Studying the dendrochronology of Anadenanthera peregrina var. falcata (Fabaceae) applying isotopes

Abstract

Dendrochronology studies trees' growth rings, its relation to climate and, as a consequence, the reponses of trees to climate changes. It allows to estimate tree age and reveals information about the species ecology. The analysis of the wood permits the reconstruction of the climate, once the plant register signals of changes in climate variables that affect its dormancy and growth (temperature and precipitation) as growth rings. Phenology studies the occurrence of repetitive biological events, its relation to climate and also biotic factors. Thus, the cyclic rings, which are anatomical responses, if related to a determined phenophase, may allow a phenological reconstruction and an evaluation of climatic factors influencing these reconstructed historic phenology and the ecological implications. Therefore, dendrochronology may be an important tool to understand climate changes effects on phenological patterns. The elevation of atmospheric concentrations of CO2, one of the main effects of global warming, may influence the metabolism and, consequently, plant growth. Nevertheless, there are few observable evidences of increasing atmospheric CO2 in growth rings. The analysis of stable carbon isotopes is an approach that is producing important results in the comprehension of how atmospheric CO2 is influencing the plants. The present research proposal aims to analyze the possible influences of increasing CO2 concentration in the last years on trees of Anadenanthera peregrina var. falcata. To do it so, cellulose samples of five individuals growth rings were obtained and previously dated by dendrochronological methods. The cellulose samples will be submitted to 13C analysis. With these data, correlations with climate and values of intrinsic efficiency of water use (Wi) will be calculated to investigate the relationship betweenCO2 concentration and growth rings. (AU)