母草科親緣關係與系統分類研究
No Thumbnail Available
Date
2016
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
母草科植物由Rahmanzadeh等人(2005)以葉綠體分子親緣關係將其由廣義玄參科中獨立，本科主要分布於熱帶，共包含13屬約160種。然而在先前的親緣研究中，主要以非洲地區物種為主要研究材料，而缺乏全面而詳細的研究，且科內各屬的關係仍未明瞭。本研究的主要目標為：1. 以更全面的採樣建構母草科的親緣關係。2. 綜合重要的分類形態特徵、地理分布與親緣關係探討母草科各屬的起源與形態特徵的演化。3. 綜合親緣關係與形態特徵重新修訂母草科的範圍與建立科內分類系統。
本研究在形態上討論了植物體、葉脈、萼筒、花冠、雄蕊、種子等形態特徵，並以形態特徵分群結果作為祖先特徵重建與親緣關係探討的依據。在親緣關係建構上，本研究使用葉綠體DNA的rps16、matK、trnL/F片段與低複製數的核DNA RPB2片段進行親緣關係建構，結果顯示非洲產的Stemodiposis位於本科最基群，而其餘的各類群則形成一高度支持的單系群，而該單系群系則包含了數個高支持度的主要分支，且各分支均有形態特徵的支持，其中以雄蕊形態、種子形態具代表性，而過去分類學者所強調的萼筒形態則無法作為各分支的共衍徵。綜合形態與親緣關係，重新修訂母草科的範圍，並將科內數個屬重新獨立，同時提出新的屬。
在親緣地理的分析上，母草科包含Stemodiopsis屬起源於51.38百萬年前後的非洲，與Early Eocene Climatic Optimum的範圍相吻合；而本研究認定的母草科則為36.28百萬年左右，起源於非洲-亞洲地區，而後母草科內分為兩大分支，其中一支為非洲起源，包含了Crepidorhopalon、Lindernia、Micranthemum、Ilysanthes等屬。而另一分支則為亞洲起源，包含了Tittmannia、Torenia、Vandellia、Bonnaya等屬。其中佔非洲母草科物種半數以上的Vandellia屬則來自亞洲經長距離傳播而分化。
在分類處理部分，本研究將Stemodiopsis排除於母草科之外；Torenia、Lindernia、Vandellia重新修訂其範圍；Tittmannia、Ilysanthes分別由Vandellia與Lindernia所獨立；並提出一新屬—Grandiflorescentia。以非洲地區為主要分布的Craterostigma、Chamaegigas、Linderniella三屬則併入Vandellia屬內；Legazpia、Schizotorenia與部分Vandellia則併入Torenia。
Linderniaceae was proposed by Rahmanzadeh et al. in 2005 that were segregated from Scrophulariaceae s.l. based on cpDNA phylogeny and stamens characters. Linderniaceae is comprised of approximately 160 speices belonging to at least 13 genera that are mostly distributed in the tropics of the world. However, the phylogeny was mostly reconstructed based on African species recently, and the generic relationships were still unsolved. On the other hand, there were only limited taxonomic revisions available for most of the genera in Linderniaceae. Therefore, the main aim of this dissertation is to resolve the phylogenetic relationship of genera and species. Furthermore, Evolutionary analyses of morphological characters are integrated to address characters evolution, historical biogeography, and inferring divergence time within Linderniaceae. Herein, important taxonomic characters are examined and discussed their taxonomic significance, such as habit, venation, calyx, corolla, stamens, and seeds within Linderniaceae. For phylogenetic study, partial sequences of chloroplast DNA rps16, matK, and trnL/F and a low-copy nuclear gene RPB2 were used for phylogenetic reconstruction. The inferred phylogeny showed that Stemodiopsis is the basal group and distinct from all other Linderniaceae genera. Besides Stemodiopsis, other taxa form a highly supported monophyletic group which comprised of five well supported clades that are synapomorphic in the anterior pair stamens/staminodes and seeds surface. In contrast, the clusters of the calyx morphology are not correspondent to the phylogenetic relationships of Linderniaceae. The molecular dating suggests that the Linderniaceae and Stemodiopsis diverged since ca. 51.38 million years ago, i.e. Early Eocene Climatic Optimum period, in Africa. Lindernia are inferred to be diverged since approximately 36.28 million years ago in Africa-Asia region. Two major lineages of Linderniaceae that comprised of the Asian species and the African species, respectively, were then subsequently diverged. The African lineage includes genera Lindernia, Ilysanthes, Crepdorhopalon, and Micranthemum, and the Asian lineage is comprised of Torenia, Vandellia, Bonnaya, and Tittmannia. The biogeographic inference of the genus Vandellia, which is mostly comprised of African species, is probably origined from Asia following a long-distance colonization event to Africa with a subsequent radiation. Based on morphological and molecular evidence, Stemodiopsis is excluded form Linderniaceae; Torenia, Lindernia, and Vandellia are redifined; Ilysanthes and Tittmannia are re-stated and separated from Lindernia and Vandellia, respectively. A new genus, the Grandiflorescentia, is proposed. The African genera—Craterostigma, Chamaegigas, Linderniella are treated as synonym of Vandelia. Legazpia, Schizotorenia and partial Vandellia taxa are replaced into the genus Torenia.
Linderniaceae was proposed by Rahmanzadeh et al. in 2005 that were segregated from Scrophulariaceae s.l. based on cpDNA phylogeny and stamens characters. Linderniaceae is comprised of approximately 160 speices belonging to at least 13 genera that are mostly distributed in the tropics of the world. However, the phylogeny was mostly reconstructed based on African species recently, and the generic relationships were still unsolved. On the other hand, there were only limited taxonomic revisions available for most of the genera in Linderniaceae. Therefore, the main aim of this dissertation is to resolve the phylogenetic relationship of genera and species. Furthermore, Evolutionary analyses of morphological characters are integrated to address characters evolution, historical biogeography, and inferring divergence time within Linderniaceae. Herein, important taxonomic characters are examined and discussed their taxonomic significance, such as habit, venation, calyx, corolla, stamens, and seeds within Linderniaceae. For phylogenetic study, partial sequences of chloroplast DNA rps16, matK, and trnL/F and a low-copy nuclear gene RPB2 were used for phylogenetic reconstruction. The inferred phylogeny showed that Stemodiopsis is the basal group and distinct from all other Linderniaceae genera. Besides Stemodiopsis, other taxa form a highly supported monophyletic group which comprised of five well supported clades that are synapomorphic in the anterior pair stamens/staminodes and seeds surface. In contrast, the clusters of the calyx morphology are not correspondent to the phylogenetic relationships of Linderniaceae. The molecular dating suggests that the Linderniaceae and Stemodiopsis diverged since ca. 51.38 million years ago, i.e. Early Eocene Climatic Optimum period, in Africa. Lindernia are inferred to be diverged since approximately 36.28 million years ago in Africa-Asia region. Two major lineages of Linderniaceae that comprised of the Asian species and the African species, respectively, were then subsequently diverged. The African lineage includes genera Lindernia, Ilysanthes, Crepdorhopalon, and Micranthemum, and the Asian lineage is comprised of Torenia, Vandellia, Bonnaya, and Tittmannia. The biogeographic inference of the genus Vandellia, which is mostly comprised of African species, is probably origined from Asia following a long-distance colonization event to Africa with a subsequent radiation. Based on morphological and molecular evidence, Stemodiopsis is excluded form Linderniaceae; Torenia, Lindernia, and Vandellia are redifined; Ilysanthes and Tittmannia are re-stated and separated from Lindernia and Vandellia, respectively. A new genus, the Grandiflorescentia, is proposed. The African genera—Craterostigma, Chamaegigas, Linderniella are treated as synonym of Vandelia. Legazpia, Schizotorenia and partial Vandellia taxa are replaced into the genus Torenia.
Description
Keywords
母草科, 系統分類, 親緣關係, 演化, 分類學, Linderniaceae, Systematic, Phylogeny, Evolution, taxonomy