Determination of potassium, calcium and chlorine in some vegetables by EDXRF

Total concentration of potassium, calcium and chlorine was determined in the presence of each other and irrespective of the nature of their compounds, in the leaves of Urticae dioico L. and Spinacia oleracea L. (spinach) plants by EDXRF. The enhancement of potassium K X-rays due to calcium K X-rays and enhancement of chlorine K X-rays due to potassium and calcium K X-rays present in the samples were avoided by selective secondary excitation method of the samples. Our results were compared with other experimental results.     

X‐ray absorption spectroscopy at the Ni?K edge in Stackhousia tryonii Bailey hyperaccumulator

Young plants of Stackhousia tryonii Bailey were exposed to 34 mM Ni kg^?1 in the form of NiSO₄· 6H₂O solution and grown under controlled glasshouse conditions for a period of 20 days. Fresh leaf, stem and root samples were analysed in vivo by micro x‐ray absorption spectroscopy (XAS) at the Ni? K edge. Both x‐ray absorption near edge structure and extended x‐ray absorption fine structure spectra were analysed, and the resulting spectra were compared with spectra obtained from nine biologically important Ni‐containing model compounds. The results revealed that the majority of leaf, stem and root Ni in the hyperaccumulator was chelated by citrate. Our results also suggest that in leaves Ni is complexed by phosphate and histidine, and in stems and roots, phytate and histidine. The XAS results provide an important physiological insight into transport, detoxification and storage of Ni in S. tryonii plants. Copyright © 2008 John Wiley & Sons, Ltd.     

15N Photo-CIDNP MAS NMR To Reveal Functional Heterogeneity in Electron Donor of Different Plant Organisms

In plants and cyanobacteria, two light-driven electron pumps, photosystems I and II (PSI, PSII), facilitate electron transfer from water to carbon dioxide with quantum efficiency close to unity. While similar in structure and function, the reaction centers of PSI and PSII operate at widely different potentials with PSI being the strongest reducing agent known in living nature. Photochemically induced dynamic nuclear polarization (photo-CIDNP) in magic-angle spinning (MAS) nuclear magnetic resonance (NMR) measurements provides direct excess to the heart of large photosynthetic complexes (A. Diller, Alia, E. Roy, P. Gast, H.J. van Gorkom, J. Zaanen, H.J.M. de Groot, C. Glaubitz, J. Matysik, Photosynth. Res. 84, 303–308, 2005; Alia, E. Roy, P. Gast, H.J. van Gorkom, H.J.M. de Groot, G. Jeschke, J. Matysik, J. Am. Chem. Soc. 126, 12819–12826, 2004). By combining the dramatic signal increase obtained from the solid-state photo-CIDNP effect with ¹⁵N isotope labeling of PSI, we were able to map the electron spin density in the active cofactors of PSI and study primary charge separation at atomic level. We compare data obtained from two different PSI proteins, one from spinach (Spinacia oleracea) and other from the aquatic plant duckweed (Spirodella oligorrhiza). Results demonstrate a large flexibility of the PSI in terms of its electronic architecture while their electronic ground states are strictly conserved.     

Chromium localization in plant tissues of Lycopersicum esculentum Mill using ICP-MS and ion microscopy (SIMS)

High-resolution imaging secondary ion mass spectrometry (HRI-SIMS) in combination with inductively coupled plasma mass spectrometry (ICP-MS) were utilised to determine specific sites of chromium concentration in tomato plant tissues (roots, stems and leaves). The tissues were obtained from plants grown for 2 months in hydroponic conditions with Cr added in a form chromium salt (CrCl₃·6H₂O) to concentrations of 25 and 50 mg/L. The chemical fixation procedure used permit to localize only insoluble or strongly bound Cr components in tomato plant tissue. In this work no quantitative SIMS analysis was made. HRI-SIMS analysis revealed that the transport of chromium is restricted to the vascular system of roots, stems and leaves. No Cr was detected in epidermis, palisade parenchyma and spongy parenchyma cells of the leaves. The SIMS-300 spectra obtained from the tissues confirm the HRI-SIMS observations. The roots, and especially walls of xylem vessels, were determined as the principal site of chromium accumulation in tomato plants.     

Computational Analysis of Chlorophyll Structure and UV-Vis Spectra: A Student Research Project on the Spectroscopy of Natural Complexes

Chlorophyll was extracted from fresh spinach leaves (Spinacia L.) and its absorption spectrum was recorded. Computational methods were used to optimize the geometry and energy of chlorophyll as well as to compute UV-Vis spectra of chlorophylls a and b and to compare them with the spectrum of chlorophyll extract. Chlorophyll bands are well predicted, especially with B3LYP/CIS and TD-B3LYP methods. This research project forms a modern approach to the process of spectroscopy teaching—students can apply quantum-mechanics calculations for understanding of reaction mechanisms with the involvement of biologically active compounds and learn to interpret the absorption spectra of chlorophyll extract obtained by themselves.     

药用植物川东獐牙菜红外光谱分析与鉴别

采用傅里叶变换红外光谱法(Fourier transform infrared spectroscopy,FTIR)、偏最小二乘判别分析(partial least square discriminant analysis,PLS-DA)和系统聚类分析(hierarchical cluster analysis,HCA)快速鉴别不同产地川东獐牙菜(Swertia davidi Franch)。采集4个不同地区70株样品不同部位的红外光谱数据,原始光谱数据经预处理(自动基线校正,自动平滑,一阶求导,二阶求导)后导入OMNIC 8.2,比较吸收峰的差异;用SIMCA-Pa+10.0进行偏最小二乘判别分析(PLS-DA),以前三个主成分三维得分图比较产地鉴别效果;红外光谱数据导入SPSS 19.0,进行系统聚类分析(HCA),通过树状图比较不同部位分类效果。结果显示,(1)不同产地根的光谱图在1 739,1 647,1 614,1 503,1 271,1 243,1 072cm~(-1)附近的吸收峰有差异,不同产地茎的光谱图在1 503,1 270,1 246cm~(-1)吸收峰附近有差异;(2)相同产地不同部位的光谱特征峰有差异;(3)PLS-DA分析结果显示自动基线校正+自动平滑+二阶求导这种预处理方式分类效果最好,根的红外光谱数据产地鉴别效果最佳;(4)HCA的树状图,显示根的聚类分析结果正确率83%,茎的聚类分析结果正确率49%,叶的聚类分析结果正确率70%。FTIR技术结合PLS-DA与HCA方法能够快速准确地鉴别不同产地川东獐牙菜,不同部位产地鉴别效果有差异,根的光谱数据产地鉴别效果最佳,二阶求导处理增强了样品的特异性,使PLS-DA的三维主成分得分图分类效果更明显。     

Spectroscopic properties of spinacine – an active component of ginseng (Panax ginseng) and spinach (Spinacia oleracea)

ABSTRACT

The molecular structures and vibrational properties of spinacine in its monomeric and dimeric forms are analyzed and compared to the experimental results derived from the infrared and Raman studies. The theoretical data are discussed on the basis of density functional theory quantum chemical calculations using the Lee–Yang–Parr correlation functional. The characteristic vibrations of the imidazopyridine double-ring systems in spinacine containing compounds were identified and characterized. The sequence of bands corresponding to spinacine contains the infrared or Raman lines observed at about 1612, 1307, 1250, 730, and 530?cm^?1. The occurrence of these bands in the spectra of a plant, its extracts or pharmaceuticals confirms the presence of the imidazopyridine skeleton in these substances. The analyses of extracts of ginseng roots and spinach leaves were performed using infrared spectroscopy. The wavenumbers and integral intensities of the observed bands were used to identify components of the phenylpropanoid pathway in the extracts and to prove the presence of spinacine in these natural products. The spectra of other compounds containing the imidazopyridine unit have been analyzed.     

Application of Infrared Photoacoustic Spectroscopy in Soil Analysis

Abstract

Soil analysis has become routine work for soil management and crop production. However, laboratory analysis–based determination of soil properties is expensive and time consuming, which is not suitable for precision agriculture. Infrared spectroscopy (IR) appears as an alternative and fast technique to measure soil properties and has had wide application; in particular, a new method called infrared photoacoustic spectroscopy (FTIR-PAS) has been applied in soil analysis. The soil infrared photoacoustic spectrum is more convenient to record; the spectra contain more useful information versus conventional reflectance spectroscopy, and it appears promising for identification of soil types and measure soil properties. The step-scan function of FTIR-PAS makes it possible to explore the soil microstructure in situ; furthermore, more sensible photoacoustic cells (PA), such as a quartz-enhanced PA cell, will make FTIR-PAS a strong tool for the study of soil science. The application of infrared photoacoutic spectroscopy in soil analysis is largely dependent on spectra pretreatment and chemometrics methods due to strong interferences, and more mathematical tools models will benefit or optimize the prediction performance. To make full use of soil infrared spectra, soil spectra library construction is required in the future, which will play an important role in the application of soil analysis.     

Distribution and Utilization of 15N in Cowpeas Injected into the Stem Under Influence of Water Deficit

Abstract

Investigations were carried out on Vigna unguiculata L. Walp. to estimate the distribution and utilization of ¹⁵N in different organs after stem injection during vegetative, flowering and pod filling stage. During flowering effects of water deficit were also examined. In well watered plants, within 4 days after injection, 65% of ¹⁵N accumulated in leaves. This was drastically reduced to 42% by water deficit. ¹⁵N accumulation in stems increased under water deficit. The translocation of ¹⁵N from the stem base to roots were not altered by water deficit. During pod filling 62% of recovered ¹⁵N in the plants had accumulated in seeds, 24% in leaves and 11% in stems within 4 days, whereas the uptake of nitrogen in pod walls and roots remained low (2%). These results demonstrate that the method of injecting very small quantities (1 mg/plant) of ¹⁵N into the stem base allows an exact and detailed quantitative assessment of N translocation/distribution with regard to different organs, different growth stages and different treatments.     

Reference spectra of important adsorbed organic and inorganic phosphate binding forms for soil P speciation using synchrotron‐based K‐edge XANES spectroscopy

Direct speciation of soil phosphorus (P) by linear combination fitting (LCF) of P K‐edge XANES spectra requires a standard set of spectra representing all major P species supposed to be present in the investigated soil. Here, available spectra of free‐ and cation‐bound inositol hexakisphosphate (IHP), representing organic P, and of Fe, Al and Ca phosphate minerals are supplemented with spectra of adsorbed P binding forms. First, various soil constituents assumed to be potentially relevant for P sorption were compared with respect to their retention efficiency for orthophosphate and IHP at P levels typical for soils. Then, P K‐edge XANES spectra for orthophosphate and IHP retained by the most relevant constituents were acquired. The spectra were compared with each other as well as with spectra of Ca, Al or Fe orthophosphate and IHP precipitates. Orthophosphate and IHP were retained particularly efficiently by ferrihydrite, boehmite, Al‐saturated montmorillonite and Al‐saturated soil organic matter (SOM), but far less efficiently by hematite, Ca‐saturated montmorillonite and Ca‐saturated SOM. P retention by dolomite was negligible. Calcite retained a large portion of the applied IHP, but no orthophosphate. The respective P K‐edge XANES spectra of orthophosphate and IHP adsorbed to ferrihydrite, boehmite, Al‐saturated montmorillonite and Al‐saturated SOM differ from each other. They also are different from the spectra of amorphous FePO₄, amorphous or crystalline AlPO₄, Ca phosphates and free IHP. Inclusion of reference spectra of orthophosphate as well as IHP adsorbed to P‐retaining soil minerals in addition to spectra of free or cation‐bound IHP, AlPO₄, FePO₄ and Ca phosphate minerals in linear combination fitting exercises results in improved fit quality and a more realistic soil P speciation. A standard set of P K‐edge XANES spectra of the most relevant adsorbed P binding forms in soils is presented.     

基于近红外光谱的设施栽培水果黄瓜磷元素亏缺初期快速诊断

磷元素(P)亏缺初期,水果黄瓜植株根部叶片出现小斑点,其症状的外观特征与健康植株根部叶片老化初期类似,难以用肉眼或者计算机图像处理技术识别。本文根据近红外光谱能够反映叶片组织中有机物组分的差异,运用近红外光谱技术对水果黄瓜植株磷元素亏缺进行了快速诊断研究。精确控制营养液中磷元素含量,通过设施栽培方式培养缺磷植株和对照样本。近红外光谱仪采集了90片叶子的原始光谱(60片作为训练集,30片作为预测集),经光谱预处理和窗口宽度优化后均匀划分为27个子区间,分别提取每个子区间的10个主成分数据作为BP人工神经网络(BP-ANN)的输入变量,以叶片缺素情况作为输出变量,建立3层BP-ANN诊断模型。当主成分因子数为3时,第7个子区间对应的模型效果最佳,模型对缺磷叶片和正常叶片的预测准确率均达到100%。研究表明:近红外光谱技术结合BP-ANN快速诊断水果黄瓜磷元素亏缺是可行的。     

δ18O characteristics of lichens and their effects on evaporative processes of the subjacent soil

The study presents first data on the δ¹⁸O performance of poikilohydrous lichen ground cover, and its potential impact on the isotopic composition of water fluxes arising from subjacent soil layers. As a model organism, the globally distributed lichen Cladina arbuscula was studied under laboratory conditions as well as in the field. During a desiccation experiment, δ¹⁸O of the lichen's thallus water and of its respired CO₂ became enriched by ～7‰ and followed a similar enrichment pattern to that expected from homoiohydrous, vascular plants. However, the observed degree of enrichment was lower in comparison to vascular plants due to (i) the lichen's inherent lower evaporative resistances; and (ii) a stronger effect of the more depleted surrounding water vapour. In lichens growing in their natural habitat, this specific pattern may show substantial variations depending on prevailing microclimatic conditions. Within a field study, thallus water δ¹⁸O of lichens principally proved to become more depleted when close to equilibration with the surroundings. It thereby strongly depended on the absorption of surrounding water vapour. Moreover, the results indicate that lichen mats substantially reduce evaporation rates arising from subjacent soil layers, and may alter the isotopic signal of vapour diffusing away from these layers into more depleted values.     

An attempt to analyze the bark disease in Havea brasiliensis using X‐ray absorption near‐edge spectroscopy

The X‐ray absorption near‐edge spectroscopy (XANES) technique has been used to determine the chemical change of elements induced by bark diseases in Havea brasiliensis (rubber latex tree). The results show the good sensitivity of in situ XANES for characterizing the chemical structure of phosphorus, sulfur, potassium and calcium in healthy and diseased Havea brasiliensis. Important information for understanding the bark disease involved in the sulfur metabolism of plants was also obtained from XANES.     

α-SiN:H薄膜的光学声子与VO2基Mott相变场效应晶体管的红外吸收特性

从器件构成材料中α-SiN:H，VO₂，Al薄膜介电常数弥散特性的Lorentz多谐振模型出发，研究了器件在金属表面等离子体与VO₂，特别是α-SiN:H薄膜光学声子共同作用下的红外吸收特性；得到了在不同的光谱范围器件的红外吸收特性随着α-SiN: H钝化层几何厚度的变化关系，与中心工作波长10μm对应的且经过位相修正以后钝化层的几何厚度为λ/4n时的红外吸收光谱、以及VO₂的相变对吸收光谱的影响. 关键词： 红外吸收特性 Mott相变 场效应晶体管 二氧化钒     

濒危植物长序榆的FTIR分析及与土壤元素氮的相关性研究

应用傅里叶变换红外光谱(FTIR)法测定了8个样地长序榆的根、茎、皮、叶的红外光谱,并对这些红外光谱与土壤元素氮进行了相关分析。结果表明,根、茎、皮、叶的红外光谱存在一定差异,其 组织器官化学成分含量和土壤氮元素之间存在不同程度的相关关系,茎中化学成分含量和全氮都呈显著正相关(p<0.05);皮在3 365 cm-1波数时的化学成分含量和全氮呈显著正相关,根和叶的化学成分含量与全氮呈低度相关。土壤速效氮和长序榆根、茎、皮、叶的化学成分含量之间也存在一定程度的相关性,但相关性比全氮弱的多,均未达到统计学意义上的“显著水平”。说明土壤全氮 的变化对长序榆植物的化学成分具有一定的影响,速效氮的影响则相对较低。     

Vibrational spectroscopy of large water clusters of known size

The structure of large water clusters of known size distributions 〈n〉 = 20-2000 is investigated by vibrational spectroscopy of the OH stretch mode. The water clusters are predissociated by a pulsed tunable infrared optical parametrical oscillator (OPO) in the frequency range 2800-3800 cm^-1. Their fragments are detected off-axis by electron impact ionization and mass analyzed by a quadrupole mass spectrometer. The largest ion signal stems from the neutral water hexamer fragment. The ion yield is investigated at certain wavelengths while the size of the clusters is varied, and for certain sizes complete absorption spectra of the OH stretch motion are measured. Fingerprints of the different coordination types of the water molecules in the clusters are found and it turns out that our method is especially sensitive to amorphous structures with frequencies shifting in the range of 3300-3400 cm^-1.     

Semiconducting properties of CuIn5S8 single crystals II. Near infrared absorption

Near infrared absorption spectra of n-type CuIn₅S₈ single crystals were measured. Two structures were found in the spectra in the photon energy range from ?ω ? 0.3 eV?1.2 eV. One of them is the free carrier absorption below 0.6 eV in which the absorption coefficient increases as the third power of the wavelength. It was found that this absorption was associated with the multiple scattering mechanisms. Another structure seems, from its temperature and carrier-concentration dependences, to be associated with an absorption due to a transition from a lower lying conduction band to an upper one.     

白云鄂博天然钕独居石的振动光谱研究(英文)

Raman, infrared and energy dispersive X-ray spectra of monazites have been measured and discussed. The result shows that the mineral is enriched in cerium, lanthanum,neodymium and praseodymium (Ce＞La＞Nd＞Pr)， The monazites have marked spectral characteristics, especially their v1, V3 Raman bands and v1, v4 infrared absorption bands. The characteristics can distinguish between monazite and other phosphate minerals. In addition, based on EDS and infrared absorption spectra, a small amount of fluoro-carbonate is found in the monazites.     

Valence and conduction bands in MPS3 layered compounds studied by synchrotron radiation

Summary With the resonant photomeission technique we investigated the valence bands of FePS₃ and NiPS₃. The experimental results, support the ionic picture of the compounds and our previous identification of the valence band structures. The structures rapidly varying in intensity when the excitation energy is scanned across the Fe and NiM _2,3 absorption edge are associated to the transition metal 3d states; the nonresonating features are ascribed to the (P₂P₆)⁴⁻ cluster states. With the yield technique we measured the high-resolution absorption spectra of the phosphorus and sulphur inner-core levels in Mn, Fe and Ni thiophosphates. TheL _2,3(P) andL _2,3(S) spectra are similar to each other in all the compounds and are interpreted in terms of the projected density of states of the conduction bands derived from the (P₂S₆)⁴⁻ cluster states. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.