rate of the treatment with crayfish showed a higher trend than that of the treatment without crayfish. At 210 days, the K cumulative release rate of the treatment with crayfish showed a higher trend than that of the treatment without crayfish. After 120 days, the degree of damage to the surface structure of straw treated with crayfish was significantly greater than that without crayfish. In summary, under the rice-crayfish model, the disturbance energy of crayfish increased the degree of damage to the surface microstructure of rice straw in the middle and late stages, promoted the decomposition of rice straw and nutrient release in the late stages.
                                                                                                                   
    Abstract:
    To reveal the functions of SPL transcription factor in the developmental processes in petunia, we cloned the petunia PhSPL9b gene, and obtained rPhSPL9b by point mutation of its miR156/157 target site. Then, the overexpression vectors of 35S:PhSPL9b and 35S:rPhSPL9b were constructed and transformed into petunia and Arabidopsis, respectively. Finally, transgenic plants of Arabidopsis overexpressing PhSPL9b or rPhSPL9b, and transgenic plants of petunia overexpressing PhSPL9b, were obtained. Phenotypic analysis showed that ectopic expression of PhSPL9b or rPhSPL9b, especially 35S:rPhSPL9b, significantly reduced the number of rosettes and promoted flowering in Arabidopsis compared with the control (CK). Overexpression of PhSPL9b also observably promoted flowering in petunia. RT-PCR and qRT-PCR analysis showed that the relative expression of PhSPL9b was observably up-regulated in transgenic lines in contrast to that in CK. The experiments showed that PhSPL9b was a transcription factor with the function of transcriptional activation. These results suggest that PhSPL9b plays a relatively conservative role in the regulation of flowering time probably by activating the expression of downstream genes.
                                                                                                                   
    Abstract:
    Aiming at the problem that the existing chain-type paper pot seedling transplanters are mostly continuous chain transplanting with unadjustable plant spacing and cannot meet the requirements of large plant spacing crop transplanting, this paper explored and designed a seedling chain breaking device for chain pot seedling transplanters, taking conventional hexagonal cross-section chain pot seedlings as the test object. Based on the principle of seedling chain breaking device, the structure of key components and the value range of working parameters were determined through theoretical analysis of working process. A test bench was set up for single factor test, with the opening of the pinch finger, the inclination angle of the seedling chute and the planting frequency as the main test factors, and the success rate of seedling taking and the matrix loss rate as the evaluation indexes. The orthogonal combination test of three factors and three levels was carried out to analyze the influence of each factor on the evaluation index and optimize it. The test results showed that the effect was better when the opening of the pinch finger was 52mm, the inclination angle of the seedling chute was 20°, and the planting frequency was 45 plants/min. Under this parameter combination, the success rate of seedling taking was 91.3% and the matrix loss rate was 14.2% in the bench test, and the success rate of seedling taking was 87.5% and the matrix loss rate was 17.4% in the soil tank verification test. This study can provide reference for the development of the whole chain pot seedling transplanter.
                                                                                                                   
    Abstract:
    In the face of resource shortage and increasing carbon emissions, how to change the traditional development model and promote the green transformation of the whole society is an important issue to be solved urgently in China to adhere to the green, low-carbon and circular development path. Based on the panel data of 30 provinces in China from 2010 to 2020, this paper constructs an index system and uses the entropy weight TOPSIS model, coupling coordination degree model and spatial autocorrelation model to analyze the coupling coordination degree of digital economy, low-carbon development and new urbanization and its spatio-temporal evolution characteristics. The results show that: (1) From 2010 to 2020, the comprehensive development level of the three systems has significantly improved, showing the spatial distribution characteristics of "high in the east and low in the west"; (2) The coupling coordination degree of the three systems showed a fluctuating upward trend, and the overall level was not high after experiencing the stage of "mild imbalance → barely coordination"; (3) The spatial characteristics of the three systems are positive spatial autocorrelation, the correlation is gradually enhanced, and the spatial distribution changes to the aggregation state; (4) The high-high agglomeration type is mainly distributed in the southeast coastal and central areas and shows a significant diffusion trend, and the coordinated development level shows a "high southeast and low northwest" trend. Based on the empirical analysis results, suggestions are put forward for the coupling and coordination of digital economy, low-carbon development and new urbanization, in order to provide references for strengthening regional linkage, making up for weaknesses, and promoting green, low-carbon and circular development.
                                                                                                                   
    Abstract:
    [Objective] The spatial distribution prediction of soil total nitrogen and its influencing factors are essential for understanding nitrogen cycle and formulating soil nitrogen management measures. Combined with measured soil total nitrogen content data and multi-source environmental variables, the random forest model was established to explore the spatial distribution characteristics of soil total nitrogen content in a forest farm and the response to environmental factors. [Method] The Wangyedian Experimental Forest Farm was taken as the research area, and a quantitative relationship was established between soil total nitrogen content and environmental covariates of altitude, normalized vegetation index, slope aspect, mean annual temperature, mean annual precipitation and y coordinate at soil depths of 0-10, 10-30 and 30-50 cm using the random forest model. Soil total nitrogen content was predicted and mapped, and the controlling factors affecting its spatial variation were analyzed. [Result] The results showed that (1) the average soil total nitrogen contents at soil depths of 0-10, 10-30 and 30-50 cm were 3.20, 2.02 and 1.47 g kg-1, respectively. It decreased with the increase of soil depth. (2) Cross-validation results showed that the R2 of soil total nitrogen at the three soil depths were 0.54, 0.40 and 0.38, respectively, and the prediction accuracy of the model decreased with the increase of soil depth, indicating that the random forest model could explain 38%~54% of the spatial variation of soil total nitrogen. The effects of various environmental factors on the spatial distribution of soil total nitrogen decreased with the increase of soil depth. (3) Judged from the prognostic map, soil total nitrogen content in different soil depth showed a spatial pattern of low content in the west, north and central parts, and high content in the southwest, southeast and east parts. (4) Altitude had the greatest effect on soil total nitrogen content, and the rest was in the order of normalized vegetation index > mean annual precipitation > y-coordinate > aspect > mean annual temperature. [Conclusion] The random forest model can effectively predict soil total nitrogen content at different soil depths in this forest farm, providing a new idea for the spatial distribution prediction of other soil attributes. Meanwhile, this study provide a reference for forest soil nutrient management and sustainable use on forest farm scale.
                                                                                                                   
    Abstract:
    In order to explore the basis of climate resource allocation in the production of tobacco leaves for cigar wrapper. Taking“Yunxue-1”variety as the test material,the climate indices during the growth period of tobacco plants was changed by adjusting the transplanting period,and the multivariate statistical analysis method was used to study the basis of climate resource allocation of tobacco leaves for cigar wrapper and its influence on the agronomic traits of tobacco plants and the chemical composition of tobacco leaves after fermentation. The results of correlation analysis showed that The results of correlation analysis showed that the accumulated temperature,≥10℃ effective accumulated temperature,total precipitation and total temperature difference had a great influence on the agronomic traits of tobacco plants,and the correlation coefficient was between 0.478 and 0.939. The accumulated temperature,≥10℃ effective accumulated temperature and average temperature had a great influence on the total sugar, nicotine,total nitrogen and protein content of tobacco leaves,and the correlation coefficient was between -0.955 and -1.000. Through factor analysis,two main factors of climate accumulation factor and humidity factor were both extracted from eight climate indicies. Further through grey correlation analysis found that the above two factors were the main factors affecting the agronomic traits of tobacco plants and the conventional chemical components of tobacco leaves. Therefore,the main climatic factors determining the transplanting period of tobacco plants for cigar wrapper should be based on the comprehensive configuration of temperature,precipitation and relative humidity during the field growth period.
                                                                                                                   
    Abstract:
    In order to detect the volatile components , identify the aroma active substances, and screen the excellent aromatic varieties of Brachyceras water lilies, Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPEM-GC-MS) was conducted to detect volatile compounds in 30 cultivars of Brachyceras water lilies. The results showed that a total of 60 volatile compounds including alkanes, alkenes, terpenes, benzenoids, esters, alcohols and aldehydes were identified. Among them, alkanes and alkenes were the main categories, accounting for 42.43% and 28.61% of the total content, respectively. However, these compounds have trace fragrance characteristics. Furthermore, 19 aroma active compounds were screened by the aroma activity value (OAV). Among them, α-ionone, β-ionone, trans-β-ionone and farnesene were considered as the key characteristic aroma compounds with OAV>1. Ionone endowed water lily woody and sweet fragrance, farnesene endowed apple and typical floral aroma. The results showed that five water lily varieties, 'Blue Bird', 'Carla's Sunshine', 'Eidorado', 'Ruby' and 'Pink Diamond', which were screened based on the OAV value, were potential excellent varieties for landscape application and product processing.
                                                                                                                   
    Abstract:
    【Objective】To explore the feasibility and the optimal operation parameters combination of spraying foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV).【Method】The experiment of spraying foliar fertilizer was carried out by using XAG P20-2019 quadcopter UVA, the three-factor and three-level orthogonal test was designed, spray quality, yield, and blade quality of Acanthopanax trifoliatus were used as indicators, the effects on spray concentration, flight speed and flight height were investigated.【Result】 The results showed that flight speed and flight height had significantly influence on spray quality, while spray concentration, flight speed and flight height had significantly influence on yield and blade quality of Acanthopanax trifoliatus. Comparing and analyzing the optimal operation parameters of spray quality, yield and blade quality of Acanthopanax trifoliatus, it can be obtained that fertilization effect is best when spray concentration is 5 times the recommended concentration, flight speed is 1.0 m×s-1, and flight height is 2.0m, spray quality is the best and compared with the blank control group, yield increased by 27.46%, and chlorophyll content of Acanthopanax trifoliatus increased by 33.23%.【Conclusion】This paper proved that the feasibility of spraying high concentration foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV). This study is expected to improve the mechanized operation level of the planting industry of Acanthopanax trifoliatus and promote it, and provide reference for foliar fertilization using the same type of UVA with the popularization and application value.
                                                                                                                   
    Abstract:
    Two treatments, Zizania latifolia co cropping and crayfish (ZC) and Zizania latifolia monoculture (Z), were set up to study the effects of Zizania latifolia co cropping and crayfish on soil nitrogen and phosphorus content, Zizania latifolia yield, dry matter accumulation and N, P, K absorption and distribution of Zizania latifolia, so as to provide a theoretical basis for rational fertilization and further promotion of Zizania latifolia planting and breeding mode. The results of two years of research indicate that the Zizania latifolia and crayfish co cropping mode increased the content of total nitrogen, total phosphorus, and available phosphorus in the soil during the harvesting period by 5.45% to 38.89% compared to the Zizania latifolia single cropping mode, increase the net Zizania latifolia yield by 5.10% to 19.54%, and increase the dry matter accumulation of Zizania latifolia stems, leaves, and net Zizania latifolia during the harvest period by 10.28% to 21.45% compared to the Zizania latifolia single cropping mode. As for the content of nitrogen, phosphorus and potassium, in 2021,the nitrogen content in the leaves of Zizania latifolia and crayfish co-cropping mode was significantly increased by 25.74% than that of Zizania latifolia monoculture mode in the harvest stage, but the phosphorus content in the stem was significantly reduced by 16.76% during the pregnancy period of Zizania latifolia;In 2022, under the reduction of nitrogen fertilizer and reduced feeding, the Zizania latifolia and crayfish co cultivation mode significantly reduced the nitrogen content of the stem by 23.75% during the pregnancy stage and the phosphorus content of the leaves by 12.08% during the tillering stage compared to the Zizania latifolia single cropping mode. The potassium content of the same organ during the entire two-year growth period was not significantly different between the two modes. With regard to nutrient accumulation, in 2021,the nitrogen, phosphorus and potassium accumulation in leaves of Zizania latifolia and crayfish co-cropping mode was significantly reduced by 26.0% to 27.27% compared to the Zizania latifolia monoculture mode at tillering stage, however, during the harvesting period, the accumulation of nitrogen and potassium in the stem and nitrogen and phosphorus in the leaves significantly increased by 18.80% to 38.41% and 35.71% to 44.77%, respectively, compared to the single cropping mode of Zizania latifolia; Under the reduction of nitrogen fertilizer and reduced feeding in 2022, the phosphorus accumulation in the leaves and potassium accumulation in the stems of the Zizania latifolia and crayfish co-cropping mode significantly increased by 30.0% and 30.77% compared to the Zizania latifolia monoculture mode during the harvesting period. With regard to nutrient distribution, the nitrogen distribution of the two modes of Zizania latifolia in the pregnancy and harvest stages is mainly stem and leaf, while the distribution of phosphorus and potassium is mainly stem, with the proportion of stem distribution between 42% and 66%. As for nutrient transport, in 2021,the roots, stems, and leaves of the two modes of Zizania latifolia represented mostly "sink" organs in nitrogen and phosphorus transport, while most of them represented "source" organs in potassium transport; Under the reduction of nitrogen fertilizer and reduced feeding in 2022, the roots, stems, and leaves of Zizania latifolia in the two modes mostly represented "source" organs in nitrogen, phosphorus, and potassium transport. Therefore, appropriately reducing the input of fertilizer and feed in the Zizania latifolia and crayfish co-cropping mode can promote the formation of a reasonable source sink relationship, which is conducive to the formation of yield.
                                                                                                                   
    Abstract:
    The continuous low-temperature and overcast rain severely affects the yield and quality of flue-cured tobacco in Hubei, posing a major agricultural meteorological challenge to the tobacco planting industry in the region. This paper establishes discriminant indicators for continuous low-temperature and overcast rain during different growth stages of flue-cured tobacco. Using daily meteorological data from 32 national meteorological observation stations in the tobacco planting areas of Hubei from 1975 to 2020, the study thoroughly analyzes the spatiotemporal distribution characteristics of seven disaster indicators related to low-temperature and continuous rain in the tobacco regions of Hubei. The results show that: 1) Temporally, the average temperature during the process, the average daily precipitation, and the average total precipitation all follow a low-high-low evolutionary pattern, with the highest values occurring before maturity and the lowest during the root extension period. The average duration of these processes is around 5 days. However, the average annual number of processes, the average annual process days, and the frequency of disasters are most frequent during the late maturity stage and least frequent during the vigorous growth stage. Specifically, the frequency of disasters occurs six times in every 10 years during the late maturity stage compared to once in every 10 years during the vigorous growth stage, nearly a sixfold difference; 2) Spatially, there is a consistent north-south difference in temperature and precipitation during different growth stages. The northern tobacco region has lower temperatures, while the southern region experiences more precipitation with greater intensity. The average duration of these processes is longer in the south than in the north during the root extension and vigorous growth stages, but the opposite is true during the late maturity stage; 3) There is a significant spatial variation in the frequency of disasters. During the first three growth stages, the southern tobacco region experiences higher frequencies of occurrence compared to the northern region. During the late maturity stage, the frequency is comparable between the north and south, with both regions experiencing disaster frequencies of over 56% and an average duration of 5.7 days. The findings of this study can provide a scientific basis for the planning of tobacco cultivation in Hubei and the defense against low-temperature and continuous rain disasters.
                                                                                                                   
    Abstract:
    The study of the mechanical properties of water chestnut stalks during the transplanting period can provide a theoretical basis for the mechanization of transplanting. The radial compression test, shear test and bending test were carried out by using TMS-PRO textrometer on the stalks of water chestnut Hubei Water Chestnut No.1 and Dahongpao Water Chestnut from Tuanfeng County, Huanggang City, Hubei Province, China. The results of radial compression test showed that the radial bearing force of the stalks increased sequentially from the top to the bottom, and the average value of the lower part was between 4.0-4.1N; the longer the shelving time (within 4h), the lower the moisture content of the stalks, and the lower the radial bearing force; the effect of the loading rate on the radial bearing force was not significant. The shear test results showed that the lower part of the stalks had the highest shear force, with a mean value between 120-165 N and a shear strength of about 6 MPa; the effect of the 4 hours resting time on the shear force was not significant. The results of the bending test showed that the upper part of the stalk had the smallest bending stiffness, with a mean value between 1.4×10-3-1.6×10-3 Nm2, the middle part had the largest bending modulus of elasticity, with a mean value between 290-405 MPa, and the lower part had the largest cross-sectional moment of inertia, with a mean value between 33-35 mm4, and both were subjected to a significantly higher stress than the upper part and the middle part, with a mean value of the maximum load less than 2 N. The test results can provide a basis for the design of the machine tools for cutting and handling of seedlings, handling and transplanting.
                                                                                                                   
    Abstract:
    To accurately identify the buckwheat germplasms in Guizhou Province, currently SSR markers were used to evaluate the genetic diversity, as well as to construct DNA Molecular ID of 60 buckwheat germplasms, which maybe beneficial for genetic breeding and intellectual protection. The results demonstrated that 16 SSR primer pairs were obtained from the 100 pairs, which yielded the polymorphic and reproducible bands. Of the 60 germplasms, a total of 174 bands were scored by the screened primer pairs. The mean values of Shannon's information index, Nei's diversity index, and polymorphism information index were 0.337, 0.206, and 0.693, respectively, further reflecting the high polymorphisms in the selected primer pair. All tested germplasms might be clustered into three groups at 0.374 of Dice genetic similarity index. Further, Group A could divided into two independent subcluster at 0.484 of Dice genetic similarity index. The SSR amplification products were double-validated by capillary electrophoresis and 8% polyacrylamide gel (PAGE) electrophoresis, and the clustering results of both methods were consistent. Finally, the core primer method was employed to construct the molecular ID of 60 buckwheat germplasms, which considerably facilitated the molecular identification of buckwheat germplasms in Guizhou.
                                                                                                                   
    Abstract:
    This paper proposes a YOLOv8n night apple detection method that combines image enhancement and transfer learning to address the issues of low apple recognition rate and poor real-time performance in nighttime scenes. Firstly, embed a Zero-DCE module in the front-end of YOLOv8n to enhance nighttime images, presenting the contours and details of apples more clearly, and reducing the difficulty of recognizing nighttime apple images; Secondly, using SPD-Conv for downsampling enhances the model's ability to extract fine-grained features; On this basis, in response to the problem of small sample size in the nighttime apple dataset, a transfer learning training strategy is adopted. The MS COCO dataset containing apple categories is selected as the source domain dataset. For the target domain dataset in the nighttime scene, Zero-DCE is used to increase its similarity with the daytime apple image and fine tune the target domain model on the source domain model. Based on the above method, experiments were conducted on the nighttime apple image dataset, and the results showed that the proposed method had a model accuracy P of 97.0%, a recall R of 93.4%, and an average accuracy mean mAP0.5:0.95 of 74.6%, which was 2.3, 1.9, and 4.3 percentage points higher than the YOLOv8n original model, respectively. At the same time, the FPS of the model was 22 frames · s-1, which can meet real-time requirements. The ablation experiment showed that the combined effect of image enhancement and transfer learning exceeded the sum of the effects when applied separately. In addition, the improved model performs better than the original model in dealing with complex situations such as overlap, occlusion, green fruits, and dim lighting, and has good robustness.
                                                                                                                   
    Abstract:
    In view of the group's existing air-aspirated miniature potato seed metering devices operation requires high negative pressure, power consumption and seed metering leakage index is too large and other issues, this study based on the radius of curvature of the miniature potato potatoes, designed a ring groove-type seed dispenser disk, in order to increase the effective contact area of the miniature potatoes adhering to the disk, so as to increase the qualification index of the air-aspirated miniature potato seed dispenser. In order to save costs and reduce the research cycle, EDEM and Fluent software are used to construct a coupled simulation system of air-absorbing micro-potato seed metering to simulate the actual working process of the seed dispenser. Among them, due to the coupled simulation requirements of the minimum fluid grid size is larger than the size of the miniature potato, so the bonding model is used instead of multi sphere fitting to establish the miniature potato particles, and the fluid mesh of the seeder adopts the unstructured mesh. In this study, by taking the operation parameters (vacuum degree, seed disks rotation speed) and structural parameters (suction hole diameter, number of suction holes) of the seed discharger as influencing factors, and by taking the qualified index, missed seeding index, reseeding index and power consumption as performance indexes to conduct a single-factor test to obtain the influence law of the influencing factors on the seed discharger, and by designing a quadratic regression orthogonal rotary combinatorial test to obtain the mathematical relationship between the various test indexes of the seed metering devices and the influencing factors. The mathematical relationship between each test index and each influence factor of the seed dispenser is obtained by designing quadratic regression orthogonal rotary combination test. The mathematical model obtained above was solved by non-dominated sorting algorithm (NSGA-II) for multi-objective optimization to obtain the optimal solution set of Pareto, and the optimal solution set was sorted by hierarchical analysis of hierarchies (AHP) to obtain the relationship between the weights of each test index of the seed arranger to get the optimal structure and operating parameters of the seed arranger. The results show that when the negative pressure value of the air suction miniature potato seeder is 5060Pa, the speed of seeding disc is 35r/min, the number of suction holes is 10, and the diameter of suction holes is 10mm, the indexes of the seeder reach the optimum, i.e., the index of the seeder is 94.18%, the index of leakage is 3.14%, the index of replanting is 2.68%, and the power consumption is 10.8kW. verify the simulation optimization results of the air-absorbing miniature potato metering devices, bench tests were carried out according to the optimal parameter combinations. The results show that the simulation optimization results are basically consistent with the bench test, and the relative error of the qualification index is 0.97%. This shows that the combination of multi-objective optimization algorithm and hierarchical analysis process for weight allocation is reasonable and feasible for the performance optimization of seed metering devices.
                                                                                                                   
    Abstract:
    In view of the complex environment of paddy field, the end of the discharge port of the existing fertilizer application machinery is easily blocked by soil, resulting in the poor discharge performance of the fertilizer application machine, this paper designs a two-stage fertilizer discharge device, which can then reduce the blockage phenomenon at the end of the discharge port while improving the uniformity and continuity of fertilizer discharge. Firstly, the overall structure of the rice fertilizer application device is designed. The kinematic and kinetic analyses of key components were then carried out, and the results showed that the double gear pitch and gear speed had an important influence on the fertilizer discharge performance of the double-gear fertilizer discharger; the diameter, speed and pitch of the screw shaft had an important influence on the fertilizer discharge performance of the screw fertilizer discharger. The test results show that the uniformity of fertilizer discharge decreases and then increases with the spacing between the two gears, and when the spacing is 5mm, the fertilizer discharge performance of the double-gear fertilizer discharger is better; the coefficient of variation of fertilizer discharge stability increases with the gradual increase of pitch and diameter, and decreases and then increases with the gradual increase of rotational speed, and the combination of spiral shaft diameter, pitch and rotational speed is selected for the test. The best combination of spiral shaft diameter, pitch and rotational speed was determined as 21.292 mm, 134.07 r/min and 16.437 mm pitch, and the coefficient of variation of fertilizer discharge stability was 2.5%. The key components were designed according to the simulation parameters, and the transmission ratio of the double-gear fertilizer discharger and the spiral fertilizer discharger was determined to be 1:4 by combining theoretical calculations and discrete element simulation tests, which resulted in continuous and uniform fertilizer discharge. Finally, a comparison test between the two-stage fertilizer discharger and the spiral fertilizer discharger was conducted, and the test results showed that the consistency, stability and uniformity coefficient of variation of the two-stage fertilizer discharger were improved compared with the spiral fertilizer discharger.
                                                                                                                   
    Abstract:
    In this study, we cloned the ZmEREB46(Zm00001d015759) in maize, which encodes a transcription factor of AP2/EREBP family. Resequencing results showed that, compared with the waterlogging tolerant inbred line A3237, the coding region and promoter region of ZmEREB46 has a G/A conversion and a 911 bp fragment insertion in waterlogging susceptible inbred line A3239, respectively. The insertion of 911 bp fragment in A3239 inbred significantly inhibited the expression of ZmEREB46. Subcellular localization results showed that ZmEREB46 was localized in the nucleus. Quantitative PCR (qRT-PCR) analysis showed that ZmEREB46 was up-regulated by waterlogging stress, and the expression level of ZmEREB46 in A3237 was two-fold higher than that in A3239 after 8 h waterlogging treatment. Ectopic overexpression of ZmEREB46 could improve the waterlogging tolerance of Arabidopsis thaliana at seedling stage.
                                                                                                                   
    Abstract:
    In order to real-time and field nondestructive monitoring the potassium accumulation of flue-cured tobacco in field. Different nitrogen levels was designed and the spatial and temporal distribution and variation of potassium accumulation were studied, the canopy spectral data were also collected to analyze the quantitative relationship between the spatial and temporal distribution of tobacco potassium accumulation and canopy spectral parameters. The results showed that the potassium accumulation in the upper layer is not related to the spectral reflectance except for a few bands. The potassium accumulation in the middle and lower layers is significantly negatively related to the spectral reflectance in the visible light band, while the near-infrared band is significantly positively related. Optimal spectral estimate parameters of each leaf layer potassium accumulation are different. RVI(810,680) is the optimal spectral estimate parameters of upper layer, middle layer, middle-lower layer, and the correlation between DλRed and potassium accumulation of the lower layer, middle-lower layer,the whole plant was the highest. The potassium accumulation spectral estimation model of middle layer, lower layer, upper-middle layer, middle-lower layer and the whole plant are y =-0.002 x2+0.159 x- 0.6531 (R2=0.903**), y = 8.8736x2-4.1032x+0.5164 (R2=0.618**), y =0.0856x1.29 (R2=0.744**), y = 6.6558x2+0.5056x-0.3657 (R2=0.821**), y = 0.2803x0.5774 (R2=0.938**), separately, after verification the model have good stability.Therefore, the estimation model based on spectral parameters could effectively retrieve inversion the potassium accumulation in the middle, lower layers and the whole plant of flue-cured tobacco.
                                                                                                                   
    Abstract:
    In recent years, the thinking of using gray infrastructure for stormwater management has changed, and the function of stormwater regulation and storage from the perspective of blue-green synergy has begun to be emphasized. Taking the Nanhu catchment zone of Wuhan City as the research object, this paper simulates and analyzes the changes of annual total runoff control rate, peak flow and peak time under the sponge green space renovation measures based on the SWMM model, and reveals the characteristics of the effect of reducing stormwater runoff in the urban catchment zone green space from the perspective of blue-green synergy. The results show that: (1) the transformation of concave green space with a zoning scale of 20-30% of the urban catchment can achieve the goal of sponge city construction with an annual runoff control rate of 65%; (2) Among the different sponge green space transformation measures, the effect of complex concave green space (with aquifer and lower pipe) and simple concave green space (without aquifer and lower pipe) on a single rainfall event was not obvious, but the performance of complex sunken green space with multiple rainfall over a long period of time was more significant. Exploring the evaluation methods, modes of action and implementation paths of the ecological effects of blue-green space system to reduce water runoff, and analyzing the adaptation mechanism of blue-green space to dominate urban design, will open up new ideas and construct new methods for urban ecological planning.
                                                                                                                   
    Abstract:
    To address the issues of high breakage rate, high moisture content, and low removal rate in wet peeling of peanut kernels, research is conducted from the perspective of optimizing pre-treatment process parameters, which is of great significance for improving the quality of peanut kernel peeling. This study used the "Huayu 23" peanut variety as the experimental material. Firstly, the cold soaking temperature, cold soaking time, hot soaking temperature, and hot soaking time were determined through a single factor experiment, which had a sig-nificant impact on the removal rate, breakage rate, and moisture content of peanut kernels. Further response surface experiments revealed that the degree of influence of cold soaking temperature A, cold soaking time B, hot soaking temperature C, and hot soaking time D on the purification rate was A>C>D>B; The degree of impact on the damage rate is C>A>D>B; The degree of influence on water content is A>C>D>B. The optimal process parameters for the pre-treatment of peanut kernels with variable temperature and wet peeling were ob-tained as follows: cold soaking temperature of 19 ℃, cold soaking time of 13 minutes, hot soaking temperature of 75 ℃, and hot soaking time of 20 seconds. The removal rate, break-age rate, and moisture content were 95.7%, 11.3%, and 13.6%, respectively. This result has important guiding significance for the selection of process parameters for the wet process of removing red coating from peanut kernels.
                                                                                                                   
    Abstract:
    Soil sampling is an important part of digital soil mapping. The accuracy of data obtained from sampling points directly affects the accuracy of soil mapping. How to obtain more reliable soil-environment knowledge from existing historical sample points has become an important scientific issue in soil mapping. This paper adopts the method of sample representative revision to obtain higher knowledge accuracy, utilizes the spatial similarity relationship between the environmental covariates of the sample space and the total space, and adopts three different algorithms to explore the optimal weight for each soil sampling point based on the kernel density estimation. Moreover, the prediction mapping of soil surface organic matter content is taken as an example to verify the scientificity and validity of the method. The results show that the revised method can reduce RMSE and MAE by 10.30% and 12.74% respectively, which proves the feasibility and effectiveness of the proposed method. This study can provide technical support for the data processing of soil sample points, so as to make full use of historical data to improve the accuracy of soil mapping.
                                                                                                                   
    Abstract:
    It is of great theoretical significance to study the change characteristics of net carbon emissions and carbon neutralization capacity at regional scale for accelerating the transformation of social and economic development and realizing the goal of carbon neutrality. In this paper, the carbon emissions, carbon sinks and net carbon emissions of Hubei Province were evaluated by referring to the methods given in 《IPCC Guidelines for National Greenhouse Gas Inventories》 and《Guidelines for the Preparation of Provincial Greenhouse Gas Inventories》, carbon density method and other methods, and the change trend of net carbon emissions was analyzed to evaluate the regional carbon neutrality capacity of Hubei Province. The results of this paper show that (1) from 2000 to 2020, the total amount of regional carbon sinks in Hubei Province was 264.178 million tons, showing a significant upward trend over the years, with an increase rate of about 135.21% and an average annual growth rate of about 6.76%. (2) From 2000 to 2020, the total carbon emissions of Hubei Province was 910.331 million tons. The change trend of total carbon emissions over the past years can be divided into two stages. From 2000 to 2010, the total carbon emissions in Hubei Province showed a significant increase trend. From 2011 to 2020, the total carbon emission in Hubei Province showed a trend of fluctuation and decline. (3) From 2000 to 2010, net carbon emissions in Hubei Province showed an upward trend, and Zmk statistics passed the significance test, showing statistical significance; From 2011 to 2020, net carbon emissions in Hubei Province showed a downward trend, but Zmk statistics failed to pass the significance test, this shows that net carbon emissions in Hubei Province showed a downward trend in the second stage, but this trend was not statistically significant. The results of this paper show that there is still a large gap between the ecosystem carbon sink and carbon emissions in Hubei Province, and there is still some uncertainty in the change of net carbon emissions. Carbon emission reduction should be carried out continuously, the ecosystem carbon sink function should be optimized, and carbon capture technology and related industries should be vigorously developed.
                                                                                                                   
    Abstract:
    Pig production is an important component of animal husbandry industry in China. Domestic pig production mainly uses self-breeding mode. The semen used in pig reproduction mostly uses fresh semen or diluted semen stored in room temperature, and semen cryopreservation technology can make the long-term preservation of pig semen. Compared with cattle, mice and other species, the cryopreservation technology of pig semen needs to be further optimized and improved. This review summarizes the development of frozen pig semen, the main technical process, the key factors affecting sperm motility after freezing and thawing, including semen collection, pre-cooling balance before freezing, addition of cryoprotectant agents, and cryopreservation methods. It also covers the physicochemical changes during the sperm cryopreservation process, such as physical structural damage, functional damage, and sperm anti-freezing mechanisms. Finally, new methods to improve the cryopreservation efficiency of pig sperm are summarized, including nanotechnology treatment of semen and the study of cryopreservation biomarkers for sperm,in order to provide theoretical reference for perfecting porcine frozen semen technology and accelerating its application in pig production.
                                                                                                                   
    Abstract:
    In order to improve the yield of bio-oil production and enhance the quality of bio-oil obtained from black soldier fly larvae, as well as achieve high-value utilization of the larvae, this study employed the method of methanol-water co-solvent liquefaction of black soldier fly larvae to prepare bio-oil. The study investigated the effects of iron-based catalysts (FeS, FeSO4), molecular sieve catalysts (ZSM-5, Y-type molecular sieve), bimetallic catalysts (Ni/TiO2), and molecular sieve-supported metal catalysts (Ni/Y-type molecular sieve) on the distribution and properties of hydrothermal liquefaction products.The results showed that FeSO4 catalyst obtained the highest bio-oil yield, conversion rate, energy recovery rate, and carbon recovery rate in the co-solvent of methanol-water ratio of 4:1. The bio-oil yield reached up to 82.17%, which was 13.94% higher than the bio-oil yield without a catalyst (68.23%). The addition of FeSO4 catalyst effectively suppressed the production of solid products, and the conversion rate reached 91.1%. The improvement of bio-oil yield and conversion rate by iron-based catalysts was attributed to the ability of iron elements to promote the in-situ hydrogenation of liquefaction solvents. In-situ hydrogenation can stabilize the reaction intermediates generated by depolymerization reactions of biomass materials during liquefaction, thereby inhibiting repolymerization reactions. The study found that the esterification reaction between methanol and fatty acids dominated the liquefaction process, and the main compound in the bio-oil was fatty acid methyl ester. Among the catalysts, Ni, as a transition metal, has good redox properties and catalytic activity, can enhance the esterification reaction during the liquefaction reaction process, and inhibit the formation of amide substances during protein hydrolysis.
                                                                                                                   
    Abstract:
    Taking the purplish soil from the landfill in Yunxi Town, Yanting County, Sichuan Province as the research object, different mass ratios of silicon fertilizer (Si1: 0.5%, Si2: 1.0%) and phosphate rock (P1: 0.2%, P2: 0.4%, P3: 1.0%) compound was added to the soil and passivation cultured for 90 days. To study the changes of available heavy metal content Cd、Cu、Pb、Zn before and after passivation culture, and the soil remediation effect was evaluated by Risk Assessment Code (RAC). The results showed that high Si treatment (Si2: 1.0%) could significantly reduce the heavy metal effectiveness compared with low Si treatment (Si1: 0.5%), among which, Si2P3 treatment had the highest passivation rates of 30.79%, 27.27%, 27.13% and 36.88% for Cd, Cu, Pb and Zn, respectively; there was no significant difference between Si2P1 and Si2P2 treatments. And Si2P1 treatment could significantly reduce the toxic leaching amount and RAC Risk Assessment Code of heavy metals. The compound passivator mainly promotes the transformation of heavy metals from high activity weak acid extraction state and reducible state to low activity oxidizable state and residue state through the improvement of soil pH and EC values, and the complex-precipitation of functional groups (O-Si-O, Si-O-Si, H2PO4-, PO43-, etc.). On the whole, Si2P1 treatment passivator application amount is lower and more suitable for the remediation of heavy metal contaminated soil in landfills.
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    2015,34(4):108-113, DOI:
    [Abstract] (2804) [HTML] (0) [PDF 1.06 M] (11579)
    Abstract:
    In this study,we investigated the effect of bio-floating bed on growth and muscle quality of grass carp (Ctenopharyngodon idellus) and blunt snout bream(Megalobrama amblycephala) in ponds.Two modes of culture ponds were chosen:one equipped with bio-floating bed was the experimental pond,and the other without beds was the control pond.At the end of the experiment,we measured the growth parameters,the muscle conventional nutrients,water holding capacity (WHC),and texture characteristics using biochemical and physical methods.The results showed that the final weight of fish cultured in the experimental pond was higher than that in the control pond.The hepatic somatic index of grass carp (1.77%) in the experimental pond was significantly lower than that of the control (2.47%).The condition factors of grass carp and blunt snout bream (1.73 and 2.56,respectively) were significantly higher than those of the control (1.64 and 2.40,respectively).There was no significant difference in the eviscerated weight of both carp and bream between the experimental (91.06 and 88.28,respectively) and the control (89.22 and 88.49,respectively) ponds.The drop loss (14.49% and 10.69,respectively) and water loss rate (17.52% and 10.34%,respectively) of the experimental grass carp and blunt snout bream were significantly lower than those of the control.The cooked rate of the experimental fish was significantly higher than the control.The muscle crude fat content (1.89%) and crude protein content (14.60%) of grass carp in the experimental ponds were significantly higher than those of the control (1.54% and 13.46%),whereas muscle water content (81.68%) of the experimental fish was significantly lower than that (82.65%) of the control.There is no significant difference in muscle ash content between the two groups.Unlike grass carp,only muscle crude protein content (17.23%) of the experimental bream was significantly higher than that (15.90%) of the control.The muscular hardness,gumminess,and chewiness of the experimental carp (5 298.10 g,2 450.78 g and 770.78 g,respectively) were significantly higher than those of the control (3 226.79 g,1 881.43 g and 602.80 g,respectively).The resilience (0.31) and cohesion (0.48) of experimental carp were significantly lower than those (0.43 and 0.58,respectively) of the control.However,only the muscular springiness of the blunt snout bream in the experimental pond was significantly higher than that in the control pond.
    2015,34(4):120-124, DOI:
    [Abstract] (3208) [HTML] (0) [PDF 976.50 K] (10398)
    Abstract:
    Effects of soaking temperature,cultivation temperature and watering frequency on the growth characteristics and nutrition of mung bean sprout were investigated. Growth characteristics and nutrition of mung bean sprout were significantly affected by soaking temperature,cultivation temperature and watering frequency (P<0.05). When the bean was soaked at higher temperature (40℃),body weight of the cultivated mung bean sprout was heavier,hypocotyl was longer,contents of free amino acid (FAA),water soluble sugar (WSS) and γ-aminobutyric acid (GABA) were higher. The hypocotyl was longer while the diameter was smaller when the bean was cultivated in the relatively higher temperature (30-35℃). When the watering frequency decreased,weight,hypocotyl length and diameter decreased,WSS content decreased first and then increased,FAA content increased first and then decreased,GABA content was fluctuated. The optimal germination conditions of mung bean sprout were soaking bean at 40℃ for 5 h,with cultivation temperature of 25-30℃ and watering once per hour.
    2013,32(4):48-54, DOI: 1000-2421(2013)04-0048-07
    [Abstract] (3097) [HTML] (0) [PDF 1.58 M] (8674)
    Abstract:
    The spatial distribution of Valley County land use degree in 2009 was studied and the spatial autocorrelation of land use degree and its driving factors in different scales were analyzed.A spatial autoregressive model and geographically weighted regression model was established from the perspective of global local.The results showed that there was a certain spatial autocorrelation in land use degree and its driving factors with scale effect.Spatial regression model could estimate the overall parameter of various factors while geographically weighted regression model could give the local parameter of various factors.Scales of geographical weighted regression model could reflect the detailed geographical information to some extent.
    2015,34(3):8-12, DOI:
    [Abstract] (2769) [HTML] (0) [PDF 3.41 M] (7833)
    Abstract:
    pCB302-3 is a plant mini-binary stable transformation vector.To investigate the transient expression of pCB302-3 vector in plant,GFP was inserted into pCB302-3 vector as a reporter gene,and various factors including density of Agrobacterium cell,supplementation of gene silencing suppression p19 and days post infiltration were optimized based on agroinfiltration method in Nicotiana benthamiana leaves.Results showed that high levels of GFP expression were observed in N.benthamiana leaves 3-5 d after infiltration by Agrobacterium cell suspension contained pCB302-3-GFP with an optical density (D600) of 0.8-1.0 co-infiltrated with p19 gene.
    2012,31(1):16-22, DOI: 1000-2421(2012)01-0016-07
    [Abstract] (3328) [HTML] (0) [PDF 1.07 M] (7039)
    Abstract:
    Nitrogen is one of essential nutrients for plant growth.Under the N deficiency at different time points,the dynamic changes of the expression of genes and activity of enzymes related to nitrogen assimilation in rice were investigated.The results showed that the concentrations of ammonium and nitrate significantly reduced under the N deficiency.Under the N deficiency for a short time,the expression level of genes including NR1, NR2, NiR2,GS2,Fd-GOGAT,GDH2,GDH3 in the shoots as well as NR1,NR2,GDH4 in the roots were up-regulated,and then their expression level decreased after a long time under the N deficiency.Along with the extension of time under the N deficiency,the GS,Fd-GOGAT activities in whole plants,NR activity in shoots and NADH-GOGAT activity in roots decreased while the NADPH-GDH activity in shoots increased.In roots the activities of NR,GDH increased at first and then decreased,while in shoots the NiR activity was just the opposite.Re-supplied N after 7 days of N deficiency,the transcriptional expression level and enzyme activities of NR,NiR,GS,GOGAT,GDH restored,and expression level of some genes increased as well.
    2013,32(5):124-133, DOI: 1000-2421(2013)05-0124-10
    [Abstract] (2543) [HTML] (0) [PDF 4.01 M] (6991)
    Abstract:
    Bacterial canker is a devastating disease of kiwifruit. In recent years,the disease is showing a tendency to outbreak in such countries as Italy and New Zealand,where kiwifruit is a major crop,and has the trends to further spread worldwide,which will be a serious threat to the development of the kiwifruit industry. Based on the latest research reports, this paper summarized the symptoms,pathogen identification,rapid detection methods,virulence differences,infected mechanism,epidemiology and control technology of the disease. Meanwhile,the future research prospect of kiwifruit bacterial canker was also discussed in order to reduce the loss and risk of the kiwifruit industry.
    2015,34(1):128-135, DOI:
    [Abstract] (3031) [HTML] (0) [PDF 1.21 M] (6845)
    Abstract:
    In order to overcome the transition,field operation, and standardized batch production difficulties of the existing track cargo vehicle in mountainous orchard, as well as to raise the utilization rate, the mountain orchard detachable unidirectional traction double track cargo vehicle was developed. This paper introduced the whole machine structure, the wire rope diameter selection,the minimum track inclination,the maximum track distance,the minimum track turning radius and the working principle of the rope brake device. Load experiments were carried out to test the cargo′s synthetic track function. It is indicated by calculation that the wire rope diameter should be 7.7 mm,the minimum track inclination was 5.7°, the maximum track distance was 170 m, the minimum track horizontal turning radius was 7 m, and the minimum track vertical turning radius was 2 m. Load experiment results indicated that the cargo vehicle′s uplink average speed was 0.51 m/s, the downlink average speed was 0.54 m/s, the average energy consumption was 1.235 kW·h and the effective use degree was 100%. This cargo vehicle was suitable for fruit, pesticide, chemical fertilizer and other cargo transportation in the mountain orchard. Meanwhile, it can be applied to carry the spraying machine, the shave machine and other agricultural machines.
    2014,33(2):139-144, DOI: 1000-2421(2014)02-0139-06
    [Abstract] (1858) [HTML] (0) [PDF 968.56 K] (6560)
    Abstract:
    Algae are lower photosynthetic autotrophs which have close relationship with agricultural activities.With the deep understanding of physiological and ecological characteristics,algae have used more and more widelyin the practice of agricultural activities.This paper reviews the application of algaeas a resourcein agricultural activities including improvement of agricultural environment,utilized as food or food additives and health care products,as well as feed or bait.
    2014,33(06), DOI:
    [Abstract] (1765) [HTML] (0) [PDF 8.30 M] (6470)
    Abstract:
    The development of Golden Rice to date has taken longer than anticipated.It has been proven to have the potential to assist in the alleviation of an important public health problem,vitamin A deficiency,affecting millions.Complying with the highly precautionary,and now proven unnecessary,UN Cartagena Protocol for Biosafety has impeded scientific progress and scientific collaboration,particularly by delaying the selection of phenotypes grown in the open field.So far therefore,Golden Rice has not been able to assist in combatting vitamin A deficiency,identified by the UN as an important public health target for 25 years,and which continues to cause preventable deaths and blindness.However,the inventor’s original vision of the donation of the technology to assist the resource poor who want to benefit from it remains firm and achievable,subject to continuing philanthropic and public sector funding.
    2016,35(1):81-85, DOI:
    [Abstract] (1956) [HTML] (0) [PDF 943.32 K] (6057)
    Abstract:
    Using Mesorhizobium sp.S-15 and Paenibacillus sp.S-17 as experimental strains.After cell disruption,NH4OAc extraction,H2O2 solution digestion or without any pre-treatment,K+ content in the fermentation broth of potassium solubilizing bacteria was determined with flame photometer.The efficiency of K solubilizing by potassium solubilizing bacteria in the culture medium was calculated.The results showed that the standard curves of the three kinds of K series of standard solutions were similar with the R2 values of 0.994 4,0.999 7 and 0.999 8,respectively.After digested by H2O2 solution,concentration of K+ was detected.The efficiency of two strains was 101.1% and 125.1%,significantly higher than that of other groups.The efficiency of potassium solubilizing detected after H2O2 digestion well reflected potassium solubilization of bacteria.
    2012,31(1):127-132, DOI: 1000-2421(2012)01-0127-06
    [Abstract] (2299) [HTML] (0) [PDF 930.13 K] (5993)
    Abstract:
    Post-harvest strawberries are susceptible to the decay of fruit and deterioration of quality due to pathogenic fungi infections,a main factor leading to economic losses for both growers and retailers.With the increase of strawberries planting in China,it is urgent to effectively reduce post-harvest rots of strawberry fruits.In this review,new management developments for controlling fungal diseases in post-harvest strawberry were summarized in terms of physical,chemical and biological approaches,which can help to extend the on-shelf time of strawberry fruits.
    2012,31(5):569-573, DOI: 1000-2421(2012)05-0569-05
    [Abstract] (2144) [HTML] (0) [PDF 912.59 K] (5970)
    Abstract:
    Hydroponic experiments of strawberry were conducted with three formulations of nutrient solution to select the best formulations for soilless cultivation of strawberry.Several main characteristics of growth including the fresh weight and dry weight of overground plant and root,the growth of crown,the photosynthetic and quality of strawberry,the diameter of staminate flower,the growth amass were investigated.The results showed that the effect of nutrient solution with the content of calcium nitrate tetrahydrate,potassium nitrate,ammonium dihydrogen phosphate,magnesium sulfate and ammonium nitrate at 295,303,62,246,0 mg/L on the growing status and fruit quality of strawberry are better than that of the other 2 treatments.This nutrient solution formula was the most propitious for the growth of ‘Jingyao’ strawberry and the enhancement of the fruit quality among the three different treatnments.That is,it facilitated the growth of strawberry in alimentation growth periods,and the leaves of ‘Jingyao’ strawberry was larger and thicker with a dark-green color,and the diameter of the pedicel was also larger. In addition,the nutrient solution formula was also conducive to the flowering promotion and the reproductive growth of strawberry,and resultes showed that the single fruit weight,yield and fruit quality is the best comparing to the other treatments.The results of this study provided academic and technological basis for establishing high yield and quality of strawberry in greenhouse substrate culture of irrigation and nitrogen application system. 
    2015,34(3):134-141, DOI:
    [Abstract] (2127) [HTML] (0) [PDF 1.42 M] (5957)
    Abstract:
    Soil salinity is a major environmental constraint to agricultural productivity.It is a complex network for plant adaptation to salt stress,and it is still a great challenge to improve crop salt tolerance.Mechanisms of SOS signal transduction pathway on Na+ exclusion and compartmentation,the regulation of microRNA and transcription factors involved in salt stress were reviewed.It will provide a fundamental understanding and knowledge for studying salt resistance and breeding salt tolerance in plants.
    2014,33(2):15-21, DOI: 1000-2421(2014)02-0015-07
    [Abstract] (2406) [HTML] (0) [PDF 980.62 K] (5889)
    Abstract:
    Teosinte is the ancestor of maize,and plays an important role in maize domestication process and gene cloning.Solexa RNA-Seq was used to de novo assembly and analyze the transcriptome of teosintes.40.6 GB raw data were produced,including 175 101 250 reads of 76 bp length.After quality control and de novo assembly,58 147 teosinte transcripts with an average length of 1 335 bp were obtained.After bioinformatically comparing,it was found that 94.3% of teosinte transcripts had good matching with B73 cDNAs,and that 84.1% of the transcript had good matching with rice,84.6% with sorghum and 83.9% with brachypodium at protein level.This research will provide a reference for subsequent studies on maize evolution and gene discovery.
    2014,33(06), DOI:
    [Abstract] (2055) [HTML] (0) [PDF 2.49 M] (5824)
    Abstract:
    This review of the safety assessment of genetically modified (GM) crops is focused primarily on the process and progress in the United States (US). It reviews the development of the safety evaluation process from the Asilomar conference in 1975 considering issues relevant to recombinant DNA technology,to discussions between the US government,academic and industrial scientists between 1984 and 1994 when the first GM crops were being field tested and evaluated commercial release for food and feed production. International guidelines were also reviewed for consistency with the US system. The overall process includes consideration of information relating to history of safe or unsafe human and exposure to the gene source and expressed proteins. The primary considerations of safety for dietary proteins are whether or not some consumers are sensitized and have IgE antibodies against the protein encoded by the transgene or whether the transgene represents a risk of eliciting celiac disease. The process considers potential toxic effects of expressed proteins as well as potential impacts on human and animal nutrition. The process in the US is consistent with Codex Alimentarius recommendations. It follows a science based process based on justifiable hypotheses. To date there is no evidence that GM crops approved in the US have harmed human or animal consumers. The evaluation takes into account genetic and environmental variation in products produced by plant varieties and is intended to maintain the standard that foods developed from GM plants are intended to be as safe as non-GM genetically similar varieties.
    2014,33(01):12-17, DOI: 1000-2421(2014)01-0012-06
    [Abstract] (2022) [HTML] (0) [PDF 944.55 K] (5702)
    Abstract:
    Seventeen pairs of SSR primers with clear polymorphic bands were screened from 60 pairs of SSR locus covering 17 linkage groups of pear genetic map and amplified with 20 pear cultivars.136 polymorphic bands in total were obtained with 5~11 bands per primer locus (8.0 bands on average).The polymorphism information content (PIC) of the 17 SSR loci ranged from 0.614 to 0.848 with an average of 0.733.All pear cultivars studied could be identified with 38 different combinations of 2 markers each.Bands amplified by each marker were coded based on size of fragment and used as a molecular ID.
    2011,30(4):488-493, DOI: 1000-2421(2011)04-0488-06
    [Abstract] (2161) [HTML] (0) [PDF 1.81 M] (5635)
    Abstract:
    The morphological variations and discriminant methods of Channa argus (♂),C.maculata (♀) and their hybrid were studied using traditional morphometrics and the truss network analysis.Body color of C.argus,C.maculata and their hybrid were observed.The results showed significant differences between C.argus and C.maculata from stripe at top of head,side and base of caudal fin,and the hybrid resembled C.maculata from body color.Among eleven meristic characters,the numbers of soft ray of pelvic fin were consistent in these three species,and the numbers of soft ray of pectoral fin deviated from its male parent’s species.The other meristic characters were within the range of its parent’s,the average hybrid index was calculated to be 53.45.The chi-square analysis of meristic characters showed that:there were significant differences(P<0.05) or greater significant differences(P<0.01) between C.argus and C.maculata except the number of pectoral fin rays; greater significant differences(P<0.01) between C.argus and the hybrid except the number of tail fin rays,gill rakers,lateral line scales and scales below lateral line; and significant differences(P<0.05) or greater significant differences(P<0.01) between C.maculata and the hybrid except the number of tail fin rays and gill rakers.Among meristic characters,the number of dorsal fin rays,lateral line scales and scales above lateral line can be used as preliminary indicators to determine the three species.Among ten measurable characters,the average hybrid index was calculated to be 73.90,indicating the measurable character inclined to its male parent’s species (C.argus).Cluster analysis,discriminant analysis and principal component analysis were applied to the measurable character data and the truss network data.The results indicated that the hybrid resembled C.argus from body shape,and there were greater morphological differences among C.argus,C.maculata and their hybrid.Differences between them involved the entire body.Three species could be distinguished by using the 3 formulae established with discriminant analysis which the discrimination accuracy was 100.0%.
    2011,30(5):613-617, DOI: 1000-2421(2011)05-0613-05
    [Abstract] (2250) [HTML] (0) [PDF 914.54 K] (5608)
    Abstract:
    Pot experiment was conducted to study the effects of spraying different micronutrients and amino acids into the surface of leaves on yield and quality of Chinese cabbage (Brassica rapa L.).The results showed that methionine,zinc,molybdenum,boron and glycine could increase yield of Chinese cabbage.The treatments of spraying methionine,zinc and molybdenum increased yield of Chinese cabbage significantly.All treatments could reduce the nitrate content of Chinese cabbage with the highest decrease of 35.0% compared with the control.Molybdenum,boron,zinc and methionine might reduce nitrate content of Chinese cabbage significantly.Experiment also indicated that glycine,proline and selenium could both increase the contents of vitamin C,soluble sugar and soluble protein of Chinese cabbage.Therefore,spraying micronutrient or amino acids into the surface of leaves is a good application for increasing yield,reducing nitrate content and improving quality of Chinese cabbage.
    2010,29(3):363-368, DOI: 1000-2421(2010)03-0363-06
    [Abstract] (3334) [HTML] (0) [PDF 11.41 M] (5562)
    Abstract:
    The index of heat injury and leaf anatomical structure under the scanning electron microscope of six Primula species were measured to study the responsive mechanism of Primula to the high temperature and to select the heat resistant Primula species.The results showed that Primula forrestii and P.malacoides franch had higher heat-resistance than that of P.obconica,P.veris,P.saxatilis,P.denticulatess.,P.sinodenticulata with lowest heat-resistance.Leaf anatomical structures of Primula associated with heat-resistance included leaf thickness,tightness of mesophyll cell arrangement,the number of open stomata,the number of epidermal hair and powders of leaves.
    2014,33(2):96-102, DOI: 1000-2421(2014)02-0096-07
    Abstract:
    A 90-day study was conducted to investigate effects of dietary lipid levels on performance,fat deposition,activity and expression of lipoprotein lipase (LPL) in GIFT tilapia (Oreochromis niloticus) juvenile,and to explore the correlation between LPL gene expression and fat deposition.315 GIFT tilapia juveniles(average weight 2.63±0.16 g) were randomly divided into three groups with three replications,and fed with isonitrogenous diets with different lipid levels of 3.7% (low-lipid group),7.7%(middle-lipid group)and 16.6% (high-lipid group) by supplementing with 2%,6% and 15% fish oil as lipid source,respectively.The results showed:(1) the hepatosomatic index (HSI),viscerosomatic index (VSI) and lipid contents in liver and muscle increased with increasing dietary lipid level(P<0.05),but there was a trends for condition factor (CF) with first increased then decreased (P>0.05); (2)with increasing dietary lipid levels, the weight gain (WG) first increased, then decreased, and feed conversion ratio (FCR) decreased(P<0.05); (3)LPL gene was expressed in liver and muscle of GIFT tilapia,while the expression level in liver was significantly higher than that in muscle (P<0.05); (4) during the 48 h post-refeeding period,liver LPL activity in high-lipid group was significantly higher than that in low-lipid and middle-lipid group at 6 h,but significantly lower than that in low-lipid group at the 12 h,24 h and 48 h.There was a trend in low-lipid and middle-lipid group that liver LPL activity increased first and then decreased; (5) the expression of LPL was significantly higher in high-lipid group than that in low-lipid group (P<0.05); (6) there were a significant linear positive correlation between HSI,lipid contents in liver and muscle,and liver LPL expression in GIFT tilapia juvenile.The results indicated that LPL expression in GIFT tilapia was in a tissue specific pattern and liver was the main organ for secretion and expression of LPL; high dietary lipid level could inhibit growth of GIFT tilapia juvenile,decrease feed conversion ratio,induce the expression of LPL in liver,and promote fat deposition in liver and muscle; liver LPL expression was involved in fat deposition of GIFT tilapia juvenile.

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