Estruturas secretoras em Banisteriopsis muricata (Cav.) Cuatrec. (Malpighiaceae): aspectos estruturais, químicos e ecológicos

• Autor(a) principal: Nery, Lays Araújo
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2563
• topic: Banisteriopsis muricata; Plantas - Anatomia; Histoquímica; Ontogenia; Malpighiaceae; Banisteriopsis muricata; Plants - Anatomy; Histochemistry; Ontogeny; Malpighiaceae; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA

Banisteriopsis muricata (Malpighiaceae) occurs in all phytogeographic areas from Brazil and presents mixed populations consisting of morphotypes with glandular and eglandular flowers. Petals with glandular fimbriae and connective with glandular protrusions and extrafloral nectarines at leaf are common to both types. The aim of this study was to monitor the development and characterize the structural and chemical aspects of the secreting glands present in B. muricata and correlate them to the ecological role of these. Flower buds, flowers at anthesis and leaves in different developmental stages were processed under usual techniques of light microscopy and scanning electron microscopy, the chemical nature of the secretion was determined by chemical and histochemical tests and functionality was observed in the field. Calycine glands develop on the abaxial sepal. These glands are compoused of secretory uniseriate epidermis; thick cuticle; subcuticular space, pores and stomata absent and secretory parenchyma vascularized by xylem and phloem. Secretion was not identified in the space subcuticular and chemical analyzes identified only glucose secretion. The epidermis of the secretory region consists by bulky cell with thin cuticle and thin walls with pores and presents content translucent. The non secretory cells are bulky and have thin walls and accumulate phenolics. Chemical analysis showed the accumulation of proteins and polysaccharides that are released by rupture of the pore, which seems to be an effect of the contact with pollinators. The fringes of the petals have anatomical features similar of calycine glands and accumulate anthocyanins. The calyx glands of B. muricata are not elaiophores and seem to act as floral nectaries; glands petals act as signaling for floral visitors and secretion released by glands of the connective are a vehicle for the transfer of pollen grains favoring cross pollination. The leaves have EFN that develop on the abaxial surface. The EFN are the type elevated and consists of secretory uniseriate epidermis, nectary parenchyma with few layers of cells and vascularized subnectariferous parenchyma. There was no pores or cuticular ruptures to release the secretion which accumulates in the subcuticular space. The secretion is scanty, viscous and has glucose, proteins and pectins. The observation of the visit of ix ants reinforce the occurrence of insect-plant interactions and the EFN exert protective role against herbivory. Considering the occurrence of two morphotypes, no elaiophores, the presence of orientation petals, appearance of the connective gland and presence of EFN, B. muricata can be used as a model for understanding of the ecological aspects of the secretory structures and the study of these may contribute to the phylogeny of Malpighiaceae. Furthermore, our findings indicate that B. muricata has developed new strategies to attract pollinators.