我国果树玻璃化试管苗特征、成因、机理及控制研究进展

该研究统计了我国已报道的出现玻璃化试管苗的果树种类多达50种,并基于近年果树工作者的相关研究,总结并系统论述了玻璃化试管苗的生理生化特性、形态解剖学特征、DNA的MSAP分析、成因、发生机理及控制措施,对系统研究果树试管苗玻璃化现象、增加转基因植株的遗传稳定性、保存和恢复珍贵材料无性系、提高次生代谢物产量和消除毒性及工厂化育苗都具有十分重要的意义。     

地熊蜂为重庆地区设施番茄授粉的效果研究

为评价地熊蜂在重庆地区设施番茄的授粉效果,在重庆市荣昌区龙舌嘴村开展授粉效果比较试验,分析地熊蜂授粉对设施番茄产量、果实品质及畸形果率的影响。试验结果显示,经地熊蜂授粉的设施番茄平均产量为2 206.44 kg/667 m2,与未授粉组相比显著提高了104.95%,授粉组的单果质量、果纵径、果最大横径、可溶性固形物含量、VC含量及总糖含量显著高于未授粉组。由此,认为地熊蜂适宜为重庆地区设施番茄授粉,且能够显著提高重庆地区设施番茄的产量与品质。     

外源ACC通过激活乙烯合成及信号转导诱导小豆抗锈性

大量研究表明, 乙烯可激发植物对死体营养型真菌的抗性, 但我们前期研究发现, 乙烯合成前体ACC可提高小豆对活体营养型真菌——锈菌的抗性, 为初步明确其机制, 本研究分析了ACC处理对小豆乙烯合成及信号转导的影响, 结果表明, ACC处理显著提高了乙烯合成基因VaACS1及信号通路关键基因VaEIN2?VaEIN3?VaERF5的表达水平?此外, ACC处理后再接种锈菌, 小豆锈病的发病程度显著降低?对接种锈菌后不同时间VaPR2和VaPR4的表达分析表明, 相比ACC处理后不接种对照, ACC处理后再接种锈菌的处理, 接种后1~5 d这两个基因表达量显著升高; 与水处理不接种锈菌相比, 水处理接种锈菌5~8 d后VaPR2和VaPR4的表达量虽显著上调, 但应答时间较ACC处理滞后, 且总体表达水平低, 表明ACC激活乙烯通路进而诱导防卫反应基因上调表达是其诱导小豆抗锈性的关键?     

水氮调控对苜蓿与无芒雀麦混播草地生长和辐射利用的影响

针对我国内陆干旱区人工草地生产管理粗放及气候资源利用不充分等问题,探究合理的牧草种植与水氮供应模式,以充分挖掘区域牧草的生产潜力。采用3 a生(2018年播种)紫花苜蓿(简称‘苜蓿’)和无芒雀麦,分析种植模式(苜蓿与无芒雀麦混播,D1;无芒雀麦单播,D2)、施氮量(低氮量N1:60 kg·hm^-2;高氮量N2:120 kg·hm^-2)和灌水量(以灌水下限占田间持水量θ_f的百分比计,分枝期均充分灌水(75%～85%θ_f),现蕾和初花期轻度亏水W1:65%～75%θ_f、中度亏水W2:55%～65%θ_f、重度亏水W3:45%～55%θ_f,灌水上限均为85%θ_f)对牧草叶面积指数(LAI)、干物质累积量、累积截获光合有效辐射量(CIPAR)、辐射利用效率(RUE)、产量(Y)、耗水量(ET_a)、水分利用效率(WUE)和氮肥偏生产力(PFP_N)的影响。结果表明：(1)牧草LAI和...     

Physiological but not morphological adjustments along latitudinal gradients in a human commensal species,the Eurasian tree sparrow

Human commensal species take advantage of anthropogenic conditions that are less likely to be challenged by the selective pressures of natural environments. Their morphological and physiological phenotypes can therefore dissociate from habitat characteristics. Understanding how these species adjust their morphological and physiological traits across latitudinal gradients is fundamental to uncovering the eco-physiological strategies underlying coping mechanisms. Here, we studied morphological traits in breeding Eurasian tree sparrows (ETSs; Passer montanus) among low-latitude (Yunnan and Hunan) and middle-latitude (Hebei) localities in China. We then compared body mass; lengths of bill, tarsometatarsus, wing, total body, and tail feather; and baseline and capture stress-induced levels of plasma corticosterone (CORT) and the metabolites including glucose (Glu), total triglyceride (TG), free fatty acid (FFA), total protein, and uric acid (UA). None of the measured morphological parameters varied with latitude except in the Hunan population, which demonstrated longer bills than those in other populations. Stress-induced CORT levels significantly exceeded baseline levels and decreased with increasing latitude, but total integrated CORT levels did not vary with latitude. Capture stress-induced significantly increased Glu levels and decreased TG levels, independent of site. However, the Hunan population had significantly higher baseline CORT, baseline and stress-induced FFA levels, but lower UA levels, which differed from other populations. Our results suggest that rather than morphological adjustments, physiological adjustments are mainly involved in coping mechanisms for middle-latitude adaptation in ETSs. It is worth investigating whether other avian species also exhibit such dissociation from external morphological designs while depending on physiological adjustments.     

Frequency Refining Analysis and Its Applications in the VIs

Frequency refining is an important spectrum analyzing tool, and is one of the main function of signal processing and the virtual instrument. This paper introduces several typical frequency refining analysis methods including DFT and multiple modulation and so on. It also probes into their advantages and disadvantages, and proposes a new frequency refining method combining subband decomposing DFT and multiple modulation, which inherits the advantages of multiple modulation, needs not to design a specific filter, reduces the amount of calculation, and is fit for real-time refining analysis. At last, it exhibits several frequency refining algorithm and their effects with applications in virtual instruments.     

An Analysis of Principal-Agent of Game under the Asymmetric Information in Venture Capital

The relationship of investors and venture capitalists is an important part in venture capital. Based on asymmetric information, this paper analyzes the principal agent relationship between investors and venture capitalists with game theory. And this paper mainly discusses the choosing, controlling and incentive problem. It suggests that only the capable and self confident venture capitalists could accept the terms of the limited partnership. It also indicates that recompense mechanism which holds the interest of investors and that of venture capitalists tightly is the center of the limited partnership. Rate of yield is the key of recompense mechanism, it not only reflects the incentive on venture capitalists, also reflects the share of risk between investors and venture capitalists. At last, the market credit play an important role in venture capital.     

Stability Contrast of Landslide Disaster After Repeating Control

Xiang-jiapo landslide,which consists of shallow layer,middle layer and deep layer,is a multi-landslide with several layers.Influenced by geological condition and rainfall,it have not obtained good effect even after three-time control.Because the distortion of landslide increase so fast, the government planed to control the landslide for the forth time.Based on monitoring data of the landslide movement,the paper make a constrast analysis of 3D numerical simulation's calculating between the formal control and the forth time control by a non-linear finite elements programm ABAQUS.Both results of numerical simulation and monitoring indicate that the forth time control have achieved good effect.     

发动机用平板型空滤器流动阻力特性分析和改进

为减小平板型空滤器流动阻力以增大进气量,对平板型空滤器流动阻力特性开展了实验研究,获得了空滤器流动阻力随流量变化的规律和阻力构成成分。阻力随流量的增大而加速增大,滤芯阻力约占整个空滤器阻力的一半,入口流量为120 m 3/h时,总阻力为915.3 Pa,滤芯阻力为426.4 Pa。在实验获得滤芯阻力参数的基础上,提出采用多孔介质跃升模型对平板型空滤器内部流场开展三维数值仿真分析,结果表明,仿真结果与实验结果比较吻合,最大误差为5.67%。滤芯阻力同样约占整个阻力的一半,另一半阻力主要为出口处阻力,其余壁面阻力约占15%。最后,在实验和仿真分析的基础上,提出了改进模型并进行了仿真分析。结果表明,改进模型阻力有较大程度的下降,入口流量为120 m 3/h时,总阻力为588.2 Pa,较原始模型下降了32.2%;增大空滤器流通横截面积是减小阻力以增大进气量的有效手段,改进空滤器壁面的平滑性是补充措施。     

叶菜型甘薯新品种百薯1号的选育及其特征特性

百薯1号是由安薯07自交选育而成的叶菜型甘薯新品种。株型半直立,基部分枝数25~30个,茎蔓细嫩,最长蔓长80~100cm,叶片小,全身无茸毛,适口性好,茎尖产量一般22500kg/hm2以上。薯块产量夏栽30000kg/hm2以上,春栽37500kg/hm2以上。在茎尖产量22500kg/hm2左右条件下,薯块产量可达19500kg/hm2左右。