Uncovering a phylogenetic signal in plant biopolymer chemistry: a comparison of sporopollenin isolation approaches for use in palynological research
Uncovering a phylogenetic signal in plant biopolymer chemistry: a comparison of sporopollenin isolation approaches for use in palynological research
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DOI：
10.1111/pala.12683
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发表时间：
2023-11
期刊：
影响因子：
2.6
通讯作者：
P. Jardine;M. Kent;W. Fraser;K. Knorr;B. Lomax
中科院分区：
文献类型：
--
作者：
P. Jardine;M. Kent;W. Fraser;K. Knorr;B. Lomax
孢子形态（花粉和孢子）是研究过去植被的支柱，越来越多的孢子形态化学被用作古生态学工具。为了使现存的孢子形态直接与化石标本相比较，新鲜的材料被处理以去除不稳定的化合物并分离孢粉素壁。目前正在使用一系列处理方法，但这些不同技术产生的化学物质尚未在一系列分类群中进行比较。因此，尚不清楚它们在有效分离孢粉素而不改变其化学结构方面如何进行比较，以及它们对分类群之间的相对化学相似性和差异有什么影响（即，无论它们如何处理，更密切相关的物种是否总是在化学上更相似）。在这里，我们测试这一点，通过应用五种不同的处理方法，从15个分类群的孢子形态，从整个维管植物生殖系统。我们发现，每种方法都有自己的特质，在孢子化学的影响。在大多数情况下，一个共同的模式之间分类群的化学变异被发现，并支持孢粉化学内的系统发育信号。使用光谱导数通常会增加不同处理方法之间的一致性，但会降低系统发育信号的强度。没有一种处理方法是理想的，选择使用哪种方法可能取决于研究的目标、处理的材料的类型和数量以及可用于处理的实验室设施。
Sporomorphs (pollen and spores) are a mainstay of research into past vegetation, and increasingly sporomorph chemistry is being used as a palaeoecological tool. To make extant sporomorphs directly comparable to fossil specimens, fresh material is processed to remove labile compounds and isolate the sporopollenin wall. A range of processing approaches are currently in use, but the chemistries produced by these different techniques have not yet been compared across a range of taxa. It is therefore not clear how they compare in terms of efficiently isolating sporopollenin without changing its chemical structure, and what impact they have on relative chemical similarities and differences among taxa (i.e. whether more closely related species will always appear chemically more similar, regardless of how they have been processed). Here, we test this by applying five different processing approaches to sporomorphs from 15 taxa from across the vascular plant phylogeny. We show that each approach has its own idiosyncrasies in terms of impacts on sporomorph chemistry. For the most part a common pattern of among‐taxon chemical variability is uncovered, and a phylogenetic signal within sporopollenin chemistry is supported. Working with spectral derivatives generally increases agreement among the different processing approaches, but decreases the strength of the phylogenetic signal. No one processing approach is ideal, and the choice of which to use is likely to depend on the goal of the study, the type and quantity of material being processed, and the laboratory facilities available for processing.