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1.
通过小麦与长穗偃麦草远缘杂交创制附加系、代换系及易位系是小麦遗传改良中利用长穗偃麦草优良基因的重要途径。本研究将长穗偃麦草特异分子标记、染色体计数、基因组原位杂交(GISH)及非变性原位杂交(ND-FISH)等多种方法相结合,对硬粒小麦Langdon(AABB)与小偃麦8801(AABBEE)的杂交后代群体进行分子细胞学鉴定,创制出硬粒小麦-长穗偃麦草3E、6E染色体双体附加系Du-DA3E和Du-DA6E,硬粒小麦-长穗偃麦草1E(1B)染色体双体代换系Du-DS1E(1B)以及硬粒小麦-长穗偃麦草1AS-1EL染色体易位系Du-T1AS·1EL。创制的4个种质中长穗偃麦草染色体均能稳定遗传,这不仅增加了硬粒小麦-长穗偃麦草附加系和代换系的类型,还为后续利用长穂偃麦草优良基因改良小麦提供了特殊种质资源。  相似文献   
2.
我国油菜根肿病发病面积在66.7万公顷左右,约占总生产面积的10%,已严重威胁到油菜的安全生产。基于此,本研究以含有CRb抗根肿病位点的大白菜材料CR Shinki为供体亲本,以甘蓝型油菜国审杂交种华油杂62的父本Pol.CMS恢复系Bing409为受体亲本,通过杂交、回交及自交等育种程序,结合前景和遗传背景筛选,将CRb抗病位点导入到Bing409中。在BC3F2代获得了遗传背景高度接近Bing409且含CRb抗病位点的抗根肿病新恢复系Bing409R,进而成功选育了我国首个抗根肿病杂交油菜新品种华油杂62R。CRb抗病位点在甘蓝型油菜背景中表现为单基因显性遗传,根肿病抗性遗传改良的同时并未对Bing409R及由其配制的杂交种华油杂62R的产量、品质造成不良影响,Bing409R及华油杂62R对我国四川、湖北、安徽等地区根肿菌生理小种具有免疫抗性。本研究的开展为我国油菜抗根肿病育种提供了宝贵资源,为我国抵抗油菜根肿病的威胁提供了重要保障。  相似文献   
3.
王言聿  郭旭  成志强 《油气储运》2021,(2):215-221,227
与传统管线钢管相比,复合材料增强管线钢管(CompositeReinforcedLinePipe,CRLP)具有承压能力高和质量轻等优势,但对其压力设计的研究尚不充分。CSAZ662-2015《油气管道系统》和GB/T35185—2017《石油天然气工业用复合材料增强管线钢管》中最大许用操作压力的设计思路不同,且设计结果差别较大。针对此问题,基于组合薄壁圆筒模型对承压CRLP进行分析,对最大许用操作压力下材料的名义许用应力和真实许用应力进行了区分,进而导出真实许用应力的显式表达形式,并以此作为设计安全裕度的评价指标。分析表明:现有规范和标准中的设计公式均无法保证管线钢和复合材料的真实许用应力为常量,对应两种设计方法,各组分材料的真实许用应力均随CRLP规格差异而发生变化,并且随着试压/预应力处理的历程而改变。基于上述分析和CRLP极限状态下的承载特征,提出一种改进的压力设计方法。新方法优先保证复合材料的真实许用应力为常量,并可由设计系数直接确定;在最大许用操作压力的计算中,考虑了加载历程的影响,物理意义明确。算例表明,其设计安全裕度较现有方法更为合理,对于CRLP压力设计的改进有参考价值。  相似文献   
4.
This study evaluated the status of native and stocked fish species in 13 prairie lakes in central Canada over eight years (2007–14) using three metrics: resource-use (benthic versus pelagic carbon via stable isotopes); body condition (relative weight index Wr); and parasite load (cestode gut enumerations). Analyses included game and non-game fishes, like naturally occurring northern pike, Esox lucius L., and yellow perch, Perca flavescens Mitchill, but focused on stocked walleye, Sander vitreus (Mitchill) because it supports a robust recreational fishery. Walleye and northern pike were significantly more reliant on benthic carbon than yellow perch or forage fishes (p < 0.05), but this reliance was not associated with any measured environmental variables for any species. In lakes with game fishes, forage fishes exhibited higher reliance on benthic energy, possibly due to predator avoidance strategy, particularly yellow perch. Walleye body condition index was consistently lower (<95–105) than values exhibited by the other two game fishes (81–139), and parasites were only common in walleye and associated with lake-water salinity (r2 = 0.93, p < 0.05) and sex (p < 0.05). Based on the results, the most desirable game fish, walleye, appears less resilient to environmental variability than northern pike and yellow perch, making this species more susceptible to impacts of future climate change.  相似文献   
5.
成渝地区位于中国西部、长江上游,生态区位重要,生态地位突出,是支撑“一带一路”、长江经济带的纽带与核心腹地。区域内竹资源丰富,竹产业优势独特,在全国竹产业发展中占有重要地位。文章围绕“成渝地区双城经济圈建设”国家重大区域发展战略,聚焦国家和区域战略需求,坚持问题导向、目标导向、市场导向,坚持创新驱动发展,从战略高度,按照现代产业“延伸产业链、融通供应链、提升价值链”的要求,对竹产业助推成渝地区双城经济圈建设进行探讨,分析竹产业发展优势和突出问题,谋划四川竹产业高质量发展布局,提出了重点实施“智慧竹业、人文竹业、商贸竹业”3大工程的建议。  相似文献   
6.
  1. Many species and populations of odontocetes have modified their behaviour to take advantage of feeding opportunities provided by fishing activities, with depredation of fishing gear being the most common type of adaptation.
  2. The northern Adriatic Sea has been identified as an important marine mammal area because of a regular occurrence of common bottlenose dolphins. Boat surveys were conducted within a 3,000 km2 sector of the Adriatic Sea off the coast of Veneto, Italy, between April and October 2018–2019. Based on 76 days at sea, 10,711 km of navigation, and 81 h 26 min of dolphin tracking, this study contributes novel quantitative information on dolphin spatial distribution, and on their occurrence in the wake of beam trawlers, otter trawlers, and midwater pair trawlers.
  3. A combined generalized additive model and generalized estimation equation framework indicated that trawling—along with other physiographic, biological and anthropogenic variables—influenced dolphin distribution. In days of trawling, the chance of encountering dolphins increased by ~4.5 times (95% confidence interval 1.8–11.0) near active beam trawlers, by ~16.0 times (7.1–36.0) near otter trawlers, and by ~28.9 times (12.0–69.6) near midwater pair trawlers.
  4. Spatial modelling was used to create maps of predicted distribution, suggesting differences in habitat use between trawling and no-trawling days. Spatial modelling for all days identified a dolphin distribution hotspot of 832 km2, situated off the Po river delta.
  5. Evidence contributed by this study can be used to inform management action within one of the world's areas most heavily impacted by fishing and other human encroachment. Such management action would help enforce the European Union's Habitats Directive and Marine Strategy Framework Directive, while also informing EU's Maritime Spatial Planning.
  相似文献   
7.
为了研究甜菜单体附加系M14品系RIN4基因耐盐功能,本研究以甜菜M14品系为实验材料,通过PCR技术获得BvM14-RIN4基因cDNA全长序列,对BvM14-RIN4基因进行了生物信息学分析、组织特异性和应答盐胁迫分析。BvM14-RIN4基因ORF长度为264 bp,编码87个氨基酸,蛋白分子量为 9.67 kDa,理论等电点为9.64,初步鉴定该蛋白为亲水性蛋白;BvM14-RIN4蛋白质二级结构主要由延伸链和无规卷曲组成;BvM14-RIN4蛋白质三级结构预测出该蛋白的保守结构域和疏水区;系统进化树分析结果表明BvM14-RIN4蛋白与菠菜SoRIN4和藜麦CqRIN4蛋白亲缘关系最近;荧光定量PCR结果显示,BvM14 -RIN4基因在根中表达量是叶的2.26倍,说明其具有组织特异性;该基因在200 mmol/L NaCl处理后的根中上调表达,说明它参与甜菜M14品系应答盐胁迫过程。本研究在挖掘甜菜M14品系优质基因和开展甜菜遗传改良工作等方面具有重要意义,为后续该基因的功能研究提供了重要参考。  相似文献   
8.
耐低温耐低氧萌发野败不育系赣野A的选育   总被引:1,自引:0,他引:1  
赣野A是江西省农科院水稻研究所将东乡野生稻的耐冷性和耐低氧萌发能力导入抗稻瘟病保持系赣香B后再与赣香A测交和回交育成的野败型三系籼稻不育系。该不育系败育彻底,异交结实率高,配合力较强,具有较强的耐冷性和耐低氧萌发能力,在直播杂交稻育种中应用前景广阔。2019年通过了江西省品种审定。  相似文献   
9.
  1. Humanity is facing a biodiversity crisis, with freshwater-associated biodiversity in a particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for the conservation of freshwater and riparian biodiversity. Many of these artificial ecosystems are subject to a high intensity of recreational use, however, which may limit their biodiversity potential.
  2. The species richness of several taxa (plants, amphibians, dragonflies, damselflies, waterfowl, and songbirds) was assessed and a range of taxonomic biodiversity metrics were compared between gravel pit lakes managed for recreational fisheries (n = 16) and unmanaged reference lakes (n = 10), controlling for non-fishing-related environmental variation.
  3. The average species richness of all the taxa examined was similar among lakes in both lake types and no substantial differences in species composition were found when examining the pooled species inventory. Similarly, there were no differences between lake types in the presence of rare species and in the Simpson diversity index across all of the taxa assessed.
  4. Variation in species richness among lakes was correlated with woody habitat, lake morphology (surface area and steepness), and land use, but was not correlated with the presence of recreational fisheries. Thus, non-fishing-related environmental variables had stronger effects on local species presence than recreational fisheries management or the presence of recreational anglers.
  5. Collectively, no evidence was found that anglers and recreational fisheries management constrain the development of aquatic and riparian biodiversity in gravel pit lakes in the study region; however, the conservation of species diversity in gravel pit lakes could benefit from an increasing reliance on habitat enhancement activities.
  相似文献   
10.
为了探究干扰素调节因子2 (interferon regulatory factor,IRF2)如何通过调控干扰素(IFN)表达影响鱼类的免疫,实验从青鳉中克隆了irf2 (Olirf2),发现该基因在青鳉各个组织中均有表达;将构建的真核表达载体pTol2/CMV-IRF2/IE1-pr转染到胖头鱥肌肉细胞系(FHM)后,发现瞬时过表达Olirf2能够显著促进鲤春病毒血症病毒(spring viremia of carp virus,SVCV)的复制,并抑制抗病毒相关基因mx1、ifn和irf3的表达。进一步通过双荧光素报告系统发现,Olirf2能够显著抑制NF-κB和ISRE的活性,说明Olirf2可能通过抑制细胞的天然免疫应答进而促进病毒的增殖。然而持续过表达Olirf2则增强了细胞的抗病毒能力,同时促进干扰素相关基因mx1、ifn和irf3的表达。因此,Olirf2基于表达的持续时间不同而具有抗病毒或者促病毒的双面效果。实验通过研究Olirf2在抗病毒信号通路中发挥的作用,为通过基因编辑或者转基因手段来构建抗病毒的鱼类提供了理论基础。  相似文献   
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