Deposição de Pólen Heteroespecífico em Plantas de Sub-Bosque de uma Floresta Na Amazônia Central

Abstract

In co-flowering communities, pollinator movement can lead to the transfer of heterospecific pollen between species. This can affect the reproductive success of individuals, either by preventing the conspecific pollen from reaching the stigma or by the pollen lost during transportation. Environmental and plant characteristics can affect heterospecific pollen proportions. To analyse this pattern in Amazon Forest, we investigated biotic characteristics related to capacity of attracting pollinators, such as flower size, number of flowers, floral display, symmetry, and distance from one flowering individual to another. The study was carried out in riparian plots of the Reserva Florestal Adolpho Ducke, Central Amazon during the rainy season. Stigmas and anthers were removed from all flowering understory plants that were encountered in permanent plots. Slides were mounted and all conspecific and heterospecific pollen grains identified and counted. We then fitted a model to determine how each variable is related to heterospecific pollen deposition. In this study, the mean of heterospecific pollen deposition in individuals was 5.8% and 61% of individuals had no heterospecific pollen and from the 15 species found, two had no heterospecific pollen. Flower size, number of flowers and floral display had significant relationships with the heterospecific pollen deposition in the model fitted. Despite the great variation in floral types in the Amazon, there was a low percentage of heterospecific pollen deposition. This is probably due to highly specific plant-pollinator interactions that reduce inappropriate pollen deposition on stigmas.