Characterizing Modern and Fossil Gymnosperm Exudates Using Micro-Fourier Transform Infrared Spectroscopy
Characterizing Modern and Fossil Gymnosperm Exudates Using Micro-Fourier Transform Infrared Spectroscopy
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使用微傅里叶变换红外光谱表征现代和化石裸子植物分泌物
DOI：
10.1086/657277
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发表时间：
2011
影响因子：
2.3
通讯作者：
K. Muehlenbachs
中科院分区：
文献类型：
--
作者：
R. Tappert;A. P. Wolfe;R. McKellar;Michelle C. Tappert;K. Muehlenbachs
利用显微傅里叶变换红外光谱仪测定了65种裸子植物分泌物的红外吸收光谱。在红外光谱的基础上，可以区分三种组成不同的渗出物：树脂、富含挥发物的树脂和树胶。树脂和富含挥发物的树脂主要由萜类化合物组成，而树胶是多糖。树脂和富含挥发物的树脂仅限于针叶树（Pinophyta）。另一方面，树胶由包括南洋杉科和罗汉松科的一些针叶树科;包括银杏（Ginkgophyta）、苏铁（Cycadophyta）和Welwitschia（Gnetophyta）的非针叶裸子植物;以及被子植物产生。使用光谱带比，针叶树树脂可以被细分为两个不同的树脂类型，反映其萜类成分和广泛平行的不同针叶树家族的组成差异定量。第一种类型的树脂（松科树脂）由松科成员产生，主要由基于松香烷/海松烷骨架结构的二萜组成。第二种类型（柏科树脂）与柏科，Sciadopityaceae，南洋杉科和罗汉松科的成员有关，主要由基于labdanoid结构的二萜组成。树脂光谱内的变异性与游离羟基的数量相关，并且其可用于评估树脂聚合度。富含挥发物的树脂仅在松科中发现，反映了该家族树脂中挥发性单萜和倍半萜类化合物的丰度通常较高。FTIR光谱的结果有直接的影响，现代和化石裸子植物分泌物的化石潜力和化学分类学解释的评估。
Infrared absorption spectra of exudates from 65 species of gymnosperms were measured using micro–Fourier transform infrared (FTIR) spectroscopy. On the basis of the infrared spectra, three compositionally distinct groups of exudates can be distinguished: resins, volatile-rich resins, and gums. Resins and volatile-rich resins are mainly composed of terpenoids, whereas gums are polysaccharides. Resins and volatile-rich resins are restricted to conifers (Pinophyta). Gums, on the other hand, are produced by some conifer families including Araucariaceae and Podocarpaceae; nonconifer gymnosperms including Ginkgo (Ginkgophyta), cycads (Cycadophyta), and Welwitschia (Gnetophyta); and angiosperms. Using spectral band ratios, conifer resins can be subdivided quantitatively into two distinct resin types that reflect compositional differences in their terpenoid constituents and broadly parallel different conifer families. The first type of resin (pinaceous resin) is produced by members of Pinaceae and consists mainly of diterpenes that are based on abietane/pimarane skeletal structures. The second type (cupressaceous resin) is associated with members of the Cupressaceae, Sciadopityaceae, Araucariaceae, and Podocarpaceae and consists mainly of diterpenes that are based on the labdanoid structures. Variability within the resin spectra correlates with the number of free hydroxyl groups, and it can be used to assess the degree of resin polymerization. Volatile-rich resins are found exclusively within Pinaceae, reflecting a generally higher abundance of volatile mono- and sesquiterpenoids in resins of this family. The results of the FTIR spectroscopy have direct implications for the assessment of the fossil potential and the chemotaxonomic interpretation of modern and fossil gymnosperm exudates.