Anatomia foliar de treze espécies brasileiras da tribo Trimezieae (Iridaceae): estrutura e histoquímica subsidiando a taxonomia

Abstract

Despite Trimezieae be clearly monophyletic, there is a divergence between the authors about the delimitation of genus and species. The study of internal morphology is an important ally for correct identification of plants. Therefore, it aimed to investigate diagnostic characters through foliar anatomical analyzes that can be used to resolve such treatments taxonomic and phylogenetic studies, as well as better characterize the representatives of the tribe. For the preparation of structural and histochemical analysis, we selected 13 species representing the four Trimezieae genus from herbarium and living collection. The usual techniques of plant anatomy were used and obtained photomicrographs with micrometer scales designed under the same optical conditions. Anatomically, all species are amphistomatic with anomocytic stomata, have secretory structures of the type idioblasts containing phenolic compounds and alkaloids, collateral vascular bundles with fibers surrounding the phloem and elongated epidermal cells in the margins. As a highligthed result, the layout and size of vascular bundles and idioblasts were the main characters that showed variation among the species studied, considered here as probable anatomical synapomorphies. In general, the work shows their relevance to discuss aspects of leaf anatomy inferring some characteristics able to discriminate more accurately the genus and species and speculating on the latest taxonomic treatment of the tribe.