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Magnus Lidén - One of the best experts on this subject based on the ideXlab platform.
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Studies in Dactylicapnos (Papaveraceae–Fumarioideae) part II. Revision of Dactylicapnos sect. Pogonosperma sect. nov., with D. arunachalensis sp. nov.
Nordic Journal of Botany, 2014Co-Authors: Magnus Lidén, Mitilesh K. PathakAbstract:Dactylicapnos sect. Pogonosperma Liden & M. K. Pathak sect. nov. is established and revised based on morphology, and found to include four species: D. gaoligongshanensis from west Yunnan, D. arunachalensis Liden & M. K. Pathak sp. nov., endemic to central Arunachal Pradesh, D. grandifoliolata (syn. D. ventii) and D. paucinervia (K. R. Stern) Liden & M. K. Pathak comb. nov., the two latter species widespread in the east Himalayas.
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studies in dactylicapnos papaveraceae Fumarioideae part ii revision of dactylicapnos sect pogonosperma sect nov with d arunachalensis sp nov
Nordic Journal of Botany, 2014Co-Authors: Magnus Lidén, Mitilesh K. PathakAbstract:Dactylicapnos sect. Pogonosperma Liden & M. K. Pathak sect. nov. is established and revised based on morphology, and found to include four species: D. gaoligongshanensis from west Yunnan, D. arunachalensis Liden & M. K. Pathak sp. nov., endemic to central Arunachal Pradesh, D. grandifoliolata (syn. D. ventii) and D. paucinervia (K. R. Stern) Liden & M. K. Pathak comb. nov., the two latter species widespread in the east Himalayas.
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Phylogeny and classification ofFumariaceae, with emphasis onDicentra s. l., based on the plastid generps16 intron
Plant Systematics and Evolution, 1997Co-Authors: Magnus Lidén, Tatsundo Fukuhara, Johan Rylander, Bengt OxelmanAbstract:The phylogeny of Fumariaceae , as inferred from rps 16 intron sequences, is compared with morphological data, and nrDNA-ITS. The different data sets are largely congruent and indicate that (1) Dicentra and the tribe Corydaleae as hitherto circumscribed are polyphyletic, (2) Lamprocapnos (= Dicentra spectabilis ) is sister group to the rest of subfam. Fumarioideae , (3) Ehrendorferia , gen. nov. (= Dicentra chrysantha and D. ochroleuca ) is basal in the latter group, (4) the morphologically aberrant Ichtyoselmis , gen. nov. (= Dicentra macrantha ) groups with Dicentra s. str., (5) the genus Cysticapnos should be included in the tribe Fumarieae , (6) Dactylicapnos (= Dicentra subg. Dactylicapnos ) is sister group to Corydalis , (7) the genus Corydalis is monophyletic, and consists of three subgenera: Chremnocapnos , stat. nov., Sophorocapnos , stat. nov., and Corydalis. The following new combinations are validated: Ehrendorferia chrysantha, E. ochroleuca, Ichtyoselmis macrantha , and Lamprocapnos spectabilis.
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seed coat anatomy in fumariaceae Fumarioideae
Botanical Journal of the Linnean Society, 1995Co-Authors: Tatsundo Fukuhara, Magnus LidénAbstract:Seed-coat anatomy is described in 122 species of Fumarioideae, which represent all the genera, subgenera, and most sections. Nine seed-coat types were recognized: (I) Dicentra subg. Hedycapnos , (II) Dicentra subg. Chrysocapnos , (III) Dicentra subg. Macranthos , (IV) Dicentra subg. Dicentra , (V) Corydalis p.p. , (VI) rest of Corydaleae, Cysticapnos, Pseudofumaria and Ceratocapnos , (VII) Discocapnos and Sarcocapnos p. p. , (VIII) Sarcocapnos p. p., Platycapnos and Trigonocapnos , and (IX) Fumariinae. Variable characters are polarized based on the comparison with Fumariaceae-Hypecooideae, Papaveraceae and Pteridophyllaceae. It is assumed that endotestal seed-coat type (I) is most primitive, that exotestal seed-coat types (II–VIII) are derived therefrom, and that the reduction of the mechanical layer, including the origin of thin seedcoat type (DC) occurred repeatedly in combination with indehiscent, hard-walled fruits. Dicentra subg. Hedycapnos (with type I) possesses a combination of primitive testai characters unique within the subfamily, suggesting it represents a sister group to the rest of the subfamily. Each of the other subgenera (with II, III or IV) is also characterized by a unique combination of seed-coat characters, which are found in the outgroups but not in the other genera. Seedcoat characters support the monophyly of Fumarioideae exclusive of Dicentra subg. Hedycapnos , Fumarioideae exclusive of Dicentra , of Dicentra subg. Dicentra , of Corydalis p.p. , and of Fumariinae.
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Seed‐coat anatomy in Fumariaceae‐Fumarioideae
Botanical Journal of the Linnean Society, 1995Co-Authors: Tatsundo Fukuhara, Magnus LidénAbstract:Seed-coat anatomy is described in 122 species of Fumarioideae, which represent all the genera, subgenera, and most sections. Nine seed-coat types were recognized: (I) Dicentra subg. Hedycapnos , (II) Dicentra subg. Chrysocapnos , (III) Dicentra subg. Macranthos , (IV) Dicentra subg. Dicentra , (V) Corydalis p.p. , (VI) rest of Corydaleae, Cysticapnos, Pseudofumaria and Ceratocapnos , (VII) Discocapnos and Sarcocapnos p. p. , (VIII) Sarcocapnos p. p., Platycapnos and Trigonocapnos , and (IX) Fumariinae. Variable characters are polarized based on the comparison with Fumariaceae-Hypecooideae, Papaveraceae and Pteridophyllaceae. It is assumed that endotestal seed-coat type (I) is most primitive, that exotestal seed-coat types (II–VIII) are derived therefrom, and that the reduction of the mechanical layer, including the origin of thin seedcoat type (DC) occurred repeatedly in combination with indehiscent, hard-walled fruits. Dicentra subg. Hedycapnos (with type I) possesses a combination of primitive testai characters unique within the subfamily, suggesting it represents a sister group to the rest of the subfamily. Each of the other subgenera (with II, III or IV) is also characterized by a unique combination of seed-coat characters, which are found in the outgroups but not in the other genera. Seedcoat characters support the monophyly of Fumarioideae exclusive of Dicentra subg. Hedycapnos , Fumarioideae exclusive of Dicentra , of Dicentra subg. Dicentra , of Corydalis p.p. , and of Fumariinae.
Sophie Nadot - One of the best experts on this subject based on the ideXlab platform.
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Zygomorphy evolved from disymmetry in Fumarioideae (Papaveraceae, Ranunculales): new evidence from an expanded molecular phylogenetic framework
Annals of Botany, 2015Co-Authors: Hervé Sauquet, Catherine Damerval, Laetitia Carrive, Sophie Nadot, Julie Sannier, Noëlie Poullain, Catherine Damerval, Sophie NadotAbstract:Background and Aims Fumarioideae (20 genera, 593 species) is a clade of Papaveraceae (Ranunculales) characterized by flowers that are either disymmetric (i.e. two perpendicular planes of bilateral symmetry) or zygomorphic (i.e. one plane of bilateral symmetry). In contrast, the other subfamily of Papaveraceae, Papaveroideae (23 genera, 230 species), has actinomorphic flowers (i.e. more than two planes of symmetry). Understanding of the evolution of floral symmetry in this clade has so far been limited by the lack of a reliable phylogenetic framework. Pteridophyllum (one species) shares similarities with Fumarioideae but has actinomorphic flowers, and the relationships among Pteridophyllum, Papaveroideae and Fumarioideae have remained unclear. This study reassesses the evolution of floral symmetry in Papaveraceae based on new molecular phylogenetic analyses of the family. Methods : Maximum likelihood, Bayesian and maximum parsimony phylogenetic analyses of Papaveraceae were conducted using six plastid markers and one nuclear marker, sampling Pteridophyllum, 18 (90 %) genera and 73 species of Fumarioideae, 11 (48 %) genera and 11 species of Papaveroideae, and a wide selection of outgroup taxa. Floral characters recorded from the literature were then optimized onto phylogenetic trees to reconstruct ancestral states using parsimony, maximum likelihood and reversible-jump Bayesian approaches. Key Results : Pteridophyllum is not nested in Fumarioideae. Fumarioideae are monophyletic and Hypecoum (18 species) is the sister group of the remaining genera. Relationships within the core Fumarioideae are well resolved and supported. Dactylicapnos and all zygomorphic genera form a well-supported clade nested among disymmetric taxa. Conclusions : Disymmetry of the corolla is a synapomorphy of Fumarioideae and is strongly correlated with changes in the androecium and differentiation of middle and inner tepal shape (basal spurs on middle tepals). Zygomorphy subsequently evolved from disymmetry either once (with a reversal in Dactylicapnos) or twice (Capnoides, other zygomorphic Fumarioideae) and appears to be correlated with the loss of one nectar spur.
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Asymmetric morphogenetic cues along the transverse plane: Shift from disymmetry to zygomorphy in the flower of Fumarioideae
American journal of botany, 2013Co-Authors: Catherine Damerval, Hélène Citerne, Martine Le Guilloux, Séverine Domenichini, Justine Dutheil, Louis Ronse De Craene, Sophie NadotAbstract: Key Results: We found that an early disymmetric groundplan is common to all species studied, and that actinomorphy was acquired after sepal initiation in Papaveroideae. The shift from disymmetry to zygomorphy in Fumarioideae was associated with early asymmetric growth of stamen fi laments, followed by asymmetric development of nectary outgrowth and spur along the transverse plane. Patterns of P APSTL expression could not be clearly related to spur formation. P APCRC and P APCYL genes were expressed in the nectary outgrowths, with a pattern of expression correlated with asymmetric nectary development in the zygomorphic species. Additionally, P APCYL genes were found asymmetrically expressed along the transverse plane in the basal region of outer petals in the zygomorphic species. Conclusion: Genes of P APCRC and P APCYL families could be direct or indirect targets of the initial transversally asymmetric cue responsible for the shift from disymmetry to zygomorphy in Fumarioideae.
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ASYMMETRIC MORPHOGENETIC CUES ALONG THE TRANSVERSE PLANE: SHIFT FROM DISYMMETRY TO ZYGOMORPHY IN THE FLOWER OF Fumarioideae
American Journal of Botany, 2013Co-Authors: Catherine Damerval, Hélène Citerne, Martine Le Guilloux, Séverine Domenichini, Justine Dutheil, Louis Ronse De Craene, Sophie NadotAbstract:Premise of the Study: Zygomorphy has evolved multiple times in angiosperms. Near-actinomorphy is the ancestral state in the early diverging eudicot family Papaveraceae. Zygomorphy evolved once in the subfamily Fumarioideae from a disymmetric state. Unusual within angiosperms, zygomorphy takes place along the transverse plane of the flower. Methods: We investigated floral development to understand the developmental bases of the evolution of floral symmetry in Papaveraceae. We then assessed the expression of candidate genes for the key developmental events responsible for the shift from disymmetry to transverse zygomorphy, namely CRABSCLAW for nectary formation (PAPCRC), SHOOTMERISTEMLESS (PAPSTL) for spur formation, and CYCLOIDEA (PAPCYL) for growth control. Key Results: We found that an early disymmetric groundplan is common to all species studied, and that actinomorphy was acquired after sepal initiation in Papaveroideae. The shift from disymmetry to zygomorphy in Fumarioideae was associated with early asymmetric growth of stamen filaments, followed by asymmetric development of nectary outgrowth and spur along the transverse plane. Patterns of PAPSTL expression could not be clearly related to spur formation. PAPCRC and PAPCYL genes were expressed in the nectary outgrowths, with a pattern of expression correlated with asymmetric nectary development in the zygomorphic species. Additionally, PAPCYL genes were found asymmetrically expressed along the transverse plane in the basal region of outer petals in the zygomorphic species. Conclusion: Genes of PAPCRC and PAPCYL families could be direct or indirect targets of the initial transversally asymmetric cue responsible for the shift from disymmetry to zygomorphy in Fumarioideae.
Tatsundo Fukuhara - One of the best experts on this subject based on the ideXlab platform.
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Seed and Funicle Morphology of Fumariaceae‐Fumarioideae: Systematic Implications and Evolutionary Patterns
International Journal of Plant Sciences, 1999Co-Authors: Tatsundo FukuharaAbstract:This article reports the seed and funicle morphology of Fumarioideae with dehiscent fruits, covering 11 genera (106 species) for seeds and 11 genera (48 species) for funicles. The results are discussed referring to a hypothetical phylogeny based on chloroplast DNA sequences and morphology. Weak seed curvature is a synapomorphy of the Ichtyoselmis‐Dicentra clade, and the truncate hilar region and laterally elongated arilbase ambiguously support the Dactylicapnos‐Corydalis clade, but in both cases, it is necessary to assume reversals or parallel changes elsewhere in the subfamily. Otherwise, seed morphological characters are poor phylogenetic markers at the genus level as a result of high homoplasy and polymorphism within the operational taxonomic units. Although seed morphology is not very informative for the phylogeny among the terminal taxa, most of them can be identified by a combination of characters. Ehrendorferia, Dicentra, Dactylicapnos sect. Dactylicapnos (except for Dactylicapnos paucinervia), Cys...
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seed and funicle morphology of fumariaceae Fumarioideae systematic implications and evolutionary patterns
International Journal of Plant Sciences, 1999Co-Authors: Tatsundo FukuharaAbstract:This article reports the seed and funicle morphology of Fumarioideae with dehiscent fruits, covering 11 genera (106 species) for seeds and 11 genera (48 species) for funicles. The results are discussed referring to a hypothetical phylogeny based on chloroplast DNA sequences and morphology. Weak seed curvature is a synapomorphy of the Ichtyoselmis‐Dicentra clade, and the truncate hilar region and laterally elongated arilbase ambiguously support the Dactylicapnos‐Corydalis clade, but in both cases, it is necessary to assume reversals or parallel changes elsewhere in the subfamily. Otherwise, seed morphological characters are poor phylogenetic markers at the genus level as a result of high homoplasy and polymorphism within the operational taxonomic units. Although seed morphology is not very informative for the phylogeny among the terminal taxa, most of them can be identified by a combination of characters. Ehrendorferia, Dicentra, Dactylicapnos sect. Dactylicapnos (except for Dactylicapnos paucinervia), Cys...
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Phylogeny and classification ofFumariaceae, with emphasis onDicentra s. l., based on the plastid generps16 intron
Plant Systematics and Evolution, 1997Co-Authors: Magnus Lidén, Tatsundo Fukuhara, Johan Rylander, Bengt OxelmanAbstract:The phylogeny of Fumariaceae , as inferred from rps 16 intron sequences, is compared with morphological data, and nrDNA-ITS. The different data sets are largely congruent and indicate that (1) Dicentra and the tribe Corydaleae as hitherto circumscribed are polyphyletic, (2) Lamprocapnos (= Dicentra spectabilis ) is sister group to the rest of subfam. Fumarioideae , (3) Ehrendorferia , gen. nov. (= Dicentra chrysantha and D. ochroleuca ) is basal in the latter group, (4) the morphologically aberrant Ichtyoselmis , gen. nov. (= Dicentra macrantha ) groups with Dicentra s. str., (5) the genus Cysticapnos should be included in the tribe Fumarieae , (6) Dactylicapnos (= Dicentra subg. Dactylicapnos ) is sister group to Corydalis , (7) the genus Corydalis is monophyletic, and consists of three subgenera: Chremnocapnos , stat. nov., Sophorocapnos , stat. nov., and Corydalis. The following new combinations are validated: Ehrendorferia chrysantha, E. ochroleuca, Ichtyoselmis macrantha , and Lamprocapnos spectabilis.
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seed coat anatomy in fumariaceae Fumarioideae
Botanical Journal of the Linnean Society, 1995Co-Authors: Tatsundo Fukuhara, Magnus LidénAbstract:Seed-coat anatomy is described in 122 species of Fumarioideae, which represent all the genera, subgenera, and most sections. Nine seed-coat types were recognized: (I) Dicentra subg. Hedycapnos , (II) Dicentra subg. Chrysocapnos , (III) Dicentra subg. Macranthos , (IV) Dicentra subg. Dicentra , (V) Corydalis p.p. , (VI) rest of Corydaleae, Cysticapnos, Pseudofumaria and Ceratocapnos , (VII) Discocapnos and Sarcocapnos p. p. , (VIII) Sarcocapnos p. p., Platycapnos and Trigonocapnos , and (IX) Fumariinae. Variable characters are polarized based on the comparison with Fumariaceae-Hypecooideae, Papaveraceae and Pteridophyllaceae. It is assumed that endotestal seed-coat type (I) is most primitive, that exotestal seed-coat types (II–VIII) are derived therefrom, and that the reduction of the mechanical layer, including the origin of thin seedcoat type (DC) occurred repeatedly in combination with indehiscent, hard-walled fruits. Dicentra subg. Hedycapnos (with type I) possesses a combination of primitive testai characters unique within the subfamily, suggesting it represents a sister group to the rest of the subfamily. Each of the other subgenera (with II, III or IV) is also characterized by a unique combination of seed-coat characters, which are found in the outgroups but not in the other genera. Seedcoat characters support the monophyly of Fumarioideae exclusive of Dicentra subg. Hedycapnos , Fumarioideae exclusive of Dicentra , of Dicentra subg. Dicentra , of Corydalis p.p. , and of Fumariinae.
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Seed‐coat anatomy in Fumariaceae‐Fumarioideae
Botanical Journal of the Linnean Society, 1995Co-Authors: Tatsundo Fukuhara, Magnus LidénAbstract:Seed-coat anatomy is described in 122 species of Fumarioideae, which represent all the genera, subgenera, and most sections. Nine seed-coat types were recognized: (I) Dicentra subg. Hedycapnos , (II) Dicentra subg. Chrysocapnos , (III) Dicentra subg. Macranthos , (IV) Dicentra subg. Dicentra , (V) Corydalis p.p. , (VI) rest of Corydaleae, Cysticapnos, Pseudofumaria and Ceratocapnos , (VII) Discocapnos and Sarcocapnos p. p. , (VIII) Sarcocapnos p. p., Platycapnos and Trigonocapnos , and (IX) Fumariinae. Variable characters are polarized based on the comparison with Fumariaceae-Hypecooideae, Papaveraceae and Pteridophyllaceae. It is assumed that endotestal seed-coat type (I) is most primitive, that exotestal seed-coat types (II–VIII) are derived therefrom, and that the reduction of the mechanical layer, including the origin of thin seedcoat type (DC) occurred repeatedly in combination with indehiscent, hard-walled fruits. Dicentra subg. Hedycapnos (with type I) possesses a combination of primitive testai characters unique within the subfamily, suggesting it represents a sister group to the rest of the subfamily. Each of the other subgenera (with II, III or IV) is also characterized by a unique combination of seed-coat characters, which are found in the outgroups but not in the other genera. Seedcoat characters support the monophyly of Fumarioideae exclusive of Dicentra subg. Hedycapnos , Fumarioideae exclusive of Dicentra , of Dicentra subg. Dicentra , of Corydalis p.p. , and of Fumariinae.
Catherine Damerval - One of the best experts on this subject based on the ideXlab platform.
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Zygomorphy evolved from disymmetry in Fumarioideae (Papaveraceae, Ranunculales): new evidence from an expanded molecular phylogenetic framework
Annals of Botany, 2015Co-Authors: Hervé Sauquet, Catherine Damerval, Laetitia Carrive, Sophie Nadot, Julie Sannier, Noëlie Poullain, Catherine Damerval, Sophie NadotAbstract:Background and Aims Fumarioideae (20 genera, 593 species) is a clade of Papaveraceae (Ranunculales) characterized by flowers that are either disymmetric (i.e. two perpendicular planes of bilateral symmetry) or zygomorphic (i.e. one plane of bilateral symmetry). In contrast, the other subfamily of Papaveraceae, Papaveroideae (23 genera, 230 species), has actinomorphic flowers (i.e. more than two planes of symmetry). Understanding of the evolution of floral symmetry in this clade has so far been limited by the lack of a reliable phylogenetic framework. Pteridophyllum (one species) shares similarities with Fumarioideae but has actinomorphic flowers, and the relationships among Pteridophyllum, Papaveroideae and Fumarioideae have remained unclear. This study reassesses the evolution of floral symmetry in Papaveraceae based on new molecular phylogenetic analyses of the family. Methods : Maximum likelihood, Bayesian and maximum parsimony phylogenetic analyses of Papaveraceae were conducted using six plastid markers and one nuclear marker, sampling Pteridophyllum, 18 (90 %) genera and 73 species of Fumarioideae, 11 (48 %) genera and 11 species of Papaveroideae, and a wide selection of outgroup taxa. Floral characters recorded from the literature were then optimized onto phylogenetic trees to reconstruct ancestral states using parsimony, maximum likelihood and reversible-jump Bayesian approaches. Key Results : Pteridophyllum is not nested in Fumarioideae. Fumarioideae are monophyletic and Hypecoum (18 species) is the sister group of the remaining genera. Relationships within the core Fumarioideae are well resolved and supported. Dactylicapnos and all zygomorphic genera form a well-supported clade nested among disymmetric taxa. Conclusions : Disymmetry of the corolla is a synapomorphy of Fumarioideae and is strongly correlated with changes in the androecium and differentiation of middle and inner tepal shape (basal spurs on middle tepals). Zygomorphy subsequently evolved from disymmetry either once (with a reversal in Dactylicapnos) or twice (Capnoides, other zygomorphic Fumarioideae) and appears to be correlated with the loss of one nectar spur.
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Asymmetric morphogenetic cues along the transverse plane: Shift from disymmetry to zygomorphy in the flower of Fumarioideae
American journal of botany, 2013Co-Authors: Catherine Damerval, Hélène Citerne, Martine Le Guilloux, Séverine Domenichini, Justine Dutheil, Louis Ronse De Craene, Sophie NadotAbstract: Key Results: We found that an early disymmetric groundplan is common to all species studied, and that actinomorphy was acquired after sepal initiation in Papaveroideae. The shift from disymmetry to zygomorphy in Fumarioideae was associated with early asymmetric growth of stamen fi laments, followed by asymmetric development of nectary outgrowth and spur along the transverse plane. Patterns of P APSTL expression could not be clearly related to spur formation. P APCRC and P APCYL genes were expressed in the nectary outgrowths, with a pattern of expression correlated with asymmetric nectary development in the zygomorphic species. Additionally, P APCYL genes were found asymmetrically expressed along the transverse plane in the basal region of outer petals in the zygomorphic species. Conclusion: Genes of P APCRC and P APCYL families could be direct or indirect targets of the initial transversally asymmetric cue responsible for the shift from disymmetry to zygomorphy in Fumarioideae.
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ASYMMETRIC MORPHOGENETIC CUES ALONG THE TRANSVERSE PLANE: SHIFT FROM DISYMMETRY TO ZYGOMORPHY IN THE FLOWER OF Fumarioideae
American Journal of Botany, 2013Co-Authors: Catherine Damerval, Hélène Citerne, Martine Le Guilloux, Séverine Domenichini, Justine Dutheil, Louis Ronse De Craene, Sophie NadotAbstract:Premise of the Study: Zygomorphy has evolved multiple times in angiosperms. Near-actinomorphy is the ancestral state in the early diverging eudicot family Papaveraceae. Zygomorphy evolved once in the subfamily Fumarioideae from a disymmetric state. Unusual within angiosperms, zygomorphy takes place along the transverse plane of the flower. Methods: We investigated floral development to understand the developmental bases of the evolution of floral symmetry in Papaveraceae. We then assessed the expression of candidate genes for the key developmental events responsible for the shift from disymmetry to transverse zygomorphy, namely CRABSCLAW for nectary formation (PAPCRC), SHOOTMERISTEMLESS (PAPSTL) for spur formation, and CYCLOIDEA (PAPCYL) for growth control. Key Results: We found that an early disymmetric groundplan is common to all species studied, and that actinomorphy was acquired after sepal initiation in Papaveroideae. The shift from disymmetry to zygomorphy in Fumarioideae was associated with early asymmetric growth of stamen filaments, followed by asymmetric development of nectary outgrowth and spur along the transverse plane. Patterns of PAPSTL expression could not be clearly related to spur formation. PAPCRC and PAPCYL genes were expressed in the nectary outgrowths, with a pattern of expression correlated with asymmetric nectary development in the zygomorphic species. Additionally, PAPCYL genes were found asymmetrically expressed along the transverse plane in the basal region of outer petals in the zygomorphic species. Conclusion: Genes of PAPCRC and PAPCYL families could be direct or indirect targets of the initial transversally asymmetric cue responsible for the shift from disymmetry to zygomorphy in Fumarioideae.
Leo J. Hickey - One of the best experts on this subject based on the ideXlab platform.
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Potomacapnos apeleutheron gen. et sp. nov., a new Early Cretaceous angiosperm from the Potomac Group and its implications for the evolution of eudicot leaf architecture
American Journal of Botany, 2013Co-Authors: Leo J. HickeyAbstract: Premise of the study: Eudicots diverged early in the evolution of flplants and now comprise more than 70% of angiosperm species. In spite of the importance of eudicots, our understanding of the early evolution of this clade is limited by a poor fossil record and uncertainty about the order of early phylogenetic branching. The study of Lower Cretaceous fossils can reveal much about the evolution, morphology, and ecology of the eudicots. Methods: Fossils described here were collected from Aptian sediments of the Potomac Group exposed at the Dutch Gap locality in Virginia, USA. Specimens were prepared by degaging, then described and compared with leaves of relevant extant and fossil plants. We conducted a phylogenetic analysis of morphological characters using parsimony while constraining the tree search with the topology found through molecular phylogenetic analyses. Key results: The new species is closely related to ranunculalean eudicots and has leaf architecture remarkably similar to some living Fumarioideae (Papaveraceae). Conclusions: These are the oldest eudicot megafossils from North America, and they show complex leaf architecture refl ecting developmental pathways unique to extant eudicots. The morphology and small size of the fossils suggest that they were herbaceous plants, as is seen in other putative early eudicots. The absence of co-occurring tricolpate pollen at Dutch Gap either (1) refl ects low preservation probability for pollen of entomophilous herbs or (2) indicates that some leaf features of extant eudicots appeared before the origin of tricolpate pollen.
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Potomacapnos apeleutheron gen. et sp. nov., a new Early Cretaceous angiosperm from the Potomac Group and its implications for the evolution of eudicot leaf architecture
American journal of botany, 2013Co-Authors: Nathan A. Jud, Leo J. HickeyAbstract:Premise of the study Eudicots diverged early in the evolution of flowering plants and now comprise more than 70% of angiosperm species. In spite of the importance of eudicots, our understanding of the early evolution of this clade is limited by a poor fossil record and uncertainty about the order of early phylogenetic branching. The study of Lower Cretaceous fossils can reveal much about the evolution, morphology, and ecology of the eudicots. Methods Fossils described here were collected from Aptian sediments of the Potomac Group exposed at the Dutch Gap locality in Virginia, USA. Specimens were prepared by degaging, then described and compared with leaves of relevant extant and fossil plants. We conducted a phylogenetic analysis of morphological characters using parsimony while constraining the tree search with the topology found through molecular phylogenetic analyses. Key results The new species is closely related to ranunculalean eudicots and has leaf architecture remarkably similar to some living Fumarioideae (Papaveraceae). Conclusions These are the oldest eudicot megafossils from North America, and they show complex leaf architecture reflecting developmental pathways unique to extant eudicots. The morphology and small size of the fossils suggest that they were herbaceous plants, as is seen in other putative early eudicots. The absence of co-occurring tricolpate pollen at Dutch Gap either (1) reflects low preservation probability for pollen of entomophilous herbs or (2) indicates that some leaf features of extant eudicots appeared before the origin of tricolpate pollen.
