Floral Morphoanatomy and Pollen Viability in Miconia polystachya (naudin) r. Goldenb., (Miconieae, Melastomataceae)

Abstract

Abstract Many Melastomataceae are distributed in highland rocky fields (Campos rupestres) landscapes with their intrinsic environmental factors. These factors influence the expression of morphoanatomical characteristics and determine which adaptations are necessary for survival, including reproductive processes. The genus Miconia belongs to the Neotropical tribe Miconieae, the largest in Melastomataceae. Species of Miconieae are known to engage in apomixis, which results in much of the tribe possibly carrying out autonomous or pseudogamous reproduction. Thus, this study seeks to describe the morphoanatomy of the flowers of Miconia polystachya (Naudin) R. Goldenb. and contribute to the understanding of their reproduction. For this, flowers were collected at different stages of development in different seasons (autumn and spring) for morphoanatomical study. The flowers were fixed and cross and longitudinal sections were carried out with a rotating microtome. Pollen viability tests were also performed. The individuals of Miconia polystachya studied in highland rocky fields of the state of Paraná have a high percentage of unviable pollen, verified by the structure of pollen grains showing different degrees of degeneration. However, individuals with mature fruits were observed, corroborating the association between reproduction of this species with apomixis. The described morphological characteristics are similar to those found in previous studies for the family and genus. However, our study provides novel ecological information about the flowering and floral anatomy of M. polystachya, emphasizing the anatomy of hypanthium, fertile verticils and embryonic development of the species.

Keywords

• apomixis
• agamospermy
• highland rocky fields
• parthenogenesis
• reproduction