扫描次数对番茄叶漫反射光谱和模型精度的影响研究

近红外光谱分析技术因其诸多优点成为近年来发展最快的定量和定性分析技术之一,它是依据有机分子中的含氢基团(C—H, O—H, N—H)振动的合频与各级倍频的吸收获得信息。但是,近红外光谱易受到光谱仪的工作状态和扫描时各种参数的设置,如波长的准确性、仪器的分辨率、噪声、扫描次数、样品粒度的均匀性等的影响。为了给建立实际模型时选择最佳的测量条件提供依据,文章以番茄叶为研究对象,分析了扫描次数对番茄叶漫反射光谱和叶绿素定量模型精度的影响。结果发现扫描次数对番茄叶漫反射光谱和模型精度有较大的影响。随着扫描次数的增加,近红外光谱的均方根噪声的方差值逐渐变小。扫描次数越多,光谱的质量较高,但是仪器产生的系统误差也会增大;扫描次数越少, 光谱的质量较差,但是光谱较为光滑,系统的误差较小。在128次扫描次数下,叶绿素定量模型的决定系数较高,但是模型不稳定。当扫描次数为32时,模型的决定系数较低,但该模型比较稳定,检测时间也较短。同时,不同扫描次数下所建模型都用于预测叶绿素含量,发现没有显著差异(α＝0.05)。在采集光谱建立模型时,应考虑综合因素选择合适的扫描次数。     

Separation and identification of some common isomeric plant triterpenoids by thin-layer chromatography and high-performance liquid chromatography

Chromatographic separation of 10 triterpenoids (α-amyrin, β-amyrin, δ-amyrin, lupeol, lupenon, lupeol acetate, cycloartenol, cycloartenol acetate, ursolic acid, oleanolic acid) and 2 sterols (stigmasterol and β-sitosterol) was studied. The chromatographic techniques included silica gel and reversed-phase (C₁₈ RP) thin-layer chromatography (TLC) and C₁₈ RP high-performance liquid chromatography (HPLC) using UV and mass spectrometric (MS) detection with atmospheric pressure chemical ionization (APCI). The TLC separation of the isomeric triterpenols lupeol, α-amyrin, β-amyrin and cycloartenol was achieved for the first time using C₁₈ RP-HPTLC plates. Cycloartenol could be separated from related compounds only on C₁₈ RP-TLC but not on the C₁₈ RP-HPLC. δ-Amyrin isolated from the tomato fruit surface extract could be separated from other amyrins only by HPLC. Tandem mass spectrometry allowed discrimination between the isomers lupeol, α-amyrin, β-amyrin, δ-amyrin, cycloartenol and between lupeol acetate and cycloartenol acetate. The combination of 3 TLC methods and 2 HPLC methods enables qualitative determination of all 12 compounds and proves to be useful for the analysis of plant extracts. It is recommended that TLC screening on silica gel and C₁₈ RP be performed before HPLC analysis.     

An investigation of the structural aspects of the tomato fruit by means of quantitative nuclear magnetic resonance imaging

In this study, magnetic resonance imaging (MRI) was applied to study the structural aspects of the tomato fruit. The main study was performed on tomatoes (cv. Tradiro) using a 0.2-T electromagnet scanner. Spin-echo images were acquired to visualize the tomato macrostructure. The air bubble content in tissues was evaluated by exploiting susceptibility effects using multiple gradient echo images. The microstructure was further studied by measuring spin–spin (T₂) and spin–lattice (T₁) relaxation time distributions. Nuclear magnetic resonance relaxometry, macro vision imaging and chemical analysis were used as complementary and independent experimental methods in order to emphasize the MRI results. MRI images showed that the air bubble content varied between tissues. The presence of gas was attested by macro vision images. Quantitative imaging showed that T₂ and T₁ maps obtained by MRI reflected the structural differences between tomato tissues and made it possible to distinguish between them. The results indicated that cell size and chemical composition contribute to the relaxation mechanism.     

基于光谱技术的航天育种番茄品种鉴别方法的研究

为了实现航天育种番茄不同品种的快速光谱鉴别,采用主成分分析法对光谱数据进行聚类分析,并将小波变换用于对大量光谱数据的压缩,同时结合神经网络建立了番茄品种鉴别模型.该模型将压缩后的数据作为神经网络的输入,加速了神经网络的训练速度.通过对太空育种突变株M1和M2及其亲本番茄品种的共105个番茄叶片样本建立训练模型,并用每个品种15个样本,共45个番茄叶片的样本进行预测.结果表明,用该方法对航天育种番茄不同品种的鉴别正确率达到97.8%.说明文章提出的方法具有很好的分类和鉴别作用,为航天育种番茄不同品种的快速鉴别提供了一种新方法.     

三十烷醇在GA3 影响水稻幼苗生长和生理性状中的增效作用

微量三十烷醇(TRIA)与GA3 配合使用, 比GA3 单独使用能明显地促进幼苗生长和增加幼苗干物质 积累.同时还增强了GA3 对幼叶中叶绿素含量、可溶性蛋白质含量、呼吸速率、细胞膜透性和过氧化物酶 活性的影响.GA3 +TRIA 与GA3 处理相比, 促进幼叶内源GA3 水平提高, 稳定保持内源ZT 于一定水平, TRIA 在GA3 低浓度时降低IAA 水平, 在高浓度时则提高IAA 水平.作者认为TRIA 可作为GA3 处理时 的增效剂     

Synthesis,characterization and evaluation of biological properties of selenium nanoparticles from Solanum lycopersicum

Synthesis of nanoparticles by green synthesis has a large number of biomedical applications worldwide. In this study, Selenium Nanoparticles (SeNPs) were synthesized by using sodium salt of selenium and Solanum lycopersicum (tomato) fruit juice and seeds extract. The plant extracts were used as a reducing agent in ratio 1:4 i.e. sodium selenite salt (Na₂SeO₃). SeNPs were characterized by UV–visible spectrophotometry, FTIR and Zeta Sizer analysis. The UV-graphs indicated the highest peak of absorbance at 350 nm. Whereas, FTIR analysis of SeNPs indicated absorbance bands at 3262.35–1633.72 cm^?1. Zeta sizer analysis showed the average size of SeNPs for Fruit juice extract as 1020 d.nm. with PDI 0.432. In case of seeds extract, average size was 1155 d.nm. with PDI 0.761; and the PDI value for both extracts showed polyderse nature of these NPs. SeNPs possessed significant antimicrobial activity against selected strains of E. coli, S. aureus, M. luteus, S. enterica, B. subtilis, K. pneumoniae and P. aureginosa. The α-amylase inhibitory assay of these SeNPs indicated that they had antidiabetic role with IC₅₀ value 24.4642 µg/mL. The DPPH assay showed that SeNPs of Solanum lycopersicum have antioxidant activity with IC₅₀ value of 20.7398 µg/mL.     

光谱及分子探针方法研究番茄Metacaspase蛋白与Ca~(2+)的相互作用

Metacaspases(MCPs)是发现于植物、真菌、原生动物体内的一种结构上类似多细胞动物Caspase的半胱氨酸蛋白酶家族,其大多数成员的激活依赖于钙离子,但钙离子如何影响MCPs的激活机制有待深入研究。借助圆二色谱技术、Terbium/Stains-all探针技术以及荧光光谱技术,以番茄Ⅱ型Metacaspase(LeMCA1)重要位点突变的三种体外原核表达重组蛋白,包括LeMCA1C139A(活性催化位点突变体)、LeMCA1K223G(自降解位点突变体)以及预测的Ca2+结合位点突变体LeMCA1D116A/D117A为研究材料,探究了MCPs与Ca2+相互作用机制。实验结果表明,Ca2+与LeMCA1之间既不存在强烈的结合作用,也不影响蛋白的二级结构,但Ca2+通过相互作用改变LeMCA1的三级结构来实现对LeMCA1的酶原激活过程。其中,LeMCA1蛋白的Asp-116,Asp-117氨基酸残基作为预测的与Ca2+作用的重要位点,其缺失将导致蛋白与Ca2+相互作用能力下降。利用圆二色谱、荧光光谱结合离子探针技术研究了典型茄科植物番茄中Ca2+与LeMCA1的相互作用特性,结合之前同源序列比对、位点突变结果确定了LeMCA1中的Asp-116,Asp-117氨基酸残基影响着Ca2+与蛋白质的相互作用。该结果对后续LeMCA1的生化特性及晶体结构的解析研究有着重要的参考价值。     

ICP-AES法测定番茄酱中Ca、Cu、Fe、Zn、Mn、K、Al、Sr、P等9个元素

本文采用ＩＣＰ－ＡＥＳ法对新疆地区出口番茄酱中Ｃａ,Ｃｕ,Ｆｅ,Ｚｎ,Ｍｎ,Ｋ,Ａｌ,Ｓｒ,Ｐ等九个元素进行了同时测定,根据仪器的特点,最大限度地避开了干扰及合理地扣除了光谱背景,改变了以往原子吸收法测定时的繁琐,费时情况,本法的准确度,精密度,回收率（９２．５％￣１０４．１％）均达到满意结果。     

离子束诱变水稻多胚苗突变株的筛选及其多胚来源

以低能氮离子束为诱变源, 通过对同源四倍体水稻品系“IR36 4X”进行离子注入后在其第2代群体内筛选得到了1株具有多胚苗性状特征的突变株（IR36 双）, 对该突变株后代的多胚苗形态特征及其多胚来源进行了研究。 结果表明, 多胚苗突变株系“IR36 双”在双胚苗性状的表现形态上有其特异性, 在同一纯合株系的群体内双胚苗的苗位有非完全双苗和完全双苗两种类型。 非完全双苗包括单胚轴单胚根双苗和单胚根异胚轴双苗这两种类型; 完全双苗也可以进一步划分为正常双苗和异常双苗两种类型。 在多胚苗材料中, 单胚根单胚轴双苗所占的比例相对较大。 其多胚（额外胚）的来源主要有4种可能性, 即双套胚囊形成多胚、 多卵卵器形成多胚、 反足细胞团发育形成不定胚及胚乳细胞形成不定胚（胚乳细胞胚状体）。 由此可见, “IR36 双”植株表现双胚苗性状有其胚胎学根源。     

高效液相色谱法研究邻烯丙基苯酚在小麦植株中的向基传导和分布

采用一种快速、灵敏的高效液相色谱-二极管阵列检测器法(HPLC-DAD)研究拟银杏杀菌剂邻烯丙基苯酚在小麦幼苗中的自顶向基传导作用,并定量分析其进入小麦植株后的具体分布。HPLC-DAD检测条件为:等度流动相65%乙腈/水(0.1%醋酸),HYPERSIL BDS C18,5μm,250 mm×4.6 mm i.d色谱柱,检测波长280 nm。邻烯丙基苯酚的线性回归方程为Y=8.0266X 5.019(r=0.9999),在2~500 mg/L浓度范围内线性关系良好。日内与日间精密度均≤12.44%;平均回收率为83.55%;最低检出限为1.5 ng,最低定量限为2 mg/L。分析方法符合小麦体内药物含量测定的要求。经HPLC-DAD检测,确证了邻烯丙基苯酚具有自小麦叶部向基部传导的特性,施药4h后即可传至根部。给药处理72 h后药剂在小麦叶、茎及根部的积累水平相当,基本完成自顶向基传导过程。