Floral anatomy of Bromeliaceae species occurring in the coastal restinga of Florianópolis, Santa CatarinaState, Brazil

Abstract

Bromeliaceae Juss., predominantly found in the Neotropics, exhibits trimerous and pentacyclic flowers,
characterized by the presence of septal nectaries. These nectaries, along with other secretory structures, are essential for
reproduction, pollinator attraction, and floral protection. This study aimed to characterize the floral anatomy and histochemistry
of Aechmea comata, Dyckia encholirioides, and Vriesea friburgensis. Pre-anthesis flowers were collected, fixed in FAA
50 and FNT, and subjected to standard plant anatomy techniques. Histological sections were stained with Astra Blue and
Safranin, while histochemical tests detected compounds such as proteins (Xylidine Ponceau), polysaccharides (PAS), and
lipids (Sudan IV). The transmitting tract was identified in stigma and style, with secretions rich in proteins, mucilage, and
lipids. Septal nectaries (A. comata) and infralocular nectaries (D. encholirioides and V. friburgensis) displayed similar
secretions. Secretory canals in the sepals of V. friburgensis were described for the first time, containing mucilage and proteins.
This study contributes to the anatomical and functional understanding of secretory structures in Bromeliaceae, emphasizing
their ecological and phylogenetic significance. The findings highlight the role of secretory tissues in pollinator interactions
and floral protection, paving the way for future investigations into their evolutionary relevance.