A andromonoicia de Solanum lycocarpum A. St. Hil. (Solanaceae): variação na manifestação do sistema sexual ao longo do tempo e espaço
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2018-04-26
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Universidade Federal de Goiás
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Andromonoecy is a sexual system in which the same individual produces hermaphrodict and male flowers. In this sense, the objective of this dissertation was to analyze functional, population and temporal variations in the expression of this sexual system in Solanum lycocarpum A. St. Hil. The flowers of the floral types had their measurements taken, analyzed as to the production and viability of the pollen, ovules count and the formation of the fruits and seeds. The phenology was analyzed through the index of intensity and activity. Mating system experiments were carried out on the two floral types and focal observations to verify the behavior of the visitors. In S. lycocarpum, the sexual expression of individuals varied over time and between populations, so that the distribution of flower types may indicate that individuals may respond to differences in environmental conditions. There were still individuals who were only male, making such a system found does not correspond to the andromonoecious system. In addition, it was observed that the hermaphrodict flowers, besides having the larger stylet than the male ones, are larger in length and width. In relation to the quantity and pollen viability, this differentiated between the floral types, being that the hermaphrodicts have a greater quantity of pollen grains and, whereas the male flowers have a greater viability than the hermaphrodicts. In hermaphrodicts flowers, 85% of the ovules form seeds, while in the male, the "ovules" are not fertile. Thus, the lower energy expenditure in the production of smaller male flowers, with reduced pistils and with unviable ovules, could make them more abundant and produce more viable pollen. The reduction in the number of flowers was accompanied by the production of the fruits, which could indicate an economy of the resources that would already be used in the production of the fruits, since these are large and with many seeds. The species is self-incompatible, and only the hermaphrodite flowers produce fruit. S. lycocarpum fits into the buzz pollination syndrome, being pollinators bees with vibration capacity. Bees of smaller body size vibrated the anthers individually, having no or little contact with the stigma, unlike the larger ones that vibrated the cone, having contact between the stigma and the abdomen of the bee. In S. lycocarpum, the lower percentage of pollen viability in the hermaphrodite flowers, besides the presence of exclusively male individuals, could indicate a system in evolutionary path for other sexual systems, such as androdioecy.
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MARCELO, V. G. A andromonoicia de Solanum lycocarpum A. St. Hil. (Solanaceae): variação na manifestação do sistema sexual ao longo do tempo e espaço. 2018. 32 f. Dissertação (Mestrado em Biodiversidade Vegetal) - Universidade Federal de Goiás, Goiânia, 2018.