Comparison of the distribution of mineral nutrients and active substances in dehydration- and salinity-stressed Aloe vera L.

Changes in growth and distribution of inorganic mineral elements and organic active substances in seedlings of A. vera were examined under treatments of ?0.44 and ?0.88 MPa polyethylene glycol 6000 (PEG) and corresponding isosmotic sodium chloride (NaCl). All stress treatments inhibited plant growth, with NaCl severely inhibiting the growth of the seedlings than PEG. However, leaf biomass did not change significantly. The nitrogen concentration under PEG was maintained higher than that under NaCl. Salinity caused more severe ionic imbalance than dehydration. However, when the concentration of NaCl was increased, ion homeostasis was maintained. Stressors induced an increase in aloin concentration in leaves, especially in young leaves. Polysaccharide concentrations in leaves did not change under dehydration. However, the polysaccharide concentration decreased in the middle and base leaves under NaCl. A. vera exhibited high adaptability to suitable osmotic stress, which increases its main active ingredients in leaves.     

Tick control methods used by resource-limited farmers and the effect of ticks on cattle in rural areas of the Eastern Cape Province,South Africa

A survey to document tick control methods used by resource-limited farmers in the control of cattle ticks in the Eastern Cape Province of South Africa was conducted by interviewing 59 cattle farmers using structured questionnaires and general conversation. Information collected was on external parasites of cattle, their effects and their control methods. Ticks were reported to be a major problem causing diseases like anaplasmosis (89.8%), babesiosis (55.9%) and ehrlichiosis (16.9%), as well as wounds that predispose to screwworm infestation, tick worry and teat damage to cows troubling farmers in their farming enterprises. The main tick control methods were; acaricides provided by government, however 94.9% of the farmers interviewed were of the opinion that the dip wash is not effective in killing the ticks. As a result, farmers complement the government dipping service with their own initiatives like spraying with conventional acaricides (22%), household disinfectants such as Jeyes fluid (18.6%), used engine oil (10.2%), chickens (5.1%), manual removal (5.1%), and pouricides (1.7%). In addition, some farmers also use plants (6.8%), mainly the leaf of Aloe ferox and the bark of Ptaeroxylon obliquum. The study revealed ticks to be a major problem in the study area.     

芦荟汁对废电池胁迫下小麦种子萌发及幼苗生长发育的影响

[目的]研究芦荟汁对废电池胁迫下小麦种子萌发及幼苗生长发育的影响。[方法]采用不同浓度的芦荟汁分别对废电池胁迫下的小麦种子及幼苗进行处理,观察其对小麦种子萌发及幼苗生长发育的影响。[结果]与对照组相比,废电池浸出液处理下,小麦幼苗的根长、芽长、根数减少,根系活力、种子发芽率、发芽势明显降低。芦荟汁处理能够明显增强废电池胁迫下小麦根系的活力,改善多项指标。[结论]废电池浸出液对小麦种子的萌发和幼苗的生长发育有抑制和毒害作用,适宜浓度的芦荟汁能够缓解废电池对小麦种子萌发及幼苗生长发育所造成的抑制和毒害作用。     

Characterization of phosphate solubilizing fluorescent pseudomonads from the rhizosphere of Aloe vera (L.)

Soil phosphorous (P) deficiency is a major constraint to plant production which is overcome by adding inorganic-phosphate as chemical fertilizers. Fluorescent pseudomonads are the diverse group of bacteria able to mobilize sparingly soluble phosphate form. Total three hundred seven fluorescent Pseudomonas isolates were obtained from the Aloe barbadensis (Miller) rhizosphere. These Pseudomonas strains were further evaluated in vitro for their ability to solubilize phosphate and to produce indole acetic acid (IAA), hydrogen cyanide (HCN), siderophore and 1-aminocyclopropane 1- carboxylate (ACC) deaminase. Fifty three (36.8%) isolates produced IAA and 52 (36.1%) isolates produced siderophores whereas 36 (25.0%) and 31 (21.5%) isolates produced HCN and ACC deaminase, respectively. A positive correlation existed between siderophore and ACC deaminase producers. Cluster analysis showed rhizosphere as the major factor influencing the ecological distribution and physiological characterization of phosphate solubilizing bacteria (PSB). Based on partial 16S rRNA gene sequencing PSB were identified as Pseudomonas putida, Pseudomonas sp. and Pseudomonas plecoglossicida with highest phosphate solubilization ability. In conclusion, these phosphate solubilizing fluorescent pseudomonads would help in understanding their role in phosphorus solubilization and identification of potent phosphorus solubilizers from the rhizosphere of commercially grown A. barbadensis.     

超声波辅助萃取芦荟中蒽醌类化合物工艺研究

[目的]研究影响超声波辅助提取芦荟中蒽醌类化合物的主要因素,并确定其最佳提取条件。[方法]在单因素试验研究不同乙醇浓度、料液比、超声波功率和硫酸水解时间对芦荟中蒽醌类化合物提取率影响的基础上,设计正交试验优化芦荟中蒽醌类化合物超声波提取工艺。[结果]超声波辅助萃取芦荟中蒽醌类化合物的最佳工艺条件为：乙醇浓度70%,料液比1∶25,超声波功率300W,硫酸水解时间40min,在此工艺条件下,提取率可达6.41mg/g。[结论]超声波技术应用于芦荟中蒽醌类化合物的提取能够节省时间,提高提取效率。     

遮荫对3种芦荟蒽醌类物质的影响

采用高效液相色谱技术,研究遮荫对中华芦荟、库拉索芦荟和木立芦荟叶片中主要有效成分蒽醌类物质的影响。结果显示:遮荫处理导致库拉索芦荟和木立芦荟中总蒽醌、芦荟素和芦荟大黄素含量明显降低,中华芦荟中这些物质的含量却显著增加;库拉索芦荟和木立芦荟中蒽醌类物质种类减少,中华芦荟中物质种类增加。结果说明,遮荫处理,不利于库拉索芦荟和木立芦荟中蒽醌类物质的积累,但能刺激中华芦荟中芦荟素等蒽醌类物质的合成。     

芦荟中蒽醌化合物的提取和检测及药用价值研究进展

综述了芦荟中蒽醌化合物的提取、检测及药用价值研究进展,重点介绍了芦荟中蒽醌化合物的提取方法。     

大孔树脂精制芦荟叶黄酮的研究

研究了大孔树脂对芦荟叶干粉中黄酮的最佳精制工艺。在相同条件下对五种不同的大孔树脂静态吸附率和解吸率的进行测定,优选出树脂,并研究了优选树脂在不同条件下对芦荟叶干粉中黄酮的静态、动态吸附与解吸特性,确定了树脂精制芦荟叶干粉中黄酮的最佳工艺。结果表明:芦荟叶干粉黄酮精制优选大孔树脂为H1020,在室温下,吸附液pH为3.0,静态吸附能力最强,解吸剂以体积分数φ(乙醇)=80%的效果最好;动态吸附以芦荟黄酮粗提物溶液的质量浓度为12mg/mL吸附效果最好,解吸以体积分数φ(乙醇)=80%,流速为2.0mL/min洗脱效果最好。     

芦荟黄酮在聚酰胺树脂上的吸附特性

采用聚酰胺树脂分离纯化芦荟叶粗黄酮,通过对聚酰胺树脂静态吸附性能及不同条件下动态吸附与解吸特性的研究确定聚酰胺树脂对芦荟叶粗黄酮的优化精制工艺。结果表明,聚酰胺树脂精制芦荟叶黄酮的优化工艺条件为:室温下柱流速为2.0 mL/min,芦荟粗黄酮溶液质量浓度为12 mg/mL时,聚酰胺树脂吸附能力最强,用体积分数为60%的乙醇溶液洗脱时效果最好。     

芦荟原生质体融合的研究

以芦荟叶片为试材,采用酶解方法进行原生质体分离,并在此基础上对斑纹芦荟和不夜城芦荟进行原生质体融合。结果表明,以芦荟的叶肉细胞为试材,可成功分离出原生质体,而且活力较高,达90%以上。聚乙二醇（PEG）融合的结果可获得部分融合体。芦荟原生质体的成功分离主要取决于材料的来源、酶液的组成,另外还受酶解液的渗透压、温度和pH值等影响。融合的效率主要受融合剂的浓度、原生质体的生理状态及处理的时间等影响。