自然低温胁迫下3种桉树的叶绿素荧光特性研究   总被引：2，自引：0，他引：2  

靖长柏  张利阳  童再康  许基全  温国胜 《浙江林业科技》2011,31(1)

对临安市3种桉树幼苗叶片叶绿素荧光特性进行研究,结果表明,自然低温下,各桉树表现出不同的适应性,总的来说,邓桉>柳桉>巨桉;自然低温(日最低气温-3.6℃)对柳桉和巨桉造成较大损害,而邓桉可通过维持相对较高的光化学效率,以及利用不断增加的qN来进行耗散,具有较强的抵抗低温胁迫伤害的能力。  相似文献   

植物免疫诱抗剂的作用机理和应用研究进展     

刘艳潇  祝一鸣  周而勋 《分子植物育种》2020,(3):1020-1026

植物免疫诱抗剂除了能诱导植物免疫反应以使植物获得或提高对病菌的抗性外,也可以激发植物体内代谢调控过程,促进植物生长,增加作物产量。植物免疫诱抗剂可以诱导植物产生系统获得抗性以使植物对病原菌产生广泛、长期的抗性。本综述全面、系统地介绍了植物免疫诱抗剂的种类及其目前在生产、病害防治上的应用状况,阐述了其作用机理,并展望了植物免疫诱抗剂的应用前景。通过对植物免疫诱抗剂发展历史和应用现状的分析,旨在为植物免疫诱抗剂未来的开发和应用提供一定的理论和实践依据。  相似文献   

Outpacing the resistance tsunami: Antimicrobial stewardship in equine medicine,an overview     

J. F. Prescott 《Equine Veterinary Education》2021,33(10):539-545

Antimicrobial stewardship (AMS) is the term increasingly used to describe the multiple approaches needed to sustain the efficacy of antimicrobial drugs in the face of the increasing development and spread of antimicrobial resistance in bacterial pathogens, and the global crisis in medicine that it is engendering. The concept and the practices associated with AMS continue to evolve but the general approach is a dynamic and multifaceted one of continuous improvement based on reducing, improving, monitoring and evaluating the use of antimicrobials so as to preserve their future efficacy and to protect human and animal health. Using many equine examples, this basic overview discusses the multiple and interacting elements of AMS: Practice guidelines, infection control and prevention, clinical microbiology, resistance and use surveillance, dosage, pharmacokinetics and pharmacodynamics, regulation, education and owner compliance, leadership, coordination and measurement. There have been impressive advances in recent years in reporting and analysis of AMR in horses, in the scrutiny and assessment of how antimicrobial drugs are used in horses and in identification of areas for improvement including dosing, surgical prophylaxis, infection control, development of practice standards and the use of clinical microbiology. Antimicrobial stewardship is taking shape as we start to see the emergence of evidence-based recommendations but far more is required. Containing and even rolling back AMR will need the continued engagement of practitioners, equine national and international practitioner organisations, researchers and educators in the academic community, horse owners, regulators and others.  相似文献   

Development of resistance to insecticides in the invasive mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae) in Pakistan     

《Crop Protection》2016

The mealybug Phenacoccus solenopsis has been a serious pest of cotton, vegetables, ornamentals and other plants since its invasion into Pakistan in 2005. Its susceptibility to commonly-used insecticides was monitored during 2005–2013 by a nymphal dip bioassay. Initially, P. solenopsis was found susceptible to a range of insecticide classes. Lethal concentration values were particularly low for organophosphates and pyrethroids. After a year of its exposure to insecticides, P. solenopsis developed moderate to high levels of resistance to pyrethroids. After two years, resistance to organophosphates methidathion and chlorpyrifos also rose to moderate to high levels. After five years of use, resistance to pyrethroids, organophosphates, neonicotinoids, endosulfan, carbosulfan, and thiocyclam was generally high to very high. Acetamiprid resistance was slow to develop, as it reached moderate level of resistance after seven years of its extensive applications. Insecticide resistance in P. solenopsis could have been managed in Pakistan if the effective and diverse insecticides were used in rotation, along with other integrated pest management tactics, at the initial stages of resistance development.  相似文献   

温室黄瓜新品种中农33号的选育     

张圣平  顾兴芳  王烨  苗晗 《中国蔬菜》2018,1(11):68-70

中农33号是以自交系09676和12173为父母本配制的黄瓜一代杂种。植株生长势强,耐低温弱光性好。果实商品性好,颜色深绿、有光泽,腰瓜长约35 cm,瓜粗3.4 cm左右,瓜把长约4.5 cm,心腔较小,果肉为淡绿色。白刺、密,瘤小,无棱。高抗WMV,中抗CGMMV、枯萎病、黑星病。早熟性好,持续结果及丰产优势明显。温室长季节栽培每667 m~2产量高达10 000 kg以上。适宜日光温室和春棚栽培。  相似文献   

Modelling Wheat Stomatal Resistance in Hourly Time Steps from Micrometeorological Variables and Soil Water Status          下载免费PDF全文

D. Neukam  U. Böttcher  H. Kage 《Journal of Agronomy and Crop Science》2016,202(3):174-191

An accurate estimation of stomatal resistance (r_S) also under drought stress conditions is of pivotal importance for any process‐based prediction of transpiration and the energy budget of real crop canopies and quantification of drought stress. A new model for r_S was developed and parameterized for winter wheat using data from field experiments accounting for the influences of net radiation (R_Net), air temperature (T_Air) and vapour pressure deficit of the atmosphere (VPD) interacting with an average water potential in the rooted soil (ψ_RootedSoil). r_S is simulated with a limiting factor approach as maximum of the metabolic (related to photosynthesis) and hydraulic (related to drought stress) acting influences assuming that, if drought stress occurs, it will dominate stomatal control: r_S = max(r_S(T_Air), r_S(R_Net), r_S(VPD, ψ_RootedSoil)). This transitional approach is suited to reproduce measured daily time courses of r_S with a varying accuracy for the single measurement dates but performed satisfactorily for the whole data set (r² = 0.63, RMSE = 59 s m^?1, EF = 0.60). This new semi‐empiric approach calculates r_S directly from external environmental conditions. Therefore, it can be easily implemented in existing model frameworks as link between operational crop growth models that use the concept of radiation use efficiency instead of mechanistic photosynthesis modelling and soil–vegetation–atmosphere transport models.  相似文献   

Role of integrons in the proliferation of multiple drug resistance in selected bacteria occurring in poultry production     

P. Racewicz  M. Majewski  Z. E. Madeja  A. Łukomska  M. Kubiak 《British poultry science》2020,61(2):122-131

ABSTRACT

• 1. The increase in microbial resistance, and in particular multiple drug resistance (MDR), is an increasing threat to public health. The uncontrolled use of antibiotics and antibacterial chemotherapeutics in the poultry industry, especially in concentrations too low to cause inhibition, and the occurrence of residues in feed and in the environment play a significant role in the development of resistance among zoonotic food-borne microorganisms.

• 2. Determining the presence and transmission methods of resistance in bacteria is crucial for tracking and preventing antibiotic resistance. Horizontal transfer of genetic elements responsible for drug resistance is considered to be the main mechanism for the spread of antibiotic resistance.

• 3. Of the many well-known genetic elements responsible for horizontal gene transfer, integrons are among the most important factors contributing to multiple drug resistance. The mechanism of bacterial drug resistance acquisition through integrons is one of the essential elements of MDR prevention in animal production.

  相似文献   

不同播期对黄秋葵长势、抗病性和产量的影响     

宋聚红  吴然  王海山  刘玉芹 《蔬菜》2019,(1):23-31

为在河北省推广种植黄秋葵,在安国、保定、邯郸、衡水和石家庄5个试验点进行黄秋葵分期播种试验,研究了不同播期对石秋葵1号、红玉和五福3个品种生长势、抗病性和产量的影响。结果表明:播期对石秋葵1号、红玉和五福生长势、抗病性和产量具有较大的影响,随着播期的推迟,3个品种的茎粗大致呈逐渐增高的趋势,株高呈先降后升的趋势(除2018年的红玉外),单株结果数则先增加后减少,单果质量(除五福外)逐渐增大;以4月20日、25日和30日为播期,得到的黄秋葵单株产量和折合667 m~2产量较高。综合得出,河北省黄秋葵种植以4月20日、25日、30日为播期最为适宜。  相似文献   

Biology,impact, and management of Echinochloa colona (L.) Link     

《Crop Protection》2016

Echinochloa colona (L.) Link. is one of the most problematic weeds across the world. It is an annual C₄ summer grass, native to tropical and subtropical Asia, emerged as a serious and persistent threat in 35 cropping systems in more than 60 countries. E. colona is reported as an important associated weed species in transplanted and direct-seeded rice. Diverse ecotypes, high seed production, short seed dormancy, rapid growth, competitive potential, allelopathic interaction, and resistance against several herbicides makes it a more adaptable and persistent challenge in various agro-ecosystems. Development of resistance to recommended or higher doses of numerous herbicides, including ametryn, atrazine, bispyribac-sodium, clefoxidym, cyhalofop-butyl, fenoxaprop-p-ethyl, glyphosate, metribuzin, propanil, and triazine, is a serious concern for the farming and scientific community. Crop infestation with resistant E. colona biotypes may ultimately increase the weed control cost. Unfortunately, investigations on seed dormancy release, genetic diversity, allelopathic interference, and competitive ability of this weed are inadequate in accomplishing its appropriate control in different environments. Therefore, a comprehensive review is presented here to gather the existing information, to pin point key findings, and to highlight the research gaps in the biology, interference, and management of E. colona. Different management options have been discussed in relation with eco-biology of this noxious weed. The potential research endeavours have also been highlighted in order to provide an insight of its existing scenario and to facilitate the future management strategies.  相似文献   

Transgenic expression of a sorghum gene (SbLRR2) encoding a simple extracellular leucine-rich protein enhances resistance against necrotrophic pathogens in Arabidopsis     

《Physiological and Molecular Plant Pathology》2015

Plant leucine-rich repeat (LRR) domain-containing proteins are known to play important roles in signaling transduction and defense responses. In sorghum, SbLRR2 is pathogen-inducible gene encoding a simple extracellular LRR protein. Here, we demonstrated an earlier and stronger expression of SbLRR2 in a sorghum resistant genotype in comparison to a susceptible genotype following inoculation with the anthracnose pathogen (Colletotrichum sublineolum). In addition, SbLRR2 expression was found to be induced strongly by methyl-jasmonate treatment. Functional analysis was performed in SbLRR2 over-expression (OE) Arabidopsis plants, which showed enhanced resistance against the necrotrophic pathogens Botrytis cinerea and Alternaria brassicicola. In addition, the OE lines were found to have elevated expression of several jasmonate acid (JA)-associated genes and higher endogenous JA contents. Hence, the SbLRR2-mediated defense responses in transgenic Arabidopsis are likely to be dependent on JA-signaling through increased JA production. On the other hand, the OE lines remained susceptible to Pseudomonas syringae pv. tomato like the wild type plants. Consistently, there was no up-regulation of salicylic acid (SA) defense marker gene expression or SA levels in the OE lines. Our results suggested that SbLRR2 is potentially useful for enhancing resistance against necrotrophic pathogens in transgenic dicot crops.  相似文献