Anatomia de raízes de nove espécies de Bromeliaceae (Poales) da região amazônica do estado de Mato Grosso, Brasil

Abstract

(Tillandsioideae), that occur in Amazonian regions (Mato Grosso-MT), in order to find features of taxonomic value and ecological importance. The studied species are epiphytes and their roots are characterized by a multi-layered velamen, differentiated cortex, uniseriate endodermis and pericycle, polyarch vascular cylinder and medulla with thickened cell walls. Anatomical structures, such as the number of layers and kind of cell wall thickening of the velamen, the kind of thickening of the exodermis and endodermis walls, the presence of idioblasts containing crystals and the number of protoxylem poles help seperate these species within different genera and subfamilies. The presence of mucilage canals in the cortex of A. castelnavii is a diagnostic feature. The roots of Dyckia and Tillandsia share more common features, so there is greater similarity between Pitcairnioideae and Tillandsioideae. Roots with velamen, an exodermis with thickened cell walls constituting a mechanical layer, mucilage canals, air gaps in the inner cortex and idioblasts with crystals are structures adapted to the epiphytic habit.

Anatomy of vegetative organs, inflorescence axis and pedicel in the Neoregelia bahiana complex (Bromeliaceae): taxonomic and ecological importance

“…An epivelamen with root hairs has been reported for other species of Bromeliaceae (Pita and Menezes 2002, Segecin and Scatena 2004a, Proença and Sajo 2008a, Silva and Scatena 2011a. It contributes to the fixation of the plants on the rocks and increases the capacity to absorb water and nutrients (Peterson and Farquhar 1996).…”

“…Many of the characters observed in Neoregelia bahiana are common in the family, including the root with multi-layered velamen, heterogeneous cortex, one-layered endodermis and pericycle, polyarch vascular cylinder, and pith with thick-walled cells (Tomlinson 1969, Pita and Menezes 2002, Segecin and Scatena 2004a, Proença and Sajo 2008a, Silva and Scatena 2011a).…”

“…An endodermis with cells with only thickened anticlinal walls in the roots characterises Bromelioideae and Pitcairnioideae, and has also been observed in species of Acanthostachys Klotzshc, Aechmea Ruiz & Pav., Ananas Mill., (Pita and Menezes 2002, Proença and Sajo 2008a, Silva and Scatena 2011a). On the other hand, endodermal cells with thin walls or with O-shaped or U-shaped thickened walls are common among the Tillandsioideae Scatena 2004a, Proença andSajo 2008a).…”

“…It contributes to the fixation of the plants on the rocks and increases the capacity to absorb water and nutrients (Peterson and Farquhar 1996). However, an epivelamen with cells undifferentiated into root hairs also occurs in Tillandsia (Segecin and Scatena 2004a, Proença and Sajo 2008a, Silva and Scatena 2011a and is probably associated with the epiphytic life form of most of its species. In N. bahiana, the velamen, as well as the outer cortex, both have lignified cells which may favour the rupicolous life form by providing mechanical support and minimising water loss, as demonstrated for epiphytic orchids (Dycus andKnudson 1957, Zotz andWinkler 2013).…”

“…In this context, anatomical characterisation of individuals from different populations of Neoregelia bahiana may provide additional diagnostic characters for the species, and may help ascertain the existence of intraspecific or interpopulational variations related to the environment. The importance of anatomical data for the taxonomic and ecological understanding of Bromeliaceae has already been demonstrated in many studies involving different organs such as roots, stems, leaves and the inflorescence axis (Tomlinson 1969, Sajo et al 1998, Pita and Menezes 2002, Aoyama and Sajo 2003, Segecin and Scatena 2004a, b, Proença and Sajo 2004, 2007, 2008a, b, Scatena and Segecin 2005, Horres et al 2007, Versieux et al 2010, Monteiro et al 2011, Silva and Scatena 2011a, b, Faria et al 2012, Reinert et al 2013, Santos-Silva et al 2014.…”