Anatomia foliar de bromélias ocorrentes em áreas de cerrado do Estado de São Paulo, Brasil

Abstract

RESUMO -(Anatomia foliar de bromélias ocorrentes em áreas de cerrado do Estado de São Paulo, Brasil). Visando apontar características inerentes à família Bromeliaceae e indicar possíveis adaptações anatômicas encontradas nas espécies de cerrado, foram estudadas as folhas de cinco Bromelioideae, sete Tillandsioideae e uma Pitcairnioideae. Em geral, nas Bromelioideae, os estômatos estão aprofundados na epiderme e verifica-se um tecido mecânico epidérmico e subepidérmico; observa-se um tecido parenquimático armazenador de água, células esclerificadas não relacionadas aos tecidos vasculares, além de canais de aeração percorrendo longitudinalmente o mesofilo. Nas Tillandsioideae, as folhas são densamente recobertas por escamas, os estômatos ocorrem nas duas superfícies e o mesofilo é bastante compacto. Em Pitcairnioideae, a estrutura foliar é bastante semelhante à das Bromelioideae, embora os estômatos sejam ligeiramente elevados em relação à epiderme e não ocorram grupos de células esclerificadas extravasculares. Os resultados foram avaliados dentro de um contexto adaptativo e taxonômico. Palavras-chave: Bromeliaceae, anatomia foliar, cerrado, Estado de São PauloABSTRACT -(Leaf anatomy of bromeliads from the cerrado of São Paulo State, Brazil). Our aim was to indicate typical features of Bromeliaceae as well as possible adaptive features found in cerrado species. We studied the leaves of five Bromelioideae, seven Tillandsioideae and one Pitcairnoideae. Usually the stomata of Bromelioideae are located only on the abaxial leaf surface, there is epidermal and subepidermal mechanical tissue present, as well as water-storage parenchyma, sclerified cells not related to the vascular tissues, and longitudinal air canals. The leaves in Tillandsioideae are densely covered by peltate trichomes, and there are stomata on both surfaces and a compact mesophyll. In Pitcairnioideae, the leaf structure is very similar to that of the Bromelioideae but the stomata are slightly raised above epidermal cell level and there are no sclerified cell groups. The results were evaluated in an adaptive and taxonomic context.

Anatomy of the floral scape of Bromeliaceae

“…Silica bodies also occur in other Poales, such as Poaceae, Cyperaceae, Thurniaceae, Rapateaceae, Centrolepidaceae, Ecdeiocoleaceae and Joinvilleaceae , suggesting that this feature is a plesiomorphy for the order. In Bromeliaceae, the silica bodies are always of spherical shape and only occur in the epidermal cells as reported by Krauss (1948Krauss ( , 1949a, Tomlinson (1969), Flores (1975), Souza & Neves (1996), Sajo et al (1998), Aoyama & Sajo (2003), Arruda & Costa (2003), Proença & Sajo (2004), Scatena & Segecin (2005), Sousa et al (2005) and Proença & Sajo (2007) for both vegetative and reproductive organs. This fact corroborates the supposition of Prychid et al (2004) for whom the shape and localization of these bodies, although genetically controlled and little influenced by environmental factors, can present a systematic potential for some groups of monocotyledons.…”

“…The occurrence of raphides also has been registered in both vegetative and reproductive organs of Bromeliaceae (see Krauss 1948Krauss , 1949aBraga 1977;Brighigna et al 1984;Souza & Neves 1996;Arruda & Costa 2003;Aoyama & Sajo 2003;Segecin & Scatena 2004a, b;Sajo et al 2004Sajo et al , 2005Scatena & Segecin 2005;Sousa et al 2005;Proença & Sajo 2007). Within Poales (APG II 2003), such crystals occur in Eriocaulaceae, Joinvilleaceae, Sparganiaceae and Typhaceae (Dahlgren et al 1985) and probably represent a plesiomorphy for the order.…”

“…According to Fahn & Cutler (1992) these crystals has been considered to be of adaptive value in xerophytic conditions. However, the occurrence of raphides has been registered in many bromeliads that occupy different habitats (see Braga 1977;Arruda & Costa 2003;Segecin & Scatena 2004a, b;Sousa et al 2005;Proença & Sajo 2007), indicating that, in this case, the presence of such crystals is not related to water availability in the environment.…”

Are the wing's cells alive? Study case in Vriesea trichomes

“…Recent studies carried out by Aoyama & Sajo (2003), Proença & Sajo (2004, 2007, Scatena & Segecin (2005), Souza et al (2005), Monteiro, Forzza & Mantovani (2011), Silva, Oliveira & Scatena (2011 and Mantovani et al (2012) describe absorbent peltate trichomes in different genera of Bromeliaceae, but make no reference to the content of these cells. Moreover, an anatomic study on species of the genus Vriesea carried out by Arruda & Costa (2003) mentioned the presence of cytoplasm in the wing cells.…”

“…These authors have also described the basal stalk and the domecells with densely cytoplasmic contents. Recently, studies elaborated by Proença & Sajo (2004, 2007 …”