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標題: | 亞洲產秋海棠屬植物分子親緣關係研究以及對其系統分類學與生物地理學的影響 Molecular Phylogenetics of Asian Begonia (BEGONIACEAE): Systematics and Biogeographic Implications |
作者: | Wai-Chao Leong 梁慧舟 |
指導教授: | 鍾國芳 |
關鍵字: | 亞洲,秋海棠屬,秋海棠科,大屬,生物地理,演化,雜交,分子親緣關係,生物系統學,分類學, Asia,Begonia,Begoniaceae,Big Genus,Biogeography,Evolution,Hybridization,Molecular Phylogeny,Systematics,Taxonomy, |
出版年 : | 2017 |
學位: | 博士 |
摘要: | 秋海棠屬為開花植物第六大屬,全世界約有1,600 種,分布於亞洲、非洲與美洲的熱帶及亞熱帶地區,本屬分佈地域廣,但多數種類分布非常狹隘,物種特有性甚高,極易因棲地破壞而有滅絕之虞,其豐富的物種多樣性與特殊的生物地理分布式樣為研究植物多樣性起源與維持機制的絕佳素材。本研究嘗試檢討並改進亞州秋海棠各組(Section)間劃分方式,使用葉綠體DNA標記重建了亞洲秋海棠親緣關係,結果顯示亞洲秋海棠主要分成亞洲大陸支序群與南洋群島支序群,除了前人根據分子證據重新劃分的側膜組(Section Coelocentrum)與菲律賓秋海棠組(Section Baryandra)外,其他主要的組皆非單一起源。祖先性狀重建分析(Acenstral State Reconstruction Analysis)的結果認為過去用於組別劃分的生殖構造特徵多不穩定。建議將秋海棠組重新定義成一群屬於亞洲大陸支序群的,具有球莖的落葉性秋海棠,並且建議把亞洲大陸支序群中常綠性物種全數扁果組。分子定年與祖先區域重建分析(Ancestral Area Reconstruction Analysis)的結果顯示亞州大陸秋海棠屬植物起源自非洲,並在到達亞洲後以喜馬拉雅/橫斷山脈與雲南/中南半島地區為中心,向外擴散至亞洲南洋群島、中國及台灣等地區。其豐富多樣性的產生,可能與六百萬年前中新世末期喜馬拉雅—西藏板塊的隆起有關。為了解種間雜交現象在秋海棠種化過程中扮演的角色,本研究利用二組低拷貝核內核苷酸DNA標記(PI, RPB2)與葉綠體標記所重建的親緣關係結果兩相比對,同時配合染色體數目資料,同時探討雜交事件對秋海棠果實性狀的演化過程造成的影響,發現多個經由種間雜交產生的異源多倍體,顯示種間雜交種化現象對秋海棠種化有一定貢獻,而不同果實性狀物種間雜交並種化的現象顯示果實性狀的演化歷史相當複雜。 Begonia (Begoniaceae) is the 6th largest plant genus, with estimated 1,600 species occurring throughout tropical and subtropical America, Africa, and Asia. The rich diversity and unique biogeographic patterns of Begonia also present an unprecedented opportunity to test hypothesis regarding the origin and maintenance of biodiversity in tropical and subtropical regions. This study is focus on sectional delimitation of Asian Begonia. Molecular Phylogeny of Asian Begonia was reconstructed by using Chloroplast DNA markers. The result suggests that Indian species are early derived among Asian Begonia and the rest can be divided into two major clades, Continental Clade and Malesian Clade. Except Section Coelocentrum and Section Baryandra, which have been recircumscribed by molecular evidences, all main sections of Asian Begonia are not monophyletic. The result of Acenstral State Reconstruction Analysis also suggests that reproductive characters using for sectional delimitation in traditional taxonomy are highly homoplastic. I suggest to redefine Section Diploclinium as a group of tuberous species in the Continental Clade. At the same time, all evergreen species in the Continental Clade was included into Section Platycentrum. The results of Molecular dating and Ancestral Area Reconstruction Analysis reveals that Asian Begonia disperesd from Africa. After arrived and diversified in the Himalayas/Hengduan Mt. and Yunnan/Indochina Area, and subsequently dispersed to Malesia, China, and Taiwan. The high species diversity of Continental Asia Begonia may related to the uplifting of Himalaya-Tibetan Plateau since late Miocene. Approach by assembling chloroplast and two nuclear DNA sequence data (PI, RPB2) suggests that fruit type evolution of Asian Begonia is interfered by hybridization events between capsular and berry-like fruit parent combinations. Studies of speciation mechanism of Begonia were previously focused on geographical isolation. This study primarily assesses the importance of hybridization in Begonia speciation process by providing molecular data. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2587 |
DOI: | 10.6342/NTU201700606 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 森林環境暨資源學系 |
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