Hibridação interespecífica e predição da distribuição natural em Astrocaryum aculeatum Mart. e Astrocaryum acaule Mart.

Abstract

Palm trees native to the Amazon are largely found in wild or semi-wild (pre- domesticated) condition, such as Astrocaryum acaule Mart. (tucumãi) and Astrocaryum

aculeatum Mart. (tucumã-do-Amazonas). This body of work aimed to characterize populations and natural interspecific hybrids as well as study the forecasting of current distribution and future scenarios of A. aculeatum and A. acaule in Brazilian biomes for use and conservation. In Chapter I: "Natural interspecific hybridization in populations of Astrocaryum acaule and Astrocaryum aculeatum palm trees in Tarumã-Açu, Amazonas, Brazil" multielement genetic-population and phenotypic analyses were performed on species in the common occurrence zone of Tarumã-Açu, on the Najatuba property, Manaus, Amazonas - Brazil. 97 individuals from the site previously identified species and supposed natural hybrids were analyzed using nine microsatellite markers. Flow cytometry was performed on five individuals from each species and on supposed natural interspecific hybrids. Multielementary analyses by total reflection X-ray fluorescence (TXRF) were performed on nine individuals of A. aculeatum, seven of A. acaule and one interspecific hybrid confirmed by genetic analysis. High genetic information content was observed in a total of 215 alleles. Higher DNA content occurred in “Híbrido 01” when compared to A. acaule, A. aculeatum and “Híbrido 02”. It was possible to detect 23 chemical elements, five macronutrients, seven micronutrients, four essential elements and seven trace elements, which allowed us to differentiate the species and their relationships with the hybrids. Thus, it was concluded that microsatellite markers, flow cytometry and multielement analysis are efficient techniques that can be used to discriminate A. acaule, A. aculeatum and help to confirm the natural interspecific hybridization in coincidence zones of occurrence. In Chapter II: “Prediction of the geographic distribution of Astrocaryum acaule and Astrocaryum aculeatum (Arecaceae)” Amazonian palms”, the effect of global changes on the geographic distribution of species in future climate scenarios was analyzed utilizing ecological niche modeling. The modeling was based on bioclimatic variables, including minimum and maximum temperatures and rainfall, obtained from the Worldclim website. Future projections were evaluated using two different scenarios, with trends in the concentration of GHGs (Representative Concentration Pathways) - RCP = 4.5, less pessimistic, and RCP = 8.5, pessimistic, in two periods (2020-2050 and 2051- 2070).

The Environmental Distance algorithm showed greater similarity regarding the distribution of the species with the area under the curve with the maximum discriminatory value (1.00). Both A. acaule and A. aculeatum have potential occurrence in the five Brazilian biomes (Amazon, Pantanal, Caatinga, Cerrado and Atlantic Forest). The dispersal patterns were very similar between the two palms. Moreover, the results showed that A. aculeatum is a less resistant species and is sensitive to climatic variations. Therefore, it is concluded that A. acaule is more resilient to future climate changes, being able to recolonize the southern portion of the Amazon in the RCP 8.5 scenario, in 2070, in addition to areas common to A. aculeatum.