Anatomical and histochemical characterization of vegetative organs of Brazilian species of Renealmia (Zingiberaceae)

Abstract

Abstract Renealmia comprises approximately 85 herbaceous and rhizomatous plants in Africa and America known for their metabolite diversity. This study characterized the anatomy and histochemistry of the vegetative organs of three native Brazilian Renealmia species, R. breviscapa and R. nicolaioides, collected from the Amazon Forest in Acre and R. chrysotricha from the Atlantic Forest in Rio de Janeiro. Samples were fixed and processed using conventional plant anatomy and micromorphology techniques, including histochemical tests to identify classes of compounds in vegetative organs. Characteristics including oil idioblasts, dorsiventral leaf structure, tetracytic stomata, unicellular trichomes, and prismatic crystals were common among the studied species of Renealmia, and thus significant for the family. Distinctive characteristics were identified in the vegetative organs of the three species, including the cellular distribution of root phloem, covering of rhizome tissue, different types and distributions of idioblasts and phenolic trichomes in rhizomes and leaves, presence or absence of petiole, and subepidermal layer in the intercostal region of leaves. Mineral content importance as a diagnostic characteristic of the genus is also emphasized. The results of this study advance the understanding of the distinctive anatomical characteristics of the three species of Renealmia in different environments, two in the Atlantic Forest and one in the Amazon Forest.