Qiu Juan, Lin Musen, Tan Dunyan
Xinjiang Key Laboratory for Ecological Adaptation and Evolution of Extreme Environment Biology, College of Life Sciences, Xinjiang Agricultural University, Ürümqi, 830052, China.
Bot Stud. 2023 Nov 29;64(1):33. doi: 10.1186/s40529-023-00405-9.
Leaf morphology and epidermal characters are important for phylogenetic and taxonomic studies of many plants, but there is currently insufficient data to use them to help distinguish species of Gagea, which is a taxonomically difficult genus mainly due to polyploidy and hybridization. Therefore, leaf morphology and epidermal characters of Gagea were studied to assess the characters that can be used to elucidate the taxonomy and systematics of 14 species of Gagea collected in Xinjiang, China. Using light microscopy (LM), six qualitative and three quantitative leaf epidermal anatomical characters were examined for both the adaxial and abaxial surfaces. Hierarchical cluster analysis (HCA) was employed to reveal the similarities based on leaf morphology and epidermal characters of the investigated species.
Basal leaf of these species can be terete or flat, and it is triangle, flat, or circular in transverse section. Anticlinal wall patterns of the leaf epidermal cells were straight and sinuous, and only three species had epidermal hairs. Shape of long cells varies, ranging from quadrangular to irregular. HCA revealed that the 14 species could be divided into two groups. Group A was arranged into three subgroups (A1, A2 and A3), based on the Euclidean distance of 6.96. Subgroup A1 consisted of three species with indumentum; subgroup A2 had four species with sinuous type anticlinal walls; and subgroup A3 comprised of two species with a fistulose basal leaf. Group B included five species with short cells.
Leaf morphology and epidermal characters did not differ significantly among populations of the same species in Gagea, whereas they differ significantly among species. Thus, leaf morphology and epidermal characters provide diagnostic information for differentiating G. nigra and G. filiformis; G. altaica, G. jensii and G. alberti, which are morphologically similar species.
叶片形态和表皮特征对许多植物的系统发育和分类研究很重要，但目前尚无足够数据利用它们来帮助区分顶冰花属植物，该属在分类上存在困难，主要原因是多倍体和杂交。因此，对顶冰花属的叶片形态和表皮特征进行了研究，以评估可用于阐明在中国新疆采集的14种顶冰花属植物的分类学和系统学的特征。使用光学显微镜（LM），对叶片近轴面和远轴面的六个定性和三个定量叶片表皮解剖特征进行了检查。采用层次聚类分析（HCA）来揭示基于所研究物种的叶片形态和表皮特征的相似性。
这些物种的基生叶可为圆柱形或扁平状，横切面呈三角形、扁平状或圆形。叶片表皮细胞的垂周壁样式为直线形和波状，只有三个物种有表皮毛。长细胞形状各异，从四边形到不规则形不等。HCA显示，14个物种可分为两组。基于6.96的欧几里得距离，A组分为三个亚组（A1、A2和A3）。亚组A1由三个有毛被的物种组成；亚组A2有四个垂周壁为波状类型的物种；亚组A3由两个基部叶为中空的物种组成。B组包括五个有短细胞的物种。
顶冰花属同一物种的不同种群之间叶片形态和表皮特征差异不显著，而不同物种之间差异显著。因此，叶片形态和表皮特征为区分形态相似的物种黑顶冰花和丝状顶冰花；阿尔泰顶冰花、延氏顶冰花和阿尔伯特顶冰花提供了诊断信息。
