自然状态下竹子的抗寒性研究

在自然状况下,研究了几个竹种叶片的电导率与叶绿素含量随温度的变化趋势,并对几个竹种的抗寒性强弱进行了分析对比。结果表明,叶绿素含量与温度的变化成正相关,电导率与温度的变化成负相关。在这几个竹种中黄秆京竹、罗汉竹、淡竹的抗寒性较强,平安竹、黄槽石绿竹、黄秆乌哺鸡抗寒性中等,紫竹、黄条金刚竹、翠竹、铺地竹、菲白竹抗寒性最弱。     

提水泵站空流段流量配合问题探讨

通过对水泵性能差异引起的水泵出水量的变化分析,提出了调节级间流量差的小机组流量的确定方法,解决了多级提水泵站空流段的级间流量配合问题。     

红花刺槐茎段组织培养研究

红花刺槐为刺槐的变型,其组织培养至今尚未见报道。为提高红花刺槐的繁殖系数,进行了红花刺槐茎段外植体诱导成活、初代培养基和继代培养基以及生根培养基的筛选试验,并对愈伤组织成苗进行了探索。结果表明当年生枝条茎段组织培养春天比秋天成活率高,绿色致密的愈伤组织能够成苗。初代培养以SH为基本培养基为好,继代培养以B5为基本培养基为好,生根培养以1/2MS为基本培养基为好,繁殖系数达每芽30天4.7株,生根率为84.4%。表7参22。     

内场致发射电极在电解水中的电化学行为

内场致发射电极是根据内场致发射原理制备的一种电极。把它应用于电化学实验中是最近几年新兴起的一个学术研究领域。本文介绍了内场致发射电极的基本原理及在电解水中的应用，讨论了它在电解水中的电化学行为的规律，得出了内场致发射电子可以参加电化学反应的结论。     

采食水平对东北民猪代谢热量的影响

以哈白猪为对照，研究２０℃条件下，低（Ｌ，７５０ｇ／ｄ），中（Ｍ１０５０ｇ／ｄ）高（Ｈ，１３００ｇ／ｄ）三种采食水平（饲料ＭＥ含量为１２．３７ＫＪ／ｋｇＣＰ：１６％）对体重２０～２５ｋｇ的民猪产热量的影响，研究结果表明，随采食水平提高，产热量有逐渐增加的趋势，但产不显著（Ｐ〉０．０５），三种采食水平下，民猪和哈白猪的产热量分别为３３．５，３４．５，３５．９和３１．９，３３．８，３４．９ＫＪ／ｋｇ＾     

Changes in the volatile compounds and chemical and physical properties of Kuerle fragrant pear (Pyrus serotina Reld) during storage

Volatiles from stored Kuerle fragrant pears (Pyrus serotina Reld) were studied using high-resolution gas chromatography and the solid-phase microextraction (SPME) method of gas chromatography/mass spectrometry (GC/MS). The dominant components were hexanal, ethyl hexanoate, ethyl butanoate, ethyl acetate, hexyl acetate, ethanol, alpha-farnesene, butyl acetate, and ethyl (E,Z)-2,4-decadienoate. By using GC-olfactometry, it demonstrated that the volatile compounds from SPME were responsible for the aroma of the Kuerle fragrant pear. The levels of sugars, organic acids, and phenolic acids in Kuerle fragrant pears were investigated using high-performance liquid chromatography (HPLC). Fructose was the dominant sugar, followed by glucose and sucrose. With increasing storage time, sucrose levels decreased; however, changes in fructose and glucose levels were not remarkable. There was a slight decrease in flesh firmness during storage. The general soluble solids concentration (SSC) declined slightly after 5 months storage. Some aroma-related volatile components increased during storage, while others decreased, especially the esters. The organic acids and phenolic acids also changed. The flavor of the Kuerle fragrant pears was affected by the change of volatile compounds and changes in chemical and physical properties.     

Mechanism of wine lactone formation: demonstration of stereoselective cyclization and 1,3-hydride shift

The cyclization mechanism of (E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid to wine lactone under acidic aqueous conditions was investigated using the two stereoselectively deuterium-labeled precursors (2E,6R,7Z)-[8-2H]-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid and (2E,7E)-(+/-)-[8-2H]-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid. A detailed analysis of the generated wine lactone isomers by enantioselective multidimensional gas chromatography (MDGC)/ion trap tandem mass spectrometry demonstrates that the formation of wine lactone proceeds via a nonenzymatic stereoselective cationic cyclization cascade that includes a 1,3-hydride shift. Usually, such mechanisms are features of cyclization reactions that are catalyzed by terpene cyclases. This nonenzymatic conversion of an acyclic precursor to a bicyclic monoterpene under relevant cationic cyclization conditions has rarely been observed and confirms recent suggestions that the precursor itself can provide the chemical functionality required for specific steps in the cyclization cascade.     

四川烟区烟叶化学成分与海拔的关系

采用偏最小二乘回归的方法研究四川烟叶化学成分与海拔间的关系.结果表明,四川烟区海拔变化幅度较大,烟叶中的总糖、还原糖以及总氮质量分数变幅较大,淀粉质量分数变幅较小.建立烟叶化学成分与海拔的偏最小二乘回归分析模型:上部叶(海拔=0.205x1+0.179x2-0.050x3+0.205x4-0.086x5-0.352x6 +0.122x7)、中部叶(海拔=0.382x1+0.168x2-0.012x3+0.243x4-0.05625-0.211x6-0.026x7)以及下部叶(海拔=0.349x1+0.202x2-0.073x3+0.001x4+0.006x5-0.060x6-0.199x7),总糖、还原糖以及总氮质量分数与海拔呈正相关,总烟碱以及钾质量分数与海拔呈负相关,上、中、下部位间淀粉和氯质量分数的相关性不一致;烟叶中的糖类指标与海拔呈高度正相关,钾质量分数与海拔呈高度负相关.     

基于不可替代性的三江源地区自然保护区评估及空缺分析

根据三江源生物多样性特征,在系统保护规划方法(SCP)框架下,利用地理信息系统(GIS)技术与保护规划软件C-Plan,计算三江源区域内各规划单元的不可替代性值及已建自然保护区对该地区生物多样性保护的贡献率,评估三江源地区现有保护区的保护贡献,分析分区间主要保护对象的互补性及各区保护效率,在此基础上分析该地区现有保护区的保护空缺。贡献率评估结果显示:三江源地区现有的2个最重要的保护区,可可西里自然保护区和三江源自然保护区(包含6个区域)基本涵盖本研究确定的所有保护对象,已经达到保护目标的保护对象占其总数量的80%;不可替代性高的区域与现有保护区核心区在空间分布上基本吻合,其贡献率达到61.20%,核心区+缓冲区贡献率为77.57%,核心区+缓冲区+实验区总贡献率达到91.20%;可可西里自然保护区及三江源自然保护区6大区域内核心区间的互补性较高,说明核心区区域的划分较为合理,主要保护对象类型区分较为明显。空缺分析显示:在三江源地区现有保护区体系下,还有8.80%的保护目标没有实现,未达到保护目标的保护对象占保护对象总数的20%,其中包括生态系统类型1种,动植物物种7种,保护空缺主要分布在唐古拉湖泊、冰川雪山及高寒草甸区,约改-巴干高寒草原区,泽库-河南高寒灌丛草甸区与隆宝-拉秀森林灌丛区等4个区域。     

一步法RT-PCR检测东北油豆角上3种病毒

对普通菜豆中常见的3种病毒在哈尔滨市栽培的油豆角上的发生情况进行了调查,为解决油豆角病害问题,发展油豆角生产,提供有益的探索。