Sex-biased mortality analysis in chick embryos during the entire period of incubation     

《The Journal of Applied Poultry Research》2012,21(3):508-512

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影响猪精子介导基因转移效果的因素研究     

宋成义  吴晗  周辉云  谢雨琇  李庆平  高波  王宵燕  李碧春  毛九德 《家畜生态》2012,(1):23-28

为优化猪精子载体法技术参数,利用荧光定量PCR、荧光显微镜检测和精液常规检测方法,分析不同DNA转染剂、不同孵育温度和不同形态DNA对猪精子转染外源DNA的影响。结果表明,PEI和TransFast转染剂能极显著提高猪精子转染效果,且PEI优于TransFast,而NanoFect转染剂包裹DNA不能转染精子。随着转染温度的升高,精子的活力和活率均明显下降,而转染率和内化外源DNA量基本保持稳定,而吸附外源DNA量呈下降趋势。环状DNA和线性化DNA在与精子共孵育后,两者的精子活力、活率、转染率和内化外源DNA量差异均不显著,精子吸附线性化DNA量极显著高于环状DNA量。综合分析表明,外源DNA形态对猪精子转染效果无显著影响;PEI和TransFast能够显著提高猪精子转染效果;共孵育温度以17℃为最佳,本结果为开展精子载体法制备转基因猪研究提供了基础试验依据。  相似文献   

Redoxtrons – An experimental system to study redox processes within the capillary fringe     

Kristof Dorau  Daniel Uteau  Markus Maisch  Andreas Kappler  Stephan Peth  Tim Mansfeldt 《European Journal of Soil Science》2023,74(1):e13347

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Nutrient release pattern of organic and inorganic resources used in cassava production (Manihot esculenta Crantz)     

Seena Radhakrishnan A.R. 《Journal of plant nutrition》2019,42(11-12):1301-1315

The major constraint in the promotion of organic farming, a safe and sustainable alternative, is lack of availability of quality organic resources in sufficient quantities. The quality of resources can be ascertained by monitoring its nutrient release pattern, which has not yet been attempted. A controlled condition pot experiment was conducted at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India, in completely randomized design to study the nutrient dynamics of various organic and inorganic resources, commonly used in cassava production, at monthly intervals up to six months. The release of almost all nutrients and activity of soil enzymes were higher at the middle (3 or 4?months) of the incubation period. The pH showed an increasing trend and electrical conductivity, organic C and Fe content declined from initial. Averaging over stages, organic practice favored the activity of soil enzymes and release of almost all nutrients over conventional system significantly, except N.  相似文献   

Effects of rice husk biochar on selected soil properties and nitrate leaching in loamy sand and clay soil     

《国际水土保持研究(英文)》2019,7(3):258-265

Biochar is a product of pyrolysis of biomass in the absence of oxygen and has a high potential to sequester carbon into more stable soil organic carbon (OC). Despite the large number of studies on biochar and soil properties, few studies have investigated the effects of biochar in contrasting soils. The current research was conducted to evaluate the effects of different biochar levels (0 (as control), 1% and 3%) on several soil physiochemical properties and nitrate leaching in two soil types (loamy sand and clay) under greenhouse conditions and wet-dry cycles. The experiment was performed using a randomized design with three levels of biochar produced from rice husks at 500 °C in three replications. Cation exchange capacity increased significantly, by 20% and 30% in 1% and 3% biochar-amended loamy sand soil, respectively, and increases were 9% and 19% in 1% and 3% biochar-amended clay soil, respectively. Loamy sand soil did not show improvement in aggregate indices, including mean weight diameter, geometric mean diameter, water stable aggregates and fractal dimension, which was contrary to the results for the clay soil. Rice husk biochar application at the both rates decreased nitrate leaching in the clay soil more than in the loamy sand. Our study highlights the importance of soil type in determining the value of biochar as a soil amendment to improve soil properties, particularly soil aggregation and reduced nitrate leaching. The benefits of the biochar in the clay soil were greater than in the loamy sand soil.  相似文献   

Filamentous fungi in wrapped forages determined with different sampling and culturing methods     

Jessica Schenck  Annika Djurle  Dan Funck Jensen  Cecilia Müller  Martin O'Brien  Rolf Sprndly 《Grass and Forage Science》2019,74(1):29-41

The use of wrapped forage bales with high dry‐matter (DM) content implies risk of fungal growth inside the wrapping, and impaired feed quality. Since fungi may be unevenly distributed in bales, the method of sampling can influence the outcome of the analysis. Three common sampling methods for detection of fungi in wrapped forage were compared: direct plating of visible mouldy patches on bale surfaces (Method I), direct plating of pieces of foliage from drilled core samples (Method II) and quantitative analysis dilution series of drilled core samples (Method III). All samples were cultured on two media at two temperatures. Samples were collected from 124 farms in Sweden and Norway. Using Methods I, II and III, fungi were detected on 52%, 77% and 56% of the farms respectively. Fifty‐two fungal species were identified using a combination of culturing and molecular methods. The most predominant species were Arthrinium spp., found on 55% of the farms, followed by Penicillium roqueforti at 48% of the farms. Incubation at 25°C resulted in higher numbers of all genera, except Aspergillus, compared to incubation at 37°C. The different methods of sampling and culturing did not identify the same fungal species within the same bale. Analysing one bale per farm resulted in detection of less than half the number of species compared to analysing three bales. Of the sampling and culturing methods compared, direct plating of drilled core samples cultivated at malt extract agar at 25°C performed best in terms of qualitative analysis of fungi species.  相似文献   

Dynamics of upward and downward N₂O and CO₂ fluxes in ploughed or no-tilled soils in relation to water-filled pore space, compaction and crop presence     

B.C. Ball  I. Crichton  G.W. Horgan 《Soil & Tillage Research》2008,101(1-2):20-30

Sharp peaks in nitrous oxide (N₂O) fluxes under no-tillage in wet conditions appear to be related to near surface soil and crop cover conditions. Here we explored some of the factors influencing tillage effects on short-term variations in gas flux so that we could learn about the mechanisms involved. Field investigations revealed that a cumulative emission of 13 kg N₂O–N ha⁻¹ over a 12-week period was possible under no-tillage for spring barley. We investigated how reducing crop cover and changing the structural arrangement of the water-filled pore space (WFPS) by short-term laboratory compaction influenced N₂O and carbon dioxide (CO₂) fluxes in upward and downward directions in core samples from tilled and untilled soil. Increasing the downward flux of N₂O within a soil profile by changing soil or moisture conditions may increase the likelihood of its further reduction to N₂ or dissolution. We took undisturbed cores from 3 to 8 cm depth, equilibrated them to −1 or −6 kPa matric potential, incubated them and measured N₂O and CO₂ fluxes from the upper and lower surfaces in a purpose-designed apparatus before and after compaction in an uniaxial tester. We also measured WFPS, air permeability, bulk density and air-filled porosity before and after compaction. Spring barley was tested in 1999 and winter barley in 2000.Fluxes of N₂O were from 1.5 to 35 times higher from no-tilled than ploughed even where the soil was of similar bulk density. Reduction of the crop cover increased CO₂ flux and could reduce N₂O flux. The effects of structural changes induced by laboratory compaction on the fluxes of N₂O and CO₂ were not influenced greatly by the tillage and crop cover treatments. Fluxes from the upper surfaces of cores (corresponding to 3 cm soil depth, upwards direction) could be up to 100 times greater (N₂O) or 8 times (CO₂) than from the lower surfaces (8 cm depth, downwards direction). These differences between surfaces were greatest when N₂O fluxes were very high in no-tilled soil (4.2 mg N₂O–N m⁻² h⁻¹) as occurred when WFPS exceeded 80% or became blocked with water, an effect that was increased by our compaction treatment. In general N₂O fluxes increased with WFPS. The production and emission of N₂O were strongly influenced by the soil physical environment, the magnitude of the water-filled pore space and continuity of the air-filled pore space in particular, produced in no-till versus plough cultivation.  相似文献   

Identification of hypothalamic genes in associating with food intake during incubation behavior in domestic chicken     

Misa Takeda  Takeshi Ohkubo 《Animal Science Journal》2019,90(9):1293-1302

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Artificial incubation of Great bustard (Otis tarda) eggs     

Wang Jingjun  Tian Xiuhua  Gao Zhaohong  Dong Fenggou  Huang Shouhua  Xu Meirong  Zhang Xinru  Wei Shuqing  Song Jinbao  Ning Yongqiang  Xu Qing 《林业研究》1998,9(2):81-86

A trial of artificial incubation to great bustard (Otis tarda) egg was conducted from 1995 to 1997. Among the 45 collected eggs, 28 eggs were fertilized and 26 hatched, with fertilizing rate 62.2% and incubation rate 92.85%. The mean incubation-days for great bustard egg was confirmed as 24.4 (21–28 days) with the formula for caculating fresh egg weight (W=KwLB ²) and that for counting the incubated days by parents birds in field (Id=24(w−y)/0.144y). The proper incubation temperature and relative humidity were 36–37.8°C and 50–65%, respectively. The egg weights and egg size average 130.45 g and 77.4±1.42×55.5±0.65 mm respectively. The total weight loss of egg was 18.38±0.646 g, daily weight loss 0.748±0.071 g in the incubation time, with a weight loss rate of 13.6±1.02%. A linear regression equation to discribe the relationship between the egg weight and incubation days, was built,y=130.73−0.619x (x-incubation day,y-egg weight) r=−0.978. Twenty-eight hours were nassassary for great bustard embryo to complete the fledging when the were put in gas room. The mean weight of fledglings was 86.3±3.29 g(n=26). (Responsible Editor: Chai Ruihai)  相似文献   

我国南方地区典型土壤有机硫矿化速率及供硫潜力研究   总被引：3，自引：0，他引：3  

胡正义  曹志洪 《中国农业科学》1999,32(6):69-74

利用开放培养技术研究了21个中国南方代表性土壤有机硫矿化动力学。结果表明,182d培养土壤有机硫矿化量（S）为61.86～145.1mg/kg(均值88.56mg/kg),其中22.45%～48.03%(均值32.74%)来自前14d的矿化。14d和182d土壤有机硫矿化量分别占土壤总有机硫1.5%～8.2%(均值3.6%)和6.73%～19.8%(均值10.6%)。实测数据拟合方程发现,土壤有机硫矿化符合一级动力学方程S#-t=S#-0[1-e#+（-kt）]。21个土壤有机硫矿化势（S#-0）为62.76～133mg/kg(均值84.94mg/kg)。试验还发现第四纪红土母质发育的土壤有机硫供硫潜力及速率明显大于花岗岩、砂页岩和紫砂岩母质。  相似文献