早稻田捕食性天敌种群数量变动及其数学模拟     

张润杰 《中山大学学报论丛》1989,(1)

根据田间系统调查材料,分析了狼蛛等5种捕食天敌种群在早稻田的数量变动,并用逻辑斯谛方程模拟其变化过程.结果指出:狼蛛等5种捕食天敌总密度的数量变动,符合逻辑斯谛增长曲线,即水稻插植初期,这些天敌数量较少,随着禾苗生长,稻田天敌数量逐渐增多,到水稻生长中后期,其种群密度在一个平均密度的上、下波动.  相似文献   

梦:一次精神游走的人生历险--另眼看《米》     

刘培延 《钦州学院学报》2005,20(2):54-58

小说<米>发表十余年来,众评论家从文化、人性、精神等角度加以评说,而无人认识到这是作者苏童有意考验评论界的一个圈套.事实上,作者把"故事"写成了人物五龙的一个梦,故意没把作品写完,所以,有必要解开这个圈套并据之重新予以阐释,而这种阐释方法自然地上升到了一种方法论的意义,以留待诸家评说.  相似文献   

通过同源三倍体固定水稻杂种优势的新设想   总被引：1，自引：0，他引：1  

黄群策  刘峰  向茂成 《湘潭师范学院学报(社会科学版)》1995,(6)

文章提出了通过利用无融合生殖基因和培育同源三倍体来固定水稻杂种优势的新设想，指出了这一新设想的两大优点和急待解决的４大问题。笔者认为，通过常规育种手段将无融合生殖基因引入同源三倍体遗传组成中将可望消除其有性胚，而通过无性胚的产生来保持其遗传组成的相对稳定，进而可以达到固定水稻杂种优势的目的。  相似文献   

陶渊明"不为五斗米折腰"考辨     

秦崇海 《河南广播电视大学学报》2002,15(2):23-24

陶渊明的“吾不能为五斗米折腰”一句中的“五斗米”,历来被多数人理解为“陶的微薄奉禄”,其实,这种理解并不准确。考查历史典籍有关记载及陶的思想发展轨迹,分析陶弃官的当时背景和一些事件的联系,我们认为此句中的“五斗米”,应是指“五斗米的信徒”这种意义。  相似文献   

黄酒混浊沉淀的原因及防止措施     

权美平  田呈瑞 《长治学院学报》2004,21(2):47-49

黄酒是我国一种古老的、营养丰富的低酒度饮料。但由于在存放过程中易产生混浊、沉淀 ,严重影响其感官质量。文章就黄酒出现混浊 ,沉淀的原因进行了较深入的分析 ,并且提出了相应的解决措施。  相似文献   

亚精胺浸种对水稻生长及其产量的影响     

余海兵  杨安中  熊祖煦 《安徽科技学院学报》2002,16(4):47-49

用0.1～1.5mmol/L的亚精胺浸种处理水稻中籼898.结果表明:亚精胺浸种能提高水稻种子的呼吸强度和发芽势;促进秧苗生长;提高籽粒产量.处理浓度以1.0～1.5mmol/L效果为好.  相似文献   

水稻插秧机后插式分插机构研究   总被引：2，自引：0，他引：2  

陈德俊 《金华职业技术学院学报》2001,1(4):1-3

本文用计算机对水稻插秧机后插式分插机构进行了分析研究。通过秧针端点运动轨迹上的6个特定点，分析了后插式分插机构的运动学和动力学。经理论分析和田间试验表明，后插式分插机构的结构参数选择是合理的，插秧性能是优良的。  相似文献   

Characterization of enhancer trap and gene trap harboring Ac/Ds transposon in transgenic rice     

金维正  汪少敏  徐敏  段瑞君  吴平 《浙江大学学报(A卷英文版)》2004,5(4)

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F2 populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice.  相似文献   

Characterization of high-yield performance as affected by genotype and environment in rice     

Chen S  Zeng FR  Pao ZZ  Zhang GP 《Journal of Zhejiang University. Science. B》2008,9(5):363-370

We characterized yield-relevant characters and their variations over genotypes and environments (locations and years) by examining two rice varieties (9746 and Jinfeng) with high yield potential.9746 and Jinfeng were planted in two locations of Shanghai,China,during 2005 and 2006.The results show that there was a large variation in grain yield between locations and years.The realization of high yield potential for the two types of rice was closely related to the improved sink size,such as more panicles per square meter or grains per panicle.Stem and leaf biomasses were mainly accumulated from tillering stage to heading stage,and showed slow decline during grain filling.Meanwhile,some photosynthetic characters including net photosynthesis rate (Pn),leaf area index (LAI),specific leaf area (SLA),fluorescence parameter (maximum quantum yield of PSII,Fv/Fm),chlorophyll content (expressed as SPAD value),as well as nutrient (N,P,K) uptake were also measured to determine their variations over genotypes and environments and their relationships with grain yield.Although there were significant differences between years or locations for most measurements,SLA at tillering and heading stages,Fv/Fm and LAI at heading stage,stem biomass at heading and maturity stages,and leaf nitrogen concentration at tillering and heading stages remained little changed,indicating their pos-sible applications as selectable characters in breeding programs.It was also found that stem nitrogen accumulation at tillering stage is one of the most important and stable traits for high yield formation.  相似文献   

Functional genomics in the rice blast fungus to unravel the fungal pathogenicity   总被引：1，自引：0，他引：1  

Jeon J  Choi J  Park J  Lee YH 《Journal of Zhejiang University. Science. B》2008,9(10):747-752

A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.  相似文献