3种附生兰气生根初生结构的种间差异比较

doi:10.7525/j.issn.1673-5102.2025.04.016

摘要/Abstract

摘要：

为理解附生兰气生根结构与功能间的关联，该研究采用石蜡包埋技术获取了美花石斛（Dendrobium loddigesii）、文心兰（Oncidium flexuosum）和金钗石斛（D. nobile）气生根初生结构的横截面切片，通过皮层组织和维管组织等结构横截面积，以及皮层细胞与导管的数量和尺寸等特征，分析这些植物气生根横截面积变化的解剖学原因。结果表明：（1）气生根横截面积在不同种类间存在显著差异（P<0.05），其中，金钗石斛的气生根横截面积最大，文心兰次之，美花石斛最小。在各个种中，根被和皮层占根横截面积的比例较高，分别为43.97%~57.03%、37.46%~48.80%，从而与根横截面积呈现高度相关（r=0.91~0.98，P<0.05）。（2）皮层组织面积与皮层细胞特征、维管组织面积与导管特征之间也存在显著相关性（P<0.05）。其中，皮层组织面积与平均皮层细胞直径的关联（r=0.68~0.90）强于与皮层细胞层数间的关联（r=0.56~0.66），而维管组织面积与导管数量的关联（r=0.64~0.77）强于与平均导管直径的关联（r=0.58~0.71）。（3）金钗石斛的皮层和维管组织面积占根横截面积的比例显著低于其他2种植物，而根被面积比例显著更高，同时具有更多且更粗的导管，总导管面积更大，但导管密度更低，体现了不同种类附生兰在资源获取和应对干旱胁迫策略上的多样性。综上所述，该研究明晰了3种附生兰气生根横截面积变化的解剖学机制及资源获取策略的种间差异，并为深入理解植物根系结构与功能间关系提供了新的科学视角。

关键词: 气生根, 解剖结构, 附生兰, 热带雨林, 关联

Abstract:

To understand the correlation between structure and function of aerial roots of epiphytic Orchidaceae plants， the paraffin embedding technique was used to obtain cross-sectional slices of the primary structures of aerial roots of Dendrobium loddigesii， Oncidium flexuosum and Dendrobium nobile. By measuring the cross-sectional areas of cortical tissue， vascular tissue and other structures of the primary roots， as well as the characteristics such as the number and size of cortical cells and vessels， the anatomical reasons for cross-sectional area changes of the aerial roots were analyzed. The results indicated that：（1）there were significant differences in the cross-sectional area of aerial roots among three species（P<0.05）， the cross-sectional area of the aerial root of D. nobile was the largest， followed by O. flexuosum and D. loddigesii. For each species， the proportions of velamen and cortex areas to the root cross-sectional area were relatively high（37.46%-57.03%）， thus the velamen and cortex had high correlations with the root cross-sectional area（r=0.91-0.98，P<0.05）. （2）Significant correlations existed between cortex area and cortical cell traits， vascular tissue area and conduit traits（P<0.05）. The correlation of cortex area with the mean cortical cell diameter（r=0.68-0.90） was stronger than that with cortical cell layers（r=0.56-0.66）. In addition， the correlation of vascular tissue area with conduit quantity（r=0.64-0.77） was closer than that with mean conduit diameter（r=0.58-0.71）. （3）D. nobile had significantly lower proportions of cortical and vascular tissue area but a significantly higher proportion of velamen area to the root cross-sectional area， when compared to the other two species. Besides， D. nobile also had thicker and more conduits and larger total conduit area， but lower conduit density， which reflected the diversity of different epiphytic orchid species in resource acquisition and strategies for drought stress tolerance. In summary， this study clarified the anatomical mechanisms underlying the cross-sectional area changes of aerial roots of three epiphytic orchids as well as the interspecific differences in resource acquisition strategies， and provided a new scientific perspective for understanding the relationship between plant root structure and function.

Key words: aerial root, anatomical structure, epiphytic orchids, tropical rainforests, correlation

中图分类号:

Q944.53

任隐, 王文娜. 3种附生兰气生根初生结构的种间差异比较[J]. 植物研究, 2025, 45(4): 648-658.

Yin REN, Wenna WANG. Comparison of the Interspecific Difference of Primary Structure of Aerial Roots among Three Epiphytic Orchids[J]. Bulletin of Botanical Research, 2025, 45(4): 648-658.

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