台灣產唐松草屬之親緣關係與傅氏唐松草複合群之系統分類

Phylogeny of the genus Thalictrum (Ranunculaceae) in Taiwan and systematics of Thalictrum urbaini complex

李香瑩(Hsiang-Ying Li)

指導教授 ： 王震哲

國立臺灣師範大學/理學院/生命科學研究所/碩士(2011年)

摘要

台灣產唐松草屬(Thalictrum)植物根據台灣植物誌第二版處理成六個分類群，除了T. sessile外，其餘類群在中國植物志的處理中分屬叉枝唐松草組(Sect. Leptostigma)及唐松草組(Sect. Tripterium)。本研究從外部形態、生態與地理分布及分子親緣分析等各方面對台灣產唐松草屬植物重新進行分類研究。綜合結果顯示台灣植物誌紀錄為微毛爪哇唐松草的類群為一新種，暫定名為能高唐松草(Thalictrum nokoensis H. Y. Li sp. nov)。利用核DNA ITS片段及兩個葉綠體DNA matK、trnL-F片段之分子序列資料所建構之本屬植物親緣關係樹，結果顯示台灣的類群可以分為兩支序，一個支序包含T. rubescens、T. urbaini var. urbaini、T. urbaini var. majus，此三者在分子上關係不明，但形值分析結果顯示萼片長、果柄長和瘦果長為三者主要的區分特徵；另一支序則包含其餘類群，此一結果不支持中國植物誌在屬下階層的處理，顯示本屬依形態建構的屬下分類系統有進一步檢討的必要。
根據第一部份結果，本研究第二部份中將T. rubescens、T. urbaini var. urbaini、T. urbaini var. majus合稱為傅氏唐松草複合群，利用分子標記探討此複合群的遺傳分化程度。由核DNA合併三個葉綠體DNA片段所獲得的單套型來看，其分布模式與地理位置不具相關性。最小關聯網狀圖(minimum spanning network)顯示傅氏唐松草複合群之單套型彼此均為姐妹型(sister haplotype)，加上不同類群擁有相同的基因型，本研究推論本複合群可能在近期產生分化，尚處於支序排列不完全(lineage sorting incomplete)的狀態。

關鍵字

毛茛科 ； 唐松草屬 ； 親緣關係 ； 系統分類

並列摘要

Six taxa of the genus Thalictrum are recognized in Flora of Taiwan 2nd-ed. Excluding T. sessile, two taxa are classified into Sect. Leptostigma and three into Sect. Tripterium in Flora of China Chinese Ed.. In this study, the genus Thalictrum is taxonomically revised based on morphological, geographical, ecological and molecular data. According to the result, T. javanicm var. puberulum is revised as a new species named Thalictrum nokoensis H. Y. Li sp. nov. To examine the phylogenetic relationship of the genus, DNA sequences from nrDNA ITS and two chloroplast DNA intergenic spacers, matK and trnL-F were analyzed. The phylogenetic tree reveals that the taxa in Taiwan are grouped into two clades. One clade consists of T. rubescens、T. urbaini var. urbaini and T. urbaini var. majus although their relationships are still unsolved. Results from morphometrics suggest that the major distinguishing characters are sepal, fruit stalk and achene length. The other clade comprises the remainding taxa. The incongruence between molecular clusters and the infrageneric system of Flora of China suggests that a reappraisal of the infrageneric system is necessary.
According to the results of part one, T. urbaini var. urbaini, T. urbaini var. majus together with T. rubescens are defined as T. urbaini complex here. Highly similar morphology and closely-related phylogenetic relationships are found in the T. urbaini complex with differentiation in habitats and altitudinal distribution. In this study, data based on sequences of nrDNA ITS and three chloroplast DNA fragments describing genetic differentiation of the complex and the analysis of minimum spanning network reveal that haplotypes comprise sister haplotypes, and that the distribution of haplotypes in T. urbaini complex doesn’t have geographical structure. In addition, some different taxa have the same genotype. This could be due to recent differentiation and/or ancient incomplete lineage sorting.

並列關鍵字

Ranunculaceae ； Thalictrum ； phylogeny ； systematics

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