SEM images, quantitative analysis code of SEM images, and data analysis code for "Grass pollen surface ornamentation is diverse across the phylogeny: evidence from northern South America and the global literature"

The grasses are one of the most diverse plant families on Earth, however, their classification and evolutionary history are obscured by their pollen stenopalynous (similar) morphology. A combination of high-resolution imaging of pollen surface ornamentation and computational analysis has previously been proposed as promising tool to classify grass taxonomic boundaries. In this study, we test this hypothesis by studying Poaceae pollen across the phylogeny from plants collected in northern South America, but also from published literature across the globe. We assessed if morphotypes that we establish using descriptive terminology are supported by computational analysis, if they vary along six (a)biotic variables and how vary across the phylogeny. Based on this analysis, we constructed a reference framework for pollen surface ornamentation morphotypes. Our results showed that there is a very wide variation of grass pollen surface ornamentation. We identified nine new and six known morphotypes and established our dataset of 223 species (243 individual plant specimens) from 11 subfamilies. Computational analysis showed that our morphotypes are well-supported by two quantitative features of pollen sculptural elements (size and density). The specific dataset and mapping of the phylogeny confirmed that pollen morphological sculpture is unrelated to (a)biotic variables but is diverse across through the phylogeny.

禾本科（Poaceae）是地球上物种多样性最为丰富的植物类群之一，但其分类与演化历史却因花粉具有窄孢粉学（stenopalynous，即形态高度相似）的特征而模糊不清。此前有研究提出，将高分辨率花粉表面纹饰成像与计算分析相结合，可作为划分禾本科分类界限的极具潜力的手段。本研究针对采集自南美洲北部、覆盖系统发育全分支的禾本科植物花粉，并结合全球范围内已发表的相关文献数据，对前述假说开展验证。我们采用描述性术语构建了花粉纹饰形态类型，并从三个维度展开评估：其一，该形态类型能否得到计算分析的支持，其二，其是否随6种非生物/生物变量发生变化，其三，该形态类型在系统发育树上的分布模式如何。基于上述分析，我们构建了一套针对禾本科花粉表面纹饰形态类型的参考框架。研究结果显示，禾本科花粉的表面纹饰存在极为广泛的变异。本研究共识别出9种全新的花粉纹饰形态类型与6种已知形态类型，并建立了涵盖11个亚科、223个物种（含243份单株植物标本）的数据集。计算分析结果表明，我们所建立的形态类型可通过花粉纹饰结构的两项定量特征——尺寸与密度——得到良好支持。本研究的专属数据集与系统发育映射结果证实，禾本科花粉的表面纹饰与非生物/生物变量并无关联，但其多样性却贯穿整个系统发育分支。