Staminal wing and a novel secretory structure of asclepiads

Author(s)

Demarco, Diego

• Document type: Journal article
• Source: BOTANY; v. 95, n. 7, p. 763-772, JUL 2017.
• Web of Science Citations: 1

Abstract

Asclepiads (Asclepiadoideae, Apocynaceae) have morphologically complex flowers with a wide range of secretory structures related to their defense and pollination. A striking feature of the flowers is the presence of a guide rail formed by staminal wings, which is related to the guidance of the pollinator to the pollinarium translator and the retention of the pollinium. Previous analyses of floral ontogeny in asclepiads detected the presence of a possible gland on the staminal wing during flower development. The goal of the present study was to verify the occurrence of a secretory structure on the staminal wing and its possible function through ontogenetic and histochemical analyses of the presumed gland. Staminal wings are formed early in developing flowers, and a gland is originated in the outer and inner margins of the guide rail in all species. This gland releases a secretion composed of mucilage and lipids, which likely assists in the introduction of the pollinator appendage into the narrow guide rail by lubricating the staminal wings. The gland degenerates before anthesis, increasing the space within the guide rail and enabling the introduction of the pollinarium. This new secretory structure may be present in floral buds of all asclepiads. (AU)

• FAPESP's process: 02/11881-3 - Floral secretory structures and foliar collectors of Aspidosperma Mart & Zucc. and Blepharodon Decne. (Apocynaceae s.l.) in the Cerrado
• Grantee: Diego Demarco
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 03/12595-7 - Floristic composition, structure and functioning of the Dense Rainforest nuclei of Picinguaba and Santa Virgínia of Parque Estadual da Serra do Mar, State of São Paulo, Brazil
• Grantee: Carlos Alfredo Joly
• Support type: BIOTA-FAPESP Program - Thematic Grants