Ecofisiologia de vegetação savânica como indicador para estudos de interação biosfera atmosfera na Amazônia. Estudo de caso Vila de Ponta de Pedras, Pará

Abstract

Among the various ecosystems in the Baixo Amazonas there is the savannah. However, ecophysiological studies are non-existent in this area, but essential, on their importance in ecosystem services. Thus, this study aimed to characterize the ecophysiological behavior of woody species in an Amazonian savanna. The physiological variables were analyzed: photosynthesis, transpiration, stomatal conductance, leaf temperature and water use efficiency. The equipment used was a gas analyzer in the infrared region (IRGA). The eight species were studied; Byrsonima crassifolia (L.) Kunth., Salvertia convallariaeodora A. St.- Hil., Anacardium occidentale L., Tocoyena formosa (Cham. & Schltdl.) K. Schum., Byrsonima coccolobifolia Kunth., Xylopia aromatica (Lam.) Mart., Dioclea bicolor Benth., Miconia rubiginosa (Bonpl.) DC. The results showed that D. bicolor was more sensitive to water loss and B. coccolobifolia more tolerant. Analysis of variance the two criteria showed that differences in photosynthesis in relation to time and the species were not significant, but for transpiration, the differences were significant in relation to time and species. There was homogeneity about the strategies for water regulation through the control of stomatal conductance. High temperatures in leaves were observed in time higher irradiance. The efficiency of water use by species was affected by the period of day, being higher in the early morning hours. Analysis of Correlation Matrix demonstrated deep dependency between transpiration and stomatal conductance for all species. The biosphere-atmosphere interaction by studying the ecophysiology of savanna vegetation showed that the dry period that environment affected transpiration, leaf temperature and water use efficiency.