O lenho de espécies ocorrentes em três fitofisionomias nordestinas do Brasil

Abstract

The Brazilian Northeast region show a high diversity of phytophysiognomies, between them, the mesic and xeric formations. The coastal vegetation is generally more mesic, like the Restinga, while those farthest from the coast are usually more xeric, such as the Cerrado and the Caatinga. The knowledge of the plant species anatomy from Northeast Brazil is still scarce. The present study had the objective of evaluating the ecological trends on the microscopic structure of the wood, seeking, therefore, characteristics that allow the occurrence of those species in the different environments. For this, wood samples of five species were collected in each one of the three physiognomies, Restinga, Cerrado and Caatinga, totalizing 15 species sampled. These samples were collected by cutting discs at a height 1,30 m from the ground in all the areas and later submitted to usual techniques in plant anatomy to craft histological slides and maceration. The samples were analyzed in optic microscope 12 quantitative parameter, 5 qualitative and, also, the mesomorph and vulnerability indices. The Principal Components Analysis to evaluates the similatiry among the species and the evioroments was performed in PAST software. The results showed little quantitative trends related to environments, although a tendency of longer cellular elements in Restinga species was observed, when compared to the other environments. On the other hand, growth rings are predominant in Cerrado and Caatinga, while diffuse-porosity and simple perforation plates are essentially present in every environments. We concluded that species from Restinga show a diverse wood structure, while those from Caatinga have a structure with more xeric characteristics. Therefore, we verified the influence of the environmental factors on wood structure of the species from different environments.