Pollen-flower-pollinator adaptive relation: morphological variations and taxonomic importance in species of Gesnerioideae (Gesneriaceae)

Abstract

The pollen grains and the flowers of some genera representative of the tribes and subtribes of Gesnerioideae will be studied: Anetanthus Hiern ex Benth. & Hook.f., Asteranthera Hansl., Bellonia L., Besleria Plum. ex L., Coronanthera Vieill. ex C.B.Clarke, Depanthus S.Moore, Diastema Benth., Drymonia Mart., Episcia Mart., Gasteranthus Benth., Gesneria L., Mitraria Cav., Napeanthus Gardner, Negria F.Muell., Paliavana Vell. ex Vand., Phinaea Benth., Rhabdothamnus A.Cunn., Sinningia Nees, Sphaerorrhiza Roalson & Boggan, Titanotrichum Soler. and Tylopsacas Leeuwenb. The objective of the present work is to characterize and describe the morphology of pollen grains, as well as to detect the presence of pollenkitt and other substances (lipids, polysaccharides, acids and proteins) and to analyze variations in the morphology of Gesnerioideae flowers, providing pollen and floral data species of the main clades of this subfamily, and thus to understand the possible co-adaptive relationships in the establishment of pollination syndromes. The pollen grains will be acetolyzed, measured and photographed under light microscopy. The ornamentation of the exine and the occurrence of pollenkitt and other substances will be analyzed in scanning and transmission electron microscopy. In addition, floral morphometric analyzes will be performed. The quantitative data will receive statistical treatment appropriate to the size of the samples and will be subjected to a multivariate analysis to identify which pollen and floral characters are important in distinguishing between groups. All the analyzed characters will be used for the characterization of the species, understanding the evolution of pollen and flower, as well as the interrelation with its pollinators. (AU)