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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/64709
標題: | 中國廣西石灰岩岩溶植物的演化—報春苣苔屬之親緣關係 Tempo and mode of plant evolution on limestone karst in Guangxi, China—Insights from phylogenetics of Primulina (Gesneriaceae) |
作者: | Hsuan Chang 章璿 |
指導教授: | 鍾國芳 |
關鍵字: | 小花苣苔屬,趨同演化,苦苣苔科,距離隔離模式,岩溶洞穴,石灰岩岩溶地形,分子定年,報春苣苔屬, Chiritopsis,convergence,Gesneriaceae,isolation by distance,karst cave,limestone karst,molecular dating,Primulina, |
出版年 : | 2012 |
學位: | 碩士 |
摘要: | 中國廣西石灰岩喀斯特岩溶地形蘊含了極高的植物多樣性及特有度。其獨特之喀斯特地貌被認為是驅動了此特殊生態系中植物演化的重要動力。苦苣苔科報春苣苔屬(Gesneriaceae: Primulina) 包含了唇柱苣苔屬唇柱苣苔族Chirita sect. Gibbosaccus、小花苣苔屬Chiritopsis、文采苣苔屬Wentsaiboea及原本之單種屬之報春苣苔屬,為此區最具代表性之石灰岩植物之一。為了解廣西石灰岩植物的演化,本研究利用細胞核內轉錄區間(ITS)及葉綠體 trnL-F片段重建97種(147個樣本)報春苣苔之親緣關係。同時配合分子定年及特徵重建來討論分歧時序及形態的演化。研究結果顯示報春苣苔之親緣關係與地理分布有明顯正相關性,親緣關係較近的物種其地理分布同樣較近,地理因素因為影響其演化之關鍵。根據定年結果,報春苣苔的演化時序大致與廣西喀斯特地形發育時程相吻合,皆界於第三紀中晚期(40到25百萬年前)。綜合以上結果,廣西報春苣苔之演化與當地喀斯特地形有密不可分的關係,現今各種間異域隔離分布的模式應為破碎的石灰岩喀斯特棲地所催化導致。同時,獨特的喀斯特生境對於報春苣苔形態之演化亦有影響。根據特徵重建,原屬小花苣苔屬之洞穴物種的共同特徵—小型花及白色花冠為適應洞穴生境所導致的趨同演化。 The limestone karst landscape of Guangxi, China, harbors extremely high-level of biodiversity and endemism of vascular plants. It has been hypothesized that the unique geological features of karst topography could have driven the evolution of plants there. Primulina (Gesneriaceae), a recently re-circumscribed genus including Chirita sect. Gibbosaccus, Chiritopsis, Wentsaiboea and the original monotypic Primulina, is one of the most representative limestone plant taxon inhabiting this area. In this thesis, we conducted phylogenetic analyses of 79 species (128 samples) of Primulina and allied genera using ITS and trnL-F sequences to study the plant evolution in Guangxi. Divergence date estimates and ancestral character analysis were conducted to infer timing of clade diversification and character evolution. Phylogenetic analysis indicates that species distributed in geographical proximity are also phylogenetically closely related. Significant positive correlation between genetic and geographic distance is detected in most geographically-confined groups, implying the importance of geography in generating species diversity. Divergence time estimates suggest that Primulina evolved corresponding to the development sequences of Guangxi karst (middle to late Tertiary, from 40 MYBP to 25 MYBP). Our results reveal that the evolution of Primulina is highly likely associated with Guangxi limestone karst landscape and the deriving of allopatric-distributed species was triggered by the fragmented habitats caused during karsification. The unique features of karst landscape also contribute to the morphological diversification of Primulina. The small-flowered and white-colored ‘Chiritopsis-like’ characters in cave-dwelled Primulina species are suggested to be the results of convergence driven by the cave environment. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/64709 |
全文授權: | 有償授權 |
顯示於系所單位: | 森林環境暨資源學系 |
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