氟化钠对洋葱根尖细胞有丝分裂的影响

用不同浓度的氟化钠溶液 ,分别处理洋葱根尖 ,发现在有丝分裂的细胞中 ,出现了滞后染色体、染色体桥和多极化现象。有些细胞中还出现了微核。同时 ,在实验中还观察到 ,随着溶液浓度的增加和染毒时间的延长 ,细胞增殖率下降 ,有丝分裂指数递减     

Speciation analysis of selenium enriched green onions (Allium fistulosum) by HPLC-ICP-MS

Green onions (Allium fistulosum) enriched with 10 or 100 μg mL^− 1 Se(IV) or SeMet were analyzed for total selenium and species distribution. Anion and cation exchange chromatographies were applied for the separation of selenium species with mass spectrometric detection. Two different sample preparation methods (NaOH and enzymatic) were compared from the Se extraction efficiency point of view. Total selenium concentration accumulated by the onions reached the 200 μg g^− 1 level expressed for dry weight when applying SeMet at a concentration of 100 μg mL^− 1 as the source of Se. Speciation studies revealed that both in onion bulbs and leaves the predominant form of organic selenium is Se-methyl-selenocysteine (MeSeCys). When Se(IV) was applied for Se-enrichment at a concentration level of 100 μg mL^− 1 both onion leaf and bulb contained a significant amount of inorganic selenium. An unknown compound was also detected.     

原子吸收光谱法测定苦藠中微量元素的含量

苦藠别名小野蒜是食用地下鳞茎及嫩茎叶的野生蔬菜,属药食同源的百合科多年生草本植物.有温中散结,宽胸通阳,祛湿止痢作用~([1,2]).在食疗方面有:(1)降脂作用,且性味辛温,能温阳散结,可用来治疗高胆固醇和高血脂症.(2)降低血压的奇妙作用,常食有通阳气、宽胸的效果.     

高师生实验探究洋葱中挥发性化学物质

利用实验室一般仪器,对洋葱中挥发性化学成分如含硫化合物、醇类、醛类、羧酸进行了定性检测,旨在让高师生体验探究学习,掌握探究方法,发展实验设计和探究能力。     

Facile synthesis of monodisperse silver nanoparticles by bio-template of squama inner coat of onion

This paper describes a facile sy]nthetic method for preparing monodisperse silver nanoparticles by bio-template of the squama inner coat of onion. The method is able to make silver nanoparticles with average diameters in the range of 4.6–7.9 nm with narrow size distribution. The important factors in the synthesis of monodisperse silver nanoparticles were discussed. The nanoparticles were characterized by transmission electron microscope, Powder X-ray diffraction and UV-Vis spectroscopy. A possible formation mechanism was also proposed. Because of its simple apparatus, high yield, convenient operation and mild conditions, this synthetic method will have potential application in preparing nanoparticles.     

Raman spectroscopic probing of plant material using SERS

We report surface‐enhanced Raman studies on intact plant material using onion layers as a biological target, and silver nanoaggregates and silver island films as enhancing plasmonic structures. Surface‐enhanced Raman scattering (SERS) enhancement allows the detection of strong Raman signatures of chemical constituents of the surface of the onion layer such as cellulose, proteins, and flavonols. Because of long‐time incubation, SERS sensors can access the extracellular space in the inner of the layer. The location of silver nanoparticles inside the onion layer has been monitored by the SERS images collected from chemicals present in the onion and/or reporter molecules attached to the nanoparticles. Our studies show a competitive adsorption of intrinsic bio molecules of the onion layer and reporter molecules. Different spectra from different places of the layer indicate the complex heterogeneous chemical structure of the plant material. The pH‐sensitive reporter molecule para mercapto benzoic acid attached to the nanoparticles allows us to infer pH values inside the extracellular matrix of the onion layer. Copyright © 2015 John Wiley & Sons, Ltd.     

Sequestration of Aqueous Lead(II) Using Modified and Unmodified Red Onion Skin

The efficacy of onion skins, both unmodified and chemically modified with thioglycolic acid, was investigated as alternative low-cost adsorbents for the sequestration of aqueous lead(II) ions from aqueous solution. The adsorbents were characterised using Fourier transform infrared spectroscopy and scanning electron microscopy – energy dispersive X-ray spectroscopy. Adsorption experiments were performed using batch sorption processes. The effects of contact time, pH, initial Pb(II) concentration, adsorbent dose, and temperature were investigated. Optimum sorption conditions were found at pH 4 and a 150?min equilibrium time for the modified onion skin and unmodified onion skin. The Langmuir, Freundlich, Dubinin-Radushkevich and Temkin models were used to characterize the equilibrium experimental results. The equilibrium process was best described by the Freundlich isotherm. The maximum adsorption capacities of 4.878 and 6.173?mg/g were obtained for modified and unmodified adsorbents, respectively, using the Langmuir model. Kinetic studies indicated that the sorption of Pb(II) ions followed a pseudo-second-order model. Thermodynamic parameters such as standard enthalpy change (ΔH°), entropy change (ΔS°), and free energy change (ΔG°) were evaluated from the sorption experimental measurements. The results showed that the sorption process of Pb(II) ions on unmodified and modified onion skins was feasible and exothermic under the conditions used in this study. The sorption process followed the mechanism of physisorption.     

影响洋葱表皮细胞骨架制片效果的探讨

以洋葱表皮细胞为材料,探究其经卡诺氏液固定后进行细胞骨架制片观察时,1%Triton X-100抽提非骨架蛋白的最佳时间,并研究洋葱不同表皮细胞及经不同理化因素处理的材料,经卡诺氏液固定后进行细胞骨架制片的步骤及制片效果。结果表明:经卡诺氏液固定后,1%Triton X-100抽提非骨架蛋白内表皮30min较佳,外表皮25min较佳;不同成熟度的鳞片叶细胞骨架形态及稳定性有差异;经紫外线、温度、秋水仙素处理后增加固定步骤再制片对制片观察结果基本无影响。     

特色蔬菜种子高效设施生产温控研究

试验针对西昌洋葱种子生产夏季易出现极端高温的难题,建立顶部遮阳网,在0~100%幅度内调控设施棚光通量,通过遮光进行温控。对设施棚不同部位温度与设施棚外的温度变化分析研究表明:在夏季高温时择时用遮阳网在0~100%的范围内覆盖调控光照,降温效果明显,能显著改变设施棚内的局部环境,有利洋葱种子的开花结实。     

Changes in Antioxidant Properties and Amounts of Bioactive Compounds during Simulated In Vitro Digestion of Wheat Bread Enriched with Plant Extracts

Cereal preparation can be an excellent source of substances with proven health-promoting properties. Unfortunately, some types of bread, such as white flour bread, are devoid of many valuable nutrients. Therefore, it is necessary to look for ways to increase its density and nutritional value. The aim of the study was to investigate the effect of stabilized plant extracts on the quality of bread, its antioxidant activity and polyphenol content, and to evaluate the stability of bioactive compounds and antioxidant activity during in vitro digestion. The research material was the wheat bread baked with spray dried microcapsules of hawthorn bark, soybeans and onion husks in maltodextrin or inulin carriers. The addition of plant extracts resulted in the presence of phenolic compounds in the wheat bread, and its antioxidant activity significantly increased. There was no significant difference in antioxidant activity between breads containing microcapsules with different carriers. During in vitro digestion, procyanidins and isoflavones in bread were more resistant to the digestive processes than other compounds. The antioxidant activity during simulated digestion was the highest at the stage of gastric digestion, and its value depended on the extract used and the analytical method applied.