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BACKGROUND AND AIMS: The systematic position of the genus Metagentiana and its phylogenetic relationships with Crawfurdia, Gentiana and Tripterospermum have not been explicitly addressed. These four genera belong to one of two subtribes (Gentianinae) of Gentianeae. The aim of this paper is to examine the systematic position of Crawfurdia, Metagentiana and Tripterospermum and to clarify their phylogenetic affinities more clearly using ITS and trnL intron sequences. METHODS: Nucleotide sequences from the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the plastid DNA trnL (UAA) intron were analysed phylogenetically. Ten of fourteen Metagentiana species were sampled, together with 40 species of other genera in the subtribe Gentianinae. KEY RESULTS: The data support several previously published conclusions relating to the separation of Metagentiana from Gentiana and its closer relationships to Crawfurdia and Tripterospermum based on studies of gross morphology, floral anatomy, chromosomes, palynology, embryology and previous molecular data. The molecular clock hypothesis for the tested sequences in subtribe Gentianinae was not supported by the data (P < 0.05), so the clock-independent non-parametric rate smoothing method was used to estimate divergence time. This indicates that the separation of Crawfurdia, Metagentiana and Tripterospermum from Gentiana occurred about 11.4-21.4 Mya (million years ago), and the current species of these three genera diverged at times ranging from 0.4 to 6.2 Mya. CONCLUSIONS: The molecular analyses revealed that Crawfurdia, Metagentiana and Tripterospermum do not merit status as three separate genera, because sampled species of Crawfurdia and Tripterospermum are embedded within Metagentiana. The speciation and rapid radiation of these three genera is likely to have occurred in western China as a result of upthrust of the Himalayas during the late Miocene and the Pleistocene. 相似文献
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用nrDNA ITS序列探讨狭蕊龙胆属及其近缘属 (龙胆科)的系统发育 总被引:2,自引:0,他引:2
运用核糖体DNA内转录间隔区ITS序列对狭蕊龙胆属Metagentiana10种及其近缘属22种植物进行了系统发育分析。ITS分析结果表明狭蕊龙胆属是一个多系群:在系统发育树上,双蝴蝶属Tripterospermum和蔓龙胆属Crawfurdia的种类位于狭蕊龙胆属各分支中,而且双蝴蝶属和蔓龙胆属的种类也相互交叉;这一结果不支持将3个属各自独立为属。但是,在所有分析中,3个属共同形成一单系分支,是龙胆属Gentiana的姊妹群;这一结果与形态学、花部解剖学、细胞学、孢粉学和胚胎学等证据基本一致,狭蕊龙胆属应该从龙胆属中分离出来,它与双蝴蝶属和蔓龙胆属有更为密切的亲缘关系。根据分支图,在狭蕊龙胆属、双蝴蝶属和蔓龙胆属组成的复合群中,现已知的染色体基数x=17、21和23可能存在网状和平行进化。 相似文献
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双蝴蝶属和蔓龙胆属(龙胆科)种子表面特征的研究 总被引:4,自引:1,他引:3
在扫描电镜下观察了龙胆科双蝴蝶属8个种和蔓龙胆属6个种的种子表面纹饰,观察结果表明,2属的种子表面特征均为网状纹饰类型。其中Tripterospermun cordatum,T.volubile,T.chinense,T.discoideum,T.japonicum,T.filicaule,Crawfurdia delavayi和C.pri-cei的种子表面为细网状;T.hirticalyx,T.pingbianense,C.puberula,C.tibetica,C.campanu-lacea和C.crawfordioides的种子表面为粗网状,在龙胆属Gentiana的不同组中均存在网状纹饰,因此,从种子表面特征可看出,龙胆属,双蝴蝶属和蔓龙胆属3属间具较近的亲缘关系。同时,在双蝴蝶属中,种之间在种子表面特征上有分化。在表面纹饰的具体特征上存在较大差别,而在蔓龙胆属中种间差别很小,仅在一些种子表面有无附属物上存在差异。 相似文献
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华南龙胆科植物拾零 总被引:1,自引:0,他引:1
林祁 《热带亚热带植物学报》1997,5(2):13-15
本文对华南龙胆科植物做了修订和补充。将白花田草的名称更正为百金花;将美丽獐牙菜归并入狭叶獐牙菜;报道了新记录种5个,即:念珠脊龙胆、流苏龙胆、新店獐牙菜、峨嵋双蝴蝶、玉山双蝴蝶。 相似文献
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以湖北双蝴蝶带芽茎段、不带芽茎段及叶片为外植体,以MS为基本培养基,通过添加不同的植物生长物质种类和浓度配比,建立湖北双蝴蝶组培快繁体系。结果如下:在所有实验方案中,带芽茎段的出愈率最高,是理想的离体快繁材料。较适宜的初代培养基为MS+BA2.0mg/L+蔗糖3.0%,增殖培养基为MS+BA2.0mg/L+NAA0.1mg/L+蔗糖3.0%,而根的诱导则在1/2MS+NAA0.5mg/L+蔗糖1.5%的培养基上进行较为适宜。同时对组织培养过程中湖北双蝴蝶植株再生的方式进行了讨论。 相似文献
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Oleanolic acid, mangiferin, and two new xanthone glucosides, named lanceoside (1,8-dihydroxy-3,7- dimethoxyxanthone- 4-O-β-d-glucoside) and lancerin (C-4-β-d-glucosyl-1,3,7-trihydroxyxanthone), respectively, were isolated from the aerial parts of Tripterospermum lanceolatum. 相似文献
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