FLORAL MORPHOLOGY AND COLOR VARIATIONS IN FLORAL PIECES OF Pleroma granulosum (DESR.) COGN (MELASTOMATACEAE) Mariana Fernandes Rocha, Verônica Rubim Apolônio, Thaisa Mara Miyamoto Martarelli

Abstract

Pleroma granulosum, plant of the Melastomataceae, occurs in the Atlantic Forest, showing flowers with color ranging from pink to purple, with great potential to be used as ornamental. The color represents one of the floral attributes that can indicate the presence of resources to pollinators. In this study, we aimed to characterize the flower of Pleroma granulosum in terms of its morphology and reproductive features. In addition, we investigated whether there is variation in the ultraviolet spectrum, perceptible to the pollinator, during the floral anthesis. In the first days of sampling, the anthers showed very accentuated coloration, which declined abundantly in 24 hours, making the intensity practically null during the last day. The results showed that the flowers in the first day after opening have a greater curve of UV reflectance than those from other days, indicating that the flower, during the first hours of anthesis, emits greater intensity of UV reflectance and that decrease sequentially, according the period of anthesis. In this study, it was possible to elucidate that, in fact, there is variation in the ultraviolet spectrum and decrease in the fluorescence of compounds in the anthers, during the floral anthesis.