Evolution of fleshy fruits in Myrtaceae: initial impressions in the subgenera of Syzygium

Nayara Machado ¹, Káthia S. M. Mourão ¹, Eve J. Lucas ²

Universidade Estadual de Maringá ¹, Royal Botanic Gardens ²

The Myrtaceae family, included in the Myrtales order, exhibits great diversity, particularly in the Neotropical region. Traditionally, the family’s classification has been based on anatomical characters, especially reproductive ones such as flowers, fruits, and embryos. Currently, phylogenetic proposals are based on molecular analysis. However, we believe that more characteristics, such as variation in the anatomy of the fleshy fruit (homoplastic in Myrtaceae), could be relevant to understanding phylogenetic patterns or in the context of the heterogeneous distribution of diversity across genera. The aim of this study is to perform a comparative analysis of the pericarp anatomy of species found in lineages that exhibit fleshy fruits (Syzygieae, Myrteae, Xanthomyrteae,), with the goal of understanding the evolution of this trait in the family. Initially, floral buds and fruits from five species present in different subgenera of the Syzygieae tribe were processed according to standard anatomical techniques, sectioned using a rotary microtome, and analyzed under an optical microscope. Our results so far show a certain homogeneity in the presence and location of secretory cavities, idioblastic crystals of the druse type, and vascular bundles among the species and subgenera analyzed, except for Syzygium claviflorum (Subgenus Perikion), which exhibits a circular arrangement of short fiber bundles in the mesocarp. The compitum, a structure that did not show a consistent pattern among the species analyzed so far, is one of the characters that will be further examined at a later stage due to its importance in the relationship between the number of ovules and viable seeds. Further studies, expanding the number of species from other tribes, are ongoing to better understand the diversification of fleshy fruits in the family and the relationship between patterns for this structure.

Main author career stage: PhD student

Contribution type: Poster

First choice session: 4. Structure, physiology, and development

Second choice session: 1. Systematics, phylogenetics, biogeography and evolution