地带性木本植物群落功能型的水热分布格局

植物功能型是对环境条件做出相似的反应和对关键生态学过程具有相似影响的植物组合.不同功能型植物对生态系统过程的作用不同,通过植物功能型的分析对揭示生态系统功能至关重要.甘肃省境内5种地带性木本植物群落(亚热带常绿落叶阔叶林、暖温带落叶阔叶林、温带针阔混交林、寒温性针叶林和荒漠旱生灌木群落)依据植物体的高度、叶片的生长对策及果实类型可划分出23种功能型.其分布格局与水热因子的相关分析表明:1)湿热的生境利于乔木、大灌木、藤木、寄生植物和常绿植物及翅果、坚果、核果、NFDA5NFDA6果、颖果类植物的发育,干冷生境利于灌木、小灌木和落叶植物以及蒴果类植物的发育.2)干果类和肉果类的成因可能与植物生长环境中水分供应状况密切相关,即潮湿的生境利于肉果类植物的发育,干旱的生境有利于干果类(如胞果)的发育.3)研究区域地带性木本植物群落物种丰富度和功能型的丰富度格局主要受制于水分梯度影响,而良好的水热组合可孕育木本植物群落最丰富的果实类型.     

捕食性昆虫螨类及蜘蛛的捕食作用

文章综述了昆虫、螨类及蜘蛛捕食作用研究的近况，重点介绍了昆虫及捕食性螨类和蜘蛛的捕食功能反应，血清学法研究捕食作用的概况，分析了ELISA法的优缺点，并总结了捕食作用的研究现状，指出了面临的问题及发展方向。     

多酚羧酸合成功能高分子材料研究(I)——没食子酸与纤维素的酯化合成及产物功能特性试验

研究了以没食子酰基为功能性基团、纤维素为分子骨架的功能高分子材料的合成。将没食子酸先用醋酐进行乙酰化保护酚羟基,后与酰氯化剂SOCl2或PCl5反应,制得三乙酰基没食子酰氯,得率分别为80%和90%;再以吡啶为催化剂与纤维素进行酯化反应制得三乙酰基没食子酰纤维素;然后脱去乙酰基制得功能高分子化合物没食子酰纤维素,酯化率为43.6%。功能特性试验表明,该产物具有吸附结合明胶和络合Fe3+能力,在稀酸、醇和热水中稳定并可再生。1g干产物可结合明胶65.5mg,解吸率约98%;可络合Fe3+76.5mg,解吸率约98%。本研究为进一步研制可用于酿造过程的能结合蛋白质和络合金属离子的新型功能高分子材料奠定了技术基础。     

The role of indigenous trees for the conservation of biocultural diversity in traditional agroforestry land use systems: The Bungoma case study: In-situ conservation of indigenous tree species

In order to precisely assess the role of agroforestry for the conservation of (agro-)biological diversity there is a need to adjust sampling methods used in plant sociology. This study is on the contribution of agroforestry land use to the in-situ conservation of indigenous trees within a typical East-African smallholder farming system in Western Kenya. A modified approach to measuring species richness and abundance is presented. The selection of tree-rich structures was done according to management patterns rather than considering syntaxonomic classifications from the vegetation science point of view. This approach, which is better suited to the strongly human-influenced vegetation of agroecosystems, employs between-management unit diversity measures to help evaluate abundance and constancy of species in particular management units. The predominant off-farm vegetation patterns are riverine forests, rocky hillsides, hedgerows, wooded grassland relicts, woodlands or colline forest relicts and tree groves whereas the noticeable tree-rich on-farm management units are homegardens, homesteads, life fences, coffee- and banana-groves and annual cropping fields. 98% out of all indigenous tree species known from Bungoma, occur in off-farm lands. 53% of the indigenous tree species occur in tree rich on-farm management units while 47% of the indigenous trees are dependent on the maintenance of off-farm lands. Hedgerows embody the most promising secondary vegetation structure that shows ample potential to accommodate a wide range of indigenous perennial species outside the natural vegetation formations. The pattern of distribution of various vegetation structures, and the mixture with diverse tree-based on-farm plots are interesting features in regard to floristic and eco-diversity on a landscape level. In this respect, three areas that show different population densities and distinct agro-historical conditions were compared. In regions of particular high population density the degree of association of various functional land use forms and woodland structures – each characterised by its own floristic make-up – is comparatively high. In contrast, in regions with less population but that were settled at a later date, one encounters fewer stands of woody plants with lower numbers of species. This revised version was published online in June 2006 with corrections to the Cover Date.     

核磁共振技术在竹木材研究中的应用

核磁共振技术在竹木研究相关领域起到了重要的作用,以其它方法无法比拟的优势越来越多的应用于竹木材研究之中。文章在阅读文献的基础上,结合实验数据,阐述了核磁共振技术在研究竹木材高分子组成、抽提物以及胶粘剂化学结构方面的应用。     

Construction of cDNA Library from Populus euphratica

1 Introduction Populus euphratica is a salt tolerant tree species, which is mainly distributed in the desert regions in northwest China (Wei 1993). Moreover, it is the only large tree species, which can survive and develop into forest in these arid and saline-alkali areas. P. euphratica forest plays a very important role in restraining the expansion of desert, maintaining ecological environment in west China, protecting the biological diversity and raising the local people抯 living standard…     

杨木和杉木木材表面性质的研究

以人工林杨木和杉木木材为研究对象 ,对其表面自由能、表面极性和表面化学官能团等木材表面特征因子进行测定 ,并探讨不同温度处理条件下木材表面特性的变化机理。研究结果表明 :杉木比杨木有较高的总表面自由能 (42 35mN·m- 1 对 38 93mN·m- 1 )和非极性表面自由能 (41 6 1mN·m- 1 对 35 5 2mN·m- 1 ) ,而杨木的极性表面自由能比杉木要高 (3 4 1mN·m- 1 对 0 74mN·m- 1 )。杨木和杉木木材经过不同温度处理后 ,其总表面自由能和非极性表面自由能都随着处理温度的升高而下降 ,而极性自由能则有不同程度的升高。产生此种现象的原因主要为木材表面羟基缔合状态的解除及表面脱羟基作用的综合结果。木材表面 3种主要化学官能团为羟基、烷基和缩醛基 ,在高温处理条件下 ,两种木材羟基对烷基和缩醛基吸收峰面积之比都有所下降 ,说明高温处理过程是一个使木材表面羟基密度减少的过程。木材表面自由能与木材表面化学官能团变化有明显的相关性。     

分子模拟活性炭的方法及其应用进展

介绍了分子模拟和传统吸附理论的关系,综述了使用巨正则蒙特卡洛模拟和密度泛函理论方法对活性炭结构的研究,归纳了近年来分子模拟技术在作为特殊吸附剂的活性炭的理论设计、吸附性能预测和指导表面基团改性方面应用过程中的研究进展。目前对活性炭微观孔结构的分子模拟研究,多停留于理论层面的模拟研究,而缺少对微观结构和宏观性质之间关系的分析。在实际应用中结合发挥分子模拟微观层面分析的优势,是分子模拟技术在活性炭研究中的重要发展方向。     

RNA-Seq技术在瘤胃微生物研究中的应用进展

反刍动物瘤胃内多种多样的微生物组成一个复杂的微生态系统,它们在瘤胃内物质消化过程中发挥重要作用。RNA-Seq技术的出现为反刍动物瘤胃微生物的研究提供了前所未有的机遇。本文主要从新一代高通量测序技术出发,阐述RNA-Seq技术在瘤胃微生物代谢酶特性、瘤胃微生物的多样性、瘤胃微生物新功能基因方面的应用,以期为瘤胃微生物的研究提供参考。     

INTRAARTERIAL INJECTION OF IODINATED CONTRAST MEDIUM FOR CONTRAST ENHANCED COMPUTED TOMOGRAPHY OF THE EQUINE HEAD

Minimizing the volume of contrast administered for contrast‐enhanced computed tomography (CT) of the equine head is desirable for reducing costs and risks of adverse reactions, however evidence‐based studies on the effects of varying volumes on image quality are currently lacking. The objective of the current study was to determine whether low‐volume intraarterial administration of contrast medium would result in an equivalent image quality and tissue attenuation vs. high‐volume intravenous bolus administration. A prospective cross‐over experimental design was used in a sample of six horses. After anesthetic induction, the right carotid artery was exposed surgically and catheterized. Four CT scans of the cranium were performed for each horse: baseline, immediately following intraarterial contrast injection, five‐min postinjection (return to baseline) and a final scan after intravenous contrast administration. Soft tissue attenuation in predetermined regions of interest (ROI); and length, width, and height measurements of the pituitary gland were recorded at each time point. Horses were euthanized and measurements of the pituitary gland were repeated postmortem. No adverse reactions to contrast administration were observed. Intraarterial and intravenous administration of contrast medium resulted in significantly greater soft tissue enhancement of some brain ROI's and the pituitary gland vs. baseline values. Pituitary gland measurements made on postcontrast CT images did not differ from those obtained during postmortem examination. Findings indicated that low‐dose intraarterial administration of contrast material in the equine head resulted in comparable soft tissue enhancement vs. high volume intravenous administration.