Searching for biological pigments and structural color in fossil plants

寻找植物化石中的生物色素和结构色

• 批准号: 465336934
• 负责人: Privatdozentin Dr. Carole T. Gee
• 金额: --
• 依托单位: Abteilung Paläontologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465336934?language=en
• 关键词: Searching; biological; pigments; structural; color

Although the dazzling colors in living plants are well studied, those in fossil plants have received little attention. In the extant flora, plant color is primarily produced by biological pigments, also known as biochromes, which are expressed in a huge array of hues such as green, yellow, orange, red, pink, blue, violet, ultraviolet, tan, brown, gray, and white. Colors in plants can also arise from structural color or, rarely, from bioluminescence. Structural colors come from the physical and structural modification of surfaces through periodically arranged material on the micro- or nanoscale that make plants appear metallic blue, silver, or iridescent. It is highly likely that biochromes and structural color existed in plants in deep time. However, only a handful of cases of pigmentary color have been studied in fossil plants, and examples of structural color in fossil leaves or fruits have not been reported. Green Cenozoic leaves and a distinctly pink-colored Jurassic alga are among the few intriguing examples of fossil plants known to have pigmentation. Yet, given the highly accurate and sensitive instrumentation and methodology available today, it should be possible to extract, identify, and quantify plant pigments such as chlorophylls, carotenoids, and anthocyanins and their derivatives in fossil plants today. Several Cenozoic floras with colored leaves show promise for pigment research, such as the Miocene Clarkia flora in Idaho, USA, and the Eocene Geiseltal flora in eastern Germany. While derivatives of chlorophyll have been extracted and identified from green fossil leaves from both floras, it is likely that other pigments have also survived the 15 to 45 million years since deposition, which the newly purchased, highly sensitive and accurate Sciex QTRAP 6500+ System, a triple quadrupole/linear ion trap LCMS/MS mass spectrometer, in the Pharmaceutical Institute at the University of Bonn will be able to detect and measure. Non-destructive methods, such as confocal Raman spectroscopy, will be developed for the detection, identification, and chemical analysis of pigments. For field work and reconnaissance in museum collections, the non-destructive use of a hand-held spectrometer for the initial evaluation of promising specimens with pigmentary color remains will also be explored. Similarly, the use of a non-destructive, high-resolution approach, such as low-vacuum scanning electron microscopy, will be employed to search for nanostructures on the surface of fossil leaves that may have produced structural color. Because structural color is most common as a shimmery iridescence in the shade leaves of rainforest plants, we will analyze leaves from Cenozoic conservation lagerstätten such as the tropical Eocene flora from Messel near Frankfurt with the newly acquired, high-performance, variable-pressure TESCAN Vega 4 SEM at the Division of Paleontology at the University of Bonn.

尽管对活体植物的耀眼色彩进行了深入研究，但化石植物中的色彩却很少受到关注。在现存植物区系中，植物颜色主要是由生物色素产生的，也称为生物色素，它们以多种色调表达，如绿色、黄色、橙色、红色、粉色、蓝色、紫色、紫外线、棕褐色、棕色、灰色和白色。植物的颜色也可能来自结构色，或者很少来自生物发光。结构颜色来自于通过微米或纳米尺度上周期性排列的材料对表面进行物理和结构修饰，使植物呈现金属蓝色、银色或虹彩。生物色素和结构色很可能在很久以前就存在于植物中。然而，仅研究了植物化石中色素颜色的少数案例，并且尚未报道化石叶子或果实中的结构颜色的例子。绿色的新生代叶子和明显粉红色的侏罗纪藻类是已知具有色素沉着的植物化石中为数不多的有趣例子。然而，考虑到当今可用的高度准确和灵敏的仪器和方法，应该可以提取、识别和量化当今化石植物中的植物色素，例如叶绿素、类胡萝卜素和花青素及其衍生物。一些具有彩色叶子的新生代植物群显示出对色素研究的前景，例如美国爱达荷州的中新世 Clarkia 植物群和德国东部的始新世 Geiseltal 植物群。虽然叶绿素衍生物已从这两个植物群的绿色化石叶子中提取并鉴定出来，但其他色素很可能自沉积以来也保存了 15 至 4500 万年，波恩大学制药研究所新购买的高灵敏度和准确的 Sciex QTRAP 6500+ 系统（三重四极杆/线性离子阱 LCMS/MS 质谱仪）将能够 检测和测量。将开发共焦拉曼光谱等非破坏性方法用于颜料的检测、识别和化学分析。对于博物馆藏品的现场工作和勘察，还将探索如何无损地使用手持式光谱仪对具有色素残留的有前景的标本进行初步评估。同样，使用非破坏性的高分辨率方法，例如低真空扫描电子显微镜，将用于寻找化石叶子表面上可能产生结构颜色的纳米结构。由于结构色在雨林植物的遮荫叶子中最常见的是闪闪发光的虹彩，因此我们将使用波恩大学古生物学系新购置的高性能变压 TESCAN Vega 4 SEM 来分析新生代保护大型植物区系的叶子，例如来自法兰克福附近梅塞尔的热带始新世植物群。