SECRETORY STRUCTURES IN ROSALES SPECIES

Abstract

Secretory structures are responsible for the production, isolation and / or release of special metabolites in plants. They occur as individualized cells or as multicellular structures of varying forms in almost every part of the plant body. They are a prominent subject in Botany, because they exhibit great morphological and chemical diversity, and play an important role in plant-animal and plant-environment interactions. Several approaches have been presented for such structures, especially for angiosperms: morphology, chemical composition of the compounds produced, secretion dynamics, some experimental studies and, more recently, comparative and evolutionary studies. Even so, there is still a gap in terms of integrative and diversity studies, as well as little studied taxonomic groups, especially those with tropical distribution. This gap presents a great challenge and an opportunity, mainly because there is still much difficulty in discriminating the function of each type of secretory structure for the plant. Thus, with the purpose of advancing these aspects of knowledge, the present project aims to study in detail the secretory structures reported in the families of recognized economic importance of the order Rosales (Cannabaceae, Moraceae, Ulmaceae, Urticaceae, Elaeagnaceae, Rhamnaceae and Rosaceae). The following secretory structures will be studied: secretory cavity and duct, mucilaginous idioblast, laticifer, floral nectary, scent gland and secretory trichome. Leaf, stem and floral organs will be sampled from at least 28 species of 22 genera belonging to seven of the nine families that compose the Rosales order. These types of secretory structures were studied in a project previously financed by Fapesp (AP 2014 / 07453-3), in which the focus was the flower of urticalean rosids (Cannabaceae, Moraceae, Ulmaceae, Urticaceae). Routine and advanced microscopy techniques will be employed, including surface analysis (SEM), histology (ML), histochemistry (ML), 3D structure analysis (confocal and micro-CT) and ultrastructure (MET). The data of vegetative organs and those related to reproduction will be compared in order to better understand the roles of secretory structures for the studied plants. (AU)