不同紫花苜蓿品种植株浸提液对种子萌发和幼苗生长的自毒效应

以5个紫花苜蓿品种为浸提液提取材料,分别用不同浓度(0、10、30、50、70g/L)的根、茎、叶浸提液处理甘农3号紫花苜蓿种子及幼苗,研究不同处理对其种子萌发和幼苗生长的影响。结果表明:5个苜蓿品种植株浸提液对甘农3号种子萌发和幼苗生长具有明显自毒效应,其效应因苜蓿品种、器官和浸提液浓度不同而存在显著差异。同一品种、相同浓度下自毒效应强弱顺序为叶茎根;同一品种和器官的浸提液随着浓度的增大,甘农3号苜蓿种子的发芽势、发芽率、发芽指数、活力指数均显著降低,胚根长、胚芽长及根系活力显著减小;随着浸提液浓度逐渐增大(10~70g/L),种子发芽势、发芽率的化感指数(RI)也逐渐增大(0.002 6~12.640 0),同时受抑制程度逐步增强,而且,叶浸提液对种子发芽势、发芽率抑制作用最强,根浸提液抑制作用最弱,茎浸提液抑制作用居中。同样的,随着浸提液浓度增大,幼苗的胚根长、胚芽长受抑制程度也逐步增大(1.3%~54.1%),其中根浸提液抑制率在1.3%~31.3%,茎浸提液抑制率在4.0%~34.1%,而浓度为50g/L叶浸提液抑制率达到54.1%,浓度为70g/L叶浸提液甚至致使苜蓿种子和幼苗腐烂或死亡,检测不到胚根长、胚芽长。不同苜蓿品种的自毒作用存在差异;同一苜蓿品种,根、茎、叶浸提液的自毒效应叶浸提液最强,其次为茎浸提液,根浸提液自毒效应最弱。苜蓿自毒作用会抑制种子萌发和幼苗的胚根、胚芽生长。     

Identification and distribution of fungal pathogens associated with seedling blight of rice in the southern United States

Surveys were conducted in the five southern rice-producing states of Arkansas, Louisiana, Mississippi, Missouri and Texas in the United States during the 2018 and 2019 cropping seasons to determine the distribution and pathogenicity of fungal pathogens associated with seedling blight in rice. A total of 349 pathogenic fungal isolates were collected and identified as belonging to four genera: Rhizoctonia solani, Fusarium spp., Sclerotium rolfsii and Marasmius graminum based on morphological characteristics, molecular analysis and Koch's postulates. R. solani (252 out of 349 pathogenic isolates) was the most prevalent fungus isolated from diseased samples. Of the 252 pathogenic R. solani isolates, 245 were further classified as anastomosis group 11 (AG-11) and 7 as AG-4. Isolates of R. solani AG-4 and M. graminum were the most aggressive, with the highest stand loss (63% to 100%) and median disease rating (DR; 5.0), followed by isolates of R. solani AG-11 (stand loss = 4% to 100% and DR = 0.6 to 5.0), Fusarium spp. (stand loss = 26% to 48% and DR = 2.0 to 5.0) and S. rolfsii (stand loss = 33% to 48% and DR = 2.0 to 3.0) in causing seedling blight in rice. R. solani (62% to 83% of total pathogenic isolates) and Fusarium spp. (10% to 24% of total pathogenic isolates) were predominant in all the five states surveyed. S. rolfsii and M. graminum were present only in Louisiana and Texas. The results of this first systematic survey of rice seedling diseases in the southern United States will help develop effective fungicide seed treatment strategies for control of stand loss caused by seedling blight, one of the major factors limiting rice production.     

不同基因型大麦苗期对干旱胁迫的响应及HvPIPs基因表达特征分析

为研究不同基因型大麦苗期对干旱胁迫的响应,挖掘优质抗旱的大麦种质资源,以4份不同基因型大麦(2个高抗品种ZDM5430和ZDM5458,2个干旱敏感型品种7DCADA和IL-12)为材料,利用聚乙二醇(PEG-6000)模拟干旱条件,综合分析不同品种大麦的苗期抗旱性差异;并通过对不同品种根系进行PIPs实时定量分析,研究水通道蛋白AQPs基因与干旱胁迫之间的应答关系。结果表明,持续干旱胁迫会使大麦生长变缓,各处理苗长、根长、叶含水量和根含水量都呈下降趋势,其中,4个品种的大麦叶含水量在干旱胁迫14 d时下降最为显著,与对照相比,其降幅分别为29.14%、52.64%、21.67%和72.15%。干旱胁迫对大麦苗期干物质积累量和根冠比的影响较小,各处理间差异不显著;但持续干旱后,抗旱品种ZDM5430的根冠比呈上升趋势,在胁迫7、14、21 d时较CK分别增加了4.92%、42.86%和21.05%。随着胁迫时间的延长,大麦旗叶叶绿素含量和根系活力也呈下降趋势,其中ZDM5430和ZDM5458较对照组降幅较小,说明抗旱品种的形态指标、叶绿素含量及根系活力受干旱胁迫的影响较小。通过PIP...     

FLUENT软件及其在植保机械方面的应用

FLUENT软件是流体力学中通用性较强的商业软件之一，由于FLUENT软件的应用，节省了大量的人力和物力。对实际应用有重大的指导作用。为此，通过简述FLUENT在植保机械方面的应用实例，提出了FLUENT在植保机械方面的发展前景。     

Knowledge Representation for Rotative Machine Fault Diagnosis Based on Semantic Net

Aiming at knowledge representation problem of expert system for rotary machinery fault diagnosis, semantic net knowledge representation is discussed. Semantic net to represent expert knowledge of rotary machinery fault diagnosis is explored. Its realizing method is afforded in computer language, in addition, demostrating model is also developed in Visual C++. The result shows good validity of the knowledge representation.     

Tissue Culture and Rapid Propagation of Actinidia chinensis

It has been briefly studied and reported that Actinidia chinensis , one of economic woody plants, has been bred with the method of plant tissue culture. Aim at the shortage of traditional plant tissue culture ways which ignored the refinement and transplant of test-tube seedling, it strengthen the study to breeding and management of Actinidia chinensis seedlings before they grow up and become mature seedlings. Through our explore, the transplant survive rate of tissue-culture seedlings attain to about 85%.This study is the improvement to traditional breeding seedling means and it is helpful to the rapid propagation of those economic woody plants.     

Tissue Culture and Rapid Propagation of Echinacea Purpurea

It is a burgeoning application field for the biotechnology that to apply the technique of plant tissue culture breed seedling. The authors study the responses of Echinacea purpurea to different proportion plant growth hormone or auxin through adopting the culture tissue technique on the MS. The integrated seedling of Echinacea purpurea can be cultivated by callus, subculture, differentiation and rhizogenesis. The surviving rate of Echinacea purpurea seedling transplant are improved by appropriate sound stimulation appropriate. Study harvest offers the gist for the large-scale breeding seedling and the officinal resource exploitation of Echinacea purpurea in our country, and avoid some traditional handicap in breeding seedling of Echinacea purpurea, such as the difficult of seed collection, low burgeoning rate, and the disadvantage for large-scale propagation.     

葡萄组培苗瓶外生根技术研究

采用不同种类和浓度的生长素诱导葡萄组培苗瓶外生根，并观察组培苗在不同处理基质、不同的温度、不同的生理年龄条件下生根的效果。通过优化技术参数，建立了葡萄组培苗瓶接生根的技术优化体系，结果表明，用浓度为0.3mg/L的IBA浸蘸处理的插条，在温度为27~29℃的环境条件下在基质珍珠岩上培养，瓶苗茎段的生根率可达85.5 %，移栽后苗木的成活率达98 %，相对于其他方法有了较大的提高。该技术的建立有助于实现葡萄工厂化育苗技术的商业化扩大。     

东北地区农机制造业的地位和作用及发展措施

农业装备是农业现代化的重要物质基础,是提高农业生产效率、保障资源充分与有效利用和环境友好与可持续发展的有效工具,是用工业化和信息化改造传统农业的有效载体,是装备"三农"的战略产业,对保障国家粮食安全、农民增收、农业增效、农村发展起着重要作用.为此,分析了农机制造在机械工业、东北区域经济中的地位与作用;阐述了农机制造业存在的问题;鉴于目前东北地区农机制造业的现状,提出了其今后发展的措施.     

新型柴油机喷油规律测试系统的设计

基于柴油机喷油器,设计了一种柴油机喷油规律测试系统.对喷油器进行改装设计,用以容纳、计量柴油机在喷油过程中喷出的油量,用位移传感器测量喷出油量的容积变化,通过数据处理得到喷油规律;设计了卸压装置,以防止测量系统因油压过高而受损.实验结果表明,该测试系统可以快捷地测量柴油机的喷油规律.