Structural analysis of wheat wax (Triticum aestivum, c.v. 'Naturastar' L.):: from the molecular level to three dimensional crystals
Structural analysis of wheat wax (Triticum aestivum, c.v. 'Naturastar' L.):: from the molecular level to three dimensional crystals
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DOI：
10.1007/s00425-005-0081-3
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发表时间：
2006-01-01
期刊：
影响因子：
4.3
通讯作者：
Broekmann, P
中科院分区：
文献类型：
--
作者：
Koch, K;Barthlott, W;Broekmann, P
为了阐明植物表皮蜡的自组装过程，以及晶体内的分子排列，研究了生物和非生物表面上的蜡片的重结晶。从小麦（Triticum aestivum L.，c. v.'Naturastar'，禾本科）。通过气相色谱法（GC）和质谱法（MS）分析蜡。二十八烷-1-醇被发现是最丰富的化学成分的蜡混合物（66 m%），也是决定化合物的形状的蜡片。电子衍射图表明蜡混合物和纯的二十八烷-1-醇都是结晶的。用扫描隧道显微镜（STM）、原子力显微镜（AFM）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了天然蜡混合物和纯二十八烷-1-醇的重结晶。小麦蜡和纯二十八烷-1-醇在非极性高度有序热解石墨（HOPG）上的结晶导致形成与植物表面上发现的那些类似的片状结构。与此相反，不规则的蜡形态和平坦的躺板上形成的玻璃，硅，盐晶体（NaCl）和云母表面。小麦蜡在离体铃兰中的运动导致了典型的小麦蜡片，其排列方式复杂，为铃兰的典型特征。majalis。纯二十八烷-1-醇在HOPG上的单分子膜的STM表明，分子的排列严格遵循衬底晶体的六方结构。小麦蜡在非极性结晶HOPG衬底上的重结晶表明，技术表面可用于产生微结构的仿生表面。AFM和SEM研究表明，衬底的模板效应决定了再生长晶体的取向。这些影响的结构和极性的基板上的表皮蜡的形态是相关的了解生物以及技术表面和蜡之间的相互作用。
In order to elucidate the self assembly process of plant epicuticular waxes, and the molecular arrangement within the crystals, re-crystallisation of wax platelets was studied on biological and non-biological surfaces. Wax platelets were extracted from the leaf blades of wheat (Triticum aestivum L., c.v. 'Naturastar', Poaceae). Waxes were analysed by gas chromatography (GC) and mass spectrometry (MS). Octacosan-1-ol was found to be the most abundant chemical component of the wax mixture (66 m%) and also the determining compound for the shape of the wax platelets. The electron diffraction pattern showed that both the wax mixture and pure octacosan-1-ol are crystalline. The re-crystallisation of the natural wax mixture and the pure octacosan-1-ol were studied by scanning tunnelling microscopy (STM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Crystallisation of wheat waxes and pure octacosano-1-ol on the non polar highly ordered pyrolytic graphite (HOPG) led to the formation of platelet structures similar to those found on the plant surface. In contrast, irregular wax morphologies and flat lying plates were formed on glass, silicon, salt crystals (NaCl) and mica surfaces. Movement of wheat wax through isolated Convallaria majalis cuticles led to typical wax platelets of wheat, arranged in the complex patterns typical for C. majalis. STM of pure octacosan-1-ol monolayers on HOPG showed that the arrangement of the molecules strictly followed the hexagonal structure of the substrate crystal. Re-crystallisation of wheat waxes on non-polar crystalline HOPG substrate showed that technical surfaces could be used to generate microstructured, biomimetic surfaces. AFM and SEM studies proved that a template effect of the substrate determined the orientation of the re-grown crystals. These effects of the structure and polarity of the substrate on the morphology of the epicuticular waxes are relevant for understanding interactions between biological as well as technical surfaces and waxes.