Functional anatomy of the transmitting tissue of Blepharodon bicuspidatum E.Fourn. (Asclepiadoideae, Apocynaceae)

• Grant number: 13/20663-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: January 01, 2014
• End date until: December 31, 2014
• Field of knowledge: Biological Sciences - Botany - Plant Morphology
• Principal Investigator: Diego Demarco
• Grantee: Nelly Cristiany Camargo Araya
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Species of Asclepiadoideae (Apocynaceae) have flowers that present extremely elaborate forms related to precise mechanisms of removal and insertion of pollinia, besides a highly efficient transmitting tissue guiding the pollen tubes through the pistil. Although the pollination biology of the species of this subfamily has been studied for centuries, little is known about the mechanisms that effectively direct the pollen tube through the tissues of the gynoecium. The aim of this study is to analyze anatomical and histochemically flowers artificially pollinated based on serial sections of the gynoecium of Blepharodon bicuspidatum. After pollination, the flowers will be collected and fixed in specific time intervals and the interaction between the apex of the pollen tubes and its relation to the different transmitting tissues will be analyzed based on its structure and secretion (when present). Thus, we intend to understand which factors are involved in directing and nutrition of pollen tubes during their growth through the pistil, the occurrence of compitum in this species and the possible advantages or disadvantages that these features may represent in evolutionary terms, considering the diversity and geographic distribution of the species of Asclepiadoideae.