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Gonçalves BCF, Mansano VDF, de Moraes RS, Paulino JV. Comparative floral development in Mimosa (Fabaceae: Caesalpinioideae) brings new insights into merism lability in the mimosoid clade. J Plant Res 2024; 137:215-240. [PMID: 38070055 DOI: 10.1007/s10265-023-01507-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 10/29/2023] [Indexed: 02/28/2024]
Abstract
The genus Mimosa L. (Leguminosae; Caesalpinioideae; mimosoid clade), comprising more than 500 species, is an intriguing genus because, like other members of the mimosoid clade, it presents an enormous variation in floral characteristics and high merism lability. Thus, this study aimed to elucidate the floral development and identify which ontogenetic pathways give rise to merism variation and andromonoecy in Mimosa caesalpiniifolia, M. pudica, M. bimucronata, and M. candollei. Floral buds at various stages of development and flowers were collected, fixed, and processed for surface analysis (SEM). The development of the buds is synchronous in the inflorescences. Sepals appear simultaneously as individualized primordia in M. caesalpiniifolia and in reversed unidirectional order in M. bimucronata, with union and formation of an early ring-like calyx. Petal primordia appear in unidirectional order, with a noticeably elliptical shape in M. caesalpiniifolia. The wide merism variation in Mimosa results from the absence of organs from inception in the perianth and androecium whorls: in dimerous, trimerous, or tetramerous flowers, the additional organs primordia to compose the expected pentamerous flowers are not initiated. The haplostemonous androecium of M. pudica results from the absence of antepetalous stamens from inception. In the case of intraspecific variations (instabilities), there is no initiation and subsequent abortion of organs in the events of reduction in merosity. In addition, extra primordia are initiated in supernumerary cases. On the other hand, staminate flowers originate from the abortion of the carpel. Mimosa proved to be an excellent model for studying merism variation. The lability is associated with actinomorphic and rather congested flowers in the inflorescences. Our data, in association with others of previous studies, suggest that the high lability in merism appeared in clades that diverged later in the mimosoid clade. Thus, phylogenetic reconstruction studies are needed for more robust evolutionary inferences. The present investigation of ontogenetic processes was relevant to expand our understanding of floral evolution in the genus Mimosa and shed light on the unstable merism in the mimosoid clade.
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Affiliation(s)
- Bruno Cesar Ferreira Gonçalves
- Programa de Pós-Graduação em Botânica da Escola Nacional de Botânica Tropical - JBRJ, Rua Pacheco Leão, 2040 - Solar da Imperatriz - Horto, Rio de Janeiro, 22460-03, Brazil
| | - Vidal de Freitas Mansano
- Programa de Pós-Graduação em Botânica da Escola Nacional de Botânica Tropical - JBRJ, Rua Pacheco Leão, 2040 - Solar da Imperatriz - Horto, Rio de Janeiro, 22460-03, Brazil
- DIPEQ, Instituto de Pesquisas Jardim Botânico Do Rio de Janeiro, Rua Pacheco Leão 915, Rio de Janeiro, RJ, 22460-030, Brazil
| | - Renan Siqueira de Moraes
- Departamento de Produtos Naturais E Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal Do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, 21941-902, Brazil
| | - Juliana Villela Paulino
- Programa de Pós-Graduação em Botânica da Escola Nacional de Botânica Tropical - JBRJ, Rua Pacheco Leão, 2040 - Solar da Imperatriz - Horto, Rio de Janeiro, 22460-03, Brazil.
- Departamento de Produtos Naturais E Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal Do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, 21941-902, Brazil.
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Guimarães Veloso D, de Freitas Mansano V, Pádua Teixeira S, Alcantara de Oliveira C, Baratto LC, Almeida Rodrigues I, Villela Paulino J. Unveiling foliar secreting sites and secretion composition in the legume tree Swartzia flaemingii Raddi. Chem Biodivers 2024; 21:e202301616. [PMID: 38161186 DOI: 10.1002/cbdv.202301616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/28/2023] [Accepted: 12/31/2023] [Indexed: 01/03/2024]
Abstract
Secretory structures in plants play a crucial role in producing bioactive compounds. Despite the potential of the Swartzia genus, comprehensive studies in this context are still scarce. Swartzia is a legume tree (Fabaceae) that occurs in the Brazilian Atlantic Forest, a biodiversity hotspot, and includes species such as Swartzia flaemingii. Therefore, we aim to achieve: (1) identify and characterize the key secretory sites responsible for saponin production in S. flaemingii leaflets; (2) confirm the presence of saponins in S. flaemingii leaves by comparing them with known chemical profiles of other Swartzia species; (3) assess the potential hemolytic and cytotoxic effects of crude leaf extracts. Our investigation unveils the presence of phenolic idioblasts, mucilage cells, and articulate laticifers, which play pivotal roles in defense and adaptation. Notably, we report the first-ever ultrastructural details of laticifers in a legume species. Additionally, oleanane-type saponins were identified in the leaves, giving insights into the chemotaxonomic profile of Swartzia. The crude extracts show low cytotoxicity levels, showcasing as a promising alternative source of saponins. This investigation reinforces the importance of conserving plants in threatened regions like the Atlantic Forest, a global biodiversity hotspot facing substantial anthropogenic pressures.
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Affiliation(s)
- Dalton Guimarães Veloso
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Vidal de Freitas Mansano
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio de Janeiro, RJ 22460-030, Brazil
| | - Simone Pádua Teixeira
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Av. do Café, s/n., Ribeirão Preto, SP 14040-903, Brazil
| | - Carolina Alcantara de Oliveira
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Leopoldo C Baratto
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Igor Almeida Rodrigues
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
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Basso-Alves JP, da Silva RF, Coimbra G, Leitão SG, de Rezende CM, Bizzo HR, Freitas L, Paulino JV, Mansano VDF. Heteromorphic stamens are differentially attractive in Swartzia (Fabaceae). AoB Plants 2022; 14:plac041. [PMID: 36267642 PMCID: PMC9575666 DOI: 10.1093/aobpla/plac041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
The division of labour hypothesis between stamens has explained the evolution of divergent functions between dimorphic stamens in the same flower. However, little is known about whether the distinct type of stamens differs in attractiveness to pollinators. Therefore, we investigate whether the two types of stamens commonly found in Swartzia have different visual and olfactory attractants. We performed observations of anthesis dynamics, registration and collection of floral visitors, measurements of reflectance of floral parts and chemical analysis of the volatile organic compounds of the floral parts of two species, S. flaemingii and S. simplex. Both species have two distinct sets of stamens: one with smaller and abundant stamens in the centre of the flower and the other with fewer but larger abaxial stamens. The sets differ in UV reflectance (only S. simplex) and exhibit a distinct chromatic contrast. Concerning olfactory attractiveness, aliphatic compounds make up most of the odour of the two species, both whole flowers and most of their floral organs. On the other hand, only S. simplex presented apocarotenoids (as ionones) and benzenoids. Furthermore, there are differences in the proportion of volatiles emitted by the stamen in both cases, as the high proportion of sesquiterpenes among the smaller stamens compared to the larger ones. In conclusion, the two types of stamens found in S. flaemingii and S. simplex show a distinct attractiveness. In addition, our data have demonstrated diverse ways of differential attractiveness both between distinct stamens set per flower and between the two species from the same pollen flowers genus.
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Affiliation(s)
| | - Rafael Ferreira da Silva
- Departamento de Química Orgânica/GQO, Instituto de Química, Universidade Federal Fluminense (UFF), Niterói, RJ 24020141, Brazil
| | - Gabriel Coimbra
- Programa de Pós-Graduação em Botânica, Escola Nacional de Botânica Tropical, Jardim Botânico do Rio de Janeiro, Rio de Janeiro, RJ 22460-036, Brazil
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ-JBRJ, Rio de Janeiro, RJ 22460-030, Brazil
| | - Suzana Guimarães Leitão
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Claudia Moraes de Rezende
- Instituto de Química, Centro de Tecnologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 22945970, Brazil
| | | | - Leandro Freitas
- Programa de Pós-Graduação em Botânica, Escola Nacional de Botânica Tropical, Jardim Botânico do Rio de Janeiro, Rio de Janeiro, RJ 22460-036, Brazil
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ-JBRJ, Rio de Janeiro, RJ 22460-030, Brazil
| | - Juliana Villela Paulino
- Programa de Pós-Graduação em Botânica, Escola Nacional de Botânica Tropical, Jardim Botânico do Rio de Janeiro, Rio de Janeiro, RJ 22460-036, Brazil
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
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Saab GDS, Mansano VDF, Nogueira A, Maia IC, Bergamo PJ, Paulino JV. A sophisticated case of division of labour in the trimorphic stamens of the Cassia fistula (Leguminosae) flower. AoB Plants 2021; 13:plab054. [PMID: 34512942 PMCID: PMC8420109 DOI: 10.1093/aobpla/plab054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Buzz-pollinated pollen flowers have pollen as the primary resource for pollinators and must deal with a conflict between the exploitation of pollen grains by bees and pollination success. It has been hypothesized that heterostemony allows division of labour between stamens as a solution to the pollen dilemma. To test the division of labour hypothesis, we chose Cassia fistula, which has a trimorphic androecium and analysed androecium development, pollen grain release mechanisms and visitor behaviour. We explored the reflectance of floral organs and carried out an exclusion experiment to test the attractiveness of each stamen morph to the bee species. Finally, we explored the structural, ultrastructural and functional variation between the pollen grains, including pollen viability across stamen morphs. The differences among the three stamen morphs, which is developed from two whorls of the stamen, are the first evidence of the division of labour in our study system. Large Bombus and Xylocopa bees actively and exclusively exploited the pollen grains from the central poricidal anthers generating pollen deposition on their bodies. The reflectance pattern of floral organs indicated a targeting of these large bees to the central anthers, corroborated by the anther manipulative experiment where only the exclusion of the anthers positioned in the flower centre, especially the intermediate stamens, reduced bee visits. Both results revealed a division of labour, in which the intermediate stamen morph was responsible for both floral attractiveness and pollen resources. Only the largest stamen morph produced germinable pollen grains, highlighting their role as pollinating stamens. The smallest stamen morph has a less clear function, likely representing an economy in pollen production for feeding function. Our findings suggest that the evolution of the trimorphic androecium is associated with division of labour in large pollen flowers and can represent a strong strategy for circumventing the pollen dilemma, optimizing the feeding function by reducing pollen grain investment from central anthers.
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Affiliation(s)
- Gabriella da Silva Saab
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
| | - Vidal de Freitas Mansano
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio de Janeiro, RJ 22460-030, Brazil
| | - Anselmo Nogueira
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, SP 09606-045, Brazil
| | - Isabele Carvalho Maia
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, São Bernardo do Campo, SP 09606-045, Brazil
| | - Pedro Joaquim Bergamo
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio de Janeiro, RJ 22460-030, Brazil
- Programa de Pós-Graduação em Ecologia, Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Barão Geraldo, Campinas, SP 13083-862, Brazil
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-902, Brazil
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Leite VG, Teixeira SP, Godoy F, Paulino JV, Mansano VF. Resolving the non-papilionaceous flower of Camoensia scandens, a papilionoid legume of the core genistoid clade: development, glands and insights into the pollination and systematics of the group. J Plant Res 2021; 134:823-839. [PMID: 33847845 DOI: 10.1007/s10265-021-01293-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Camoensia scandens is a papilionoid legume inserted in the core genistoid clade. It has large, crepuscular, scented flowers but the corolla is non-papilionaceous, which deviates from the pattern found in the subfamily. The vexillum has a folded claw, forming a tube, which is opposed to the androecium opening; all petals have yellow-gold crinkled margins. In addition, there is a long hypanthium, which stores a translucid liquid. The goal of this study is to elucidate the ontogenetic pathways that result in such a peculiar flower and the glands responsible for the sweet fragrance of the petals. Floral buds and flowers were processed for SEM, TEM and light microscopy analyses. Five sepals arise unidirectionally followed by five petals that initiate simultaneously. After the petals, 11 stamens emerge unidirectionally; a pair of adaxial stamens is opposite to the vexillum. In the intermediate developmental stages the sepals unite basally; the two adaxial sepals unite with each other to a greater extent than with the other sepals. The filaments are basally connate, forming a tube with an adaxial opening at the base. The carpel emerges concomitantly with the two abaxial antepetalous stamens. The long hypanthium forms from the outer floral organs (base of the sepals, petals, filaments) and is attached to the base of the stipe. The corolla is noticeable in the intermediate stages of development. The crinkled golden margins house scent glands formed of a secretory epidermis with secretory trichomes and secretory subepidermal cells. The odor is composed of neutral polysaccharides, nitrogenous substances and essential oils. An extensive nectariferous region is found on the inner surface of the hypanthial tube. The nectar is translucent, viscous and released through large pores. The comparison of our data with that of other genistoid flowers enabled discussions about the pollination and systematics of the group.
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Affiliation(s)
- Viviane Gonçalves Leite
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Av. do Café, s/n, Ribeirão Preto, SP, 14040-903, Brazil
- Instituto de Pesquisa Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão, 915 Cidade Universitária, Rio de Janeiro, RJ, 22460-030, Brazil
| | - Simone Pádua Teixeira
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Av. do Café, s/n, Ribeirão Preto, SP, 14040-903, Brazil.
| | - Fernanda Godoy
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Av. do Café, s/n, Ribeirão Preto, SP, 14040-903, Brazil
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Avenida Professor Paulo Rocco s/n, Centro de Ciências da Saúde, Bloco A segundo andar sala 06, Ilha do Fundão, Rio de Janeiro, RJ, 21941902, Brazil
| | - Vidal Freitas Mansano
- Instituto de Pesquisa Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão, 915 Cidade Universitária, Rio de Janeiro, RJ, 22460-030, Brazil
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de Oliveira CA, Mansano VDF, Teixeira SP, Brandes AFDN, Baratto LC, Leitão SG, Santana MN, Rodrigues IA, Paulino JV. Bloodwood: the composition and secreting-site of the characteristic red exudate that gives the name to the Swartzia species (Fabaceae). J Plant Res 2021; 134:127-139. [PMID: 33403567 DOI: 10.1007/s10265-020-01246-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
The Swartzia species are commonly known as bloodwood due to the red exudate released from the stem after injury. This exudate has aroused great interest, and an integrative study is essential to describe it in detail. Thus, this work aimed to identify the red exudate's secreting-site in S. flaemingii and S. langsdorffii, and determine if it is a latex or a resin. Samples of the stem bark and the secondary xylem were prepared for histological analysis. Fresh exudates were dissolved in deuterated methanol and analyzed by 1H-NMR; other samples were resuspended in MeOH:H2O (9:1), partitioned with organic solvents and analyzed by direct infusion mass spectrometry. Total phenolic and total flavonoid contents were determined spectrophotometrically, and antioxidant capacity was determined using ferric reducing antioxidant power assay. The results showed that the exudate is a red latex produced by articulated laticifers located among the phloem cells. The latex is composed of sucrose, catechin glucosides, chlorophyll derivatives, and hederagenin-type saponins. Both samples of S. flaemingii and S. langsdorffii presented high amounts of phenolics and flavonoids, as well as a strong antioxidant capacity. The anatomical study showed that the secreting-site of the Swartzia red exudates were laticifers. This finding allows us to exclude other substances such as resin or oleoresin, generally produced by secretory cavities or ducts. Furthermore, since laticifers are rare in Fabaceae, this finding is significant, and represents an essential taxonomic feature. The showy red color is due to the large amounts of flavonoids. This latex probably has a protective role against microorganisms and photodamage. The bioactive potential of this exudate inspires further studies, which may boost the economic importance of Swartzia.
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Affiliation(s)
- Carolina Alcantara de Oliveira
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil
| | - Vidal de Freitas Mansano
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio De Janeiro, RJ, 22460-030, Brazil
| | - Simone Pádua Teixeira
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Av. do Café, s/n, Ribeirão Preto, SP, 14040-903, Brazil
| | - Arno Fritz das Neves Brandes
- Departamento de Biologia Geral, Instituto de Biologia, Universidade Federal Fluminense (UFF), Outeriro São João Batista, s/n, Niterói, RJ, 24020-141, Brazil
| | - Leopoldo Clemente Baratto
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil
| | - Suzana Guimarães Leitão
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil
| | - Michele Nunes Santana
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil
| | - Igor Almeida Rodrigues
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil
| | - Juliana Villela Paulino
- Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil.
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Paulino JV, Prenner G, Mansano VF, Teixeira SP. Comparative development of rare cases of a polycarpellate gynoecium in an otherwise monocarpellate family, Leguminosae. Am J Bot 2014; 101:572-86. [PMID: 24699538 DOI: 10.3732/ajb.1300355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
PREMISE OF THE STUDY Apocarpy (i.e., free carpels) is considered to be the basal condition for ovary development in angiosperms. Yet it only occurs in 10% of angiosperm species, of which another 10% are monocarpellate. Most legume flowers are monocarpellate. Species with polycarpellate gynoecia occur in about 15 genera with most representatives in Mimosoideae. In the present study, we analyze legumes with polycarpellate flowers with the aim of improving our understanding of gynoecium evolution. METHODS Flowers of nine legume species from five genera were analyzed using a scanning electron microscope (SEM). KEY RESULTS In Leguminosae, carpels usually form as individual primordia or protuberances. Inga congesta differs slightly from this pattern in that the central apex bulges outward before the formation of individual carpel primordia. While legumes usually develop entirely plicate carpels, flowers of Acacia celastrifolia and Inga bella show an intermediate type of carpel morphology with a distal plicate zone and a small proximal ascidiate zone. Carpels in Inga congesta and Archidendron glabrum are sometimes slightly fused at the ovary base. The orientation of carpel clefts seems to reflect the floral symmetry. They are directed to the floral center in mimosoids and caesalpinioids, whereas in Swartzia dipetala carpel clefts are oriented to the adaxial side. CONCLUSIONS Polycarpelly arose at least seven times independently in Leguminosae. The polycarpellate condition appears to be correlated with polyandry, and in most instances, it is accompanied by a profound change in floral organization from a closed to an open system.
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Affiliation(s)
- Juliana Villela Paulino
- Universidade de São Paulo (USP), Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Pós-Graduação em Biologia Comparada, Av. Bandeirantes 3.900, Ribeirão Preto 14040-901, SP, Brazil
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