紫外分光光度法测定胆膏及其制剂中猪胆汁酸的含量

本文用薄层层析法和紫外扫描法,鉴定出猪胆膏及其制剂—复方胆汁注射液中的胆汁酸是结合态猪胆汁酸。且经硫酸脱水后,猪胆汁酸产生共轭双键,在385±1nm有特征吸收,可用紫外分光光度法测定其含量。该法准确可靠,简便快速,可作为质量控制的常规分析方法。     

HPTLC法测定芹菜提取物中芹菜素的含量

本研究建立了测定芹菜素的高效薄层色谱(HPTLC)法。采用CAMAG全自动薄层色谱仪,高效硅胶G60薄层板,展开剂为氯仿-甲醇-水(18∶2.3∶0.35),测定波长为345nm,测定了芹菜提取物中芹菜素含量,在0.116~0.696μg/ml范围内呈良好的线性关系(R2>0.99)。该方法简单、快速,分离度好,灵敏度高,适用于芹菜提取物中芹菜素的测定。     

红壤稻田土壤溶解有机碳含量动态及其生物降解特征

本通过田间采样分析和室内培育试验,研究了不同利用年限的3种红壤水田土壤中溶解有机C(DOC)的含量动态和生物降解特征。结果表明：土壤DOC的含量随土壤深度而降低,二具有显负相关性。0-30cm土壤DOC的含量及其占总C比例随土壤有机C含量的升高而增大。DOC的季节变化明显,主要与气候因素有关：降雨和灌水可显提高DOC的含量,是落干时含量的1．44-2．50倍。淋溶试验结果表明,从试验开始,淋滤液中DOC的浓度呈增加趋势,至2l天时达到最大,其后又趋下降。在49天的培养期内,DOC的分解速率为3l％-58％,其中低分子量组分能在数天内降解掉。不同土壤间DOC的分解速率有明显差异。     

LOCAL PERCEPTIONS OF WOODY VEGETATION DYNAMICS IN THE CONTEXT OF A ‘GREENING SAHEL’: A CASE STUDY FROM BURKINA FASO

After decades of drought in the Sahel, several studies have reported a ‘(re)greening’ of the area. However, most of these studies were based on large scale climatological or remotely sensed observations, with little or no ground truthing. The aim of this study was to assess the local perceptions of the distribution of socio‐economically important tree species in the Sub‐Sahel of Burkina Faso. Semi‐structured interviews were performed with 87 groups of informants from 20 villages belonging to three ethnic groups (Mossi, Fulani and Samo). Univariate and multivariate statistics were used to compare perceptions between the targeted ethnic groups. According to the locals, more than 80 per cent of the 90 listed species were declining, with over 40 per cent identified as threatened, including numerous plants of great economic value. Increasing species were mostly drought‐tolerant plants such as Balanites aegyptiaca. A few species were listed as locally extinct. Gender and age did not significantly affect local knowledge, whereas ethnicity did. The major causes of species decline were identified to be drought, deforestation and bushfires. In all ethnic groups, informants observed a southward shift in species distribution. Local perceptions suggest a general decline in woody vegetation. Thus, the alleged (re)greening in the Sahel might not have reversed the degradation of woody species in the area. Data derived from local ecological knowledge were consistent with that of many ecological studies, suggesting the reliability of people's knowledge for obtaining ecological data. Information from this study can be used as baseline for conservation of species identified as threatened. Copyright © 2011 John Wiley & Sons, Ltd.     

EFFECT OF PROTECTION ON PLANT COMMUNITY DYNAMICS IN THE MEDITERRANEAN ARID ZONE OF SOUTHERN TUNISIA: A CASE STUDY FROM BOU HEDMA NATIONAL PARK

Ecosystems protected from heavy grazing impacts, such as national parks and refuges, are generally considered to sustain higher plant species diversity and better ecosystem composition and structure compared to heavily grazed areas. To evaluate the impact of livestock grazing, we sampled vegetation characteristics from two areas having different grazing intensity levels. The first site has high protection from grazing and is located inside the Bou Hedma National Park in Southern Tunisia. The second site has a low protection from grazing and is situated within an open area located immediately outside the park boundary where human populations and their livestock have unrestricted access to ecosystem resources. Total plant cover, density, perennial species cover and their contribution were compared between the two grazing level sites. Results show that considerable positive effects occur in the areas protected from grazing. As compared to the overgrazed (open) sites. Several species known for their high palatability, such as Cenchrus ciliaris L., Salvia aegyptiaca L., Echiochilon fruticosum Desf. and Helianthemum sessiliflorum Desf., are more abundant inside the park than outside. These results are very important for managers to apply this technique as a tool for increasing the resilience of arid ecosystems, qualified very vulnerable to climate change. Copyright © 2011 John Wiley & Sons, Ltd.     

DIVERSITY AND DYNAMICS OF MANAGEMENT OF GUM AND RESIN RESOURCES IN ETHIOPIA: A TRADE‐OFF BETWEEN DOMESTICATION AND DEGRADATION

Although the human domestication of forest and tree resources is often considered to result in resource degradation, it may also lead to improved resource potentials. This paper assesses the nature and dynamics of gum and resin focused woodland exploitation and management systems in Ethiopia in the context of degradation and domestication processes. In three sites with commercial gum resin producing woodlands and production history, we studied variation in (i) woodland management and gum resin production systems and (ii) socio‐economic and biophysical factors that condition the management and production systems. On the basis of their organizational features, we formulated nine production models and related them to different phases of domestication and different degrees of ecosystem degradation. The production systems gradually evolved from the extraction of wild trees to production in an adapted forest system. However, domesticated woodlands with an adapted forest structure and composition and increased provisioning services are still little developed despite decades of production history. Many of these woodlands are undergoing serious degradation because of low quality management practices. This is mainly attributable to existing land use practices and the social arrangements for the production of and trade in the gums and resins. The findings illustrate that domestication involves not only a change in ecological and production systems but also the development of social arrangements for production and trade. We conclude that the status of domestication in a social sense determines whether forests and/or specific forest resources are degraded or aggraded in the sense of resource enrichment. Copyright © 2011 John Wiley & Sons, Ltd.     

SOIL LOSS FROM EROSION IN THE NEXT 50 YEARS IN KARST REGIONS OF MAYABEQUE PROVINCE,CUBA

To date, neither the method nor diagnostic indices employed in Cuba to evaluate erosion of Red Ferralitic or Ferrasol Rhodic soil in karstic regions has taken into consideration morphogenesis in such geo‐ecosystems or their relationship with erosion, which has led to sequential degradation of the most productive soils in Cuba. We explore the case for considering A + B horizon depth as one of the basic indices for evaluating the severity of erosion. There is no methodology available for estimating the volume of soil lost through karstic absorption forms (dolines). This article forecasts loss of soil cover using a model which estimates losses of 268·52 to 450·52 mm y⁻¹ for future scenarios (periods of 25 and 50 years). A mean loss rate of 1·07 mm y⁻¹ was found in areas cultivated as pastureland during the period from 1986 to 2009, which exceeds the tolerance thresholds proposed by the Universal Soil Loss Equation and the soil formation rates estimated for limestone in Cuba and it is likely there is with a marked tendency for this to increase. These results should be interpreted as a first estimate for setting loss tolerances as there is no similar experience with own data for a more precise definition of the erosion of soil in karstic regions. Copyright © 2012 John Wiley & Sons, Ltd.     

Growth regulators for cereal and oil crops on the basis of 2,3‐dichloroisobutyric acid and chlormequat chloride and residue analyses of both agents in the grain of oat

Field plot experiments were established for studying the influence of growth regulators MLU 208, MLU 2081 [various mixtures of 2,3‐dichloroisobutyric acid (DCiB) with chlormequat chloride (CCC)] and CCC on length of shoot axis, susceptibility to lodging and grain yield of oat (Avena sativa L.) and oil seed rape (Brassica napus L.). Apart from this, oat grains were analysed for residues of both agents. With the lodging‐resistant oat varieties ‘Alfred‘ and ‘Solidor‘, MLU 208 and MLU 208L caused stem reductions of 10% and yield increases up to 6.5% despite the fact that the untreated controls showed hardly any lodging. CCC, applied as comparative treatments, had no yield‐increasing effect although a stem reduction of approx. 8% was recorded. Tests with ‘Samantra‘, a variety of poor culm stability, gave culm reductions of 10%, prevented lodging and increased grain yields by 7—9.5%. Applying preparation MLU 2081 to winter oil seed rape prior to flowering shortened the stem by 8—11% and contributed to a grain yield increase of about 5—8%. In case of early (EC 31/32) and also late (EC 45) application of the preparations MLU 208 and MLU 208L detectable DCiB‐residues of about 0.1 mg·kg⁻¹ were measured consistently. CCC residues increased with increasing dosage to 0.36 mg·kg⁻¹, in case of later application up to 0.43 mg·kg⁻¹. Less CCC residues were recorded in times of high precipitation or intensive irrigation. The permitted maximum concentration of 5 mg·kg⁻¹ CCC residues in the grain were reached in no case.     

60Coγ辐照对霍山石斛悬浮培养原球茎生长和生物碱积累的影响

以霍山石斛原球茎为材料,研究5、10、20和30Gy的60Co γ辐照处理对原球茎悬浮培养生物碱积累的影响。结果表明,60Co γ辐照处理能提高悬浮培养原球茎生物碱含量,且适宜辐照剂量为10Gy。 10Gy处理的原球茎培养36d时,原球茎鲜重为26.54g/瓶,生物碱含量为0.035%,此时培养液pH和原球茎电导率变化较小,培养液环境适合原球茎继续培养;同时辐照处理可促进POD、SOD、CAT和PAL酶活性,抑制PPO酶活性,从而促进石斛原球茎生长和生物碱合成。