摘要: |
玉凤花属植物的花形态变异多样,分类学问题复杂。为筛选出该属关键的分类学特征,该文以鹅毛玉凤花和粉叶玉凤花为研究对象,利用体式显微镜和扫描电镜,观察、比较了它们的花结构和合蕊柱超微特征。结果表明:(1)两种玉凤花的花结构差异显著,尤其表现在侧花瓣裂片的有无、唇瓣3裂片形态、花距与子房的长度比。(2)合蕊柱超微特征在两个种间明显不同,表现在退化雄蕊、花药室外壁细胞、“花药室管”外壁细胞、“柱头枝”及其与蕊柱交界处的乳突等结构形态。(3)花粉小块外壁纹饰在种间不同,鹅毛玉凤花具网状花粉外壁纹饰,粉叶玉凤花则为棒状→网状的花粉外壁纹饰。该研究认为,侧花瓣裂片的有无、花距形态多变、花距与子房的长度比、花粉外壁纹饰类型等是玉凤花属物种鉴定的关键分类特征。在前人的研究基础上,该文补充并分析了粉叶玉凤花的花结构及合蕊柱的超微特征,不支持粉叶玉凤花独立于玉凤花属。 |
关键词: 兰科, 花结构, 合蕊柱, 柱头枝, 外壁纹饰, 花药室管 |
DOI:10.11931/guihaia.gxzw202211038 |
分类号:Q949.58 |
文章编号:1000-3142(2024)01-0089-13 |
Fund project:国家自然科学基金(32060049)。 |
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Floral structure and gynostemium ultrastructure of two Habenaria species with their taxonomic implications |
TAO Kaifeng, ZHU Yong, WANG Yuecheng, ZHANG Yingduo, LI Lu*
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College of Biodiversity Conservation, Southwest Forestry University, Kunming 650224, China
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Abstract: |
The genus Habenaria exhibits a highly diversity in floral morphology and has complex taxonomy problems. In order to select key taxonomic features of this genus, floral structure and gynostemium ultrastructure of H. dentata and H. glaucifolia were investigated using the stereo microscope and scanning electronic microscope(SEM). The results were as follows:(1)There were significant differences in floral features between species, especially in the presence or the absence of lateral lobes of petal, morphology of 3-lobed lip, and the length ratio of the spur to the ovary.(2)The ultrastructures of gynostemium were obviously different between the two species, which were shown in shapes of staminode, outer epidermal cells of anther wall, and stigma branch.(3)Exine sculptures of massula were distinguished in two species, the reticulate type in H. dentata, and the baculate → reticulate type in H. glaucifolia. It was suggested that some floral features were selected as potentially valuable for species delimitation, including the presence or absence of lateral petal lobes, variations in spur morphology, the length ratio of the spur to the ovary, and the types of pollen exine sculpture. Additional data on floral features and ultrastructures of gynostemium were reported as supplement for understanding of H. glaucifolia. Notably, it was not confirmed that H. glaucifolia should be treated as an independent genus from Habenaria. |
Key words: Orchidaceae, floral structure, gynostemium, stigma branch, exine sculpture, anther sac channel |