Riqueza de Orchidaceae em três diferentes áreas da Amazônia Central e a biologia reprodutiva de Prosthechea aemula (Lindl.) W.E. Higgins

Abstract

Orchidaceae is one of the largest botanical families with an existing flower. It presents a great diversity and richness of species in the plants, especially in the neotropical region. In this context, the Brazilian Amazon is part of the neotropical region and orchids are actively present in this biome. As much as biodiversity is high, few studies are carried out in this region, whether taxonomic or related to species pollination. Thus, this work aimed to carry out the monograph of Orchidaceae in three Conservation Units located in the Central Amazon, namely, Adolpho Ducke Forest Reserve (RFAD), Campina Biological Reserve (REBio de Campina) and Rio Negro Sustainable Development Reserve. (Rio Negro RDS). Additionally, the reproductive biology of Prosthechea aemula was carried out at REBio de campina. For the taxonomic part, monthly visits, sometimes fortnightly or weekly, were made to the three conservation units during the period of June 2018 and July 2020 in order to collect and / or collect the existing family taxa. The specimens were collected and heborized according to the usual procedure for subsequent incorporation to the addition of the INPA herbarium of the National Institute of Amazonian Research (INPA). Descriptions and identification keys for the species of each location were prepared, in addition to comments on the ecology, habitat and distribution of each taxon. For the reproductive biology of P. aemula, floral biology, the pollination mechanism and floral visitors were recorded through focal field observations. The efficiency of pollinators was elucidated through the rate of removal and deposition of pollinators. The reproductive system was tested using controlled pollinations (cross-pollination, manual self-pollination, emasculation, spontaneous self-pollination) and open pollination. A total of 98, 64 and 57 species were found in RFAD, RDS do Rio Negro and REBio de campina respectively. These numbers are relatively equal to or exceed the number of species already surveyed for certain locations in the Amazon, which demonstrates their importance in the conservation of the family. In this context, RFAD stands out for becoming the place with the greatest wealth and biodiversity for the Brazilian Amazon. Two species are considered as new records for Brazil, namely, Epidendrum tridens and Octomeria romerorum. Four species (Coryanthes mystax, Encyclia ferreirae, Masdevallia minuta and Vanilla labellopapillata) are recorded for the first time for the Amazon and four other species (Maxillaria desvauxiana, Maxillaria obtusa, Maxillaria violaceopunctata and Sarcoglottis acaulis) have confirmed their occurrence for the state once they Amazonas was only inferred with a possible occurrence according to the list of species of Flora do Brasil. Regarding the part of reproductive biology, Prostechea aemula flourished in the rainy season between the months of December and February. It presents several characteristics that promote the attraction of floral visitors, such as a lip with purple streaks acting as nectar guides, basal callus on the lip impregnated with osmophores and a shallow cunicle. It is noteworthy that the cuncle does not produce any type of floral resource since it is apparently dry without the production of substances at any time. Prosthechea aemula several insects as floral visitors, however only Euglossa sp. (♂) was able to remove the pollinator. It is a completely self-compatible species and does not produce fruit through agamospermy or spontaneous self-pollination. Its fruit formation in the natural environment is low, as observed in other species of the genus.