Navegando por Autor "DEMARCO, Diego"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Leaf anatomical features of three Theobroma species (Malvaceae s.l.) native to the Brazilian Amazon
(Instituto Nacional de Pesquisas da Amazônia, 2014-09) GARCIA, Tarcymara Barata; POTIGUARA, Raimunda Conceição de Vilhena; KIKUCHI, Tatiani Yuriko Souza; DEMARCO, Diego; DIAS, Ana Cristina Andrade de Aguiar
Theobroma species have economic importance due to their use in the cosmetic and food industries, mainly in the production of chocolate. However, the anatomy of their vegetative structures remains poorly studied. The goal of this study was to describe the anatomical features of Theobroma grandiflorum, T. speciosum and T. subincanum to contribute to the biological knowledge of these species, as well as provide support to the biotechnological studies of native fruit plants of the Amazon. Leaves at different developmental stages were collected and analyzed under light microscopy and scanning electron microscopy. Sessile and stalked stellate trichomes and digitiform glandular trichomes were observed in the expanded leaves of T. grandiflorum and T. subincanum. These species were also similar in the morphology of the midrib, the organization of the mesophyll and the presence of starch grains in the midrib pith cells. Claviform glandular trichomes and mucilage cells in the epidermis occurred only in the expanded leaves of T. speciosum. The presence of mucilage secretory trichomes in shoot apices (colleters) of all species is a new finding for the genus Theobroma.
Acesso aberto (Open Access)
Structure and distribution of glandular trichomes in three species of Bignoniaceae
(Instituto Nacional de Pesquisas da Amazônia, 2015-12) CASTRO, Fabíola Fernandes Paiva de Castro; GAMA, Thália do Socorro Serra; SANTOS, Ana Carla Feio dos; DEMARCO, Diego; DIAS, Ana Cristina Andrade de Aguiar
Glandular trichomes play a major role in the morphological characterization of the Bignoniaceae. Due to their great diversity of forms and functions, this study aimed to inventory the glandular trichomes present in the aerial vegetative axis of Amphilophium magnoliifolium, Martinella obovata and Stizophyllum riparium, analyze their structure and register the participation of ants in these plants. Fresh samples from the nodal region, petiole and from medium to apical regions of the leaflet blade were fixed and processed according to usual methods in light and scanning electron microscopies. The glandular trichomes found were: peltate, capitate, stipitate, and patelliform/cupular. Peltate trichomes are the most abundant ones and present the most uniform distribution. Patelliform/cupular trichomes occur at specific regions, such as prophylls, leaflet blade and nodal regions. Martinella obovata is the only species that presents capitate and stipitate trichomes, which are widely distributed along the entire aerial vegetative axis. Ants were found in all species, mainly at nodal regions. The occurrence of the capitate-type trichome is reported for the first time to the genus.
Acesso aberto (Open Access)
Transfer cells in trichomatous nectary in Adenocalymma magnificum (Bignoniaceae)
(Universidade Federal do Pará, 2016-01) GAMA, Thália do Socorro Serra; DIAS, Ana Cristina Andrade de Aguiar; DEMARCO, Diego
Transfer cells are specialized cells that play an important role where there are high energy costs due to facilitation of transmembrane flow of solutes. This study aimed to investigate the ontogenesis, histochemistry and ultrastructure of glandular trichomes focusing on stalk cells and their possible transfer function. Samples of prophylls of axillary buds, calyces of flowers in anthesis, and flower buds in different stages of development were collected, fixed and processed according to the common methods of microscopy. The glandular trichomes are composed of a secretory head with its cells in columnar format. The stalk is formed by two layers of cells, with the upper layer composed of cuboidal cells where the wall starts to thicken at the beginning of the pre-secretory phase. The secretion is heterogeneous, releasing glucose, other carbohydrates, lipids and phenolic compounds, with two types of release - eccrine and granulocrine. These trichomes are functionally termed as nectaries. The stalk cells appear as transfer cells since they have a thicker anticlinal wall with irregular ingrowths. The presence of transfer cells in thenectaries suggests a high specialization because it improves transport capacity of nectar and compensation in the high energy expenditure for its production and release.