Anatomia de escapos, folhas e brácteas de Syngonanthus sect. Eulepis (Bong. ex Koern.) Ruhland (Eriocaulaceae)
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Data
2004-12-01
Autores
Scatena, Vera Lucia [UNESP]
Vich, Daniele Vital [UNESP]
Parra, Lara Regina
Título da Revista
ISSN da Revista
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Editor
Sociedade Botânica do Brasil
Resumo
Estudou-se a anatomia de escapos, folhas e brácteas de 24 espécimes de Syngonanthus sect. Eulepis, que ocorrem nos campos rupestres do Brasil. Os escapos apresentam número variado de costelas, epiderme unisseriada, com células de paredes totalmente espessadas; córtex com esclerênquima e parênquima clorofiliano alternados; endoderme contínua ou descontínua; periciclo estrelado; feixes vasculares colaterais; medula com células de paredes finas ou espessadas. As folhas e as brácteas apresentam epiderme com células de paredes total ou parcialmente espessadas, estômatos na face abaxial, margem com parênquima clorofiliano ou esclerênquima; mesofilo com hipoderme constituída de esclerênquima ou parênquima aqüífero, feixes vasculares colaterais envolvidos externamente pela endoderme e internamente pelo periciclo. Escapos, folhas e brácteas de Syngonanthus sect. Eulepis apresentam células com paredes espessadas e grande quantidade de esclerênquima, provavelmente como resposta adaptativa dessas plantas ao vento e à radiação excessiva comum nos campos rupestres. Epiderme com células de paredes espessadas, estômatos com câmara subestomática não especializada, presença de hipoderme, esclerênquima, e parênquima clorofiliano compacto, caracterizam anatomicamente escapos, folhas e brácteas de Syngonanthus sect. Eulepis. No geral, os caracteres anatômicos não são consistentes para separar os táxons dentro da seção.
The anatomy of scapes leaves and bracts of twenty four taxa included in Syngonanthus sect. Eulepis (Bong. ex Koern.) Ruhland from the Brazilian campos rupestres was studied. Scapes present a vary number of ribs, thick-walled uniseriate epidermal cells, alternate sclerenchyma, and chlorenchyma in the cortex, continuous or discontinuous endodermis, star-shaped pericycle, collateral vascular bundles, and pith with thin or thick-walled cells. Leaves and bracts have total or partial thick-walled epidermal cells, stomata on the abaxial surface, margins with chlorenchyma or sclerenchyma under the epidermis, mesophyll with hypodermis formed by sclerenchyma or aqüiferous parenchyma, and collateral vascular bundles with a double sheath: the external one, the endodermis, and the internal one, the pericycle. Thick-walled cells and sclerenchyma in the scapes, leaves, and bracts present in the species of Syngonanthus sect. Eulepis are probably a response to the typical windy and bright environment of the campos rupestres. Features such as thick-walled epidermal cells, non-specialized substomatal chamber, presence of hypodemis, sclerenchyma, and compact chlorenchyma are typical of the Syngonanthus sect. Eulepis species. These anatomical features could be used to define the taxa in the section.
The anatomy of scapes leaves and bracts of twenty four taxa included in Syngonanthus sect. Eulepis (Bong. ex Koern.) Ruhland from the Brazilian campos rupestres was studied. Scapes present a vary number of ribs, thick-walled uniseriate epidermal cells, alternate sclerenchyma, and chlorenchyma in the cortex, continuous or discontinuous endodermis, star-shaped pericycle, collateral vascular bundles, and pith with thin or thick-walled cells. Leaves and bracts have total or partial thick-walled epidermal cells, stomata on the abaxial surface, margins with chlorenchyma or sclerenchyma under the epidermis, mesophyll with hypodermis formed by sclerenchyma or aqüiferous parenchyma, and collateral vascular bundles with a double sheath: the external one, the endodermis, and the internal one, the pericycle. Thick-walled cells and sclerenchyma in the scapes, leaves, and bracts present in the species of Syngonanthus sect. Eulepis are probably a response to the typical windy and bright environment of the campos rupestres. Features such as thick-walled epidermal cells, non-specialized substomatal chamber, presence of hypodemis, sclerenchyma, and compact chlorenchyma are typical of the Syngonanthus sect. Eulepis species. These anatomical features could be used to define the taxa in the section.
Descrição
Palavras-chave
Eriocaulaceae, estrutura anatômica, Syngonanthus, Eriocaulaceae, anatomical features, Syngonanthus
Como citar
Acta Botanica Brasilica. Sociedade Botânica do Brasil, v. 18, n. 4, p. 825-837, 2004.