Biologia reprodutiva de Butia odorata (Barb. Rodr.) Noblick

Abstract

Studies of reproductive biology are essential for the conservation and management of plant species, once the reproductive period is a time of great importance for the population dynamics and species survival. This dissertation had as objective to contribute to uderstanding floral morphology, floral and reproductive biology of Butia odorata (Barb. Rodr.) Noblick. Also, to identify the pollinators and their relationship with the flowers. The study was conducted in two Countries, Uruguay (La Paloma, Rocha Department) and Brazil (Porto Alegre, Rio Grande do Sul State). Stages of flowering, and male and female anthesis were identified. The number of male and female flowers per rachille in the inflorescence, and the ratio between male and female flowers were estimated. The coloring of rachilles and flowers was verified. The morphology and morphometry of flowers were characterized. Orders of insects that visited the inflorescences, the relationship of insects with flowers, the collected floral resources and the period of visitation during the stages of flowering were identified. Flowers of Butia odorata are unisexual, hypogynous, actinomorphic, dichlamydeous and sessile. The male and female flowers occur on the same inflorescence and have different formats, being the male more numerous than the female. The male flowers are arranged throughout the rachille, with higher concentration from the middle to the apex. The female flowers are found from the middle to the base of rachille, forming triads with two male flowers. There is genetic variability for color and size of rachilles and for color of flowers on inflorescences of B. odorata. The species has mechanisms of protandry. A great diversity of insects' species, belonging to the Hymenoptera, Coleoptera and Diptera orders visit the inflorescences. During male anthesis, the Hymenoptera and Coleoptera orders are more frequent, whereas during female anthesis the Hymenoptera order stands. The insects are attracted by the resources such as pollen and nectar provided by the flowers. The understanding of the reproductive biology, presented in two chapters of this dissertation, serves as the foundation for the preservation of butiá, because this knowledge is of great importance to devise strategies for the conservation and use of genetic resources and breeding programs.