Glândulas em Parkia discolor: morfoanatomia dos coléteres e nectários atrativos de formigas e morcegos

Abstract

Parkia species (Fabaceae) are distributed in forests and flooded areas of the Amazon and have secretory structures in leaves and flowers. The present work aims to describe the morphoanatomy and histochemistry of the secretory structures of the leaves and inflorescences of Parkia discolor Spruce ex Benth. The botanical material was collected in the igapó of Rio Carú, Itacoatiara-AM. Nectar consumers were observed in the field. Samples of leaves and inflorescences were collected and fixed, following usual protocols for inclusion in resin and for anatomical and histochemical analysis. Nectaries were observed on the petiole and rachis of the leaves and on the inflorescence peduncle bracts, nectaries and colleters. The colleter is of the standard type, and this is the first record for the genus. The nectaries of the petiole, rachis and bracts are composed of a palisade secretory epidermis, thick cuticle and vascularized secretory parenchyma. The nectary of the nectariferous flower is located internally at the base of the stamens. The release of nectar from the flower occurs at night, forming voluminous drops. Bats were observed consuming the nectar on short visits and ants were seen in the extrafloral nectaries. Histochemical tests revealed the presence of proteins, lipids and phenolic compounds. Extrafloral nectars produce nectar attractive to ants, which exert anti-herbivory protection activity and in floral nectars, nectar is offered to their potential pollinators.