Sesquiterpenoids from Carpesium divaricatum and their cytotoxic activity

In the course of searching for cytotoxic terpenoids from medicinal plants in China, two new eudesmane sesquiterpenoids, 5α-hydroxy-13-methoxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (1) and 1β-hydroxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (2), along with fourteen known sesquiterpenoids were isolated from the whole plant of Carpesium divaricatum. The structures of new compounds were determined using spectroscopic methods, including IR, HRESIMS, and 1D and 2D NMR spectroscopy. The cytotoxicity of selected sesquiterpene lactones against human oral epidermoid carcinoma (KB), human breast cancer (MCF-7) and human hepatoma (HepG-2) cells was also evaluated by MTT method.     

基于光释光测年法的三江源地区高山草甸土形成年代与成因研究

[目的]分析三江源区高山草甸土壤的年代及发生发育过程,为维系该区土壤安全和生态安全提供指导.[方法]采用粗颗粒石英与钾长石光释光(OSL)测年法,对三江源区4个高山草甸土剖面夏琼(XQ)、歇武(XW)、桐勒栋(TLD)、斗地村(DDC)土壤的形成发育时间进行研究,结合土壤粒度、元素地球化学特征分析该区土壤形成过程.[结...     

莆田黑猪猪耳皮肤成纤维细胞系的建立

为获得可用于体细胞核移植中需要的供核细胞,利用组织块法培养莆田黑猪猪耳皮肤成纤维细胞,并对莆田黑猪猪耳皮肤成纤维细胞进行传代及冷冻.通过试验,获得能在体外正常传代培养的细胞系,为莆田黑猪克隆研究提供供核细胞来源.     

Establishment and Management of Fine Clones Cutting Orchard of Camellia oleifera

近年来,油茶产业迅速升温,良种苗木的缺乏制约了油茶产业的发展,其中良种壮苗和适地适树适种源,特别是良种采穗圃建设与管理是关键因素.文章综述了油茶优良无性系采穗圃品种配置方法、营建、管理、采穗以及建档等.     

Characteristics of runoff and sediment generation of forest vegetation on a hill slope by use of artificial rainfall apparatus

We studied the impact of forest vegetation on soil erosion,surface runoff, and sediment generation by using field simulated rainfall apparatus. We measured runoff and sediment generation of five 4.5 × 2.1m runoff plots (a bare soil as a control; two Pinus tabulaeformis forestplots and two Platycladus orientalis forest with row spacing of 1 m × 1m and 1.5 m × 1.5 m, respectively) in Beijing Jiu Feng National ForestPark under three rainfall intensities (0.42, 0.83, 1.26 mm per minute).Forest vegetation significantly reduced soil erosion and sediment yield.Mean total runoff volume in the four tree stand plots was 93% of that inthe control plot, demonstrating the limited effectiveness of forest vegetation in runoff control. With increasing rainfall intensity, runoff reductionin forest plots declined from 28.32% to 2.1%. Similar trends in runoff coefficient and the relationship between runoff volume and rainfall duration was observed. Mean total sediment yield and mean sediment yield reduction rate under different treatments was 55.05% and 43.17% of those in the bare soil control plot, respectively. Rainfall intensity playedan important role in runoff and sediment generation processes, and had agreater impact on runoff than on soil erosion and sediment generation.When considering several factors in runoff and sediment transport processes, the P. tabulae form plot with row spacing at 1 × 1 m had a greater effect on soil and water conservation than did other forested plots.     

室内繁育白蛾周氏啮小蜂化蛹(前)低温保存的探讨

白蛾周氏啮小蜂群集内寄生于美国白蛾蛹中,其卵、幼虫、蛹及产卵前期均在寄主蛹内度过。在自然界中,以老熟幼虫在寄主蛹内越冬。作者经多年研究得知,在当地白蛾周氏啮小蜂发育起点温度是:6.28℃(6.28±0.60);有效积温是:365.12日度(365.12±15.56)。白蛾周氏啮小蜂化蛹(前),在6℃的低温保存下,历经30天的时间;出蜂的有效积温为436.6日度。     

湖北省古树年龄鉴定方法

古树年龄是判别古树等级的重要依据,不同鉴定方法都要求一定的应用条件。笔者在外业调查和查阅文献资料的基础上,提出了湖北省古树年龄的5种鉴定方法,并对各种鉴定方法的适用性、操作步骤和注意事项进行了分析,最后比较了各种鉴定方法的优缺点,为湖北省古树保护等级划分及保护措施提供参考依据。     

葡萄糖和不同数量氮素供给对黑土氨基糖动态的影响

通过室内培养实验探讨了葡萄糖及不同数量的NH4+施入对土壤中三种氨基糖(氨基葡萄糖、氨基半乳糖和胞壁酸)动态的影响,同时利用氨基葡萄糖和胞壁酸的比值探讨了微生物在养分固持过程中的相对贡献。结果表明,土壤氨基糖数量受到外加碳源和养分的显著影响,且其变化各有特征。胞壁酸受养分影响最为显著,可在一定程度上调节并平衡碳氮元素的供给与需求;氨基葡萄糖稳定性高于胞壁酸,但在碳源极度缺乏时也可分解;养分状况对氨基半乳糖的影响并不显著。碳源是促进土壤微生物氮素固持的关键因子,在活性碳源存在下,相对丰富的氮素供给有利于细菌的快速生长,而碳源相对充足时则有利于真菌的快速增殖。     

广东省林木种质资源现状及其保护利用策略

文章概述了林木种质资源的重要作用,着重分析了广东省林木种质资源的现状及其保护利用中存在的主要问题,并提出了保护利用的有效措施和建议。