记者从中科院华南植物园获悉,该园科学家近日在粤发现了兰科植物新属种——丹霞兰。业内专家表示,该兰花独特的种子结构和唇瓣结构为针对兰科植物的进化生物学研究提供了一个新的方向。研究论文“兰科植物新属——丹霞兰属,及布袋兰族的系统学研究”近期已刊于美国《公共科学图书馆·综合》。
华南植物园物种多样性和保育研究组博士翟俊文在导师邢福武研究员和深圳市兰科植物保护研究中心教授刘仲健的指导及仁化县政府研究团队的共同努力下,在广东韶关丹霞山发现了一种具有独特结构的腐生兰花。经过解剖学、孢粉学和分子生物学等研究,研究人员确定该兰花是一个新物种,将其命名为“丹霞兰”,同时又以丹霞兰成立了兰科的一个新属——丹霞兰属,并确定其系统位置,完成了其所在的布袋兰族系统学研究。
研究人员表示,兰科植物的种子多呈灰尘状,偶见颗粒状,大小不超过1毫米,而丹霞兰的种子长达2毫米,直径可达1毫米,这是首次在兰科植物中发现有如此之大的种子。
研究表明,这个奇特的兰花与宽距兰属的宽距兰亲缘关系最为接近,同属于兰科树兰亚科布袋兰族宽距兰亚族,其因独特的种子结构、唇瓣基部双囊状的结构和唇瓣上“Y”形的附属物而区别于其他兰科植物。(生物谷Bioon.com)
doi: 10.1371/journal.pone.0060371
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A new orchid genus, danxiaorchis, and phylogenetic analysis of the tribe calypsoeae
Zhai JW, Zhang GQ, Chen LJ, Xiao XJ, Liu KW, Tsai WC, Hsiao YY, Tian HZ, Zhu JQ, Wang MN, Wang FG, Xing FW, Liu ZJ
BACKGROUND: Orchids have numerous species, and their speciation rates are presumed to be exceptionally high, suggesting that orchids are continuously and actively evolving. The wide diversity of orchids has attracted the interest of evolutionary biologists. In this study, a new orchid was discovered on Danxia Mountain in Guangdong, China. However, the phylogenetic clarification of this new orchid requires further molecular, morphological, and phytogeographic analyses. METHODOLOGYPRINCIPAL FINDINGS: A new orchid possesses a labellum with a large Y-shaped callus and two sacs at the base, and cylindrical, fleshy seeds, which make it distinct from all known orchid genera. Phylogenetic methods were applied to a matrix of morphological and molecular characters based on the fragments of the nuclear internal transcribed spacer, chloroplast matK, and rbcL genes of Orchidaceae (74 genera) and Calypsoeae (13 genera). The strict consensus Bayesian inference phylogram strongly supports the division of the Calypsoeae alliance (not including Dactylostalix and Ephippianthus) into seven clades with 11 genera. The sequence data of each species and the morphological characters of each genus were combined into a single dataset. The inferred Bayesian phylogram supports the division of the 13 genera of Calypsoeae into four clades with 13 subclades (genera). Based on the results of our phylogenetic analyses, Calypsoeae, under which the new orchid is classified, represents an independent lineage in the Epidendroideae subfamily. CONCLUSIONS: Analyses of the combined datasets using Bayesian methods revealed strong evidence that Calypsoeae is a monophyletic tribe consisting of eight well-supported clades with 13 subclades (genera), which are all in agreement with the phytogeography of Calypsoeae. The Danxia orchid represents an independent lineage under the tribe Calypsoeae of the subfamily Epidendroideae. This lineage should be treated as a new genus, which we have named Danxiaorchis, that is parallel to Yoania. Both genera are placed under the subtribe Yoaniinae.