Comparative anatomy of the flower and pollen with implications for the reproductive biology of Rhamnaceae species (Rosales)

• Grant number: 25/06043-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2025
• End date: May 31, 2027
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Simone de Pádua Teixeira
• Grantee: Vítor Hélio Piva
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 22/12533-2 - Biology of secretory cell in rosales species, AP.BTA.R

Abstract

Rhamnaceae is a cosmopolitan family within the order Rosales, characterized by generalist entomophilous pollination, despite its close relationship with the predominantly anemophilous Urticoide clade. It includes plants cultivated for medicinal, ornamental, and food purposes, such as joazeiro, Japanese grape, and sobrasil. The family exhibits unique floral morphology within Rosales, as well as a great diversity of secretory structures. Reproductive biology has been studied in some groups of the family, but many still lack detailed understanding of their pollination mechanisms. Pollen studies in Rhamnaceae have focused primarily on morphological traits with a taxonomic bias, while morpho-physiological studies remain scarce.The genera Colubrina, Gouania, Rhamnidium, and Sarcomphalus include Brazilian species of economic interest, each with distinct floral features. While flower ontogeny and some of their glands have been studied in species from these genera, their pollination mechanisms, pollen presentation, and release strategies remain unknown. Thus, this project aims to conduct a detailed comparative study of flower and pollen morphology in four species from these Rhamnaceae genera, correlating anatomical structure with floral organ function to expand knowledge on pollination mechanisms in the family.To achieve this, floral buds, unpollinated flowers, and pollinated flowers will be collected, fixed in buffered neutral formalin, and processed for light microscopy, scanning electron microscopy, and transmission electron microscopy. Comparative analysis of the flowers and pollen of the selected Rhamnaceae species may provide crucial data for understanding the group's evolutionary and reproductive history, shedding light on unique traits within these lineages. (AU)