腺齿木科系统位置评述

腺齿木科(Trimeniaceae)含2属5种。形态学研究显示腺齿木科具有许多原始性状。最新的分子系统发育研究显示,腺齿木科是现存被子植物的重要基部类群之一。但有关腺齿木科的系统位置存在争议。被子植物(有花植物)的起源与辐射一直是植物系统学家关注的热点。对该科系统位置的研究历史与现状进行评述。     

金鱼藻科系统位置评述

金鱼藻科(ceratophyllaceae)含1属7种,广布全世界。形态学研究显示,金鱼藻科具有许多难以解释的性状,与其它类群无法比较;最新的分子系统发育研究显示,金鱼藻科是现存被子植物的基部类群之一;有关金鱼藻科的系统位置存在争议,被子植物(有花植物)的起源与辐射一直是植物系统学家关注的热点。本文对该科系统位置的研究历史与现状进行评述。     

互叶梅科系统位置评述

互叶梅科(Amborellaceae)一属一种。形态学研究显示互叶梅(Amborella,tricopoda Baill．)具有许多原始性状。大多数最新的分子系统发育研究显示,互叶梅科是现存被子植物的最基部类群。但有关互叶梅科的系统位置存在争议。被子植物(有花植物)的起源和辐射一直是植物学家关注的热点。本文将对该科系统位置的研究历史与现状进行评述。     

莲科系统位置评述

莲科含1属1种2亚种,以具有最古老的有活力的种子而著称。形态学研究显示,莲不仅具有双子叶植物特征,而且又具有单子叶植物的某些性状。因此,对研究被子植物(有花植物)的起源与演化以及单子叶植物的起源具有重要价值。被子植物(有花植物)的起源与辐射一直是植物学家关注的热点,有关莲科的系统位置存在争议。该文对该科系统位置的研究历史与现状进行评述。     

互叶梅科系统位置评述

互叶梅科 Amborellaceae 一属一种 .形态学研究显示互叶梅 Amborella tricopoda Baill. 具有许多原始性状 .大多数最新的分子系统发育研究显示 ,互叶梅科是现存被子植物的最基部类群 .但有关互叶梅科的系统位置存在争议 .被子植物 有花植物 的起源和辐射一直是植物学家关注的热点 .本文将对该科系统位置的研究历史与现状进行评述     

睡莲科系统位置评述

形态学研究显示睡莲科Nymphaeaceae具有许多原始性状。睡莲科又被称为“古草本”。最新的分子系统发育研究显示,睡莲科是现存被子植物系统树根部附近最早分异谱系的演化支之一,对研究被子植物(有花植物)的起源与早期进化具有重要价值,但有关睡莲科的范围和系统位置存在争议。被子植物的起源与辐射一直是植物学家关注的热点。本文对该科系统位置的研究历史与现状进行了评述。     

被子植物起源研究中几种观点的思考

对被子植物起源研究中的几种观点进行了讨论。(1)由于被子植物存在着一组共同的性状,它们不可能是从不同祖先起源的,而是有着共同的祖先。被子植物是一个单源起源的类群。现存被子植物分类系统是依据包括形态学(广义)、分子系统学、古植物学和植物地理学等的综合性状建立的,只能表示出现存类群的亲缘关系并且追溯到它们最近的祖先。人们现在还不可能建立一个包括全部已绝灭的类群和现代生存类群的谱系发生系统。因此,现存被子植物分类系统只能看作是“亲缘”系统。(2)分析了用于推测被子植物起源时间的分子、化石和地理分布证据。我们认为,要确定被子植物起源时间,植物化石是一类重要证据,但化石只能说是植物本身可保存部分和当时当地所提供的化石条件的综合反映,它们不可能就是植物类群或种的起源时间。人们还必须考虑到化石本身的演化历史。应用分子钟也是一种手段,但误差比较大。如果我们除了利用上述两种资料之外,根据植物类群的现代分布格局及其形成,把植物的演化同地球的历史和板块运动联系起来,以推断它们起源的时间,这无疑会增加其可信度。通过对56个种子植物不同演化水平的重要科属地理分布的研究结果,我们曾提出被子植物的起源时间可能要追溯到早侏罗世,甚至晚三叠世。(3)分析了基于分子证据所提出的被子植物基部类群——ANITA成员(包括无油樟科Amborellaceae、睡莲科Nymphaeaceae、八角目Illiciales、早落瓣科Trimeniaceae、木兰藤科Austrobaileyaceae)的性质,讨论了ANITA成员在现代几个被子植物分类系统中的系统位置的不同观点,评价了它们的形态学(广义)性状。指出ANITA的成员由于包含大量的祖征,是属于原始的类群。但由于它们的共有衍征很少,如花粉球形,说明它们在被子植物演化早期就分道扬镳了,沿着不同的传代线分化。因此ANITA是一个源于不同传代线的复合群。     

水盾草科系统位置评述

水盾草科(Cabombaceae)是双子叶植物。水盾草科包括2属: 水盾草属(Cabomba Aublet.)和莼菜属(Brasenia Schreb.)。形态学研究显示水盾草科具有许多原始性状, 而且在其适应水生环境的过程中经历了性状退化。水盾草科又被称为“古草本”。最新的分子系统发育研究显示, 水盾草科是现存被子植物系统树基部ANITA类群的成员之一。但有关水盾草科的系统位置存在争议。被子植物的起源与早期分化一直是植物学家关注的热点。本文对该科系统位置的研究历史与现状进行评述。     

水盾草科系统位置评述

水盾草科（Cabombaceae）是双子叶植物。水盾草科包括2属：水盾草属（Cabomba Aublet．）和莼菜属（Brasenia Schreb．）。形态学研究显示水盾草科具有许多原始性状,而且在其适应水生环境的过程中经历了性状退化。水盾草科又被称为“古草本”。最新的分子系统发育研究显示,水盾草科是现存被子植物系统树基部ANITA类群的成员之一。但有关水盾草科的系统位置存在争议。被子植物的起源与早期分化一直是植物学家关注的热点。本文对该科系统位置的研究历史与现状进行评述。     

中国樟科物种编目:问题和展望

<正>樟科(Lauraceae)隶属于被子植物木兰亚纲(Magnoliidae)木兰超目(Magnolianae)樟目(Laurales)(RevealChase,2011)。该科的化石记录可追溯至白垩纪中期,现存50属2,500–3,000种,泛热带分布(李捷和李锡文,2004),是被子植物分类中最困难的科之一(Paton et al.,2008)。根据分子系统学研究(Chanderbali et al.,2001;RohwerRudolph,2005),樟科包含最基部的Hypodaphnis Stapf分支、厚壳桂属(Cryptocarya R.Br.)群分支、檬果樟属(Caryodaphnopsis Airy Shaw)–新樟属(Neocinnamomum     

Multigene analyses identify the three earliest lineages of extant flowering plants

Flowering plants (angiosperms) are by far the largest, most diverse, and most important group of land plants, with over 250,000 species and a dominating presence in most terrestrial ecosystems. Understanding the origin and early diversification of angiosperms has posed a long-standing botanical challenge [1]. Numerous morphological and molecular systematic studies have attempted to reconstruct the early history of this group, including identifying the root of the angiosperm tree. There is considerable disagreement among these studies, with various groups of putatively basal angiosperms from the subclass Magnoliidae having been placed at the root of the angiosperm tree (reviewed in [2-4]). We investigated the early evolution of angiosperms by conducting combined phylogenetic analyses of five genes that represent all three plant genomes from a broad sampling of angiosperms. Amborella, a monotypic, vessel-less dioecious shrub from New Caledonia, was clearly identified as the first branch of angiosperm evolution, followed by the Nymphaeales (water lillies), and then a clade of woody vines comprising Schisandraceae and Austrobaileyaceae. These findings are remarkably congruent with those from several concurrent molecular studies [5-7] and have important implications for whether or not the first angiosperms were woody and contained vessels, for interpreting the evolution of other key characteristics of basal angiosperms, and for understanding the timing and pattern of angiosperm origin and diversification.     

Development and structure of the female gametophyte in <Emphasis Type="Italic">Austrobaileya scandens</Emphasis> (Austrobaileyaceae)

Austrobaileyales, comprising the four families Austrobaileyaceae, Trimeniaceae, Schisandraceae, and Illiciaceae, are included in the basal angiosperms along with Amborellaceae and Nymphaeaceae. Here, we present the first developmental study of the female gametophyte in Austrobaileya scandens, the only species of Austrobaileyaceae, which are sister to the rest of the Austrobaileyales. Austrobaileya scandens has a four-celled/four-nucleate embryo sac as in the derived families of the order, e.g., Illiciaceae and Schisandraceae. It is monosporic, with the chalazal megaspore of a tetrad developing into the embryo sac composed of an egg cell, two synergids, and one polar nucleus. This mode of embryo sac formation was first reported in Schisandra over 40 years ago and should now be established as the Schisandra type. Its occurrence in A. scandens shows that the Schisandra-type embryo sac is likely common to the whole Austrobaileyales as well as to Nymphaeaceae. Amborellaceae were recently reported to have an eight-celled/nine-nucleate embryo sac, clarifying that none of the basal angiosperms has the seven-celled/eight-nucleate Polygonum-type embryo sac found in the majority of angiosperms, and that the Polygonum-type embryo sac represents a derived character state in angiosperms.     

CLADISTICS OF THE MAGNOLIIDAE

Abstract A cladistic resolution is presented for the origin of the angiosperms based on a parsimony analysis of 49 taxa of Magnoliidae. Hamamelidae and Alismatidae, with gymnospermous outgroup comparisons for the polarization of 104 characters. The Magnoliidae is recognized as a paraphyletic assemblage of nine orders: Calycanthales, Magnoliales, Laurales, Illiciales, Lactoridales. Ranunculales, Aristolochiales, Piperales and Nymphaeales. The Calycanthaceae and Idiospermaceae are segregated as the new order Calycanthales, which is hypothesized to be the archetype for angiosperms. Excluding Winteraceae and Lactoridaceae, the Magnoliales is monophyletic. The Austrobaileyaceae is a first branch of Magnoliales, rather than lauralean. Excluding Amborellaceae and Calycanthales, the Laurales is monophyletic. The Chloranthaceae is a first branch of Laurales, rather than piperalean. The Amborellaceae and Winteraceae are early branches of Illiciales. The Lactoridaceae is isolated as the Lactoridales. Including Papaveraceae, the Ranunculales is monophyletic, with Lardizabalaceae as a first branch. The Ranunculales is more closely related to the Hamamelidae, forming the clade Tricolpates. The Aristolochiales, Piperales and Nymphaeales are successively more closely related to the Alismatidae, forming the clade Paleoherbs. The Nelumbonaceae are nymphaealean Paleoherbs, rather than Tricolpates. The Lactoridaceae is not a Paleoherb. These results support many aspects of the strobilar-flower hypothesis for the origin of the angiosperms, as well as the plesiomorphic character states of woody shrubs with simple, pinnatelyveined leaves.     

Hamamelidaceae: Geographic Distribution,Fossil History and Origin

The family Hamamelidaceae is one of the core (or key) groups for studying the phylogeny of Hamamelids. It is an important taxon for the palaeobotanists and the botanists in discussing the origin and early evolution of the angiosperms owing to its strong differentiation of gross and pollen morphological characters. In this paper, the systematic position, modern distribution pattern and fossil history of the genera are analyzed, and the place and time of origin of the family are discussed according to the principle of the unity between the phylogeny and distribution of plants. The paper consists four parts.     

DNA C-values in seven families fill phylogenetic gaps in the basal angiosperms

The evolutionary significance of the c . 1000-fold range of DNA C-values in angiosperms (1C =  c . 0.1–127.4 pg) has often attracted interest. A recent analysis, which superimposed available C-value data onto the angiosperm phylogeny, that placed Ceratophyllaceae as the most basal angiosperm family led to the conclusion that ancestral angiosperms were characterized by small genomes (defined as 1C £ 3.5 pg). However, with the recent increase in DNA sequence data and large-scale phylogenetic analyses, strong support is now provided for Amborellaceae and/or Nymphaeaceae as the most basal angiosperm families, followed by Austrobaileyales (comprising Schisandraceae, Trimeniaceae and Austrobaileyaceae). Together these five families comprise the ANITA grade. The remaining basal angiosperm families (Ceratophyllaceae, Chloranthaceae and magnoliids), together with monocotyledons and eudicotyledons, form a strongly supported clade. A survey showed that C-value data were scarce in the basal angiosperm families, especially the ANITA grade. The present paper addresses these phylogenetic gaps by providing C-value estimates for each family in ANITA, together with C-values for species in Chloranthaceae, Ceratophyllaceae and a previously unrepresented family in the magnoliids, the Winteraceae.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 175–179.