Biologia reprodutiva e interações planta-polinizador em espécies de bromeliaceae no Parque Estadual do Ibitipoca, Minas Gerais, Brasil

Abstract

Bromeliaceae is characterized as a highly diversified group of monocotyledon plants with an essentially neotropical distribution. The Atlantic Forest, considered one of the world's biodiversity hotspots, represents one of the family's main centers of diversity, in addition to high species richness and endemism. In the Atlantic domain, many species of bromeliads also have a restricted distribution and exhibit high habitat specificity, as is the case of the species that are the focus of this study. Neoregelia ibitipocensis (Leme) Leme is a rare and endemic bromeliad, with populations restricted to the forests of Serra da Mantiqueira; Nidularium ferdinandocoburgii Wawra occurs mainly in the interior of forests between 1,000 and 1,600 m of altitude, it was recorded in Serra do Ibitipoca, Serra de Araras and Serra Negra; N. marigoi Leme occurs mainly between 1,300 to 2,700 m altitude, is typical of Serra da Mantiqueira in the southeastern states of Brazil, the species is classified as “Near Threatened” in the Red Book of Brazilian Flora and Vriesea penduliflora LBSm., is endemic to the Serra da Mantiqueira in the states of Minas Gerais and Rio de Janeiro, evaluated as “In Danger” by the Red Book of Brazilian Flora. This study was carried out in the Parque Estadual do Ibitipoca (PEIB), which integrates the Serra da Mantiqueira Complex, a region considered of extreme importance for the conservation of biodiversity. To characterize the reproductive biology of N. ibitipocensis, N. ferdinandocoburgii, N. marigoi and V. penduliflora, and assuming that the understanding of reproductive biology is essential to preserve and conserve plant species, this thesis is presented in two chapters. In the first chapter is presented with the results referring to reproductive biology of sympatric populations of N. ferdinandocoburgii and N. marigoi. Data are provided on flowering and fruiting phenology, floral biology, pollination ecology, breeding systems, natural hybridization and reproductive success of these species. Nidularium ferdinandocoburgii and N. marigoi have odorless flowers, with tubular corollas and duration of two days. The flowering peak of N. ferdinandocoburgii occurred in December, the nectar presented an average of 11.52 mg of sugars and Colibri serrirostris was observed as a pollinator of the species. The natural fruiting was 86.3%, the species is self- incompatible and presents a brief hercogamy. Only one population of N. marigoi composed of eight individuals was located in the study area, of which only one flowered. The nectar had an average of 6.97 mg of sugars, the species is self-incompatible and has pronounced hercogamy. The heterospecific crosses resulted in the production of fertile fruits only when N. marigoi acted as a pollen recipient species, originating vigorous plants. The second chapter aimed to characterize the reproductive system, phenology and pollination ecology of V. 12

penduliflora, an endangered species. Therefore, the fertility and viability of its individuals evaluated through the following parameters: production of flowers, fruits and seed formation. Vriesea penduliflora blooms in the rainy season, with flowering peak in January, its flowers present diurnal anthesis and remain open for about 11 hours. The nectar was produced continuously throughout the anthesis and presented an average of 27.79 mg of sugars. The hummingbird C. serrirostris was considered its main pollinator, but Apis mellifera was also observed pollinating its flowers. Vriesea penduliflora is self-compatible, however, it does not produce fruits under spontaneous self-pollination, being, therefore, dependent on the service of the pollinator. The florivory caused by ants of the Camponotus genus may be associated with the low reproductive success presented by the species under natural conditions. This thesis also resulted in a published article, which aimed to evaluate aspects of the reproductive success of N. ibitipocensis and investigate the magnitude of the damage caused by the intense herbivory of fruits and seeds caused by Tipulidae larvae (Diptera) in their natural habitat, the herbivory affected 100% of infructescence analyzed in the first year of the study. The reproductive system of the species was characterized, as well as the fertility and viability of its natural populations. Neoregelia ibitipocensis is partially self-incompatible, with potential for self-fertilization and crossbreeding. Parthenocarpic fruit production was observed in controlled pollination experiments and under natural conditions. Parthenocarpy seems to represent a strategy to increase the reproductive success of N. ibitipocensis, mitigating the effects caused by predation in its natural habitat. In addition, we developed an efficient protocol for the introduction and in vitro multiplication of N. ibitipocensis, whose results provide recommendations for the development of strategies for the in situ and ex situ conservation of this species. The results generated in this thesis expand the knowledge about reproductive mechanisms in Bromeliaceae and contribute to the development of conservation strategies for populations of endemic and threatened species in the Atlantic Forest.