油蒿群落不同恢复阶段的土壤水分空间异质性及植被特征

[目的]分析沙地恢复不同阶段(流动沙地、半固定沙地、固定沙地)油蒿(Artemisia ordosica)群落的土壤水分空间变异规律以及植被响应特征,为荒漠地区植被恢复提供科学依据。[方法]利用经典统计学与地统计学相结合的方法进行分析。[结果](1)从流动沙地到固定沙地的演替过程中,土壤水分逐步减少,其空间结构呈现出明显的斑块状和条带状布局特点,同时沙地土壤水分空间异质性逐步增加,土壤水分在不同恢复阶段均表现出随着土层深度的增加,空间相关性逐渐增强的特征。(2)在沙地恢复过程中,油蒿种群的植被覆盖度、生物量、密度呈现逐渐增加的趋势,而植被特征的空间变异性则趋于减弱。(3)在流动沙地和固定沙地上,油蒿种群特征与土壤水分呈现显著负相关(p0.01)。[结论]油蒿种群的植被格局在一定程度上改变了土壤水分的空间异质性与分布格局。     

沙漠水渠人工固沙区沙篙和沙拐枣灌丛的土壤水分特征对比

在古尔班通古特沙漠引水渠沿线建植5a的人工固沙区内,选择自然生长的沙蒿和沙拐枣灌丛,依据冠幅大小设置5个水平距离梯度和4个土层深度梯度.对比研究了二者的土壤水分特征.结果表明,随土层深度的增加,两种灌丛土壤含水量均呈增加趋.,中下部2层(20～40 cm和40～60 cm)土壤含水量显著(P<0.05)高于上部2层(0...     

野艾色素的研究

从野艾嫩枝叶中提制的色素,主要成分为叶绿素a和叶绿素b。野艾色素耐热性好。金属A1~(3 )和Ca~(2 )对野艾色素有不良影响,在实际生产中不能使用铝制品,不能与钙接触。低浓度的Fe~(3 )、Cu~(2 )和Zn~(2 )以及高浓度的Sn~(2 )对色素能起增色作用。     

A novel purification method of artemisinin from Artemisia annua

Treatment of uncomplicated malaria relies heavily on the sesquiterpene lactone artemisinin (ART), derived from the Chinese herb Artemisia annua. It is currently used as the first line treatment in the form of ART combination therapies in which different ART derivatives are combined with a non ART-like drug, which displays a different mechanism of action. This treatment regime is prescribed by the WHO in order to (1) effectively treat uncomplicated malaria and (2) to reduce the risk that drug resistance will develop. Considering the importance of ART in this treatment regime, various methods have been developed to increase the global production of ART. These methods include: large scale solvent extraction and purification from high yielding A. annua varieties, chemical/semi-chemical synthesis of artemisinin, and genetic engineering of unrelated organisms to produce ART in high quantities. Currently most of the commercial approaches to produce ART are based on solvent extraction and purification from the plant material. Classical extraction solvents include hexane or petroleum ether while ethanol, which is a more polar solvent, has recently been shown to be equally efficient. We developed a purification method from an ethanolic extract by using a diatomite-based purification protocol. Various volumes and ratios of solvents and diatomite were tested which resulted in ≥98% pure ART with a total recovery of around 60%. Our protocol for the isolation of ART may form a commercial scale alternative as it is both economically attractive due to the small amounts of purification materials needed and also environmentally friendlier than the methods previously described.     

Comparative chemistry and insect antifeedant action of traditional (Clevenger and Soxhlet) and supercritical extracts (CO2) of two cultivated wormwood (Artemisia absinthium L.) populations

A comparison between traditional extraction techniques (hydrodistillation and organic solvent extraction) and supercritical fluid extraction was made for two different populations and crops of Artemisia absinthium L., cultivated in the field and aeroponically. The composition of the extracts, volatile and non volatile oils, was analyzed by GC-MS and HPLC-DAD, respectively. The antifeedant and phytotoxic activity of the extracts was tested on insect pests (Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and plants (Lactuca sativa and Lolium perenne). The supercritical extracts exhibited stronger antifeedant effects than the traditional ones (up to 8 times more active) with moderate selective phytotoxic effects on L. perenne root growth (<50% inhibition).     

南艾蒿对几种田七病原菌的抑制效果试验

采用菌丝生长速率法,研究南艾蒿(Artemisia verlotorum Lamotte)乙醇提取物及其萃取物、乙酸乙酯相活性富集片段对田七(Panax notoginseng)主要病害病原菌的抑制作用。结果表明,10 mg/m L的南艾蒿乙醇提取物对田七炭疽病原胶孢炭疽菌(Colletotriehum gloeosporioides)、田七根腐病原茄镰孢(Fusarium solani)、田七黑斑病原人参链格孢(Alternaria panax)的菌丝生长抑制作用明显,最大抑制率分别为89.66%、74.42%和75.93%;萃取物中乙酸乙酯萃取物对3种病原菌抑制率最大,分别为90.41%、82.68%、71.79%;富集片段F2在10 mg/m L浓度下对3种病原菌菌丝生长抑制率均达到100%。     

不同施肥水平下青蒿氮、磷、钾养分吸收特性

通过大田试验研究不同施肥水平下青蒿氮、磷、钾的吸收、累积与分配规律。选用当地主栽青蒿品种渝青 1 号为材料,设置高肥、中肥和低肥 3 个施肥水平。于苗期、分枝初期、分枝盛期及蕾期采集植株样本,分为根、茎、 枝和叶 4 部分,测定氮、磷、钾含量,计算青蒿主要生育期植株养分吸收、累积和分配情况。结果表明：青蒿对钾肥 的需求量最多,氮肥次之,磷肥最少。高肥和中肥处理整个生育期氮在不同器官中的含量为叶>枝>根>茎。低肥处理整 个生育期氮在不同器官中的含量为叶>枝>茎>根。高肥、中肥和低肥 3 个处理整个生育期磷在不同器官中的含量均为叶 >枝>茎>根。苗期和蕾期生长阶段高肥、中肥和低肥 3 个处理钾在不同器官中的含量均为叶>枝>茎>根,分枝初期和分 枝盛期生长阶段 3 个施肥处理钾在不同器官中的含量均为枝>叶>茎>根。不同施肥处理对养分积累趋势影响不大,但可 显著影响各器官在不同生育时期的养分积累量及分配比例。养分累积吸收量在生育前期较少,生育中后期急剧增加。 养分累积量以钾最多,氮次之,磷最少。青蒿中氮磷钾的吸收、累积与分配规律在不同施肥水平下存在差异,生产中 应根据土壤肥力和产量目标,采取合理施肥措施,达到经济施肥的目的。     

北五味子藤茎的生药学研究

本文对木兰科植物五味子Schisandra chinensis(Turcz．)Baill干燥藤茎的外观性状、显微鉴别、薄层色谱等方面进行了生药学研究,为开发利用五味子藤茎提供了科学依据。     

五味子不同外植体愈伤组织的诱导

以五味子的嫩茎段、叶片、叶柄、果柄为外植体,以MS附加相同激素配比的培养基为基质,进行了诱导北五味子愈伤组织的适宜外植体及培养条件的筛选。结果表明：北五味子嫩茎段在MS＋6-BA1．0mg／L＋NAA0．2mg／L＋2,4-D0．1mg／L＋IBA0．3mg／L诱导效果较好,在附加MS＋6-BA2．0mg／L＋ZT0．1mg／L的诱导芽效果较好。     

冷蒿正种与其变种的花粉形态观察

本文以冷蒿正种(Artemisia frigida)及其变种-紫花冷蒿(Artem isia frigidavar.atropurpurea)为研究对象,采用扫描电镜(SEM),对它们的花粉形态进行了详细的观察描述,掌握了其在扫描电镜水平上的形态特征。研究结果表明:它们的花粉粒均为单粒花粉;花粉粒大小属于小型花粉;正种赤道面为椭圆形,变种赤道面为圆球形;极面为三裂圆形;萌发器官是3孔沟类型;表面纹饰为刺状-颗粒状复合纹饰。正种与变种花粉的总体形态特征基本一致;主要差异表现在细微性状方面。