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Alvarado-Reyes AJ, Paulino JV, Terra V, de Freitas Mansano V. Floral ontogeny reveals potential synapomorphies for Senegalia sect. Monacanthea p.p. (Leguminosae). JOURNAL OF PLANT RESEARCH 2024; 137:907-925. [PMID: 38963651 DOI: 10.1007/s10265-024-01554-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 06/05/2024] [Indexed: 07/05/2024]
Abstract
Senegalia was recently described as non-monophyletic; however, its sections exhibit robust monophyletic support, suggesting a potential reclassification into separate genera-Senegalia sect. Monocanthea p.p. is the largest section. It contains 164 species of pantropical distribution and includes all of the current 99 neotropical species of Senegalia; however, no morphological characteristics are available to differentiate this section. To characterize this section, we examined floral developmental traits in four species of Senegalia sect. Monocanthea p.p. These traits were previously considered as potentially distinguishing features within Acacia s.l. and include the onset patterns of the androecium, the timing of calyx union, the origin of the staminal disc, and the presence of stomata on the petals. Furthermore, we analyzed previously unexplored traits, such as corolla union types, inflorescence development, and micromorphological features related to the indumentum, as well as the presence and location of stomata. The characteristics proposed as potential synapomorphies of the group include the postgenital fusion of the corolla and the presence of a staminal disc formed at the base of the filaments. The other analyzed floral characteristics were not informative for the characterization of the group. Future studies of floral ontogeny will help to establish more precise patterns, mainly whether corolla union and staminal tube formation occur similarly in African and Asian sections of Senegalia.
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Affiliation(s)
- Anderson Javier Alvarado-Reyes
- Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Rua Monteiro Lobato, 255, Campinas, São Paulo, Brazil, 13083-862.
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Av Prof Paulo Rocco s/n Bl A 2° andar sala 06, Ilha do Fundão, Rio de Janeiro, 21941902, RJ, Brazil
| | - Vanessa Terra
- Instituto de Biologia, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil
| | - Vidal de Freitas Mansano
- DIPEQ, Instituto de Pesquisas Jardim Botânico Do Rio de Janeiro, Rua Pacheco Leão 915, Rio de Janeiro, RJ, 22460‑030, Brazil
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RamÃrez-Castro CG, Piñeyro-Nelson A, Sandoval-Zapotitla E, Arias S, Rosas-Reinhold I. Comparative analysis of floral transition and floral organ formation in two contrasting species: Disocactus speciosus and D. eichlamii (Cactaceae). PLANT REPRODUCTION 2024; 37:179-200. [PMID: 38193922 PMCID: PMC11180016 DOI: 10.1007/s00497-023-00494-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 12/14/2023] [Indexed: 01/10/2024]
Abstract
KEY MESSAGE Contrasting morphologies in Disocactus are the result of differential development of the vegetative and floral tissue where intercalary growth is involved, resulting in a complex structure, the floral axis. Species from the Cactaceae bear adaptations related with their growth in environments under hydric stress. These adaptations have translated into the reduction and modification of various structures such as leaves, stems, lateral branches, roots and the structuring of flowers in a so-called flower-shoot. While cacti flowers and fruits have a consistent structure with showy hermaphrodite or unisexual flowers that produce a fruit called cactidium, the developmental dynamics of vegetative and reproductive tissues comprising the reproductive unit have only been inferred through the analysis of pre-anthetic buds. Here we present a comparative analysis of two developmental series covering the early stages of flower formation and organ differentiation in Disocactus speciosus and Disocactus eichlamii, which have contrasting floral morphologies. We observe that within the areole, a shoot apical meristem commences to grow upward, producing lateral leaves with a spiral arrangement, rapidly transitioning to a floral meristem. The floral meristem produces tepal primordia and a staminal ring meristem from which numerous or few stamens develop in a centrifugal manner in D. speciosus and D. eichlamii, respectively. Also, the inferior ovary derives from the floral meristem flattening and an upward growth of the surrounding tissue of the underlying stem, producing the pericarpel. This structure is novel to cacti and lacks a clear anatomical delimitation with the carpel wall. Here, we present a first study that documents the early processes taking place during initial meristem determination related to pericarpel development and early floral organ formation in cacti until the establishment of mature floral organs.
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Affiliation(s)
- Cristian Genaro RamÃrez-Castro
- Instituto de BiologÃa, JardÃn Botánico, Universidad Nacional Autónoma de México, C.P.04510, Mexico City, Mexico
- Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, Mexico City, C.P. 04510, Mexico
| | - Alma Piñeyro-Nelson
- Departamento de Producción AgrÃcola y Animal, Universidad Autónoma Metropolitana-Xochimilco, C.P.04510, Mexico City, Mexico
- Centro de Ciencias de la Complejidad (C3), Universidad Nacional Autónoma de México, C.P.04960, Mexico City, Mexico
| | - Estela Sandoval-Zapotitla
- Instituto de BiologÃa, JardÃn Botánico, Universidad Nacional Autónoma de México, C.P.04510, Mexico City, Mexico
| | - Salvador Arias
- Instituto de BiologÃa, JardÃn Botánico, Universidad Nacional Autónoma de México, C.P.04510, Mexico City, Mexico
| | - Isaura Rosas-Reinhold
- Instituto de BiologÃa, JardÃn Botánico, Universidad Nacional Autónoma de México, C.P.04510, Mexico City, Mexico.
- Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, Mexico City, C.P. 04510, Mexico.
- Center for Genomics and Systems Biology, New York University, 12 Waverly Pl, New York, NY, 10003, USA.
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Min Y, Kramer EM. All's well that ends well: the timing of floral meristem termination. THE NEW PHYTOLOGIST 2023; 238:500-505. [PMID: 36600362 DOI: 10.1111/nph.18715] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Floral meristem termination (FMT) represents one of the defining features of a floral meristem relative to a vegetative meristem. Timing of FMT is a major determinant of the total number of organs in a flower, and canalization toward relatively rapid FMT is considered to have been a major force in shaping angiosperm evolution. For decades, investigation of FMT has been focused on model systems that only produce four whorls of organs in a flower, while little is known about the molecular basis that underlies nature variation in the timing of FMT. Here, we hypothesize on how known pathways could have been modified to generate variation in FMT and explain how developing new model systems will help to deepen our understanding of the genetic control and evolution of FMT.
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Affiliation(s)
- Ya Min
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 012138, USA
| | - Elena M Kramer
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA
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