臺灣細辛屬杜蘅組植物之系統分類與親緣地理研究

No Thumbnail Available

Date

2010

Journal Title

Journal ISSN

Volume Title

Publisher

Abstract

本論文主要針對臺灣細辛屬杜蘅組 (Asarum sect. Heterotropa)植物的系統分類處理、親緣關係與親緣地理模式進行探討。 在系統分類方面,本研究利用形值分析的方法重新檢視大花細辛複合群(Asarum macranthum complex),結果顯示此複合群可區分成三個分類群,包括大屯細辛(A. taitonense)、大花細辛(A. macranthum)與其變種—罈花細辛(A. macranthum var. ampulliflorum)。而柱頭與花柱形態、花被筒內壁特徵和花被筒形狀被認為是區分臺灣產杜蘅組植物的重要特徵,根據這些特徵,可將臺灣產杜蘅組植物區分成三群:下花細辛群、大花細辛群與鴛鴦湖細辛群。然而,在nrDNA的ITS片段所建構的細辛屬植物親緣關係中,顯示臺灣產杜蘅組植物亦分為三個單系群,但是與形態的分群不一致。且發現與臺灣的種類最近緣的是產於日本琉球群島與九州及本州西南部的種類。 最後,在以臺灣杜蘅組TW支序群為對象的親緣地理研究上,發現TW支序群內各族群間遺傳結構呈現高度分化,此與其特殊之生長、傳粉與種子傳播模式有關。此外,根據巢狀支序親緣地理分析 (NCPA) 及最近共祖時間推估 (TMRCA) 的結果,推論在Bayesian skyline plot上所觀察到的族群擴張與瓶頸效應的事件,除更新世冰河期循環的作用外,可能分別導因於祖先族群入侵一新的環境,以及最近一次冰河期最大值時,極度乾冷的氣候及森林範圍退縮造成族群數量變少有關。 綜合上述研究結果。確認臺灣產杜蘅組植物共計有12個分類群,包括11種及1個變種,其中有10個種類為特有種。而根據親緣關係研究則顯示這些現生分類群的祖先可能源於中國東南部與日本之間的區域。而臺灣杜蘅組植物各分類群分化的因素,除受冰期與間冰期循環的影響外,其本身的生物特性,例如對生長環境因子的需求、繁殖與傳粉策略等,亦是主要的原因之一。
In this dissertation, I focused on the systematics, phylogeny and the process of species differentiation of Asarum section Heterotropa in Taiwan. In the systematic study, I performed morphometric analyses to resolve the taxonomic problems in the A. macranthum complex. The results support that the complex should be treated as three taxa, A. macranthum, A. macranthum var. ampulliflorum and A. taitonense. The stigma and style morphologies, the patterns on the inner wall of perianth, and the shape of the perianth-tube are the most important characters to identify the Taiwanese Heterotropa. Based on these characters, we divided all Taiwanese Heterotropa into three groups. However, this grouping is inconsistent with the grouping of the nrDNA ITS phylogenetic analysis. In addition, according to ITS phylogenetic tree, the closest relations of the Heterotropa species in Taiwan are with Ryukyu Islands and south Kyusyu. Phylogeographical study on the Taiwan clade showed high differentiation in the genetic structure among the populations in the Taiwan clade. The result may be due to the specific growth patterns, pollination mechanism and seed dispersal systems of this group. According to the results of nested clade phylogenetic analysis, time of the most ancestor estimation and Bayesian skyline plot, I inferred the demographical history of the Taiwan clade should be resulted from populations invading a new environment and the influence of extremely VI dry and cold climate in Last Glacial Maximum. In conclusion, I confirmed that there are twelve Heterotropa taxa in Taiwan, including 11 species and one variety, and ten of twelve are endemic. The ancestor of Heterotropa species in Taiwan originated from the area between Southeast China and Japan based on the phylogenetic inference. In addition to the influence of Pleistocene climatic fluctuations, the main factors that affected the species differentiation of Taiwanese Heterotropa may be correlated with its biological characteristics, such as the growth patterns, pollination mechanism and seed dispersal systems in this group.

Description

Keywords

細辛屬, 杜蘅組, 形值分析, 親緣關係, 親緣地理研究

Citation

Collections