基于CiteSpace的氮沉降知识图谱计量分析

客观分析国内氮沉降研究现状,总结现阶段研究的重点与薄弱点,旨在为氮沉降的科研工作者与决策者提供数据参考.以"氮沉降"为主题词,从CNKI数据库中得到2009-2019年发表的相关文献754篇,运用CiteSpace知识图谱分析工具对关键词、作者、机构进行可视化分析,并对氮沉降的研究进展、发展趋势和资助基金等方面进行相关...     

棉花植株和花粉耐盐性的鉴定

本研究对８个耐盐性不同的棉花品种（系），利用水培的方法对其整体植株进行了耐盐性鉴定，利用液滴培养技术对其花粉的耐盐性进行了鉴定，并分析了棉花整体植株和花粉耐盐性的相关性，结果表明，在水培盐胁迫条件下，棉花叶片总面积和叶片鲜重减少的百分数是反映棉花整体植株耐盐性的指标。在液滴培养盐胁迫条件下，棉花花粉粒萌发的百分率是反映其耐盐性的可靠指标，而花粉管的长度不能反映棉花的耐盐性。棉花整体植株的耐盐性和花     

晋西旱塬地渗水地膜覆盖玉米试验

在位于晋西南黄土残塬沟壑区的隰县旱地进行了渗水地膜覆盖玉米种植试验。结果表明,与常规地膜覆盖比较,渗水地膜覆盖玉米增产３８．３％,增产效果显著;玉米生育期０－１００ｃｍ土层内土壤含水量平均提高２个百分点,天然降水的水分粮食生产效率达到２３．２５ｋｇ．ｍｍ＾－１．ｈｍ＾－２;当气温在３５℃以下时,渗水地膜与常规微膜具有相同的增温效果,当气温在３５℃以上时,渗水地膜下的增温速度明显减慢,玉米生育期株高     

Use of component analysis in QTL mapping of complex crop traits: a case study on yield in barley

Genes contributing to the quantitative variation of a complex crop trait can be numerous. However, using existing approaches, the number of quantitative trait loci (QTL) detected for a trait is limited. Therefore, rather than looking for QTL for a complex trait itself, determining QTL for underlying component traits might give more information. In this study the potential of component analysis in QTL mapping of complex traits was examined using grain yield in spring barley as an example. Grain yield was divided into three components: number of spikes/m², number of kernels/spike, and 1000‐kernel weight. These traits were measured for individuals of a recombinant inbred‐line population in field trials conducted over 2 years. By the use of an approximate multiple QTL model, one to eight QTL were detected for each trait in a year. Some QTL were mapped to similar positions in both years. Almost all QTL for yield were found at the position of or in close proximity to QTL for its component traits. A number of QTL for component traits were not detected when yield itself was subjected to QTL analysis. However, relative to the QTL for yield itself, all component‐trait QTL did not explain the variation in yield better. The results in relation to the potential of using component analysis in studying complex crop traits are discussed.     

盐胁迫对棉花幼苗子叶超氧化物歧化酶(SOD)活性的影响

棉花幼苗子叶 SOD 活性在细胞内的分布是细胞溶质部分活性最高。其次是线粒体,再次是叶绿体。各细胞器 SOD 活性对盐分的敏感程度不同,依次是叶绿体>线粒体>细胞溶质部分。在盐分胁迫初期,棉花幼苗子叶能够维持较高 SOD 活性,但随着盐胁迫强度的增加,棉花幼苗子叶 SOD 活性下降和膜透性增加,幼苗表现出盐害症状,SOD 活性下降比膜透性增加出现的早。轻度盐分胁迫随时间延长,鲁棉6号的子叶 SOD 活性有一定增加,表明棉花幼苗具有一定的耐盐能力。耐盐性不同的两个品种在 SOD 活性和细胞质膜透性变化上有差异,并对 SOD 作为棉花抗盐碱育种指标进行讨论。     

Study on A New Type of Soft Wheel for High Efficiency Grinding

The paper describes the design of high efficiency soft throw away wheel whose tension of abrasive belt is adjustable.With the airbag internal capsule and continuous spring ring structure,grinding vibration is decreased and machining accuracy is improved.     

Analysis and Computation on Dynamic Characteristics of a New Style Hydrodynamic Journal Bearing

This thesis completes 3D variational modeling design and Finite Element Simulation of a new style hydrodynamic bearing by I DEAS software,based on studying 3D solid modeling theory and Finite Element Simulation technology carefully and deeply.This thesis analyses the static and dynamic characteristics of bearing,computed the eight dynamic coefficients of oil,analyses the characteristics of this bearing after comparing with the other bearings     

Isolation and Characterization of GhLEA3 Gene from Upland Cotton and Its Expression in Response to Low Temperature Stress

[Objective] Based on the analysis of cotton GhLEA3 gene structure and its expression model in chilling stress, we investigated the resistance function of GhLEA3 in response to cold stress. [Method] We cloned GhLEA3 from upland cotton by homologous sequence cloning way. We analyzed the properties of the GhLEA3, and constructed phylogenetic tree by bioinformatics analysis. We constructed the transient expression vector 35S∷GhLEA3-GFP by In-Fusion connection technology and studied the subcellular localization of GhLEA3. The expression of GhLEA3 gene in leaves of TM-1 at three-leaf stage under low temperature stress treatments (4 ℃, 24 h) was performed. Agrobacterium tumefaciens mediated floral dipping method was used to transform the gene with expression vector 35S∷GhLEA3-GFP into Arabidopsis thaliana wild type. Low temperature germination experiment at 4 ℃ was conducted to verify germination ability of the transgenic Arabidopsis thaliana T₃ seed. The transgenic Arabidopsis seedlings were treated at 4 ℃(low temperature), and all the leaves were taken to measure their electrical conductivity. [Result] The coding sequence of GhLEA3 gene is 1 218 bp, which encodes 405 amino acids. GhLEA3 protein includes 4 functional domains of PF02987. Phylogenetic analysis showed that the similarity of amino acid sequences between upland cotton GhLEA3 and Arabidopsis thaliana AtLEA3 was 52.6%. GhLEA3 might be mainly localized in vacuoles and small vesicles. GhLEA3 was up-regulated in leaves after low temperature treatment. The germination rate of transgenic Arabidopsis thaliana of T₃ generation at low temperature was significantly higher than that of wild type, and its electrical conductivity of leaves after low temperature treatment was significantly lower than that of wild type. [Conclusion] GhLEA3 belonged to the member of LEA3 family. Phylogenetic analysis showed that GhLEA3 had the closest relationship with AtLEA3. GhLEA3 was induced by low temperature stress and may play an important role in improving cold resistance.     

露水河林业局森林景观空间自相关分析与拟合

空间自相关是建立森林景观模型中不可回避的问题,然而目前众多研究中常忽略了这一点,为了探解决考虑空间自相关性,建立森林景观模型的问题,以露水河林业局为例,采用空间自相关分析、半方差分析等手段分析红松森林景观等景观类型的空间自相关性。研究结果发现,Moran’s I指数以及半方差图显示红松在空间分布上具有较强的空间自相关性,但这种空间自相关性从1987-2003年呈现减弱趋势,红松的分布由非随机因素占主导地位逐渐变为随机因素占主导地位,采伐等人为因素对于红松的分布产生了重要影响。在此基础上分别利用经典线性回归模型和空间滞后模型建立了红松森林景观分布与环境驱动因子的模拟模型,经过比较,认为空间滞后模型的拟合度优于经典线性回归模型。     

海藻液对玉米苗期生长的影响

为了比较不同海藻液对作物生长效果的影响,利用3种类型的海藻液在玉米苗期进行水培试验,测定玉米硝酸还原酶和根系活力等指标。结果表明：3种类型海藻液均能增加玉米干物质积累,发酵海藻液、普通海藻液处理与对照相比均达差异显著水平;硝酸还原酶活性以发酵海藻液中量最高,达74.42 μg/(g?h),其次为普通海藻液的中量处理[72.32 μg/(g?h)];中量的发酵海藻液的根系活力最高达1.576 mg/(g?h),高量发酵海藻液与中量普通海藻液的根系活力次之分别为1.505 mg/(g?h)、1.503 mg/(g?h),海藻酸钠的效果不如发酵海藻液和普通海藻液。