Fan Yuerong, Li Huimin, Ma Jingze, Zhou Ting, Fan Junjun, Zhang Wangxiang
College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China.
Plants (Basel). 2025 Jun 22;14(13):1918. doi: 10.3390/plants14131918.
Leaves are the most ubiquitous plant organs, whose macrostructures exhibit close correlations with environmental factors while simultaneously reflecting inherent genetic and evolutionary patterns. These characteristics render them highly significant for plant taxonomy, ecology, and related disciplines. Therefore, this study presents the first comprehensive evaluation of leaf macrostructures for infraspecific classification. By establishing a trait-screening system, we conducted a numerical taxonomic analysis of leaf phenotypic variation across 73 germplasm (34 species and 39 cultivars). Through ancestor-inclined distribution characteristic analysis, we investigated phylogenetic relationships at both the genus level and infraspecific ranks within . A total of 21 leaf phenotypic traits were selected from 50 candidate traits based on the following criteria: high diversity, abundance, and evenness (D ≥ 0.50, H ≥ 0.80, and E ≥ 0.60); significant intraspecific uniformity and interspecific distinctness (CV¯ ≤ 10% and CV ≥ 15%). Notably, the selected traits with low intraspecific variability (CV¯ ≤ 10%) exhibit environmental robustness, likely reflecting low phenotypic plasticity of these specific traits under varying conditions. This stability enhances their taxonomic utility. It was found that the highest ancestor-inclined distribution probability reached 90% for 10 traceable cultivars, demonstrating reliable breeding lines. Based on morphological evidence, there was a highly significant correlation between the evolutionary orders of (Sect. → Sect. → Sect. ) and group/sub-groups (B → B → A). This study demonstrates that phenotypic variation in leaf macrostructures can effectively explore the affinities among germplasm, exhibiting taxonomic significance at the infraspecific level, thereby providing references for variety selection. However, hybrid offspring may exhibit mixed parental characteristics, leading to blurred species boundaries. And convergent evolution may create false homologies, potentially misleading morphology-based taxonomic inferences. The inferred taxonomic relationships present certain limitations that warrant further investigation.
叶片是最常见的植物器官，其宏观结构与环境因素密切相关，同时反映了内在的遗传和进化模式。这些特性使其在植物分类学、生态学及相关学科中具有高度重要性。因此，本研究首次对用于种下分类的叶片宏观结构进行了全面评估。通过建立性状筛选系统，我们对73份种质（34个种和39个品种）的叶片表型变异进行了数值分类分析。通过祖先倾向分布特征分析，我们研究了属水平和种下等级内的系统发育关系。基于以下标准，从50个候选性状中总共选择了21个叶片表型性状：高多样性、丰富度和均匀度（D≥0.50，H≥0.80，E≥0.60）；种内显著均匀性和种间明显差异性（CV¯≤10%且CV≥15%）。值得注意的是，所选种内变异性低（CV¯≤10%）的性状表现出环境稳健性，可能反映了这些特定性状在不同条件下较低的表型可塑性。这种稳定性增强了它们在分类学上的效用。结果发现，10个可追溯品种的最高祖先倾向分布概率达到90%，表明育种系可靠。基于形态学证据，（组→亚组→亚亚组）的进化顺序与组/亚组（B→B→A）之间存在高度显著的相关性。本研究表明，叶片宏观结构的表型变异可以有效地探究种质间的亲缘关系，在种下水平具有分类学意义，从而为品种选择提供参考。然而，杂交后代可能表现出混合的亲本特征，导致物种界限模糊。而且趋同进化可能会产生假同源性，潜在地误导基于形态学的分类学推断。推断的分类关系存在一定局限性，值得进一步研究。
