Sistema hidráulico de árvores em diferentes fitofisionomias da Mata Atlântica no Estado do Rio de Janeiro

Abstract

Rio de Janeiro stands out among the main Brazilian areas identified as a center of biological diversity and endemism. In this scenario, Ilha Grande, Angra dos Reis/RJ, is important as a biological corridor in the Serra do Mar, where the Atlantic Forest is represented by a continuous mosaic formed by different phytophysiognomies that act as a filter for the distribution of plant species. Additionally, ecological anatomy directs special attention to the morphophysiological responses of plants in the face of changing resources and environmental conditions. Thus, intra and/or interspecific comparative anatomy in different phytophysiognomies may indicate patterns that reflect resistance and vulnerability to water availability in the environment, among other aspects. However, it is still a paradox to evaluate the functional attributes that allow the survival and development of woody species in different environments in relation to altitude, temperature, and humidity. Information of this nature aims to better understand the responses and effects of organisms in relation to environmental changes, such as resistance to stress and ability to survive in different climates and ecosystems. In this context, the objective of this study was to evaluate the functional attributes of two highly representative woody species on Ilha Grande, Rio de Janeiro, Brazil, which co-occur in the phytophysiognomies of the Submontane Dense Ombrophylous Forest and Restinga, to characterize intraspecific responses modulated by the environment. In addition, to evaluate the anatomical attributes of 19 representative species of five different phytophysiognomies that occur in Ilha Grande (Ombrophylous Dense Montana and Submontana Forest, Restinga, Mangrove and Swamp Forest) to verify possible convergences of response between plants in the spatial heterogeneity of the Mata Atlantic, but in an area under the same macroclimatic conditions and geological time scale. The results obtained evidenced multiple responses of the xylem to the growth conditions, demonstrating that the environmental differences of the phytophysiognomies can modulate the anatomical traits, however that each species can present different levels of adjustments to adapt to the environmental conditions. These results constitute yet another morphofunctional aspect of the biodiversity of the tropics and open new paths for a better understanding of the hydraulic functioning of tree species in the Atlantic Forest. In addition to being good predictors of how different taxa may respond to the impacts of degradation of natural environments and, possibly, to future predictions of global warming.