2型猪圆环病毒研究进展

猪圆环病毒2型(Porcine circovirus type 2,PCV2)是一种基因组较小,但有较高进化速率的DNA病毒,其是影响养猪业经济发展的重要病原体。到目前为止,PCV2具有5种基因型-PCV2a到PCV2e,但对PCV2流行株的基因序列的检测发现,PCV2的基因型仍在持续的发展。自2012年以来,PCV2d基因型的圆环病毒在北美取代了以前主导的PCV2b基因型感染,同时在中国和韩国也有了类似的趋势。圆环病毒的新兴基因型,其毒力存在增强的可能性,基于PCV2a基因型制备的疫苗,是否对PCV2d基因型圆环病毒的感染具有保护作用,已引起各国学者的重视。本文通过对PCV2的生物学特性、抗体变异情况以及其基因进化情况进行综合的分析总结,从而为PCV2疫苗的开发与研制奠定理论基础。     

Improvement of surface property of HMPBO fibers by polyphosphoric acid/absolute alcohol under ultrasonic vibration

The surface treatment of high modulus poly(p-phenylene-2,6-benzobisoxazole) (HMPBO) fibers was performed by using a solution of polyphosphoric acid (PPA)/absolute alcohol (EtOH) (1:1, vol:vol) under ultrasonic vibration. The chemical compositions, crystallinity, and surface morphologies of HMPBO fibers were characterized by contact angles, XRD, XPS, TGA, and SEM. Results showed that the hydrophilicity of treated HMPBO fibers was improved, and the contact angles between treated HMPBO fibers and water were decreased. The treated HMPBO fibers exhibited the slight reduction in the single fiber pull-out strength and crystallinity.     

关中灌区棉花高产高效规范化栽培技术研究

本试验采用五元二次正交旋转回归设计方法 ,对影响棉花产量、品质及效益的密度、播期、底施二铵、追施尿素和化控等主要农艺措施进行了综合研究 ,并建立了相应的数学模型。通过模拟 ,筛选出霜前皮棉 >1 5 0 0 kg/hm2 、产投比 >8的最佳农艺措施组合方案为 :密度 765 3 0～ 781 5 0株 /hm2 ,播期 4月 8～ 1 0日 ,底施二铵 82 .5～ 99.0 kg/hm2 ,追施尿素 73 .5～ 94.5 kg/hm2 ,喷 DPC 5 0～ 69g/hm2 。反馈试验表明 ,优化组合方案平均增产 1 2 .1 % ,效益显著。     

黑龙江省农业工程咨询业存在的问题及对策

为了推动黑龙江省农业工程咨询业的快速发展,从而指导农业项目决策,通过分析黑龙江农业工程咨询业的现状,以及从业人员知识结构和执业能力、咨询机构规范程度、地方行政职能部门和行业协会中存在的问题,提出了加快咨询机构发展壮大,扩大社会认知度,增强市场竞争力,加强咨询队伍的综合素质,加强行政职能部门及行业协会的监管力度等解决对策。     

锡林河流域退化草地植被恢复措施及水土保持效应研究

以内蒙古北部锡林河流域退化草地为研究对象,通过对围栏封育、免耕补播、旱作人工草地、灌溉人工草地和灌溉饲料地5种措施作用下植物生长状况、土壤水分保持作用、抗风蚀能力的试验研究。结果表明:围栏封育、免耕补播在恢复退化草地植被、提高生产力方面效果显著,是退化草地生态修复的主要措施;适地实施旱作人工草地、灌溉人工草地和灌溉饲料地面积各1hm~2,可置换出退化草地面积分别为10hm~2,18hm~2和79hm~2;通过灰色关联度进行效益评价,各种植被恢复措施之间的综合效益差异不明显,植被恢复措施实施后,综合效益均达到较高水平。     

番茄细菌性溃疡病菌的定性PCR检测方法

以2个番茄溃疡病菌株和其它6种植物病原菌为试验材料,以micA、cytC、TomA等3个特异性基因为检测靶标,采用检测引物设计与优化、特异性测试、灵敏度测试等方法,研究建立番茄溃疡病菌的定性PCR检测方法。结果表明:依据这3个基因建立的PCR检测方法可特异、精准检测番茄溃疡病菌,其中,以TomA基因为检测靶标的方法灵敏度可达到5copy/μL或103 cfu/mL,优于另外2种方法,为番茄溃疡病菌的早期诊断提供了快速、准确的技术手段。     

Effects of Tillage Methods on Soil Carbon and Wind Erosion

Current interest in soil‐conserving tillage in China has developed from the concern that Chinese agricultural land loses 73·8 Mg C annually. Previous research has shown that changing from conventional tillage to conservation tillage field management increases soil C sequestration. The aim of this study is to determine if no tillage with stubble retention can reduce soil carbon loss and erosion compared with conventional tillage for a cornfield in northern China. We found that soil organic C storage (kg m⁻²) under conservation tillage in the form of no post‐harvest tillage with stubble retention increased from 28% to 62% in the soil depths of 0–30 cm (p < 0·01) compared with the conventional tillage. Retaining post‐harvest stubble with a height of 30 cm and incorporating the stubble into the soil before seeding the next spring increased soil organic carbon the most. Carbon storage (kg ha⁻¹) in aboveground and belowground biomass of the corn plants in seedling and harvest stages was significantly greater (p < 0·01) with stubble retention treatments than with conventional tillage. Carbon content in root biomass in all treatments with stubble retention was significantly greater than that with conventional tillage. Soil erosion estimates in the study area under conservation tillage with stubble retention was significantly lower than that under conventional tillage during the monitoring period. Given the complexities of agricultural systems, it is unlikely that one ideal farming practice is suitable to all soils or different climate conditions, but stubble retention during harvesting and incorporation of the stubble into soil in the next spring appears to be the best choice in the dry northern China where farmlands suffer serious wind erosion. Copyright © 2015 John Wiley & Sons, Ltd.     

兔害防治措施及评价

该文对目前兔害防治使用的十几种措施进行了阐述，并对铁(钢)丝索套捕兔法、生物防治、P-1拒避剂防治、政策性收购等方法给以肯定，对树干涂白灰、林地洒羊血、灭鼠雷炸兔、电网捕捉、氧化乐果废柴油涂干等措施予以否定，针对化学杀鼠剂防治兔害出现的误杀有益动物、毒杀天敌动物的严重问题，明确指出野外大面积使用化学杀鼠剂是错误的，必须禁止或限制使用，即使对于大隆、溴敌隆第二代抗凝血药剂，也只有在防治地下害兽和进行药饵投洞防治时才可使用。提醒人们在兔害防治中应牢固地树立保护生态环境和保护天敌动物的观念。     

Parameterization and testing of a coupled photosynthesis-stomatal conductance model for boreal trees

A coupled photosynthesis-stomatal conductance model was parameterized and tested with branches of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) trees growing in the Northern Study Area of the Boreal Ecosystem-Atmosphere Study (BOREAS) in Manitoba, Canada. Branch samples containing foliage of all age-classes were harvested from a lowland old black spruce (OBS) and an old jack pine (OJP) stand and the responses of photosynthesis (A(n)) and stomatal conductance (g(s)) to temperature, CO(2), light, and leaf-to-air vapor pressure difference (VPD) were determined under controlled laboratory conditions at the beginning, middle, and end of the growing season (Intensive Field Campaigns (IFC) 1, 2, and 3, respectively). The parameterized model was then tested against in situ field gas-exchange measurements in a young jack pine (YJP) and an upland black spruce (UBS) stand as well as in the OBS and OJP stands. Parameterization showed that Rubisco capacity (V(max)), apparent quantum yield (alpha') and Q(10) for sink limitation were the most crucial parameters for the photosynthesis sub-model and that V(max) varied among different measurement series in the laboratory. Verification of the model against the data used to parameterize it yielded correlation coefficients (r) of 0.97 and 0.93 for black spruce and jack pine, respectively, when IFC-specific parameters were used, and 0.77 and 0.87 when IFC-2 parameters were applied to all IFCs. For both measured and modeled g(s), the stomatal conductance sub-model, which linearly relates g(s) to (A(n)h(s))/c(s) (where h(s) and c(s) are relative humidity and CO(2) mole fraction at the leaf surface, respectively), had significantly steeper slopes and higher r values when only the VPD response data were used for parameterization than when all of the response data were used for parameterization. Testing the photosynthesis sub-model against upper canopy field data yielded poor results when laboratory estimates of V(max) were used. Use of the mean V(max) estimated for all upper canopy branches measured on a given day improved model performance for jack pine (from a nonsignificant correlation between measured and modeled A(n) to r = 0.45), but not for black spruce (r = 0.45 for both cases). However, when V(max) was estimated for each branch sample individually, the model accurately predicted the 23 to 137% diurnal variation in A(n) for all stands for both the upper and lower canopy. This was true both when all of the other parameters were IFC-specific (r = 0.93 and 0.92 for black spruce and jack pine, respectively) and when only mid-growing season (IFC-2) values were used (r = 0.92 for both species). Branch-specific V(max) estimates also permitted accurate prediction of field g(s) (r = 0.75 and 0.89 for black spruce and jack pine, respectively), although parameterization with all of the response data overestimated g(s) in the field, whereas parameterization with only the VPD response data provided unbiased predictions. Thus, after parameterization with the laboratory data, accurately modeling the range of A(n) and g(s) encountered in the field for both black spruce and jack pine was reduced to a single unknown parameter, V(max).