Morfologia funcional de estiletes em Cassiinae (Leguminosae)

Abstract

Species of the genusSennapresent enantiostyly and flowers with rich morphological diversity. The flowers have poricidal anthers and are pollinated by bees capable of vibrating the stamens (vibration pollination). The study was carried out at the Pedra Biological Reserve. This dissertation is divided into two chapters. The first aims to investigate the proportion of floral morphs from the morphological and functional evaluation in three species of Cassiinae. Our hypothesis is that the proportion of morphs is similar in the morphological evaluation, and distinct in the functional evaluation, with the presence of the central morph. Our data show that, in the morphological evaluation, the proportion of left and right flowers was similar. However, functionally left (FE), right (FD) and central (FC) morphs occurred in different proportions in all species, with the variation and overlapping of the positioning of the stigma of the right and left morphs occurring differently in the three species. On the other hand, the high variation and overlapping of stylet placements need to be better investigated in order to have a real understanding of the selective pressures that led to them and also their functionality, which may mean greater use of pollen in the pollinator's body. The second chapter aims to investigate the influence of the morphological variation of the styles and stigmas in the capture of pollen in the bodies of the pollinators, guiding us by the following questions: P1) How the shape of the gynoecium and the area of the stigmatic surface influence the amount of captured pollen and amplitude of capture?; P2) How do different forms of gynoecium and stigmas influence the occurrence of self-pollination?. From the results it was verified similar values in the deformation of the styles of the styles, in both the tests of self-pollination and efficiency of the pollen collection, in the evaluation of phenotypic selection the form did not present to have direct influence in the reproductive aptitude of S. aversiflora, however, in the pollen collection efficiency test, the range of motion indicated directional selection for smaller stylet amplitudes, collecting larger amounts of pollen. Although there was no influence of pistil shape aspects on aptitude, the work brings important information about reproductive aspects ofS. aversiflora.