The velamen radicum is common among terrestrial monocotyledons.
The velamen radicum is common among terrestrial monocotyledons.
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DOI：
10.1093/aob/mcx097
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发表时间：
2017-11
期刊：
影响因子：
4.2
通讯作者：
G. Zotz;Nina Schickenberg;D. Albach
中科院分区：
文献类型：
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作者：
G. Zotz;Nina Schickenberg;D. Albach
根被（velamen radicum）是一种海绵状的，通常由成熟时的死细胞组成的多层根表皮，是典型的与附生兰花相关的适应性的教科书例子。范围基于广泛的文献综述，这种结构的发生被记录在大约240属的陆生单子叶植物（162兰花和74非兰花属）和双子叶植物的一个属。映射这个字符的系统发育树显示，被膜被发现在整个单子叶植物，从早期分支天南星科的成员，以派生莎草科。结论目前对被子植物根被的描述及其与兰科植物附生生活方式的联系存在一定的误导性，这必然导致对其进化和功能的片面认识。这一发现对陆生和附生被子植物根被的发生、演化和功能提出了新的认识。
Background The velamen radicum, a spongy and usually multiple-layered root epidermis composed of dead cells at maturity, is a textbook example of an adaptation that is typically associated with epiphytic orchids. Scope Based on an extensive literature review, the occurrence of this structure was documented in approximately 240 genera of terrestrial monocotyledons (162 orchid and 74 non-orchid genera) and in one genus of dicotyledons. Mapping this character on a phylogenetic tree reveals that a velamen is found throughout the monocotyledons, ranging from members of early-branching Araceae to derived Cyperaceae. Conclusion The current depiction of the velamen radicum in angiosperms and its almost exclusive association with the epiphytic lifestyle in orchids is misleading, which inevitably leads to a biased view of its evolution and function. The findings propose a re-evaluation of the occurrence, evolution and function of the velamen radicum in both terrestrial and epiphytic angiosperms.