Implicações taxonômicas da morfologia externa das sementes na classificação das angiospermas não monocotiledôneas do Brasil

Abstract

Seeds are essential structures for the reproduction and dispersal of plants, composed of an embryo, reserve tissue, and seed coat. Their morphological characteristics, such as fleshy projections, indumentum, texture, ornamentation, color, and internal structures, are often used in taxonomic studies. Seeds stored in herbarium specimens or seed banks play a crucial role in scientific research, providing information about biodiversity, taxonomy, and conservation. However, the conservation of seed morphological characteristics in different storage methods has not yet been systematically evaluated. Therefore, this study aims to: (1) discuss the importance of external morphological characteristics of seeds and their taxonomic potential for non-monocotyledonous Angiosperms occurring in Brazil through a systematic literature review; (2) assess the conservation of external morphological characteristics of seeds in herbarium specimens stored for over 15 years; and (3) test whether packaging type, storage period, and drying affect the maintenance of external morphological characteristics of seeds. For the literature review, articles were selected from data search platforms using Boolean operators and keywords. For the conservation of seed morphological characteristics, species with fleshy projections on their seeds were selected from the ALCB Herbarium and the UFBA Ondina campus. External morphological characteristics were evaluated in mature seeds conserved in herbarium specimens for over 15 years and in different packaging types (PET bottle, paper envelope, and glass) for 360 days. Among the 256 articles from the past 66 years that used seeds in taxonomic and evolutionary studies, field-collected seeds were the main sources for the studies. Seed morphological characteristics are valuable for the taxonomy of 67 families and were most commonly used in species identification. Prominent external morphological characteristics used include shape, length, width, coloration, and fleshy projections. External morphological characteristics were conserved in herbarium specimens for over 15 years, except for coloration and fleshy projections. Packaging type influenced width in PET bottles and seed thickness in paper envelopes. Conservation for a period of 360 days affected the maintenance of coloration and measurements of length, width, and thickness. Drying affected coloration and the maintenance of fleshy projections.