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1.
为探究甜叶菊二倍体经染色体加倍后得到四倍体的过程中,基因组序列的变化情况,采用ISSR分子标记技术对1 个甜叶菊二倍体及其5 个同源四倍体株系的遗传差异进行分析。ISSR 结果显示:从60 个ISSR 引物中筛选出多态性强、重复性好的5 个引物进行扩增,共扩增出34 条谱带,其中有19 条呈多态性,多态性占55.88%;6 个甜叶菊株系间Nei's 基因多样性指数范围在0.0059~0.2778 之间;利用聚类分析,发现CK与5 个四倍体最先分开,这说明聚类分析可以很好的将甜叶菊二倍体和同源四倍体区分开,1 和2、4 和5 两两株系最先聚在一起,这表明2 组株系各自间遗传相似度高。甜叶菊不同倍性间遗传差异较大,同一倍性不同株系间也存在一定的遗传差异。  相似文献   

2.
陈静 《种子》1995,(4):22-25
以贵州芥菜型油菜地方品种,进行含油率与各生育阶段的遗传相关与通径分析。结果表明:5个生育阶段与含油率呈不同程度的遗传相关,它们的大小顺序为:抽苔至初花〉现蕾至抽苔〉出苗至现蕾〉终花至成熟〉初花至终花。5个生育阶段对含油率的直接通径大小依次为:出苗至现蕾〉初花至终花〉抽苔至初花〉终花至成熟〉现蕾至抽苔。从遗传相关、通径分析的大小排列顺序可看出:出苗至现蕾、初花至终花、抽苔至初花这3个生育阶段是影响油  相似文献   

3.
The paper analyzes the difference of the pathogenic varieties and the relationship of the variety composition,allording to the historic material to the varieties of the main hybid fece varieties in Southeast Sichuan during 1992 to 1998.It's the first time to advance to use the camparison on rate of pathogenic isolates between norm and refrieving to define the susceptible extent of the varity.It's an scientific base to adjust the structures of the vartieties,to reach the objective of the macroscopic regulating to rice blast.  相似文献   

4.
激素及光照对甘薯茎尖分生组织培养的影响   总被引:8,自引:0,他引:8  
根据不同基因型甘薯茎尖分生组织在不同激素水平的生长反应,将4个河南主栽甘薯品种分为3类;激素不敏感硬成苗型、激素敏感易成苗型和激素不敏感难成苗型。光照时数不是甘薯茎尖培养成苗的根制因素,以不低于14h/d为好。  相似文献   

5.
杨亦桦  陈松  吴益东 《棉花学报》2008,20(4):249-255
 用辛硫磷/氟氯氰菊酯(25:1, 有效成分)混剂对棉铃虫田间种群(HN)进行33代筛选获得抗性品系(HN-R)。筛选获得的HN R抗性品系对辛硫磷和氟氯氰菊酯的抗性分别达17.4倍和144.7倍。HN-R品系对两种拟除虫菊酯产生了高水平交互抗性(对氯氰菊酯和氰戊菊酯分别为86.2和23.4倍),对久效磷产生了中等水平交互抗性(5.2倍),对甲基对硫磷(1.6倍)、丙溴磷(1.8倍)和灭多威(2.4倍)产生了低水平交互抗性。酯酶抑制剂DEF能有效抑制HN-R品系对辛硫磷的抗性(增效比为15.3倍),而多功能氧化酶抑制剂PBO则对辛硫磷没有任何增效作用;PBO则使HN-R品系对3种拟除虫菊酯的抗性显著降低(对氟氯氰菊酯、溴氰菊酯和氰戊菊酯的增效比分别为21.9、19.1和21.4倍)。DEF和PBO都能使HN-R对久效磷的抗性下降一半(增效比分别为2.2和2.5倍)。HN-R抗性品系多功能氧化酶活性(以pNA为底物)和酯酶活性(以a-NA为底物)分别为HN品系的6.5倍和1.6倍。因此,在HN-R抗性品系中至少存在2种代谢抗性机理,即增强的酯酶解毒代谢(对辛硫磷、久效磷)和多功能氧化酶介导的氧化解毒代谢(对3种拟除虫菊酯、久效磷)。本研究表明,在田间使用有机磷/拟除虫菊酯混剂可能同时选择出多种代谢抗性机理,从而导致广谱的交互抗性。  相似文献   

6.
The consultation in project prospecting and designing plays a very important role in the project construction and it is facing a great challenge after the access of China to WTO. In this paper, the countermeasure in consultation of project prospecting and designing is put forward as follows: change the idea; cultivate and develop a perfect market system; to build a market operating system in keeping with the requirement of international practice and market; to reform and perfect the trade management system; to enhance the level of the project prospecting and designing unit; to change the government's function; to strengthen the quality control to ensure the quality of the project; to form a perfect law and regulation system; to encourage and strengthen the technology reform to set a fine base for the sustainable development and to adjust and work out the encouraging policy to help the trade development.  相似文献   

7.
室内土壤滴浇法测定了苯磺隆、苄嘧磺隆对不同小麦品种的安全性和叶绿素含量的变化,结果表明:两种药剂对不同小麦品种的安全性存在较大差异,且对根长的抑制作用明显大于株高;对叶绿素含量的影响与对株高的影响结果一致。苯磺隆对周麦13的根和芽敏感,使用不当易产生药害;对偃师4110根长最安全,株高最敏感。苄嘧磺隆对高优503根长最安全,株高最敏感;对周麦13株高最安全,根长最敏感。因此,小麦田化学除草应根据不同小麦品种来选择除草剂品种、有效用量和最佳施药方法。  相似文献   

8.
利用叶斑病菌粗毒素离体筛选太子参抗叶斑病突变体   总被引:1,自引:1,他引:0  
为培育太子参抗叶斑病新品种,运用组织培养技术以太子参叶斑病粗毒素为选择压力进行胁迫培养,采用逐步正筛选法离体筛选太子参叶斑病突变体。结果表明,太子参叶斑病粗毒素对愈伤组织的诱导、增殖、不定芽分化有明显的抑制作用,逐步提高毒素浓度能够在一定程度上提高愈伤组织对毒素的抗性。25 mL/L的毒素可以作为愈伤组织突变体的筛选压力,愈伤组织存活率达15.5%;将粗毒素浓度适当降低至10~20 mL/L有利于不定芽的分化,分化率达54%~40%;60~70 mL/L的毒素可以作为苗期抗毒素突变体的筛选压力,小苗存活率为8.3%。获得了46株高抗性植株,其对毒素的抗性显著高于对照。  相似文献   

9.
Y形偏心支撑高强钢框架结构抗震性能   总被引:3,自引:1,他引:2  
在Y形偏心支撑高强钢框架结构抗震性振动台试验的基础上,建立了试验试件的有限元模型,并验证了分析的正确性。设计了一个9层的Y形偏心支撑高强钢框架结构,以耗能梁段长度、耗能梁段腹板高厚比、高跨比为参数,对9层结构进行了非线性动力时程分析,研究了以上参数对结构抗震性能的影响。研究结果表明,改变耗能梁段长度、高跨比对结构层间侧移、耗能梁段性能、框架柱弯矩、耗能能力均有不同程度的影响,对框架柱轴力、基底剪力无显著影响;改变耗能梁段腹板高厚比对结构耗能能力有影响,对结构层间侧移、耗能梁段性能、框架柱受力、基底剪力无显著影响,并给出了相关设计建议。  相似文献   

10.
张海峰 《中国农学通报》2006,22(10):529-529
为了缓解福建省粮食供需矛盾,确保福建粮食安全,分析了福建省粮食生产供求现状和制约因素,揭示了粮食产业化经营的实质特征及福建省粮食产业化经营现状,根据自主创新的内涵提出依靠自主创新加快福建粮食产业化发展步伐的8项具体措施:科技创新,提高粮食单产,进一步增加粮食总量;机制创新,完善土地使用权流转机制,逐步推进粮田的适度规模经营;开发创新,发展粮食生产产业链;市场创新,建立科学的粮食购销体系;制度创新,落实粮食风险基金制度;服务创新,建立和健全农业社会化服务体系;强化培训,努力提高劳动力素质;观念创新,发展外向型粮食产业化经营模式。  相似文献   

11.
Owning to the ability of accepting insurance enough,it is the foundation for insurance companies to operate in a long-term and steady way,a method to develop sustainably,a reflection of an insurance company's comprehensive competition ability and also a premise for an insurance company to realize developing strategy.Accepting insurance ability is very important in the development and strategic planning for an insurance company.The quantitative analysis is used to analyze the ability of accepting insurance of our country's insurance companies,in another word,the factor(analysis),which belongs to the analysis of diverse statistic,is used.Using the method to give a concrete evidence analysis to the ability of accepting insurance of our country's non-life insurance companies,so that the insurance companies can understand very well to the advantages and disadvantages of the ability of accepting insurance to each other,and as well as supplying a strategic reference for the insurance companies themselves to make decisive planning.  相似文献   

12.
Cover plants are one of the means to increase the functional biodiversity of fields and to enhance the ecological functions of the communities. However, the design of cropping systems including cover plants relies largely on expert knowledge. There is a lack of methods to select the best suited cover plants according to their role in the agrosystem. We propose to use functional traits to select cover plants suited to sustain ecological services in the banana agrosystems of the French West Indies. Our objectives were (i) to characterize a collection of cover plants on a trait basis, according to their potential to provide the services expected in a banana agrosystem and (ii) to discuss the potential use of this characterization for the design of innovative multi-species banana cropping systems. In these systems, four main services are targeted, i.e. controlling weeds, controlling plant-parasitic nematodes, improving soil fertility and particularly N availability, and avoiding competition with banana for resource acquisition. Three experiments were conducted, under field and controlled conditions, to evaluate the potential of a collection of 28 tropical cover plants to achieve the functions related to these services. For each cover plant, a functional profile was constructed from a combination of plant traits that are easy to assess experimentally. It described plants’ potential to achieve the functions expected in a banana agrosystem. Functional profiles required for cover plant usages were also identified. The comparison of the plant functional profiles and the functional profiles required for their usages enabled us to select the best suited plants for each usage. However, these functional profiles rarely corresponded, meaning that a cover plant is rarely sufficient to achieve all the functions required for a usage. Functional complementarities obtained by the mixture of different species of cover plants are thus often required. Compared to classical approaches of innovative cropping system design based on the experimental testing of spatial and temporal plant combinations, such a trait-based approach saves time by focusing on a shortlist of cover plants best suited according to their functions in the agrosystem.  相似文献   

13.
不同遮光胁迫对大豆生长发育进程及形态性状的影响   总被引:4,自引:0,他引:4  
通过遮光处理,研究不同遮光强度及持续时间对大豆的生育进程和形态性状的影响,结果表明,大豆播种后遮光20%~50%,时间持续到V3期以后,大豆各生育阶段所需生育日数减少,生育期缩短。遮光20%时间持续到V3以后,遮光30%时间持续到R1以后,遮光50%时间持续到R5以后,大豆生育期显著或极显著缩短。同一遮光持续时间,遮光强度的加强会导致R5-R8生育日数增加,使大豆生育期(VE-R8)延长。遮光强度及遮光持续时间对大豆株高、子叶节高度、茎粗和主茎节数影响显著。遮光50%持续到R5期以后,植株形态由直立变成蔓生型。  相似文献   

14.
当前中国农民增收困难的根源除了农业生产的自身特点和中国人均耕地资源不足外,最主要的是长期以来政策上的重工轻农。因此,加强对农业的政策扶持,推进农村城镇化进程,全面减轻农民的税费负担,是解决农民增收的关键。  相似文献   

15.
中国无公害农产品质量保障体系与产业化发展的对策   总被引:7,自引:1,他引:6  
就“中国无公害农产品质量保障体系与产业化发展”进行了三个方面的阐述。首先,提出了无公害农产品开发的总体思路,包括其概念、指导思想、基本原则和市场定位诸点;其次,从完善无公害农产品标准和法规、规范无公害农产品认证体系、组建无公害农产品监管体系、完善无公害农业生产技术支撑体系、建立健全农产品质量检测体系、确保无公害农产品的质量及强化品牌意识、做好无公害农产品标志管理工作等几方面阐述了如何建立无公害农产品质量保障体系。最后,提出了如下关于无公害农产品产业化发展的对策:加强宣传和舆论监督,扩大无公害农产品影响;优化产业结构,大力推进无公害农产品认证工作;加大资金扶持力度,建立多元化的投融资机制;加大无公害农产品标准化和规范化的推广力度;加强农业科技培训和服务,落实无公害生产操作规程;积极培育和开拓市场,实现无公害农产品产业化发展;科技创新,用现代科学技术推动无公害农产品产业化发展。  相似文献   

16.
Lighting quality indicators with space sense for urban lighting environment   总被引:1,自引:0,他引:1  
In order to find out a space sense indicator that can present the real appearance of human and natural in urban lighting environment, three common used indicators are studied, which are ratio of vertical illuminance to semi cylindrical illuminance, ratio of vertical illuminance to horizontal illuminance and ratio of average cylindrical illuminance to horizontal illuminance.An on site test is taken at Three Gorges Square Pedestrian Street of Chongqing. The variation law of ratio of vertical illuminance to horizontal illuminance is approximate to ratio of average cylindrical illuminance to horizontal illuminance, which varies with the changing of measure point location and reach maximum at the axial central section of pedestrian street between two streetlamps. The change of ratio of vertical illuminance to semi cylindrical illuminance is small correspondingly and it is more appropriate to be as a lighting quality indicator with space sense for urban illuminance environment.  相似文献   

17.
甘蔗组培裸根苗小拱棚大田移栽技术试验报告   总被引:1,自引:1,他引:0  
为了提高甘蔗组培裸根苗在不同季节的大田移栽成活率,通过搭建小拱棚对‘新台糖22号’甘蔗脱毒组培裸根苗进行栽培。比较不同增殖苗处理方式和小拱棚顶部不同透气孔的设置、不同假植天数及不同季节对甘蔗组培裸根苗大田移栽成活生长的影响。研究缩短甘蔗组培苗育苗周期的同时又能提高甘蔗组培苗的大田移栽成活率及生长速度的方法。结果表明:不同增殖苗处理方式之间的成活生长差异不显著;移栽当天在小拱棚顶部设置直径1~2 cm的透气孔,裸根苗移栽成活率可高达93.5%,与对照差异达到极显著水平;假植天数为20~40天,每年的2月至10月均适合运用小拱棚进行甘蔗组培裸根苗的大田移栽。从根本上达到了缩短育苗周期,减少中间生产环节,降低育苗成本的目的。  相似文献   

18.
冯鹤 《中国农学通报》2016,32(17):172-175
为了提高人员生命损失风险计算的针对性、准确性,为人工接地装置安全布设提出建设性的指导意见,通过对人工接地装置泄流时接触电压、跨步电压的计算方法的分析,确定了人工接地体泄流时接触电压、跨步电压导致人身伤亡的损害概率的定量计算方法。计算时,通过对接触电压、跨步电压计算值与人体耐受接触电压、跨步电压阈值的比较分析,确定能达到该阈值的最小雷电流幅值,再通过对项目所在位置雷电活动特征的分析,确定可能超过灾害阈值对应的雷电流幅值,即可能产生风险的雷电流所占的频率,认为该频率即为接触电压、跨步电压导致生物伤害的损害概率。对人工接地装置接触电压、跨步电压的计算以垂直接地极为例,同时考虑了冲击电流较工频电流对计算方法的影响。  相似文献   

19.
Regional economic resilience can be defined as an economy’s ability to withstand and recover quickly from shocks. The ability to measure resilience is necessary to developing our understanding of what influences resilience. In this paper, we develop a new, two‐dimensional quantitative measure of resilience using observed differences between expected and actual employment in a region following a shock and distinguish the response to the shock from random variation. We demonstrate one application of this metric to US county‐level employment data to compare county responses to the 2007–2009 national recession and discuss how different regions of the United States responded to the shock of the Great Recession in terms of resilience.  相似文献   

20.
中国农村电力普遍服务的理论基础分析   总被引:2,自引:1,他引:1  
市场化改革之后。通过交叉补贴实现电力普遍服务的机制不可能实施,中国农村电力普遍服务的理论基础值得探讨。农村电力普遍服务是一种特殊的再分配方式,它是缩小地区差距、保证地区均衡发展的重要途径。是实现社会和谐稳定的基础。认为电力产业具有的网络特性、自然垄断性和准公共物品特征,这些因素都可能导致市场失灵,要保证公众所需要的基本生活用电,必然要求建立相应有效的公共政策。  相似文献   

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