Thallus structure and isidium development in two Parmeliaceae species (lichenized Ascomycota)
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Data
2009-07-01
Autores
Barbosa, Suzana Bissacot [UNESP]
Machado, Silvia Rodrigues [UNESP]
Marcelli, Marcelo Pinto
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Editor
Pergamon-Elsevier B.V. Ltd
Resumo
(Thallus structure and isidium development in two Parmeliaceae species (lichenized Ascomycota)). Conventional techniques for structural studies under light microscope and scanning electron microscope were employed to describe and compare the histology of thallus and isidia development in Parmotrema tinctorum and Parmelinopsis minarum. Although presenting layers typical of the heteromerous structure of Parmeliaceae lichens, the studied species have very distinct anatomical details including: the type of upper cortex, medulla thickness, hyphal orientation pattern and distinct strata in this layer, variations of crystal shape, color, location and degree of association with medullary hyphae, rhizines thickness and covering by a cortical layer. Isidium formation starts with cortical cell proliferation, which results in a small protuberance on the thallus surface, followed by the photobiont cell proliferation. Medullary hyphal intrusions occur only after the formation of this protuberance. In this stage medullary hyphae grow, ramifying or not inside the protuberance. In a posterior stage, the isidium base becomes constricted, which facilitates its detachment from the thallus. (C) 2009 Elsevier Ltd. All rights reserved.
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Palavras-chave
Anatomy, Isidia, Ontogeny, Parmotrema tinctorum, Parmelinopsis minarum
Como citar
Micron. Oxford: Pergamon-Elsevier B.V. Ltd, v. 40, n. 5-6, p. 536-542, 2009.