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1.
Am J Bot ; 103(12): 2028-2057, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27919924

RESUMO

PREMISE OF THE STUDY: Revealing the relative roles of gradual and abrupt transformations of morphological characters is an important topic of evolutionary biology. Gynoecia apparently consisting of one carpel have evolved from pluricarpellate syncarpous gynoecia in several angiosperm clades. The process of reduction can involve intermediate stages, with one fertile and one or more sterile carpels (pseudomonomery). The possible origin of monomery directly via an abrupt change of gynoecium merism has been a matter of dispute. We explore the nature of gynoecium reduction in a clade of Araliaceae. METHODS: The anatomy and development of unilocular gynoecia are investigated using light and scanning electron microscopy in two members of Polyscias subg. Arthrophyllum. Gynoecium diversity in the genus is discussed in a phylogenetic framework. KEY RESULTS: Unilocular gynoecia with one fertile ovule have evolved at least four times in Polyscias, including one newly discovered case. The two unilocular taxa investigated are unicarpellate, without any traces of reduced sterile carpels. Carpel orientation is unstable, and the ovary roof and style contain numerous vascular bundles without clearly recognizable dorsals or ventrals. In contrast to pluricarpellate Araliaceae and Apiaceae, the cross zone is apparently oblique in the unicarpellate species. CONCLUSIONS: No support was found for gradual gynoecium reduction via pseudomonomery. The abrupt origin of monomery via direct change of gynoecium merism and the unstable carpel orientation observed are related to the general lability of the flower groundplan in Polyscias. The apparent occurrence of the unusual oblique cross zone in unicarpellate Araliaceae can be explained by developmental constraints.


Assuntos
Araliaceae/ultraestrutura , Flores/ultraestrutura , Araliaceae/genética , Araliaceae/crescimento & desenvolvimento , Evolução Biológica , Flores/genética , Flores/crescimento & desenvolvimento , Microscopia , Microscopia Eletrônica de Varredura , Óvulo Vegetal/genética , Óvulo Vegetal/crescimento & desenvolvimento , Óvulo Vegetal/ultraestrutura , Filogenia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/ultraestrutura , Análise de Sequência de DNA
2.
Am J Bot ; 101(9): 1519-31, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25253712

RESUMO

UNLABELLED: • PREMISE OF THE STUDY: Aspidistra is a species-rich, herbaceous monocot genus of tropical Southeast Asia. Most species are recently discovered and apparently endangered, though virtually nothing is known about their biology. Species of the genus are primarily distinguished using flower morphology, which is enormously diverse. However, the pollination process has not been directly observed in the center of diversity of the genus (N Vietnam and S China). Indirect and partly direct data on the only widely cultivated species of the genus (A. elatior) placed it among angiosperms with the most unusual pollination biology, though these data are highly controversial, suggesting pollen transfer by mollusks, crustaceans, flies, or possibly tiny soil invertebrates such as collembolans.• METHODS: Pollination of Aspidistra xuansonensis in the center of diversity of the genus was studied using visual observations and videos and light and scanning electron microscopy investigation of flowers and their pollinators. Pollinators and their larvae were molecularly barcoded.• KEY RESULTS: Aspidistra xuansonensis is pollinated by female cecidomyiid flies (gall midges). They oviposit on anthers, and larvae develop among the pollen mass. Molecular barcoding proved taxonomic identity of the larvae and the flies. The larvae neither damage floral parts nor cause gall formation, but feed on pollen grains by sucking out their content. The larvae move out of the flowers before decomposition starts. Carebara ants steal developing larvae from flowers but do not contribute to pollination.• CONCLUSIONS: More than one kind of myiophily is present in Aspidistra. Brood site pollination was documented for the first time in Aspidistra. The pollination system of A. xuansonensis differs from other kinds of brood site pollination in the exit of the larvae prior to the decomposition of floral parts.


Assuntos
Dípteros , Flores , Larva , Liliaceae/fisiologia , Pólen , Polinização , Animais , Formigas , Feminino , Oviposição , Reprodução , Vietnã
3.
Mol Phylogenet Evol ; 62(2): 693-707, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22142737

RESUMO

Phylogenetic relationships in the genus Anthyllis (Leguminosae: Papilionoideae: Loteae) were investigated using data from the nuclear ribosomal internal transcribed spacer regions (ITS) and three plastid regions (psbA-trnH intergenic spacer, petB-petD region and rps16 intron). Bayesian and maximum parsimony (MP) analysis of a concatenated plastid dataset recovered well-resolved trees that are topologically similar, with many clades supported by unique indels. MP and Bayesian analyses of the ITS sequence data recovered trees that have several well-supported topological differences, both among analyses, and to trees inferred from the plastid data. The most substantial of these concerns A. vulneraria and A. lemanniana, whose placement in the parsimony analysis of the ITS data appears to be due to a strong long-branch effect. Analysis of the secondary structure of the ITS1 spacer showed a strong bias towards transitions in A. vulneraria and A. lemanniana, many of which were also characteristic of certain outgroup taxa. This may contribute to the conflicting placement of this clade in the MP tree for the ITS data. Additional conflicts between the plastid and ITS trees were more taxonomically focused. These differences may reflect the occurrence of reticulate evolution between closely related species, including a possible hybrid origin for A. hystrix. The patterns of incongruence between the plastid and the ITS data seem to correlate with taxon ranks. All of our phylogenetic analyses supported the monophyly of Anthyllis (incl. Hymenocarpos). Although they are often taxonomically associated with Anthyllis, the genera Dorycnopsis and Tripodion are shown here to be more closely related to other genera of Loteae. We infer up to six major clades in Anthyllis that are morphologically well-characterized, and which could be recognized as sections. Four of these agree with various morphology-based classifications, while the other two are novel. We reconstruct the evolution of several morphological characteristics found only in Anthyllis or tribe Loteae. Some of these characters support major clades, while others show evidence of homoplasy within Anthyllis.


Assuntos
DNA de Cloroplastos/genética , DNA Espaçador Ribossômico/genética , Fabaceae/genética , Especiação Genética , Filogenia , Pólen/genética , Sequência de Bases , Teorema de Bayes , Evolução Biológica , Núcleo Celular/genética , Fabaceae/anatomia & histologia , Fabaceae/classificação , Íntrons , Funções Verossimilhança , Modelos Genéticos , Dados de Sequência Molecular , Plastídeos/genética , Pólen/anatomia & histologia , Pólen/classificação , Alinhamento de Sequência , Análise de Sequência de DNA
4.
Mol Phylogenet Evol ; 57(1): 471-6, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20538066

RESUMO

The Umbelliferae is a large and taxonomically complex family of flowering plants whose phylogenetic relationships, particularly at low taxonomic levels, are generally obscure based on current and widely used molecular markers. Thus, information on the phylogenetic utility of additional molecular markers at these levels is highly favorable. We investigate the utility of nuclear ribosomal DNA (nrDNA) external transcribed spacer (ETS) sequences for phylogenetic inference in Umbelliferae tribe Tordylieae, a group whose relationships have been previously difficult to resolve owing to low sequence variability, and compare the results to those obtained from the nrDNA internal transcribed spacer (ITS) region. We report that the ETS region evolves at a slightly faster rate and has a higher percentage of parsimony informative characters than that of ITS and all chloroplast DNA loci examined to date. The ETS region is a valuable phylogenetic marker in Umbelliferae for low level analysis, especially when used in combination with ITS.


Assuntos
Apiaceae/genética , DNA Espaçador Ribossômico/genética , Filogenia , Apiaceae/classificação , Teorema de Bayes , DNA de Plantas/genética , Evolução Molecular , Marcadores Genéticos , Análise de Sequência de DNA
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