Gerhard Prenner1, Domingos Cardoso2, Charles E Zartman3, Luciano P de Queiroz4. 1. Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3DS, UK g.prenner@kew.org. 2. Departamento de Botânica, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Ondina 40170-115, Salvador, Bahia, Brazil Programa de Pós-Graduação em Botânica (PPGBot), Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, Novo Horizonte 44036-900, Feira de Santana, Bahia, Brazil. 3. Instituto Nacional de Pesquisas da Amazônia (INPA), Department of Biodiversity, Av. André Araújo, 2936, Petrópolis 69060-001, Manaus, Amazonas, Brazil. 4. Programa de Pós-Graduação em Botânica (PPGBot), Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, Novo Horizonte 44036-900, Feira de Santana, Bahia, Brazil.
Abstract
PREMISE OF THE STUDY: Floral development can help to shed light on puzzling features across flowering plants. The enigmatic Amazonian monospecific genus Petaladenium of the legume family (Leguminosae) had rarely been collected and only recently became available for ontogenetic studies. The fimbriate-glandular wing petals of P. urceoliferum are unique among the more than 19000 legume species. Ontogenetic data illuminate the systematic position of the genus and foster our understanding on floral evolution during the early diversification of the papilionoid legumes. METHODS: Flower buds were collected in the field, fixed in 70% ethanol, and investigated using scanning electron microscopy (SEM). Results were compared with existing material from early-diverging papilionoid legumes. KEY RESULTS: Formation of sepals and petals shows bidirectional tendencies. Stamens arise in two whorls, and the single carpel arises concomitantly with the outer stamen whorl. Gland formation starts early on the edges of the wing petals. The carpel reopens for a short time when the initiation of ovules is visible. Stomata at the base of the hypanthium indicate that the flower functions like other standard flag blossoms. CONCLUSIONS: The floral ontogeny confirms the close affinity of P. urceoliferum with the florally heterogeneous, early-diverging papilionoid Amburaneae clade. The results strengthen the theory of a distinct experimental phase among early-branching papilionoid legumes during which a wider range of floral morphologies arose. Polysymmetry, monosymmetry, variable organ numbers, and a wide range of ontogenetic patterns laid the foundation for a successful canalization toward the more restricted but well-adapted dorsiventral papilionoid flag blossom.
PREMISE OF THE STUDY: Floral development can help to shed light on puzzling features across flowering plants. The enigmatic Amazonian monospecific genus Petaladenium of the legume family (Leguminosae) had rarely been collected and only recently became available for ontogenetic studies. The fimbriate-glandular wing petals of P. urceoliferum are unique among the more than 19000 legume species. Ontogenetic data illuminate the systematic position of the genus and foster our understanding on floral evolution during the early diversification of the papilionoid legumes. METHODS: Flower buds were collected in the field, fixed in 70% ethanol, and investigated using scanning electron microscopy (SEM). Results were compared with existing material from early-diverging papilionoid legumes. KEY RESULTS: Formation of sepals and petals shows bidirectional tendencies. Stamens arise in two whorls, and the single carpel arises concomitantly with the outer stamen whorl. Gland formation starts early on the edges of the wing petals. The carpel reopens for a short time when the initiation of ovules is visible. Stomata at the base of the hypanthium indicate that the flower functions like other standard flag blossoms. CONCLUSIONS: The floral ontogeny confirms the close affinity of P. urceoliferum with the florally heterogeneous, early-diverging papilionoid Amburaneae clade. The results strengthen the theory of a distinct experimental phase among early-branching papilionoid legumes during which a wider range of floral morphologies arose. Polysymmetry, monosymmetry, variable organ numbers, and a wide range of ontogenetic patterns laid the foundation for a successful canalization toward the more restricted but well-adapted dorsiventral papilionoid flag blossom.
Authors: In-Su Choi; Domingos Cardoso; Luciano P de Queiroz; Haroldo C de Lima; Chaehee Lee; Tracey A Ruhlman; Robert K Jansen; Martin F Wojciechowski Journal: Front Plant Sci Date: 2022-02-23 Impact factor: 5.753
Authors: Jamile Marques Casanova; Domingos Cardoso; Claudia Franca Barros; Haroldo Cavalcante de Lima; Karen L G De Toni Journal: PeerJ Date: 2022-09-08 Impact factor: 3.061