A target-site mutation is present in a glyphosate-resistant Lolium rigidum population   总被引：2，自引：1，他引：2  

AM WAKELIN  & C PRESTON† 《Weed Research》2006,46(5):432-440

Annual ryegrass (Lolium rigidum) is the only weed species to have evolved resistance to the broad‐spectrum herbicide glyphosate in Australia. A population that had failed to be controlled by glyphosate was collected from a vineyard in the Adelaide Hills region of South Australia. Dose–response experiments on this population (SLR 77) showed that it was glyphosate resistant, with an LD₅₀ that was 1.9–3.4 times higher than that of a susceptible population (VLR 1). The movement of radiolabelled glyphosate within SLR 77 plants showed that this population did not have the differential glyphosate translocation mechanism of resistance common to several other Australian glyphosate‐resistant populations. Subsequent analysis of shikimic acid accumulation within the plant after glyphosate treatment showed that this population accumulated significantly less shikimic acid than a susceptible population, but more than a glyphosate‐resistant population with the translocation mechanism, indicating the possible involvement of another mechanism of resistance. Sequencing of a portion of the SLR 77 5‐enolpyruvylshikimate‐3‐phosphate synthase gene was carried out and a mutation causing an amino acid change at position 106 from proline to threonine was identified. This mutation is likely to be responsible for glyphosate resistance in this population, as mutations in this position have been found to be responsible for glyphosate resistance in goosegrass (Eleusine indica) from Malaysia. This paper represents the first report of target‐site glyphosate resistance in L. rigidum and provides evidence that this species has at least two mechanisms of glyphosate resistance present in Australia.  相似文献   

Herbicide research and development: challenges and opportunities   总被引：2，自引：0，他引：2  

W T RÜEGG  M QUADRANTI  & A ZOSCHKE 《Weed Research》2007,47(4):271-275

The high adoption of chemical weed control and the broad range of solutions already available to manage most weed problems are significant hurdles to the development and launch of new herbicides. Business potentials are influenced by the high technical and biological standards provided by existing herbicides, as well as the intense competition in the marketplace. Other factors adding complexity are agronomic, structural and technological changes, including the introduction of herbicide‐tolerant crops, and the high costs of development for new active ingredients, mainly due to increasing regulatory requirements. In the light of increasing weed resistance to widely used herbicides, securing diversity in agronomy as well as weed management is a key to efficient crop production in future. In order to support this objective, new herbicides, preferably with new modes‐of‐action, will need to be discovered and developed.  相似文献   

偶尔露峥嵘——权力话语理论与胡适译《最后一课》     

陈丽 《安徽农业大学学报》2007,(1):121-125

本文从法国哲学家福柯的权力话语理论角度出发, 用外部权力话语、内部权力话语及中心话语等理论, 从翻译选材和译语选择两方面, 探讨了胡适翻译法国短篇小说《最后一课》的活动。认为胡适的翻译是在特定外部权力话语和内部权力话语的共同作用下, 以及受中心权力话语的影响而实现的翻译活动。  相似文献   

双组分调控系统介导革兰阴性菌耐药的作用机制     

于永峰  权衡  董文豪  邹荣华  吴晓妮  宫晓炜  陈启伟 《畜牧兽医学报》2022,53(6):1689-1701

菌群耐药已成为临床上亟待解决的关键问题,特别是革兰阴性菌引起的耐药现象尤为突出,给临床治疗带来了巨大的挑战,尽快阐明重要细菌复杂耐药表型的调控机制就显得尤为重要。双组分调控系统(two-component regulatory systems,TCS)存在于多种革兰阴性菌中,在细菌诸多生命活动中发挥关键作用,是细菌感知环境变化并产生相应调控的主要机制之一。TCS通常由两种蛋白组成,包括感受器蛋白(通常是组氨酸激酶)和反应调节蛋白(通常是转录因子),二者可通过磷酸化介导的协同作用,整合细菌周围的环境信号、调节细菌相关的基因表达及改变细菌的某些生理行为。近年来,探索细菌TCS介导的耐药性应答机制已成为一个新的研究热点。基于此,本文从TCS介导临床重要革兰阴性菌耐药的结构基础和作用机理等方面进行综述,以期增进对细菌TCS的全面认识,为今后临床上药物的科学研发提供新的思路和对策。  相似文献   

日粮组成对牛奶中乳成分合成与调控机制影响的研究     

生霞霞 《中国乳业》2022,(8):11-14

牛奶中乳蛋白和乳脂肪含量的高低直接关系到牛奶的品质和风味。牛奶中乳蛋白主要可以分为酪蛋白和乳清蛋白两种类型,其合成代谢过程均受到mTOR信号分子通路、JAK-STAT信号分子通路、GCN2-eIF2a信号分子通路的影响。牛奶中乳脂肪主要为三酰基甘油酯、磷脂等,对于牛奶的营养和风味均有重要影响,其受到脂肪酸相关酶ACACA、FAS、SCD1的调控。饲料营养是影响牛奶中乳蛋白和乳脂肪的关键因素之一,包括精粗饲料配比及饲料添加剂的应用等方面。本文对牛奶中乳蛋白和乳脂肪的合成调控机理,及日粮组成对其的影响机制进行阐述,为改善乳品质提供参考。  相似文献   

林木施肥的有效立地指数区间与目标肥效     

吴晓芙  胡曰利  吴立潮  彭必龙  王海燕 《中南林业科技大学学报(自然科学版)》1997,(1)

应用“八五”国家攻关课题“主要工业用材林施肥技术研究”及前人的研究成果，论证和确定了林木有效施肥条件和肥效目标.我国杉木施肥的有效立地指数区间为[10,18]；林木施肥的最佳经济效益目标增量与立地指数和单位产出价值成正相关，与不施肥的产量、优势木的平均养分浓度及单位投入价值成反相关；在自然上壤肥力状况下，氮磷钾均为高目标肥效的限制因子．  相似文献   

马尾松林阔叶化改造的目标和方法探讨   总被引：6，自引：0，他引：6  

童群益  徐高福  王振懂  丰炳财  钱华  洪利兴 《浙江林业科技》2004,24(5):41-46

根据马尾松林的群落结构,将马尾松林划分成以下8个主要类型:马尾松-木荷混交林、马尾松-枫香混交林、马尾松-木荷复层林、马尾松-白栎复层林、马尾松-连蕊茶复层林、马尾松-檵木复层林、马尾松-芒萁复层林、马尾松-白茅复层林.鉴于生态与经济协调发展,马尾松林的阔叶化改造目标拟定位在以阔叶树种为主要种群结构的近自然的阔松混交林.阔叶化改造的方法应围绕目标林分实行分类指导,分别采用封育、留养抚育、适度透光间伐、适当清理林下灌木、补植木荷等目的树种等改造方法,以供参考应用.  相似文献   

从我国木材资源的变化看普通刨花板的发展   总被引：2，自引：0，他引：2  

王新男  岳群飞 《林业机械与木工设备》2005,33(3):4-7,11

分析了国内普通刨花板及其成套生产设备的现状及与国际先进水平的主要差距。通过对我国木材资源结构变化状况的论述，阐明了普通刨花板产业在我国的适应性以及发展趋势。介绍了苏福马公司在普通刨花板成套生产线设备发展中的实践及发展目标。  相似文献   

苗木施肥生理基础及优化施肥的研究     

左永忠  任宏忠  刘滨  李海军  赵建勇  杨克忠  许国华 《河北林果研究》1994,(Z1)

试验研究了定县白杨、毛白杨、小黑杨、香椿、花椒、黑枣等“三北”防护林地区常用造林树种苗木施肥生理及生长变化。合理施肥处理，明显提高叶绿素ａ含量，速生期净同化率是对照处理的２．６６倍。试验确定了不同苗木的适宜肥料用量和配比。施肥适宜比对照处理，合格苗产量增加９５％～２３７％。  相似文献   

Plant antifreeze proteins and their expression regulatory mechanism     

LinYuan-zhen LinShan-zhi ZhangZhi-yi ZhangWei LiuWen-feng 《中国林学(英文版)》2005,7(1):46-52

Low temperature is one of the major limiting environmental factors which constitutes the growth, development,productivity and distribution of plants. Over the past several years, the proteins and genes associated with freezing resistance of plants have been widely studied. The recent progress of domestic and foreign research on plant antifreeze proteins and the identification and characterization of plant antifreeze protein genes, especially on expression regulatory mechanism of plant antifreeze proteins are reviewed in this paper. Finally, some unsolved problems and the trend of research in physiological functions and gene expression regulatory mechanism of plant antifreeze proteins are discussed.  相似文献