Measures of equatorial and polar lengths of pollen grains in Sorbus, Aria and Hedlundia from Norway

The genus Sorbus s.l. consists of small to medium-sized trees primarily found in coastal areas, with three European hotspots of diversification: Fennoscandia, South-East Europe, and the British Isles. Taxonomic classification of Sorbus s.l. in Europe is still unresolved, and this study aims to address this issue by examining the pollen morphology of various Sorbus hybrids. Pollen morphology of 16 specimens from 13 species of Sorbus s.str., Aria and Hedlundia, some of them common, others are endemic and listed as threatened species, were studied. Measurements of the polar and equatorial axis of all pollen grains show that there are variations in pollen size and shape among different hybrids, with a correlation between ploidy levels and the equatorial diameter of the pollen. Surface structures of the pollen were observed using SEM. Principal Component Analysis (PCA) was performed to analyze the pollen characters, and the results show that it is possible to separate Aria from Sorbus and He..., Specimens were collected from various parts of Norway in 2019, either from native stands or from cultivated plants of known origin (Figure 1, Table1). Inflorescences were collected and dried of samples of Aria edulis (Wild.) M.J. Roemer, Aria obtusifolia (DC.) Sennikov & Kurtto, Aria rupicola (T.C.G. Rich) Sennikov & Kurtto, Hedlundia hybrida 1 (L.) Sennikov & Kurtto, Hedlundia hybrida 2 (L.) Sennikov & Kurtto, Hedlundia lancifolia (Hedl.) Sennikov & Kurtto, Hedlundia meinichii 1 (Lindeb. ex Hartman) Sennikov & Kurtto, Hedlundia meinichii 2 (Lindeb. ex Hartman) Sennikov & Kurtto, Hedlundia mougeotii (Soyer-Willemet & Godron) Sennikov & Kurtto, Hedlundia neglecta (Hedl.) Sennikov & Kurtto, Hedlundia sognensis (Hedl. ex Sennikov, Hjertson & Salvesen) Sennikov & Kurtto, Hedlundia subarranensis (Hyl. ex Sennikov, Hjertson & Salvesen) Sennikov & Kurtto, Hedlundia subpinnata 1 (Hedl.) Sennikov & Kurtto, Hedlundia subpinnata 2 (Hedl.)..., , # Pollen grain measures of Sorbus, Aria and Hedlundia The dataset contain measures of the polar axis (P) and equatorial axis (E) of 100 pollen grains of each specimen. Anthers were treated with 10% KOH to remove cell contents, followed by acetolysis to remove cellulose (Fægri et al., 1989). The pollen was stained using fuchsine and mounted in glycerol. Using a light microscope (LM) the polar axis (P) and equatorial axis (E) of 100 pollen grains of each specimen were measured. Measurements of the polar and equatorial axis of all pollen grains show that there are variations in pollen size and shape among different hybrids of Sorbus, with a correlation between ploidy levels and the equatorial diameter of the pollen. Taxonomic classification of Sorbus s.l. in Europe is still unresolved, and this study aims to address this issue by examining the pollen morphology of various *Sorbus* hybrids. Pollen morphology of 16 specimens from 13 species of *Sorbus* s.str., *Aria* and *Hedlundia*, so...广义花楸属（Sorbus s.l.）包含中小型乔木，主要分布于沿海区域，拥有三个欧洲物种分化热点：芬诺斯坎迪亚、东南欧与不列颠群岛。欧洲广义花楸属的分类学界定仍未明确，本研究通过分析多种花楸杂交种的花粉形态，旨在解决这一分类难题。本研究对隶属于狭义花楸属（Sorbus s.str.）、白毛花楸属（Aria）与赫德兰花楸属（Hedlundia）的13个物种的16份标本开展了花粉形态观察，其中部分物种为广布种，其余则为特有濒危物种。所有花粉粒的极轴与赤道轴测量结果显示，不同花楸杂交种的花粉大小与形态存在显著差异，且倍性水平与花粉赤道直径存在相关性。研究通过扫描电子显微镜（SEM）观察了花粉表面结构，并采用主成分分析（PCA）对花粉性状进行分析，结果表明可将白毛花楸属与花楸属、赫德兰花楸属进行区分（原文此处有截断）。标本于2019年采自挪威多地，涵盖原生林种群与已知起源的栽培植株（图1、表1）。本研究采集了如下物种的花序并制成干燥标本：钝叶白毛花楸（Aria edulis (Wild.) M.J. Roemer）、钝齿白毛花楸（Aria obtusifolia (DC.) Sennikov & Kurtto）、岩生白毛花楸（Aria rupicola (T.C.G. Rich) Sennikov & Kurtto）、杂交赫德兰花楸1（Hedlundia hybrida 1 (L.) Sennikov & Kurtto）、杂交赫德兰花楸2（Hedlundia hybrida 2 (L.) Sennikov & Kurtto）、披针叶赫德兰花楸（Hedlundia lancifolia (Hedl.) Sennikov & Kurtto）、迈氏赫德兰花楸1（Hedlundia meinichii 1 (Lindeb. ex Hartman) Sennikov & Kurtto）、迈氏赫德兰花楸2（Hedlundia meinichii 2 (Lindeb. ex Hartman) Sennikov & Kurtto）、莫氏赫德兰花楸（Hedlundia mougeotii (Soyer-Willemet & Godron) Sennikov & Kurtto）、疏忽赫德兰花楸（Hedlundia neglecta (Hedl.) Sennikov & Kurtto）、松恩赫德兰花楸（Hedlundia sognensis (Hedl. ex Sennikov, Hjertson & Salvesen) Sennikov & Kurtto）、近伞花赫德兰花楸1（Hedlundia subarranensis (Hyl. ex Sennikov, Hjertson & Salvesen) Sennikov & Kurtto）、近伞花赫德兰花楸2（Hedlundia subpinnata 1 (Hedl.) Sennikov & Kurtto）、近伞花赫德兰花楸3（Hedlundia subpinnata 2 (Hedl.) ...）（原文此处有截断）。# 花楸属、白毛花楸属与赫德兰花楸属的花粉粒测量数据 本数据集包含每份标本的100粒花粉的极轴（P）与赤道轴（E）测量数据。 花药经10%氢氧化钾（KOH）处理以去除细胞内含物，随后通过乙酰解去除细胞壁纤维素（参照Fægri等，1989）。花粉经碱性品红染色后，以甘油封片。使用光学显微镜（LM）对每份标本的100粒花粉的极轴与赤道轴进行测量。 所有花粉粒的极轴与赤道轴测量结果显示，不同花楸杂交种的花粉大小与形态存在显著差异，且倍性水平与花粉赤道直径存在相关性。欧洲广义花楸属的分类学界定仍未明确，本研究通过分析多种花楸杂交种的花粉形态，旨在解决这一分类难题。本研究对隶属于狭义花楸属（Sorbus s.str.）、白毛花楸属（Aria）与赫德兰花楸属（Hedlundia）的13个物种的16份标本开展了花粉形态观察（原文此处有截断）。